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Active subwoofer module

Last response: in Other Consumer Electronics
June 4, 2011 12:07:34 AM

hi I need a amplifier module that has 600 watts rms for my subwoofer im building
July 24, 2011 12:40:11 AM

parts express has some plate amps and a component sub woofer amp, not sure of how good these are or aren't i do know one of them has a reported hum that can be heard while idle , the highest wattage amp doesn't though . other than parts express there are not many options other than high end $$$$. one might try a crown amp , it is a pa amp , but crown is much better quality than a lot of pa amps .most of your pa amps in a house seem noisy and probably are, crown is among the cleaner pa amps , qsc is a little better but they cost a bit more too. crown is also a stout robust amplifier , read their warranty and tell me what kind of product they have . transferable , no-fault , crown has a solid amp!

i think pa amps or something from the high end are about your options for that kind of wattage .good luck ;) 
July 24, 2011 2:14:35 AM

some of the kids have proven a car audio amplifier can be hooked up into the house.

with a computer power supply that has enough amperage.. you should be able to get some number close to 600 watts.

this means you have to connect each of the different rails together.
usually they are split at 30 amps each.
if you need it..
you could get a kinetik power cell and connect that between the pc power supply and the amplifier.
that should give you plenty to power the amp.

and sometimes it is necessary when you cant find a 120v amp with enough clean power.
obviously it is going to be more expensive.
if the subwoofer has audio quality, then you would want the benefit of the cleaner amp.

i dont think it is silly at all.
where you get the quality amplifier is key.
how you power the amp is whatever the amp needs.

it is actually a decent trick to get a bit more power for less money.
depends on whether you find the power supply new or used.
depends on whether you find the amp new or used.

because there are some amplifiers that hold claims to be sound quality oriented.
with the right amp.. you can make your favorite sub sound a bit better by making the match.

it boils down to the harmonic distortion percentage.
looking at some new crown amps..
i am seeing 0.5% and 1%
both of those are really high.
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July 24, 2011 2:31:24 AM

well you know if you don't push the amp very hard the chances are you won't get to close to the rated distortion ,and for a subwoofer i am not so sure that it would be as easy to notice that .5-1%, but again that number is at rated power to so if you were to require 600 Watts and purchased an amp rated for 1000 you probably wouldn't get too close to the amps rated output for power or distortion .

i had no idea that a computer power supply had that large of a capacity. which power supplies is it that you would think to be suitable for this purpose.
July 24, 2011 7:25:48 AM

no real way to say specific brands.
a good look at the sticker label on the side of it should tell you how many amps are on the 12 volt rail.

i am not one to have tried it, mainly because i cant afford to play.
i am one to take some notes on what the possibilities are.

and to that i say..
12 volts is sometimes rather low for the amplifier.
depends on whether the amplifier wants only the current.. or if it works/sounds better with the current and some extra voltage.

i know some amps can run at 17 volts.
the 12 volt rails with the 5 volt rails on a computer power supply.....
well i really dont know if touching those two together will be an instant addition, or if there is going to be something in the design that doesnt allow the combination to spread its wings fully.

obviously.. if you had an amp with an undervoltage (or some under power) protection system.
you could try only the 12 volt rails.. and set it up to trip the protection circuit.
then add a 5 volt rail to see if the protection circuit trips early or later or the same.

obviously you could consider the high-end brand names for their low ripple.
that doesnt mean they are going to tolerate an amplifier sucking on the electricity with various amounts of sucking as the song plays.

you could put a filter on the power supply, such as a capacitor, to keep the electricity sucking coming from the capacitor more than the power supply.
i have no idea how the kinetik power cell likes to recharge itself.
if it is a match with the power supply.. then it shouldnt make the power supply angry.

i think the most ideal would be to match the ripple of the power supply to whatever is most healthy for the capacitor or power cell.
it could lead to more power, or longevity of the power cell.
maybe the ripple from the power supply being absorbed by the capacitor or power cell would actually cause the power supply to collapse and die.

these would be my instructions for myself if i had the tools and know-how.

as far as the harmonic distortion numbers go for the subwoofer..
it would be totally dependant on the subwoofers output quality to really know if those numbers could be lower and actually put into good use.

it is true..
if the subwoofer cannot 'express' the difference.. then there really isnt any reason to buy an amp with lower harmonic distortion percentages.

