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Bass is too concentrated in the corners of my room.

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June 24, 2011 7:29:06 PM

Hello, I'm having a very annoying problem where basically the waves outputted by my sub woofer are way too concentrated in the corners of my room and are putting a lot of pressure on my ears. The reason it is putting pressure on my ears is because my computer desk is right between two corners. I have drawn out some diagrams of how my room looks and where I have tried putting the subwoofer:

http://i495.photobucket.com/albums/rr317/Yoshinat0r/DIA...

http://i495.photobucket.com/albums/rr317/Yoshinat0r/DIA...

http://i495.photobucket.com/albums/rr317/Yoshinat0r/DIA...

In picture 3, it is more evenly distributed between my ears, but turning my head even slightly will cause pressure to build up in whichever ear is facing one of the corners. Even that is just really annoying.

Interestingly enough, only tones around 80hz are what cause this pressure in my ears. It is very very annoying, I don't even like listening to music with lots of mid-high bass anymore because my ears feel so uncomfortable. I barely have this sub turned up high at all, so that is not the issue.

Is there anything any of you guys recommend that I could try? Is there anything I could buy, maybe some kind of foam, that can stop bass from concentrating in the corners like that?

EDIT: I could try moving to the other section of the desk, but I really did not want to have to resort to that, since I like this section a lot better, and it works better for my surround speakers.
June 25, 2011 3:39:42 AM

your situation is very real and very common.
there are a few ways you could change it.
1. program some reverb for the subwoofer (but none of the pictures show the sub facing a good way to make the reverb work best, since the 2nd reflection never really gets aimed at anything to start the process of calibrating the soundwaves)
2. use the diagram #2 setup and put a large file cabinet or some tall and skinny piece of furniture in that corner to stop the soundwaves from bouncing around in the corner. (one of those glass display cases with shelves inside of it would work.. but you probably need to use glue to prevent the glass from vibrating and falling out)
3. you could buy bass traps that cover the entire corner.. but you could save some money and put some cardboard in the corner with some tape.
just put the tip of the corner into the middle of the piece of cardboard, and make sure the cardboard is thick enough to withstand some mild vibration.
this is supposed to be the cheap route, and it will help if you go from top to bottom.
but
cardboard will allow the soundwaves to bounce off of it .. and if the bass is now audible from the corner and annoying, then you need some acoustic panels.
you could put the acoustic panels on top of the cardboard.. or buy some corner acoustic foam.
if the corner foam is not the type of foam for the frequency you need.. then you are still going to have a problem, only the problem will be heavily reduced.
and it might be easier to simply try the cardboard first, and if you can 'hear' the bass in the corner too much, you are going to need some acoustic paneling.
but
maybe you could get some polyfil and wrap it up with a zip tie or a cord, then hot glue the polyfil onto the cardboard.
gotta do it from top to bottom to really get it to do its job (although the tip by the ceiling might prove to be not needed since the sub is on the floor).

anyways.. 'hearing' the bass isnt the same as the pressure tickling your ear.
the tickling is from soundpressure, and the 'hearing' the bass is dB level.
you could wire two subs up.. one backwards from the other, and still get a tickling sensation in your ear without hearing much of anything at all.
(not recommended.. only spoken about to provide a showcase of the difference between SPL and dB)


dont bother wasting your time with the reverb if you cant program the reverb for the subwoofer only.
and as i said, all of the photos show the subwoofer facing parallel to an opposite wall.
technically, the soundwave is going to try and bounce back the opposite direction it came from.. and when it bumps into another wave going from the speaker to the wall, then the wave is going to spread out.
you would be better off putting the subwoofer under the shelf or under the cabinet and listening to it like that.

if you do try to use some reverb.. you will need to measure the distance from the subwoofer to the wall, and then adjust the angle and distance for the 2nd reflection until the concentration in the corner goes away.
this might take too long.. and if you do find the sweet spot for the dials, it might not decrease the pressure enough.

to make it quick and simple without doing anything but moving the subwoofer..
you could put the sub under the shelf and try to let the computer desk catch the soundwaves before they travel up the wall and accumulate energy.
or
you could put the sub under the desk (in the corner) and point it at the doorway.
or
you could put the sub in the corner at the end of the computer desk and aim it at the corner by the shelf.. and hope the dresser allows the soundwaves to bounce around in such a way that the problem is canceled out from phase opposition.
or
put the sub in the corner at the end of the desk and point it at the top corner of the dresser and hope the pressure rolls off into the shelf corner without building up much pressure.
or
put it in the same corner at the edge of the desk and point the sub at the bottom corner of the dresser and hope the corner of the dresser sends half of the soundwaves into the doorway corner, and the other half of the soundwaves would spread out along the front of the dresser, and also spread all along the right wall.
but
maybe you need to put the sub in the corner at the end of the desk and point it at the bottom wall of the dresser (the middle of the side wall)
and see if that redistributes the soundwaves enough to lower the pressure.


this might work well for one corner, moving and aiming the sub, but you might find the other corner acting up.
and it is really a job for reverb or removing the corner by putting some cardboard up to change the shape of the corner to something like a stop sign shape.
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June 25, 2011 4:02:35 PM

Thank you for the very long, informative reply :D 

I have never programmed reverb for a subwoofer, I hope it's not too complicated.

Quote:
use the diagram #2 setup and put a large file cabinet or some tall and skinny piece of furniture in that corner to stop the soundwaves from bouncing around in the corner.

I have a very tall ceiling, about 8' 6", so it is going to be difficult finding something that tall. Maybe I could find something though.

Quote:
you could buy bass traps that cover the entire corner.. but you could save some money and put some cardboard in the corner with some tape.
just put the tip of the corner into the middle of the piece of cardboard, and make sure the cardboard is thick enough to withstand some mild vibration.
this is supposed to be the cheap route, and it will help if you go from top to bottom.

I am interested in this cardboard trick, though I failed to point out one detail about my room. There is a window on each side of my seating position that directly meets each corner. Not very convenient I suppose for trying to fix something like this.

Quote:
cardboard will allow the soundwaves to bounce off of it .. and if the bass is now audible from the corner and annoying, then you need some acoustic panels. you could put the acoustic panels on top of the cardboard.. or buy some corner acoustic foam.

I wouldn't mind buying acoustic panels/foam, just hope they aren't too expensive. So for the foam, I would need to look for a foam that's designed for 80hz?

Quote:
you would be better off putting the subwoofer under the shelf or under the cabinet and listening to it like that.

Well this shelf has no underneath where I could put the sub. The only place this sub could actually fit under would be the desk, since it's rather large.

Quote:
you could put the sub in the corner at the end of the computer desk and aim it at the corner by the shelf.. and hope the dresser allows the soundwaves to bounce around in such a way that the problem is canceled out from phase opposition.

This sounds the most feasible to me, I will try pointing it at different angles towards the dresser.
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June 25, 2011 5:30:20 PM

yea no repositioning of the subwoofer is helping. I'm going to have to either try reverb, or resort to bass traps. Though with the way my room is, I think it's going to be difficult to set up bass traps.

http://i495.photobucket.com/albums/rr317/Yoshinat0r/myr...

