Subwoofer position

Archived from groups: rec.audio.high-end (More info?)

"---MIKE---" <twinmountain@webtv.net> wrote in message
news:cf30ag0r12@news1.newsguy.com...
> I have a large listening room. It is 22' X 30' with a cathedral
> ceiling. I have a subwoofer in each corner. My listening spot is in
> the exact center of the room. I get very little deep bass at that
> position but when near the corners I hear lots. I know that corners are
> the most efficient place for woofers but is there a better spot in my
> situation?
>
> ---MIKE---

They should be in the same corner. You're probably getting comb filtering.

Archived from groups: rec.audio.high-end (More info?)

I may have just posted this in response to another posting on this
group. But, here it is again.

The answer to your question is. Yes, absolutely. Without a lot of
measuring equipment and a mathematical nightmare to compute a
solution:

1. Place the subwoofer at your listening position (wherever you
*want* the bass) and play your reference music through it.

2. Walk around the room along the wall and listen for the bass peaks.

3. Place the subwoofer at one of the peak positions along the wall and
you 'll have that bass at your listening position.

I have a 17' x 28' listening room with a 10' ceiling. Using this
placement method, one 10" powered subwoofer has enough energy to sound
as good or better than any of the IMAX or other theaters I've been to.

Good listening to you.

On 7 Aug 2004 16:34:24 GMT, twinmountain@webtv.net (---MIKE---) wrote:

>I have a large listening room. It is 22' X 30' with a cathedral
>ceiling. I have a subwoofer in each corner. My listening spot is in
>the exact center of the room. I get very little deep bass at that
>position but when near the corners I hear lots. I know that corners are
>the most efficient place for woofers but is there a better spot in my
>situation?
>
> ---MIKE---

Archived from groups: rec.audio.high-end (More info?)

Corner placement will tend to give you the most reinforcement, but
also has the greatest potential for giving you "one note" bass.

Positioning and blending of subwoofers is always alot of work. Listen,
listen listen is my only advice. I ended up with the subwoofer just
off centerline, about 5 feet into the room and turned sideways (the
cone faces the right wall). I have no idea why that sounds best to me,
but there it sits!

Trust your ears!

Philip

On 7 Aug 2004 16:34:24 GMT, twinmountain@webtv.net (---MIKE---) wrote:

>I have a large listening room. It is 22' X 30' with a cathedral
>ceiling. I have a subwoofer in each corner. My listening spot is in
>the exact center of the room. I get very little deep bass at that
>position but when near the corners I hear lots. I know that corners are
>the most efficient place for woofers but is there a better spot in my
>situation?
>
> ---MIKE---

Archived from groups: rec.audio.high-end (More info?)

"---MIKE---" <twinmountain@webtv.net> wrote in message
news:cf30ag0r12@news1.newsguy.com...
> I have a large listening room. It is 22' X 30' with a cathedral
> ceiling. I have a subwoofer in each corner. My listening spot is in
> the exact center of the room. I get very little deep bass at that
> position but when near the corners I hear lots. I know that corners are
> the most efficient place for woofers but is there a better spot in my
> situation?
>
> ---MIKE---

How about under your chair?

Archived from groups: rec.audio.high-end (More info?)

That's good advise as was Stu-R's. The best position is one of the
least possible for most people due to lack of space there. Ideally,
the sub should be directly under or behind the video monitor and
center channels speaker. Since you have two subs, trying to get them
closer together along the front wall and between the main speakers
will work best. That gives you correct localization and phasing with
little effort. Subs placed in corners will have more output, but that
can be cancelled by the other sub, speakers, and room construction.
So, if you get suitable bass levels from the front wall (switch both
subs in the same phase), then that will also give you the most
seamless transition with the main speakers and not cause a weird
sensation from having the bass coming from afar. {A real simple fix
that may avoid moving anything is to just try and switch one of the
subs phase so that they are out of phase with each other. That would
be especially effective if the subs were in the opposite corners.}
Still, I always find it best to have them on the front wall where
possible.
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Philip Procter" <philip.procter@loctite.com> wrote in message
news:cf5geu0kj6@news1.newsguy.com...
> Corner placement will tend to give you the most reinforcement, but
> also has the greatest potential for giving you "one note" bass.
>
> Positioning and blending of subwoofers is always alot of work.
Listen,
> listen listen is my only advice. I ended up with the subwoofer just
> off centerline, about 5 feet into the room and turned sideways (the
> cone faces the right wall). I have no idea why that sounds best to
me,
> but there it sits!
>
> Trust your ears!
>
> Philip
>
> On 7 Aug 2004 16:34:24 GMT, twinmountain@webtv.net (---MIKE---)
wrote:
>
> >I have a large listening room. It is 22' X 30' with a cathedral
> >ceiling. I have a subwoofer in each corner. My listening spot is
in
> >the exact center of the room. I get very little deep bass at that
> >position but when near the corners I hear lots. I know that
corners are
> >the most efficient place for woofers but is there a better spot in
my
> >situation?
> >
> > ---MIKE---