i know the receivers dont tend to distort or hold lower harmonic distortion at lower volume.
it depends on the components on the circuit board.
some of them are completely designed around harmonic distortion percentages.
the distortion doesnt change unless the pieces are over-volted or too much amperage or too if the esr requested is higher than what can be output.
that means the slew rate is going to put a cap or 'lock' to keep the audio data 'bandwidth' at a limit.
it keeps the rest of the pieces happy.. and that means the amp will last for more years.

what i have heard from receivers and the components they use on the circuit board..
it seems like the higher the volume.. the better the frequency response gets.
as if the midrange gets a boost in output AND quality.. and then the treble simply gets a boost in output.

i went to one of the local stores to listen to some receivers.
the guy said the new denon models just arrived and where not hooked up yet.
they were supposed to be all connected sometime that week.
i havent made it back to give them a listen.

i know in the 1990's ... if you kept the amplifier turned down there would be much less distortion.
i know the pieces on the circuit board have changed dramatically since then.
i wouldnt be suprised if some amplifiers actually have a higher distortion at lower volume.. then things clear up before distorting again.

amplifier distortion always has two choices:
1. you raise the volume and you can hear the distortion
2. you raise the volume and things appear to get better until there is a moment when you turn the volume up and the change isnt really noticeable, but the actual stress on the pieces are much much higher then.

it is obvious..
the industry (typically the FCC or whatever government organization that controls final quality) chooses whether or not the problem is audible or if you have to monitor things a different way.

you might have an oscilloscope on your circuit to watch for changes in the waveform.
you might have a voltmeter on the circuit to watch for high voltages that are above the specifications (and safety limits) for the pieces on the circuit board.

and that means the two ways the amplifier dies is like this:
1. the distortion happens and you hear it but ignore it.. and the pieces on the circuit board age much faster because they are being abused.
this would be when the amp is broken and you cant tell what capacitors or resistors are bad.
2. the distortion doesnt really happen much that you can hear it.. or the result sounds better and you have no desire to turn it down.
the pieces then start to break down in a much more rapid chemical cycle.
things like swollen capacitors or burnt resistors would be more common here.
because the chemical inside could dry up.. or it could expand and 'roll-over' until the thing leaks (or the resistor burns).

not all of the pieces use the same chemicals.
you could say some pieces that use the same chemicals, they dont have the same measurement of ingrediants (like 1 cup this and 2 tablespoons this).
there are other pieces that use different chemicals, but if you compare them to the one above.. they are both called 'electrolytic' or whichever other type.
and then again..
some have different measurements of the ingrediants for the same voltage and capacitance rating.

it certainly isnt the exact same across the whole selection.
you might read from a list that is all the same.. or all of them play nice together.
the full list is worse than a jungle.

a car battery with a pc power supply might prove to work too.
it is the same thing.
how does the battery suck on the pc power supply?
is it sucking healthy or harmful?

the amperage from the pc power supply is too much or too less to recharge the battery?
because it might make a battery that is ment to last for 10 years last for only 1 or 2 years.
using the amplifier on the battery could also be what is causing the battery to die early.

the amperage is definitely there.
it is all about what you combine together to stack up the amperage.
more specifically (under powered not mentioned here)..
it is about how healthy those things play together.

and it does matter.
more power and faster delivery means a better sounding amp IF the amp wants the power fast.
more power and slower delivery means a better sounding amp if the amp wants the power to always be there, but slow to release.

you can get a more energetic sound from the setup.. and you could also make it last longer.
the difference between 1-2 years and 10-15 years is really high.

there are plenty of subwoofers out there than can show you the difference between one harmonic distortion percentage and the other.
usually you have to hunt down the speaker as a single speaker without any box or amplifier.

it is kinda like paint.
you can grab a can of whatever shade of color that is already there for you.
you can get some base colors and mix your own custom color.

there are thousands and thousands of things that are completely seperated from eachother.. and it forces you to go out there and grab 'em one by one / piece by piece.

there were hundreds of different kits out there that were like 70% or 90% finished.
but then there was always a part of the kit that was junk or could have been better.
it was supposed to teach you about doing things custom.. or at least piece by piece.

imagine a remote control car kit.
the wireless controller is good.
the frame is durable.
the servo is smooth and responsive.
the shocks are strong enough to drop from 3 or 4ft
the tires are durable.
the motor is slow

that puts pressure on the builder to go out and find a better motor.
maybe the suspension wasnt as stiff as it could have been.. and that means going out to find better springs.