As you can see, I have no way of making corner bass traps, since there are windows on both sides that meet the corners. Very frustrating

EDIT: You'll have to excuse the ugliness of the desk, I'm still in the process of building it lol
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June 25, 2011 7:29:48 PM

position of the sub wont help. cos corners a corners, theres always gonna be huge bass there, you cuold try reposition yourslef, opposite of the dresser, that wil defintely help.

if thats a no no, then reduce the volume of the bass. using tone controls.
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June 26, 2011 12:09:52 AM

i seen the picture of your room, and you are right.
the size of the room is too small for a reposition of the subwoofer to really help.
when you described that there was pressure build up in only one corner at a time, i thought there might be a chance to simply aim the pressure to a far away corner.
when the room is small like that, the pressure is going to build up faster than it can be released.

there really isnt a whole lot acoustic panels can do for pressure.
they are ment for decibel levels, not the air pressure in the room.
it isnt impossible to use acoustic panels for pressure, but they arent marketed with the specific description of being pressure absorbers.. at least not for audio.
the material is very different, as it feels totally different when you squeeze and compress the foam.
and some might say the foam is very delicate and shouldnt be squeeze and compressed because it wont work properly anymore.

my first thought when looking at the photo was to use some acoustic blankets.. and fold them in half into the corner.

megamer is right, when the room is smaller than the pressure, a corner is a corner.. and because the soundwaves bounce around extra inside that area, the pressure builds up.
your cheapest and easiest option is to use polyfil in the corners.
it isnt the worst thing you could do, since using the cardboard would probably be more obnoxious.

if you are a bit questionable, go grab ONE bag of polyfil (the ones that are about the size of a pillow) and hold the bag up into the corner.
my instructions for you are:
pull the whole thing out of the bag as a solid piece.. then use whatever you want to wrap around and tie the polyfil to hold it together.
you are going to need probably at least six bags (three on each side).

the polyfil has the best chance of working because the material will absorb the air pressure and slow it down.
that is what the polyfil does inside speaker boxes.
so your ringing at 80hz might drop to 60hz or 50hz or 40hz
depending on the material, it will either drop the frequency or stop it completely.

the bass traps are going to do exactly what i said, create a cardboard (or wooden) panel with an acoustic material over the front.
maybe you choose these because they look more simple and 'professional'
but
pressure inside the room is caused by the number of soundwaves that do not cross paths with an opposite phased soundwave to cancel eachother out.
putting a bass trap in one corner isnt going to solve the bass in another corner.. that area will simply be adopting a new reflection that helps FORCE the soundwaves to bump into eachother in opposite phase.

your room isnt empty.. and that is why when you put the subwoofer some place, the one corner doesnt build up pressure.
there are physical objects preventing the soundwaves from 'floating' into that area.
so with that said,
an empty room would probably need a bass trap on one corner, and another bass trap on the opposing corner for the first bass trap to really reduce and do its job.

soundwaves work the same exact way a cue ball bounces around the rails on a pool table.
so if you feel a bit confused, check out some videos or tutorials about using the rail to bounce the cue ball.
and to finalize the small tutorial, imagine every time the ball hits the rail there is a light inside the lights up.
if you throw the ball into the corner and it bounces directly into the other corner.. that means there are TWO blinks in the one spot.. and that is how you know there is extra pressure built up.


something else that is sure to work..
if you hang the appropriate density material on half of the window, then put a rod up on the wall with some screws.. lay some more of that material on the rod...
depending on the thickness of the material will determine how much the sound pressure moves it.
those curtains look like the pressure will go right through it.
if you make the corner soft enough, the pressure will go down.
the only problem is finding the right material that does the job.
you would have to go to a fabric store to choose the right density.

something like wool will be enough to 'catch' the pressure without going through it.
but
it is too heavy when it hangs, and it will stop the process of absorbing the pressure.
sometimes wool is really heavy, and other times it is medium.. and it also comes in light.
the heaviest stuff isnt going to help you much.
the other two, well if you put rods up and leave slack in the fabric between rods.. you could build it so that there are extra rods for the window, connected to the main 'junction' on the wall.
it could actually look very fashionable.


sometimes the fabric vibrates itself loose and doesnt work as good, you would need to starch the fabric to get it stiffer again.
otherwise, you would have to use diffusion panels.. and if the blocks aren't setup well enough for the frequency you need.. it is going to look 'professional' but sound like a failure.
because the pressure can hit the diffusion panels and create a little cloud inches away from the panel.. those two panels would each have a cloud that meets, and you would have pressure again.

the audio pro's would probably tell you to point your direction towards diffusion panels.. but as you said, there are windows there and you dont really want to put up some stiff material that is going to make the windows being there seem totally stupid and pointless.
with the fabric.. you could stitch a loop in the fabric by simply grabbing the fabric in the middle.. pulling it backwards until there is some fabric overlaping, and sew it or staple it together to form a loop that the rod goes in.
this might allow you to push the fabric out of the way to view out the window.
or
put the rods on a wood strip, and connect the wood strip to some hinges.. and the hinges connect to another block of wood on the wall that is used for the other rods for the other wall.

maybe some 'dickies' brand fabric (not the denim.. but the docker type fabric that comes in solid color dress pants that people wear for work)
maybe that fabric is enough to catch the sound pressure.. or maybe you need two of them back to back.
(only supposed to give you a rough idea of what a light fabric can feel like while being dense enough to capture some air pressure)


how much pressure, and the character of the air in the room.. these can make a person like me have some difficulty selecting which fabric is going to be close for the requirement.
and if you dont watch what happens each time you try, you might prove to fail more times than succeed.

you know.. if you wanted to put the corners into a stop sign shape.. you could always put the things on hinges and swing them open to look out the window.
you would have to go above the receiver and above the computer tower.. but if the pressure was coming from the side of the computer tower and not the corner.. you should be able to get your face close to there (or use a paper towel roll) to determine that the pressure is really bouncing from the computer case and not the corner.

you could also try some cardboard across the top of the room where the wall touches the ceiling.
my living room has that, and it prevents the buildup of pressure, not so much the dB.
i mean, the dB do go down because the panel shoots soundwaves into the path of other soundwaves.. and the 'injection' is in a downward direction.
that forces the reflections to go downwards instead of lingering up by the ceiling.


to understand what the speaker is doing to the pressure in the room..
imagine the entire wall suddenly shoving itself 1ft inwards and scooting your desk backwards.
the air in the room will have no where to go, and it might make your ears pop like traveling up a large hill.
maybe close the door to help stabilize the pressure, or open it to let some of it out.
some might say the speaker cone is too big, and the cone moves in and out too much for the room it is in.
you dont need pressure to hear it.

**edit**

that is a gorgeous photo by the way.
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June 26, 2011 1:20:34 AM

So i suppose the first thing I could try is buy this polyfil and put it in the corners? I'm not sure what you want me to do with it after tying it up, do I just stuff it in the corners all the way up to the ceiling?