Archived from groups: rec.audio.high-end (More info?)

twinmountain@webtv.net (---MIKE---) wrote:

>
>I have a large listening room. It is 22' X 30' with a cathedral
>ceiling. I have a subwoofer in each corner. My listening spot is in
>the exact center of the room. I get very little deep bass at that
>position but when near the corners I hear lots. I know that corners are
>the most efficient place for woofers but is there a better spot in my
>situation?
>
> ---MIKE---

Change your listening position. It's unlikely that you'll improve anything by
relocating the subwoofers except if you place the subwoofer at your present
listening position.

Your basic problem is that the geomteric center of your room is the one place
where the fewest room modes will lbe excited. Most folks think of room modes as
bad-things.

They forget that modes occur between any set of opposing surfaces. Play a 1000
Hz tone and move your head from side to side and you'll hear the sound change
...... that's a room mode. But because the wavelength is only about a foot long,
the modes are statistically dense and you'll get the same sound everywhere in
the room.

At subwoofer frequencies and wavelengths the modes are sparse and below 100 Hz
there may be only 5 of them. The modes carry the energy so if you fail to
excite then you get reduced sound pressure.

So you are simply sitting in a bad bass position. You can either move your
chair; just try some other plausible locations; or you can try putting the
subwoofer near you. That way you'll be in the direct field of the woofer and
less subject to room effects.

The problem with that approach is that any extraneous noise from the subwoofer
(port or suspension noise or internal rattles, dirstortion products ect) may
make it easier to localize the subwoofer. Try it; what do you have to lose?

Archived from groups: rec.audio.high-end (More info?)

twinmountain@webtv.net (---MIKE---) wrote in message news:<cf30ag0r12@news1.newsguy.com>...
> I have a large listening room. It is 22' X 30' with a cathedral
> ceiling. I have a subwoofer in each corner. ....................

Each corner = 4 corners?

Pardon my silly question but is it normal to have 4(four) subwoofers
in a room of your size?

I am using a 200 W sub for a room of roughly 18 x 20 and the volume of
the sub is set at around 9 to 10 o'clock. That is enough for some
earth..err….room shaking effect. Technically, I am using 3 subs if you
include the subs in my main speakers.

BTW, how are you splitting the signals into 4 sub? Sub input into four
channel Pre Amp? Or are you splitting the RCA in to four or eight?

Rgds

Archived from groups: rec.audio.high-end (More info?)

---MIKE--- <twinmountain@webtv.net> wrote:
> I have a large listening room. It is 22' X 30' with a cathedral
> ceiling. I have a subwoofer in each corner. My listening spot is in
> the exact center of the room. I get very little deep bass at that
> position but when near the corners I hear lots. I know that corners are
> the most efficient place for woofers but is there a better spot in my
> situation?

> ---MIKE---

I suggest experimenting with listening position, since your current one
probably has you sitting in a bass null. Try moving forward or back in
half-foot increments. Btw for a normal rectangular room (yours may not
qualify, having a cathedral ceiling), some research done for Harman a few years
ago on sub placement suggests the midpoint along each wall, for two or four
subs, is optimal

http://www.harman.com/wp/pdf/multsubs.pdf

For a single sub I'd still expect corner placement to be best, as it excites
room modes most evenly.

--

-S.
"We started to see evidence of the professional groupie in the early 80's.
Alarmingly, these girls bore a striking resemblance to Motley Crue." --
David Lee Roth

Archived from groups: rec.audio.high-end (More info?)

Sorry - the subs are in the two front corners. Changing my listening
position is not practical. I tried putting one sub against the side
wall in line with my listening seat. That helped a lot. The front wall
is taken up with the equipment rack and CD storage.

---MIKE---