you have to CARE about your toys to know when something is wrong.
and simply because it performs less.. that doesnt make it wrong.
it means you want more from that piece.
you dont have to go out and buy a whole new remote control car because it is slow.
check the voltage ratings and see if you can build a bigger battery pack.
see if you can change the transmission gears to make it go faster.
see if you can find a motor that spins faster.

some people dont try and they get rid of it as they search for something else that is faster.
and when they do find it..
it will probably cost more money than it would to have simply went out and bought a better motor.
there will probably be a whole new list of problems.

another thing with the amplifiers.
those things are supposed to be designed to work at a certain payload.
and that could mean the frequency response isnt as flat at 600 watts as it would be at 1,000 watts.
i'm not a hypocrite, so that means the same could be said for 1,000 watts showing a less than flat frequency response .. and things look much flatter at 600 watts.

you have to CARE to know.
and when you really start to care, you will probably quickly realize you hit a giant wall because the industry wont give you the information you need to know why it was right or why it was wrong.
they want everybody to go to school and get a certificate or degree.
and people find out after they complete the course.. there really wasnt any of the details that answered their questions.

you either have to be lucky enough to find somebody who knows and is willing to talk.
you have to be lucky enough to find somebody who knows and is willing to talk if you pay them some money.

the recession has been horrendous.
i dont expect anybody to walk into an electrical repair shop and start talking about upgrades or how something works.
you might get treated like an unwelcome punk if you do.
they simply play stupid because they dont want to talk to you.

if you really start to get into it..
you could begin looking at torroidal coils and see about connecting the coil to the wall outlet.. then the coil to a rectifier or capacitor bank.. and then from there to the power supply of the amplifier.
this means removing the power supply from the amplifier and feeding it whatever electricity it would normally get from the power supply you removed.

if the rails operate at 20 volts.. you could remove the power supply that bumps up the car voltage to 20 volts.. and then simply feed the amp the 20 volts from the contraption built that plugs into the wall outlet.

it is certainly a transformation.
and people who know enough can sometimes take apart a pc power supply and get rid of the whole 12 volt rail.
then feed the amplifier whatever the voltage is from the step-down transformer assembly.

if what i read is correct..
it always goes like this:
the torroidal coil steps down or steps up the voltage as needed.
then the voltage goes into a rectifier
then the voltage from the rectifier goes into a bank of capacitors to filter it.
anything connected to the capacitors will be about the same voltage that the torroidal coil says it puts out.

then you usually put that voltage directly onto the amplifier's main voltage rail.. and let the amplifier design do its thing.

i dont know how to approximate the amperage though.
because i know you can use as many capacitors as you need after the filter bank to keep the amperage up.
i dont know how much amperage those capacitors need to stay charged.
you have to let the capacitors in the filter bank rest at whatever amount of charge is most efficient.
as long as the charge doesnt reach 100% or go over 100% .. then you are good to go to the next step.
the amplifier will have a filter bank of capacitors too.
those need to stay charged to keep them working most efficiently.
cant get close to 100% or go over 100%
(well you might be able to get close to 100% if you use a power filter for the torroidal coil.. but any spike in electricity could bring the charge up to 100% or over 100% ... and that is why the capacitors need to be high quality to absorb that moment of abuse)

of course everything else needs to be away from 100% or close to it and be high quality enough to absorb any moments of voltage spikes.

once you get the idea down.. you can start picking out your own parts.
that way you can change the amplifier when you need to so it matches whatever speakers are connected.
you could then make a pair of speakers, that didnt sound right, sound much better.
you could also adjust things like the color of the amp or more minor, the timbre.

how good the amp sounds when you are done depends on the pieces you use.
any of the amplifier designs that are commonly used will work.. they have proven that because they really use those designs.
and that means you only need to find the part and spend the money on it.

if you shop around and get familiar enough.. you could be building your own amplifier that sounds way better (or has much more power) than anything in the $500 - $1,000 range.

more practice and your results will be worth more money.

maybe one day i will have the extra money to build an amplifier for like $600 that sounds as good as something in the $8,000 price category.

i know if you get in there and you know what you are doing.. change for the better is possible.
i know sometimes the products we buy already built and designed is not the same.
if you get in there and know what you are doing.. the results wont be any better, and probably less quality than what it was before you started.
that is generally when people take a receiver and try to beef up the wattage output.
it is because the industry level pieces are much better than the consumer available pieces.
that is why electronics recycling has become very important.
all of those good pieces you could use are being taken away by companies or organizations.
maybe they are using those pieces.. and maybe they send those pieces in to use the chemicals inside of them for new pieces.
chances are it is both.
July 25, 2011 12:55:03 AM

you sparked my interest for a moment when you mentioned computer power supplies as a potential way to run a car amp in a house , i happen to be into car audio . but i just don't think there would be enough amperage to do it . and so many of the car amps today are rated at 14.4 volts dc for the standard rating but some are rated at 12 volts as well and usually less wattage at lower voltage .it really is to bad that the home audio industry isn't a bit more like the car audio industry . having separate components like that proves to be ideal some times .