Quote:

something else that is sure to work..
if you hang the appropriate density material on half of the window, then put a rod up on the wall with some screws.. lay some more of that material on the rod...
depending on the thickness of the material will determine how much the sound pressure moves it.
those curtains look like the pressure will go right through it.
if you make the corner soft enough, the pressure will go down.
the only problem is finding the right material that does the job.
you would have to go to a fabric store to choose the right density.

something like wool will be enough to 'catch' the pressure without going through it.
but
it is too heavy when it hangs, and it will stop the process of absorbing the pressure.
sometimes wool is really heavy, and other times it is medium.. and it also comes in light.
the heaviest stuff isnt going to help you much.
the other two, well if you put rods up and leave slack in the fabric between rods.. you could build it so that there are extra rods for the window, connected to the main 'junction' on the wall.
it could actually look very fashionable.

Sorry, could you elaborate on this further? I don't understand what you're suggesting. Where do these rods go exactly on the wall? And what do you mean by the main junction of the wall?

Quote:
the audio pro's would probably tell you to point your direction towards diffusion panels.. but as you said, there are windows there and you dont really want to put up some stiff material that is going to make the windows being there seem totally stupid and pointless.

I don't mind if I can get away with only covering the top-half of the windows with the panels. I'm not concerned with being able to see out the entire windows, I just want to be able to open them in the summer so some air can get into the room.

http://i495.photobucket.com/albums/rr317/Yoshinat0r/myw...

The windows are very tall, so I can easily lose the top-half and not really care.

Quote:
you know.. if you wanted to put the corners into a stop sign shape.. you could always put the things on hinges and swing them open to look out the window.

What do you mean put the corners into a stop sign shape? Sorry I know absolutely nothing about any of this :( 

Quote:

you could also try some cardboard across the top of the room where the wall touches the ceiling.
my living room has that, and it prevents the buildup of pressure, not so much the dB.
i mean, the dB do go down because the panel shoots soundwaves into the path of other soundwaves.. and the 'injection' is in a downward direction.
that forces the reflections to go downwards instead of lingering up by the ceiling.

So I would just tape cardboard all along the top of the walls and that might solve it? Does it matter how thick the cardboard is? I have a lot of spare cardboard, but it is rather thin, like 1/2 cm

Quote:
that is a gorgeous photo by the way.

If you mean the one on my monitor, I just randomly found it on the internet, but yea, it really caught my eye and I just loved it :D 
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June 26, 2011 6:33:47 AM

Yoshinat0r said:
So i suppose the first thing I could try is buy this polyfil and put it in the corners? I'm not sure what you want me to do with it after tying it up, do I just stuff it in the corners all the way up to the ceiling?

Sorry, could you elaborate on this further? I don't understand what you're suggesting. Where do these rods go exactly on the wall? And what do you mean by the main junction of the wall?

I don't mind if I can get away with only covering the top-half of the windows with the panels. I'm not concerned with being able to see out the entire windows, I just want to be able to open them in the summer so some air can get into the room.

http://i495.photobucket.com/albums/rr317/Yoshinat0r/myw...

The windows are very tall, so I can easily lose the top-half and not really care.

What do you mean put the corners into a stop sign shape? Sorry I know absolutely nothing about any of this :( 

So I would just tape cardboard all along the top of the walls and that might solve it? Does it matter how thick the cardboard is? I have a lot of spare cardboard, but it is rather thin, like 1/2 cm

If you mean the one on my monitor, I just randomly found it on the internet, but yea, it really caught my eye and I just loved it :D 


to the ceiling probably isnt needed.. only the space where your ears are, but also a little bit higher to keep the pressure from finding its way building up in that area again.
(give a little bit extra on the upwards and downwards area of all your listening position, including when you lean back in the chair and the chair tips back)

this is a typical square room shape:
http://www.teach-nology.com/worksheets/early_childhood/...

this is a typical square room with bass traps:
http://upload.wikimedia.org/wikipedia/commons/b/b8/Vert...

reverb is a crazy thing.. you could use one speaker on ANY of those walls and the sound would appear to be coming from any of the walls.
if the speaker is on the left, sounds on the right could be much weaker.. and that means the 3d effect is broken.
a speaker on any two of the colors facing opposite of eachother and the sound can appear to be coming from any wall.
if i put an empty grill on the wall and another grill on a different wall with a speaker behind it.. you wouldnt know which grill has the speaker behind it unless you were close enough to hear the actual speaker.
that is the power of reverb, and if you used it with your sub you could get some of the pressure to cancel out in the corners.
but
your subwoofer might not be able to handle all of the reverb.
making those 3d sounds in the stop sign shape is a lot more easier than forcing the pressure to do something.

anyways..
if this picture was like the photo you took of the room .. the window rods would look kinda like this:
http://i54.photobucket.com/albums/g95/anwaypasible/rods...
the black is the rod
the red is the 'junction' that i was talking about (on the same wall as the front speakers)
the yellow is those curtain rod pieces of metal that are usually metal or plastic and shiny.
with a hinge on the red part, you could swing the far left and far right rods (not the straight rods) .. those could swing back and forth to give you access to the windows.
and again, you dont have to go all the way to the ceiling.

with the fabric on those rods .. it would look something like this:
http://i54.photobucket.com/albums/g95/anwaypasible/curt...



..and..
i wasnt talking about the picture on the monitor, i was talking about the picture of the entire room.

**also**
the rods with the yellow 'globes' on it.. those would attach to the wall like a towel rack (or towel rod if that is what you call it).
it is a bar with a connector on each side.
the bent rods would only have one connector, and that would be near the red line.
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June 26, 2011 6:39:47 AM

forgot to mention..
you would have to cover the bottom half of the windows to help your ears receiving pressure.
doing the top half is only going to adjust the problem a very small amount (if any at all)

if i was you, i would consider putting the desk on the wall with the door.
then put the sub under the desk and open the windows to allow the room to bleed out the pressure from the windows and doorway.
but
there are alternatives, and those are all spoken about above.

**edit**
and geez, if you are really desperate, put some air in some balloons and dont fill them all the way.
put some of those in the corners.
i dont know if it will work as good with only one balloon going down the corner.
you would probably put one balloon on one wall, the other balloon on the other wall and make the balloons touch to fill the corner.
they are giant diffusion panels kinda.
but
the property they have over junk diffusion panels is that the balloon can actually get pushed in by the pressure, AND push back with the wave as it goes up and down (pressure goes up and down).
technically, it is supposed to lean in and shove the pressure towards the middle of the room.
but
with two balloons in the corner..
some of that pressure will get shoved back, and some of the pressure will go into the gaps of the balloon to really help.
see
only one balloon will get pushed in by the pressure and stay there on the 'push' wave.
on the 'pull' wave, the balloon will push back and could cause the problem to grow worse :lol: 

you could actually fill them up with enough air precisely until the 80hz is gone.. but you might have a new frequency, and the balloons will lose air.
i really dont recommend using only one balloon.. because the problem has a lot of potential to grow.
the simple shape of the balloon can cause dispersion of the pressure and might alleviate enough of the pressure to make your ears stop getting tickled.
but
the two balloons are better.
you have to try both ways:
1. the balloons are supposed to not be full of air, so you should be able to smash them together to hide the corner visibly.
2. the balloons still are not full of air, but you can see the corner with gaps from the balloons not making full contact.

one of them two will provide the superior result over the other one.
and maybe a bag of balloons is cheaper to test my truth.

unfortunately, i have no idea how much pressure is in your room.
so if the pressure is really high.. the balloons are not going to show a huge improvement, and that is because your subwoofer output is way too much for the room size.
it will work for decibel accumulation, and that means it CAN work for pressure too.. but pressure is a beast compared to decibels.

the fabric should be an equal beast for the pressure.
the polyfil will probably come in second.
and the balloons come in at a far last.


the cardboard has to withstand lots of flex.
i have some twelve inch woofers that can provide enough air to blow out a cake full of candles.
i used cardboard to cover the midrange holes when i took the midranges out.
i used three layers of pizza box with screws going into the screw holes of the speaker cabinet.
it works just fine.

for the top ceiling cardboard.. you could use whatever to get the thickness of a single piece of pizza box cardboard.
but
two would be better.
three is probably overkill.

you will need to glue them together.
and if you do, dont use a scribble like you would do for ketchup or mustard.
you want to smear the glue across the whole thing like you are painting some nails or a wall.
it will keep the cardboard stiffer, most importantly, and it will also keep it from rattling in the future.


just be warned..
dolby and dts dont work for corners like that.
and if they do, stop! (wait until we have rooms built in the octagon shape before you start to entertain us in such a way.. and tell us the shape so we can select it like a DVD menu option)
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June 27, 2011 12:38:14 AM

So basically, gathering from what you've said, this is what it all comes down to:

- Bass traps aren't the best idea because they aren't specifically designed for pressure, but rather for the decibels of the bass?
- The fabric/polyfil will probably work well but I have to cover both top and bottom of the two windows.
- Balloons could work but it isn't guaranteed and frankly I'm not sure I would want balloons just randomly sitting in my corners lol
- Programming reverb is hard and might not give me the results I'm looking for

And I couldn't really "move" this desk anywhere, it is huge, and it's all connected and extends all the way down the side wall

I guess I'm screwed unless I want to put a lot of work into making these fabric rod inventions with hinges. Also one thing I have not tried is pointing the sub at the ceiling, but you said my room is simply too small for the output of the bass, so it probably wouldn't matter :sarcastic: 
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June 27, 2011 12:08:08 PM

move ur computer to the side with teh longest wall, then the corners are further away from you.
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June 28, 2011 1:09:02 AM

your ears have a height level.
and when you move your head, those height levels should be calculated too.
using anything long enough, you can touch your ear and the wall to get an idea.
then 3 - 5ft extra from that point in both directions.
you said your room is 8ft tall.. so i am thinking you will want from the receiver up, and from the desk up.
maybe you leave 2ft of space between the ceiling and the polyfil.

and yes,
bass traps will block the corner to prevent the tight squeeze that allows the pressure buildup.
that pressure will go someplace else.
bass traps should come in different widths.. so if the width isnt wide enough, then the corner technically still exists.

not everybody is going to say your room is a nightmare, they will look at the cause of the pressure.. and that is the subwoofer.

with the sub facing the ceiling.. the wall to ceiling corners would be the primary source of pressure.
then the wall to wall connections would be the secondary source of pressure.
usually the floor to the wall would be secondary, but you have lots of things in the way to prevent the pressure from 'floating' or 'bouncing' back to the floor.

maybe that is enough to get the pressure out of the corners though.
hard to know if it is absolute pressure or accumulated pressure.
you say both corners can be excited at once.. but didnt say anything about the other corners being excited at the same time.
and you also didnt say anything about the port of the subwoofer allowing you to turn it on its back.


i would simply say..
if the pressure is bothering you, the subwoofer might have too much power going to it.
and less watts with a bigger box ported to 20 - 25hz would mean you still hear the bass, but without all of the pressure.
this may not be the answer for you if the problem frequency is 80hz
and
you shouldnt have your subwoofer crossover that high to begin with.
but
with those tiny speakers, i can totally see why you would want to leave it at 80hz since the bass from those speakers isnt going to be much.


programming reverb for a subwoofer IS really hard.
because there isnt any reverbs out there that are ment for the LFE channel.
if my memory serves me correctly.. the creative x-fi reverb is for front/back/center+sub (or only the center?)
i dont have a picture of it and i dont have the software installed (my card broke).

why not use an equalizer to lower 80hz ?
or
since most crossovers are 12dB slope per octave.. why not lower the crossover a little bit and let 80hz play with a rolloff?
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June 28, 2011 11:53:17 AM

Seems like you have the situation handled, but your problem is very likely due to poor room acoustics. Also, if your subwoofer has the option of phase (either normal or reverse), try both and see if it makes a difference. May I also ask what kind of subwoofer you have?

Also, unless your sub is very weak, I recommend keeping it away from the very corners, yes bass will sound louder and deeper due, but will also sound more distorted and muddy which my ears hate, while putting it away will give you cleaner, more undistorted bass that (for me at least) feels easier on my ears.

I don't know if anywaypasible has covered what I said above, just mentioning it. The distortion from bass is what kills me, it sounds like really loud farts which gives me a headache after a while. To prevent distortion, make sure you have a good source...which means good cables, good source (either lightly compressed mp3's or .wav CD files) and and no analog connections. Oh yeah...and if the sub is passive, a good amp obviously.

Not sure if it will fix or if this is cause of your problem but its what did it for me.
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June 28, 2011 1:23:15 PM

phase only makes a differnece, if it is being crossed over to a mains speakers, or is palying together with another subwoofer....

on its own the phase doesnt amtter, cos when sound waves reflect, its waves becomes out of phase by 180 degrees, this is the same with all waves, NO MATTER what phase you project the sound waves in. (this is only on hard surface though)
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June 28, 2011 2:44:55 PM

idk how phase works, just suggested to try it, because it makes different sound on my sub when i set it to reverse and normal, different areas of the room get different bass.
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June 28, 2011 5:35:28 PM

really??? i get know difference unless i have the rull range playing with it, like at 80hz frequency which is the centre of teh cross over frquency.

by the laws of physics, phase should make no difference to the perceived sound, when its the only source available.in other words wave pattern of superimposed waves, should be exactly the same.
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June 28, 2011 7:37:37 PM

Well...on the system I'm talking about, the sub has a cut-off at 200hz (yes I know its high). and I've got another sub also. When I make the phase to reverse, the bass is extremely concentrated in the front corners and the middle gets almost no bass, while when phase is set to normal, the bass is much more equally distributed around the entire room.
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June 29, 2011 1:43:29 AM

blackhawk1928 said:
Well...on the system I'm talking about, the sub has a cut-off at 200hz (yes I know its high). and I've got another sub also. When I make the phase to reverse, the bass is extremely concentrated in the front corners and the middle gets almost no bass, while when phase is set to normal, the bass is much more equally distributed around the entire room.