my amp for bass in my suburban happens to be an alpine mrp-m500 , this a mono block rated at 500 watt rms at 2 ohms , running a pair of jl audio 13w1 subs in a sealed box . i recently got a capacitor because this amp was dimming out every light in the truck as well as pegging out the alternator gauge . my suburban come stock with a big alternator , not sure how big probably at least 80 or 100 amps. my point is that bass takes a lot of juice , amperage .

there just aren't too many places a guy can find an amp this size for home theater or home audio use without spending a bundle or compromising big time.

but if there was any area i would be willing to take a chance on a noisy amp sub woofer would be it .
July 25, 2011 8:18:18 AM

i had a kicker kx600.1 running two 12 inch subs.
my stock alternator was 90 amps, and my lights used to dim too.
then i got a 3 farad capacitor and they quit dimming.
the amp was a class D amp though, and they draw less power than a class a/b amp.

those kinetik power cells are supposed to be better than a capacitor.
their smallest one says it has the power of one hundred 1 farad capacitors.

they used to have some neat information on their website talking about how much amperage the power cell would let out at a near dead short.

you just run the amp off of that power cell and let the power supply refill the power cell.

it has faster discharge and recharge than a battery.. but slower than a capacitor.
if you have ever used a light bulb to drain your capacitor like you are supposed to.. you would know how long the capacitor has boost before it needs to be recharged.

when the power supply is pushing like 60 or 90 amps.. you put that power cell on there and the thing is going to be there for you like an extra person helping you lift something heavy.

think about this..
they say an alternator puts out about half of its amperage at idle.
so if the sticker says it is 90 amps.. that means you are putting out roughly 45 amps at idle.

my cars lights didnt dim much at all after i put my foot on the gas and increased the rpm's to start rolling.
only if i had it up about as high as it would go.. then the lights would twinkle again.

and if 3 farads can fix that.. the 600 watt version of the power cell says it is better than one hundred 1 farad capacitors.
SOMETHING should account for the other ninety-seven 1 farad capacitors.

maybe the power cell lasts 100x longer than a 1 farad capacitor.
i think the point is..
if you match the right power cell to the amount of boost you need, the thing isnt supposed to go dead ever.. as long as it is being recharged by an outside source.

if you go to you will see they have a bunch of different sizes.
kinetik isnt the only company selling these 'boosters'

it is amazing to some.. magical to others.
when you can get some of these 'boosters' to pump out 100 amps, and they only need ____ amps to keep them charged up.. you get a boost.

people who talk bad about capacitors in the car audio industry are talking about a situation when there isnt enough capacitors (or the capacitors refuse to re-charge on a stock alternator)

if you can make your system stop dimming the head lights at idle with a stock alternator.. you can run the same equipment in the house on a pc power supply.
depends on what you use to provide the boost.
maybe it is only a power cell.. maybe it is a car battery and a power cell.
it isnt impossible at all to get up to 600 watts area in the house.
you could probably get 1000 watts RMS too.
it depends on the amplifier.

the capacitors inside the amplifier can be just as dumb and stupid when it comes to re-charging.
it is all about TWO ratios:
1. the ratio of how much amperage is needed to keep the capacitors charged up (and how much amperage those capacitors put out when they are charged)
2. how much does the step-up transformer inside the amplifier boost the 12v -14.4v input.

if i had a row of 20 capacitors that put out 100 amps and only needed 20 amps to stay charged up..
that would be better than 20 capacitors that put out 100 amps and need 60 amps to stay charged up.
if the step-up transformer could take 12v - 14.4v and create 60 amps of power, then those 20 capacitors wouldnt really matter.