that is exactly how it is supposed to work.
if you have lots of acoustics on the outside perimeter, then flipping the phase will make the inside of the room more acoustical.
it is simply a matter of in and out, and where the in's are as well as where the out's are.

yes, the pressure is going to be in the corners again..
but
when two soundwaves come into contact with eachother, they can cancel eachother out..
or
they can increase in amplitude.
it should make obvious sense that the waves making contact in the middle of the room are touching eachother in a way that is canceling out the sound.
thereby flipping the phase, those soundwaves would then do the opposite.

accumulated pressure is and remains accumulated pressure within the room.. that fact can keep the corners 'air-y'
and the only way to move the pressure someplace else is reverb.
sometimes the reverb isnt powerful enough to stretch out long enough that is needed to pass the corner and continue into the middle of the room.

it is a jigsaw puzzle without visual indentification.
but
you can kinda get a glimpse yourself if you realize that the cone pushes outwards and the air is like a gelatin.
the wave will go out in all directions, and the center of the wave depends on the dustcap.
the outside of the wave depends on the shape of the cone indent.
some speakers have a completely flat cone (some old precision power subwoofers)
and even still, some subs have a much less curve.. like the jl audio w7


megamer would be right to argue when the problem is tickled ears from too much pressure.
decibels are not the same as wind that can blow out a candle.
the difference in size is humongous for sound pressure.
some speakers can spit out decibels without moving much at all.
and those speakers rely completely on the tune of the box to play lower notes.
sometimes these subwoofers dont have the box tuned right, and the subwoofer cone belches in and out (and is often pushed extra until the speaker bottoms out - or the voice coil frys)
this leads to the pressure problems.. and a whole lot of bass you can feel, as it rattles the windows.

some people consider an elegant system to be one that plays all the notes, but doesnt do it with a lot of window shaking power.
this means much much bigger boxes, and can have the benefit of less amplifier power.
pretty much how they did it in the 60's and 70's
but
i think the 70's introduced more speaker cone excursion, with enough that could rattle a window.
probably those giant paper 15 inch woofers with the 'newer' foam surround instead of the paper accordian type.
and then there was still people who had 15 inch woofers with the accordian surround, but there was more ability to move in and out.
some people went to theater type speakers (or concert speakers) because they were larger and could play the bass to keep up with the competition.

then in the 1990's..
speakers like cerwin vega really pumped up the box to speaker cone excursion ratio.
they would belch out bass.

then in the mid to late 1990's the dedicated subwoofer came out for dolby digital.
the industry has been pushed forwards towards the dedicated subwoofer ever since, and it seems like only a rare few ever look back.

i tell people pretty quick and simple.. no matter if your room has 15 inch woofers for the front/center/rear speakers.. the dumbed down audio mastering is still going to put some bass on the LFE channel.
it could be a copy of what goes onto the front or center channel.
and
it could also be something specific to make your room shake.

it should be expected that one day we will have the proper 12 or 15 inch woofers in every single speaker, and there will be tremendous bass that is positionally accurate.. and there will still be 1hz - 20hz (or is it 1hz - 10hz ?) from a very large speaker, or an array of speakers, to specifically build pressure in the room.
it isnt necessary at all when the main speakers are given all of the audio.
and any LFE effects would then be completely digital FX designed to add thrill to the experience.

weaker systems can appear to raise the floor of a room.. kinda like a 3d effect, but done with pressure.
stronger systems can make the floor appear to fall.
if there is a system put in place, the floor could be tilted front to back .. side to side .. back to front.
this could be really cute when watching some jet pilot do manuevers.
or
imagine the floor dropping every moment when the 'bullet time' was activated in the movie 'the matrix'

this is kinda far away.. because people need better dedicated listening rooms.
drywall just isnt going to cut it, as it will crack and bust to be remaining as an embarassment.
concrete works.. and maybe some blocks that have had their inside wall drinking glue.
maybe some type of fiberglass between them.. but i would think the fiberglass would crack too (just not as quick as drywall)

dedicated listening rooms of such magnitude require either going into the basement.. or choosing somewhere in the middle of the house, and put some jacks under the area to support the concrete walls.
but
concrete cracks too.. eventually.
plastic would be awesome if it didnt vibrate.
carbon fiber would vibrate too.. unless you did lots of layers, and that is too expensive.



acoustic paneling isnt going to help in this situation.
the acoustic paneling will not drop the pressure in the room without adhering to the soundwaves and their phase.
you have to realize that there is wind (like from a fan) that needs to be pointed somewhat precisely to get the wave in opposite phase to come into contact with the wave by the acoustic panel.
flat panels wont do it unless they are aimed in all sorts of crazy patterns.. and expect to lose as much as 3ft - 4ft per wall.
diffusion panels can be designed for a specific frequency.. but there is no way of them knowing how big your room is and where the panel is going to go so that they can design the shapes perfectly.
a single soundwave of 80hz is false.
there will be other soundwaves bouncing into the diffusion panel.. and if those soundwaves are 80hz too, then your chances are higher.
but
rooms dont all work like that.


since acoustic panel sellers dont openly advertise their willingness to help people with their room size and frequency.. one could assume that those details are private.
either private for 'industrial' use.
maybe private for 'commercial use'
or
downright private to force custom installers to make their own.


there are waves bouncing from one wall to the opposite wall.
waves bouncing from one wall to another connected wall.
waves bouncing from the floor to the ceiling.
waves bouncing from the wall to the ceiling.

if you wanted 'custom' help..
they would need to know where exactly the panel is going to go, and what soundwave pattern is touching that area of the wall.
that is the only way to do it correctly with perfect results (especially without any reverb).
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June 29, 2011 10:09:33 AM

blackhawk1928 said:
Well...on the system I'm talking about, the sub has a cut-off at 200hz (yes I know its high). and I've got another sub also. When I make the phase to reverse, the bass is extremely concentrated in the front corners and the middle gets almost no bass, while when phase is set to normal, the bass is much more equally distributed around the entire room.


an yes it works like that cos u have another sub. if you have mutiple subs, and switch different pahses for different subs, you will cancel out teh peaks and nulls, you can even control directivity.

but i was tlkaing abouit a single sub. im geussing you only change the phase on one of them.
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June 29, 2011 12:19:13 PM

This is standing waves.
An EQ should be used to dump one frequency, the resonant frequency of the room. When the EQ is used to dump that one frequency, the booming will stop.

Also lifting the sub off the floor, and away from the walls, will kill the efficiency.

Standing waves will form in corners, and any room has a resonant frequency. That's why there's EQs, digital or analog, software or hardware. You just subtract the one frequency and the problem is solved.

And yes, low frequency is omnidirectional...which means you can use a single mono sub on any system and it works just fine no matter where it's hidden, located, etc. Lows do not need to be in stereo to maintain a stereo image.
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June 29, 2011 12:40:30 PM

MEgamer said:
an yes it works like that cos u have another sub. if you have mutiple subs, and switch different pahses for different subs, you will cancel out teh peaks and nulls, you can even control directivity.

but i was tlkaing abouit a single sub. im geussing you only change the phase on one of them.


Yes, in my room I've two subs, a larger one and a smaller one, each from different manufacturers also, only one of them has phase control. IDK if this effects anything, but since the amp in my room has only one subwoofer pre out, I've got my bigger sub connected to the amp and then my second sub is connected to through my other sub. So when I make reverse phase it completely changes the areas of where the bass is located.
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June 30, 2011 1:04:17 AM

soundguruman said:
Lows do not need to be in stereo to maintain a stereo image.


the reason why the above quote is true is because the soundwave is long enough to reject pinpoint obtainment.
the same will not be true when the subwoofer plays a subtle change.
could be a small pop or thud, could be transients from the subwoofer.
the frequency will get higher, and the above quote will become less of a fact.

major point to remember,
simply because the subwoofer is playing low notes.. that doesnt mean there are small pops and subtle changes that have the same wavelength.


some soundwaves are long enough that it is pointless to argue that the sound is somewhat stereo.
however, every space further away from the subwoofer has the potential to muddy things up and reduce the clarity.
the picture above from the original poster is a perfect example.
when the subwoofer is tucked away in a far away corner, there will be much chance for the soundwaves to bloom.
they are not the pretty blooming that happens with flowers and plants.
the swelling is obnoxious and false.
dont forget, some speakers have been known to make use of the swelling and only provide their most accurate sound representation if you are listening in that area.
but generally, the speaker sounds like crap anyways.. and you would know it because with the speaker pointed right at you from like 3-4ft .. you could come to the conclusion that the output isnt anything close to reality.
then get far back away from the sub in an opposite corner, there might be some added sound.
it means the speaker cant play that sound loud enough for you to hear it up close to the cone, and when the walls are used, they boost that small output because the ringing of the room helped.


using an equalizer to reduce the frequency is not always the best choice.
because if your ears are in an area that is constantly destroying the shape of the soundwaves, reducing the amplitude of that frequency means the clarity of that frequency is going to drown.. as it comes subjected to the stronger standing waves.
point here.. get a speaker that can play those smaller details more loudly.
and then, if you have a blooming problem at a certain frequency.. using the equalizer to reduce that frequency will be less harmful to the results.
obviously, if it happens once.. it can happen again, and probably will.
but
your chances of maintaining something that resembles clarity is higher because the tone is heard louder.



the putting the subwoofer up off the floor is cheap and easy advice.
but
with the cone up higher, it will be louder.
since the cone is up there, the muddy pressure will go up to the ceiling and down to the floor.
could provide less pressure at ear level.. and objects in the room could totally ruin the attempt.


when you break it down to the most simple factors..
it is like there is a complaint about wind blowing.. but the person complaining refuses to turn off the fan.
the wind is air simply moving.. not that the wind is blowing directly in your face.
like trying to light a candle but the flame keeps going out because there is a breeze.
not because there is a fan pointed directly at the candle.
the subwoofer is too much when combined with the resonant frequency of the room.
since the room is already ringing at 80hz .. you could lower the crossover to like 70hz or 60hz and lose some audio clarity at 80hz.

maybe you could get some drink carriers from a local fast food place.
put those along the wall with the speakers mounted.
with the edge of the carrier touching the window (slid far to the edge of the wall) .. it might reduce some of the pressure.
see, the pressure will reduce if you force the pressure waves to slam into eachother and cancel out.
but
it is a lot of work.
you can also scatter the soundwaves, and that is like taking a solid object and smashing it into lots of tiny pieces.
the drink carrier might be able to scatter the pressure waves enough to stop the ear problem.
the poly fill scatters the pressure waves too.. but it also holds onto the air longer.
the only chance the drink carrier has to hold onto the waves is in all of the spots that have holes (and the material that blocks your view of the wall)


i really wouldnt want to reduce everything with an equalizer unless the speakers are pointed directly at you.
when you are listening to the walls of the room, that is what you hear.
you can point the speakers directly at you and try to cut your way through some of the sounds bouncing off the walls.
but
without reverb, your results will be much lower.

as of now..
you have like all of the tricks in the book available to you.
it is up to you to start trying them out and come to the conclusion which one is the best for you.




one more thing you could try..
get a beach towel and tape it to the ceiling so it is parallel with the wall that has the speakers mounted to it.
leave about 2 inches between the towel and the wall.
that should help too.
lot easier than mounting the fabric rods.. but it doesnt look as nice or 'professional'
and sometimes getting a towel to hang from a ceiling is a real pain.
tape probably wont work for long.. and if it does, it is going to pull off the paint when you are done with it.
you could get some hooks that screw into the ceiling.. and these would probably last for a long time if the threads are big enough and the drywall/plaster isnt crumbling.



i cant hang anything on my walls in the apartment i am in.. so i had to take the impulse response of the room in combination with an equalizer.
you do something like that and you will see that you will once again have pressure.. but at a lot more frequencies, and obviously the volume would have to be louder.
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July 7, 2011 10:28:19 PM

Thanks so much for the replies guys. To me, this is a crazy amount of information to try and process :lol:  But I was wondering if something like this has a chance of solving my problem:

http://www.diy-home-theater-design.com/bass-trap-build....

It looks simple enough to build and it seems like I have just enough room to put it in the corner to my left where the bass is being concentrated.

Do you guys think this would be a good thing to try, or should I stick with trying the polyfil with the rods and stuff?
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July 7, 2011 11:07:15 PM

Well I really don't specialize in bass traps, but I do know that room acoustics make a huge difference in sound quality, if your room has poor acoustics, there will be spots with extreme amounts of bass and other spots, perhaps a few feet away with virtually no bass. Perhaps bass traps can help, i'm not sure about that at all.
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July 7, 2011 11:12:05 PM

That's exactly what happens. When I walk around my room while playing a bass tone, some spots are super concentrated while other spots it disappears entirely.

I mean, when I bought my sound system, I never even thought to consider stuff like this, because I didn't know about any of it. I didn't know about my room being too small for the sub, or having to acoustically treat the walls :sarcastic: 
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July 7, 2011 11:36:02 PM

its not really about room size its about acoustics, different types of materials and surfaces absorb or reflect sound waves causing uneven and weird sound effects in a room. If you have lots of furniture in random places in the room, lots of stuff on the walls like paintings, pictures, and other stuff, they can either reflect or absorb the sound which can potentially ruin directional projections.