1,000 watts @ 12 volts = 84 amps
amps are not 100% efficient.. some are 80% efficient, and some are much worse.. like 45% efficient.

for the 80% efficient amplifier.. you need to take 84 amps and add 20%
that equals 100.8 amps

for the 45% efficient amplifier.. you need to add 55%
that equals 130 amps

the most important thing to realize..
the step-up transformer is supposed to take the 12 or 14.4 volts and bump it up.
so really..
you dont know how many volts there is.
lets say the step-up transformer is supposed to boost the amperage enough to keep the capacitors inside fully charged.
that means you go back to the 12v or 14.4v
if the step-up transformer is too small.. then the capacitors wont be fully charged.
that means you have to take however many amps needed to create the watts PLUS how ever many amps needed to keep the capacitors charged.

i really dont think 80 or 100 amps is hard to get in the house if you get the right help.
call me a punk for not actually trying any of the kinetik power cells or bat cap cells.
you can find the bat cap website here:

these things are expensive because they put out a multitude of amps compared to the amount of amps needed to keep them charged.
capacitors work quite the same way, and if you can shop for capacitors.. the same boost can be had (although their output characteristics might prove to be different)

an example..
there is a 25 farad capacitor on the bat cap website.
it says it has a 'rated' input voltage requirement of 16.2 volts
and if you feed it that.. it would output 100 amps
then it goes on to say..
if you feed it 17.1 volts.. it could 'surge' and spew out more than 400 amps.

capacitors are more known for being over-volted and using their 'surge' output.
and then it totally depends on how much amperage the capacitor drinks while it is surging.

the power cells arent supposed to surge much like that at all.
obviously.. these things are supposed to go into the hands of the less responsible.
as a safety precaution.. they deliver their amperage much slower.

that is why the kinetik 600 watt power cell claims to be able to start a v8 engine.
if it was a capacitor that was fully charged..
the moment you hook it up, the electricity would pour out and start blowing fuses.
it would all be gone in a ___ second zap.. (probably no more than 5 - 10 seconds)
the power cell would last long enough to touch the starter and expel its energy to the starter to rotate the engine enough times to fire up the ignition system.

i dont know why people forget about capacitors and how they are supposed to zap out all of their electricity in a blink of an eye.
probably because most pieces of electronics dont require a huge capacitor that does it.
the electronics that do require it use much smaller capacitors.

the stuff in the car audio industry has been designed to be less dangerous.
you touch it and it could stop your heart, and if you live.. you would probably be thirsty from all of the water in your body boiling.

i have seen some videos of capacitors that take 0 gauge (maybe it was bigger)
some thick wire that was about 14ft long..
as soon as that wire touched the positive and negative to create a short, the wire exploded with all of the strands coming unwrapped.
as if the outside layers evaporated and whatever was left in the middle was red hot and unwrapping.

the average car audio person doesnt need something that quick and dangerous in their trunk.
what is available for sale are infant toys compared to what the big industry uses.

if anything..
i would think you connect the pc power supply up to a battery.. then let the 'booster' suck off of the battery to re-charge.
that way the whole system doesnt get low on its charge for hours and hours.
if you use the power cell only.. maybe it only lasts for 1 hour.
if you use the power cell with a car battery.. maybe it would last for 8 hours.
that is when the car battery needs to be one that can handle being drained and recharged often.

kinda like nitrous oxide for engines.
it will give you a performance boost.. until the bottle runs out.
then you have to go get the bottle refilled before the car is fast again.
same thing with batteries and power cells.
you will get a boost until the electrical storage is dead.. and then it needs to be re-charged before you can use it again.

i have been wanting to run a car audio amplifier in the house for a subwoofer too.
the reason i want it is for the 0hz - 20hz range.

my receiver's crossover for the subwoofer stops at 40hz.. that isnt going to work.
the klipsch subwoofer i have (from the promedia 2.1 set) stops at about 30hz.. that isnt going to work.
i need an amp with it's own crossover that will let me stop things at 10hz to rolloff into the 20hz area to match up with my front speakers.
i live in an apartment.. so i dont think i will be getting the subwoofer setup until i move out.
unless i get some cheap subwoofer and build a box for it so that it can run off of 300 watts or less.
and whatever sub it is.. it will have to be one with a fat surround to belch out those low notes.
otherwise i will need two of 'em.

this pc power supply says it will output 100 amps and 115 amps peak:
it also has a single 12 volt rail.. so you dont have to combine any rails to get the peak amperage out of it.
and it will draw 15 amps from the wall outlet.
the circuit breakers are usually designed for 20 amps.
(although i see some are 15 amps.. 20 amps.. 30 amps.. 40 amps.. 100 amps)
i would check my electrical wire specifications and replace the circuit breaker if needed.

here we are talking about an amp for a subwoofer.
what about all of those amps that do 100 - 125 watts per channel for the front or rear speakers?
lots of selection there!