For example, if you want surround sound in a room with poor acoustic handling, a sound that should originate from for example, the Front Left speaker, will reflect off the other side of the room and reach you from what seem to be the Rear Right speaker, which messes up the surround effect. Thats why you generally want sound to be absorbed throughout the room, so its not reflected. Acoustic treatments make worlds of a difference.
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July 9, 2011 1:49:16 AM

you are steering the situation towards a room that has no ability to use the dolby surround format, much like i was.. but worse.

yes, acoustic panels all over the walls and the ceiling and floor will reduce the impulse reponse, as well as the soundwave bouncing from wall to wall.
but as i said,
you cannot get 'virtual speakers' without using the reflections.

corners will always accumulate soundwaves without any digital sound processing.. unless you put something in the corner to block the tight pinch.
round tubes are a pain in the butt to try and calibrate reverb with, since the soundwave can go in many directions because of the round surface.
that is why the bass traps use a simple flat edge, because the reflection is easy to predict.. and if you have calibrated some reverb, you wont lose all of the calibration because you created wind when you reached into the bag of popcorn and brought the popcorn to your mouth.
or because you were laying on a couch and decided to move to get more comfortable.

put two 15 inch woofers in there with 1 inch excursion each.. 500 watts each, and if those speaker cones are moving 1 inch each.. you will see that there is too much pressure without any steering.
if you keep it up, you could break a window.
might start with a crack.. or the window flex is high enough to eventually cause the window to shatter.
no amount of absorbing soundwaves is going to fix that, unless you are trying to absorb the soundwave from the subwoofer before it has any chance to send the soundwave to the wall.
and even then.. if the output is high enough from the subwoofer, you will start to see problems again with the further away the absorbing attempt is made.

you cant soak up everything, because then you wouldnt hear anything.
it is like trying to ride a bicycle without holding onto the handle bars.. you dont wanna fall, you need to grab hold of the controls.


my thoughts on the sand filled tube is this..
the only reason the sand is there is to deaden the thud from cardboard flexing.
if the thing is in the corner and the cardboard is allowed to vibrate, then it is going to sound like you can hear it.
that isnt why you put it in.
you add the sand until one of two things happen:
1. the sound from that space of the room is dead
2. you cant get the thing to sound dead, so instead.. you add/remove sand until the timbre of the sound matches the timbre coming from the speakers.
the whole concept is ment to do one of two things:
1. provide some sound deadening for the corner of the room, usually because the corner is blocked and the soundwave reflection pattern hits the round tube and scatters everywhere.
2. provide a cheap way to put a 'virtual speaker' into the room.


i think this is hilarious..
because what turns out to be an inexpensive corner bass traps was also a very expensive trick to widen the soundstage.

say for example you have two speakers in the front and want the sound to appear 'wider'
usually these tubes would be recommended as a cheap alternative to redesigning the entire room.
you could twist the front speakers in such a way that the reflection from the rear wall would bounce forward and hit the tube, and then bounce towards the listening position again.
sometimes you needed to have a board on the back wall to help point the soundwave to the tube.
and you would have to move the tube until the soundwave hitting it would bounce at the right angle so the listener could hear it.



apparently the original poster doesnt seem to think the sound pressure is enough to make any difference.
tickled ears from sound pressure isnt going to go away without pointing it at a place in the air where it can be extinguished.

that is like saying you have a room full of newspapers stacked up along the walls.. and there is a plastic swimming pool holding water somewhere in the room.
a person hands you a flamethrower and says 'dont catch any of the paper on fire'
meaning.. you have to aim at the water ONLY.

there comes a time when you put that round thing into the corner after you were complaining about hearing bass from the corner.. and it only makes it worse.
depends on how the soundwaves hit the left side and the right side of the tube.

when you are complaining about a corner.. it is like there is a lightbulb in the corner shining.
you say 'i am trying to look at the screen and dont need the light in the corner of my eye'
so naturally, you want the light bulb to get much dimmer.. to the point of going out completely if needed.
and without any care, you put the tube into the corner and see that the light from the bulb actually gets brighter (or stays roughly the same).

when you start dealing with digital sound processing.. it works like this at the beginning..
you have a dim light in each of the four corners.
you mess around with the settings until the light is moved from the corners and is put into the space of the middle of the walls.
that means there will be light at the middle of the wall and it will slowly fade out as the light gets closer to the corner.
if your digital sound processing was more advanced.. you would take the light and force it to move to the center of the room where all four come into contact with eachother.
then you have the option to try and force the light to die, or you could seperate them a little bit until it looks like a number four on a piece of dice.. and then adjust the position until your head is in the middle of those four dots.

pre-programmed digital sound processing, or because there is furniture in the way, can cause lights to form again.
they will be less bright, but inevitably there.
some sound absorption can keep those lights from re-appearing, but the absorption will also make those lights in the middle of the room less bright.

it means you need more power from the amplifier, more power handling from the speakers, and lots of detail pumping out of the speakers... because speakers that sound really good in a room with no carpet are going to sound like complete trash with all of their flaws revealed when you put them into a room with lots of sound absorption.

meaning the price of the whole setup is going to go through the roof.
it is bad enough as it is nowadays, you get a speaker and you dont know if it is going to sound better in a carpeted room or a bare room.
once you take it away, you shouldnt expect to get it back.
bare room reverb can be custom programmed to form the timbre in the air space.
all peaks and dips can be eliminated, depending on programming intelligence and processor power.


it helps to know if the phase of the sound from the corner is 0 degrees.. 380 degrees.. or 180 degrees.
BECAUSE the phase that leaves the corner is going to be coming into contact with the soundwaves between your ear and the corner.
you design some reverb that puts 180 degrees of phase spewing out of the corner, and then run a line of soundwaves between your ear and the corner with 0 degrees of phase.. when the two come into contact with eachother, they will cancel out and you wont hear much of anything from that space in the air.
it gets pretty simple tricky...
if 0 degrees bumps into 180 degrees in a head on collision.. there will be no sound at the spot they collide.
if 0 degrees t-bones into a 180 degree soundwave (hits it directly in the side) ... then the sound will be cut in half.
just think of it like ripples in the water.
what happens when you push down on the water in a tempo'd pattern while you are in the tub?
the water will run to the edges and violently splash.. and in the corners, the water will probably go out of the tub.
if you get your timing right.. you can get the water in the corner to fly straight up and even fall back into the tub more than it splashes out of the tub... meaning it goes up and falls inwards.
lots of tubs have the rear corners angled so you can lay back.. and those arent the corners i am talking about.
you would be lucky to see the water in that corner go straight up into the air and fall back down straight.


sound absorption panels are not supposed to stop reflections, but they probably do a mighty fine job of slurring the reflection angle.
just about anything that sits on the wall and continues to allow the corner to keep its shape is not going to help eliminate the sound coming from the corner.
cheap materials will help a little bit.. the more expensive stuff will bright the audible level down lower, but wont stop it.
must re-shape the corner or use digital signal processing.
the fabric on a rod idea is supposed to work like a spider web.. the web is invisible and lets the insect clumbsily find their way into the web, and once it makes contact.. it is probably stuck there for good.
same with the fabric on the rods.. it lets the soundwaves linger into the corner, and instead of allowing those reflections to happen.. they hit a really soft spot and die.
doesnt always work 100% .. but as long as the pressure and soundwaves isnt blasting right through the fabric, the success rate is guaranteed.
that is why i said it is important to get the fabric right.


i mean,
you could try the tube, it will do one of three things:
1. completely work
2. sound exactly the same
3. make the sound from the corner worse

the professionals would want to know exactly what the shape of the soundwaves are in the corner before they start to sell you something.
that is how they go to their shelf and pick the least expensive product that is going to work.
it saves them money from not wasting anything.. and it makes them look good because it works.

i am no professional.. but i am consciously aware, just not as consciously aware as the pro's.
any professional that recommends a bass trap is being a punk.
they dont know what angle the soundwave is hitting the corner, and that means they dont know what angle the soundwave is going to be hitting the bass trap.
and to try and save their butts from being wrong and looking stupid.. they put some sound absorbing material on the face of the bass trap.. making the cost of the product go up like 3 or 4 times (maybe more).
you would hate to put a mirror in the corner and turn your head to the corner and see the subwoofer staring you in the face. (of course you would need a mirror on the other wall too but, that is how soundwaves work.. although sometimes the angle is a bit off).

i would tell you to try the tube if you want to.
but if you dont fill it with sand, the cardboard can vibrate.. and the sound wont be as dead as it could be.
and with that said.. the reflections that do bounce off of the tube without any sand, they will be increasingly sharp with more sand added (because the cardboard is more resistance to vibration.. as if to say, the cardboard is harder)

i dont know where you are going to put the tube.
if you cut it so that it fits on the shelf your receiver is on.. that is gonna be like 20 - 30 lbs of sand probably.
hoping the shelving unit can hold all of the weight.

things get a bit simple again too..
because if you put sand in the bottom and pack it tight.. you can get a gradual rise in the cardboard vibration.
that means the very tops of the tube can be allowed to vibrate up by the ceiling and make the sound appear as if the entire wall is talking to you.
and back in the day.. that is what people paid for when they hired somebody to calibrate their system.
the installers would be construction workers who constructed the room until the desired effect was made.

common requests would be:
make it sound like the whole wall is talking
make it sound like this mantel in the middle of the wall is talking
make the back wall stop talking
make it sound like the dome in the ceiling is talking

these requests are all forms of pleasure that dates back to the roman times with their cathedrals.
each request is like asking them to build a miniature cathedral.

any of the professionals should agree, if you have a problem with a corner.. change the shape of the corner.
and your room has those windows there, so it makes every 'corner change' a pain.

people with a clear knowledge of today's technology would tell you to change the signal timing with a digital signal processor.

see.. the cone moves in and out at a set speed for each frequency, but the reality is.. the cone could be moving slower or faster than the frequency and suffering from overtones (usually because the room is supposed to help).
people can get in there and tell the speaker to move faster if the speaker can handle it.. or slower.. to try and change the soundfield in the room.
chorus does something like this with their oscillation and echo.
except.. the echo works by slowing down the signal, and using pitch-correction to keep the audio the same pitch as it is slowed down.
this continues to happen for a short time, and then the chorus plugin starts to double the output and you hear the echo.
but in reality, you could keep slowing the sound down and using pitch-correction.
eventually your speakers wont handle it, or your amp wont handle it.
it is kinda like introducing a square wave into the signal.. but instead of the top of the square being flat, there is audio information there.
to try and help the speaker or the amp.. you start to introduce oscillation, and that is supposed to flip the phase from positive to negative.
it can keep the voice coils cooler (or safe from short circuiting), and it can keep the amp from being destroyed (again, running cooler or short circuiting - falling/blooming short).
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July 9, 2011 2:40:21 AM

i just watched a most beautiful video on youtube that compares sound with and without room treatments (absorbers and diffusors).
you can see and listen to it yourself here:
http://youtu.be/dB8H0HFMylo?hd=1

but as i have already said.. the room full of treatment does not work with dolby digital or dts sound effects. (much of the reason why they have stopped trying to create 'virtual speakers' and simply put a physical speaker there.. and the results come up extremely short)
see.. you could put a 'virtual speaker' in one single spot.. and a physical speaker could recreate that single spot.
but
when the 'virtual speaker' is casting a sound across the length of the room.. there is no comparison, as the sound is fluid.. meaning there are no gaps whatsoever.

a room with no absorbers or diffusion can use spatial technology to make it sound like a lawnmower is running up from behind you.
literally... from the back wall and it sounds like someone is pushing the mower closer and closer to you.

with the absorbers or diffusors, you wont get the same effect.
you would be LUCKY if the lawnmower gets louder and louder to 'tease' the thought of the mower getting closer to you.
but all of the timing necessary to trick the brain into thinking there is a real presence creeping up closer to you.. all of that is gone.

it is an effect.. used to fill in the gaps between speakers and make the surround sound possible.
most times you arent in an atmosphere, and that means you arent in surround sound.

a big difference between having rear speakers and having surround sound.
the word itself 'surround' should be enough to explain itself.
but if it isnt enough.. try the word 'blanket' or 'drown'

it is a bit annoying to see the audio industry trying to push out the tool to every home.. only to have things like room treatments come along and destroy any chance of something special.

i see clearly that the stereo music doesnt have a whole lot of spatial effects.. and that leads to the complaints about the room sounding like crap.
get an equalizer to flatten out the frequency response and you wont be complaining anymore.
the equalizer calibration can translate to the dolby digital and dts audio.
for the dolby digital and the dts audio to work perfectly.. your rt60 times need to be as flat as possible.
but thanks to squared digital sound processing.. those high rt60 times can actually help make the audio echo go away faster.. since it can be designed to use the echo to an advantage.

as always..
a flat frequency response and a flat rt60 is going to keep the timing and the frequency amplitude 'referenced'

you need it to be taking audio seriously.
and it can help with problems in the corners.
since you will either raise or lower the amplitude until all of them are the same.
and then your only complaint would be where the sound is actually coming from.
that is something reverb can conquer.
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July 12, 2011 4:20:19 PM

Just saw this thread so if I repeat something I am sorry.
1. EQ as was suggested. You never mention what the sub is connected to, PC or surround system. If it is a PC then you can use the eq that may be available in the driver for your sound card or playback software.
2. You never mention brand and model of sub. Many if not most subs have a built in peak at 80hz (the port is tuned here) which gives that greatest subjective amount of bass at the expense of quality. The sub may be making the room acoustic problem worse.
3. Try aiming the woofer up to the ceiling. Try blocking the port of the sub. If your sub is bandpass and you cannot see the speaker itself you cannot do this so aim the port to the ceiling. This type of sub where the speaker is not firing directly into the room but ONLY through the port has the worst performance and is to be avoided.
4. Corner traps will have to be pretty big to work and you may not have room. You could try to build a flat panel resonator which can be made from 2x6 lumber and plywood. Make a frame out the 2x6 with the 6" dimension as the depth and cover the front of the frame with the plywood. This will hang on a wall so size to fit. If this works you can cover the plywood with a rug, foam or posters to make it look better.
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July 18, 2011 5:00:39 AM

equalizer , cut some bass or play with speaker placement there are some other things you could probably try but it looks to me as if you have plenty of suggestions if your sub is ported and nothing else produces results you might try plugging the port and de-tuning your sub. some people prefer a sealed enclosure for their to sub for sound quality purposes , porting is usualy done increase sound output, sometimes porting increases noise.
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!