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View Full Version : how many watts for subwoofers is sufficient?



Drache713
06-28-2005, 08:34 AM
Hey guys, I have 2 12" kenwood subs, and they are each rated at 400 watts rms each, 4 ohms. Right now I have em hooked up to a 2 channel pioneer amp giving each sub 75 watts. I would wire them in to parallel and bridge the amp but my amp isn't 2 ohm stable. Anyways, I was just curious for your guy's input on how many watts YOU think is enough. Like, I want more bass, but I don't want it to be super frickin gut tearing loud, I just need to know how many watts you guys consider to be enough ( i don't think i really need a 1000 or 1600 watta mp...). Also, as a side note, I've heard that it's beter to run your regular speakers off of an amp and not the deck's power, may i ask why this is? I found an old 4 channel 25 watts @ 4 ohms amp i might use for this purpose.

SteveDX89
06-28-2005, 09:12 AM
I quit.

88accordalltheway
06-28-2005, 10:18 AM
get a kenwood 800 or 900 watt amp. I have last years 800 watt model, and it slams. I dunno about kenwood amps, they just seem to have really good rms power for their price.
good luck.

Vanilla Sky
06-28-2005, 11:04 AM
get an amp that puts aout about 400 watts RMS each channel and turn the gain down to about 3/4.

as for amping the full range speakers, it's mostly becuase the internal amps in your deck has almost no headroom, and is very low wattage to begin with. most are rated at 15-25 watts RMS, with a peak of 30-50 peak per channel. consider that an external amp requires at least an 8 guage power wire at those levels, what makes you think the deck can actually put that much power out with the stock power leads?

Drache713
06-28-2005, 01:29 PM
800-900 watts? 400 watts each channel? damn, do i want to have heavy bass or rattle my car into a million pieces? :kekeke:

Vanilla Sky
06-28-2005, 01:37 PM
800 watts is more than enough.

oh, and you asked, i answered...

88accordalltheway
06-28-2005, 02:10 PM
800-900 watts? 400 watts each channel? damn, do i want to have heavy bass or rattle my car into a million pieces? :kekeke:
then why are you wasting your trunk space? thats what two 12"s are suppost to do. If you only want a little bit of bass, go with only one 12", possibly one 10". If your not going to use the potiential of the speakers(or even close to it), whats the point in having them? For show?

sorry if i sound like an ass, but it bugs me when i see people running two 12s or 10 and a 100w amp.

halxi
06-28-2005, 03:26 PM
besides, your subs are probably closed to shot as of now.

This is something i recently learned in amp/sub stuff while i was in missouri last week, if you have an amp that doesnt efficiently power your subs, youll fry one of your coils open. Why you ask? Lower wattage amps put out more DC power, bad for subs, you dont notice it when youre listening to music because of the changing notes but, the sub sticks at max excursion in (i cant remember the exact term he used) for a split second thus causing damage to your coil. On solid note songs for competitions you can hear it sticking, and its a horrid sound. The guy was showing us with my friends toasted Diamond 10, rather interesting.

88accordalltheway
06-28-2005, 03:40 PM
besides, your subs are probably closed to shot as of now.

This is something i recently learned in amp/sub stuff while i was in missouri last week, if you have an amp that doesnt efficiently power your subs, youll fry one of your coils open. Why you ask? Lower wattage amps put out more DC power, bad for subs, you dont notice it when youre listening to music because of the changing notes but, the sub sticks at max excursion in (i cant remember the exact term he used) for a split second thus causing damage to your coil. On solid note songs for competitions you can hear it sticking, and its a horrid sound. The guy was showing us with my friends toasted Diamond 10, rather interesting.
:ugh: :huh:

Vanilla Sky
06-28-2005, 05:05 PM
halxi, please try to keep the partial misinformation down to a minimum. you are explaining a very real situation. the only way you are going to destroy a good sub with a clipped signal is if that's all the driver ever sees. i'm willing to bet that the sub saw the DC rail about 10% of the time. when the driver sees the DC rails that much, they don't cool enough and overheat, which is what causes most driver failures.

halxi
06-28-2005, 05:13 PM
i couldnt remember exactly what he said it was, and i tried my best to explain it. Sorry

Vanilla Sky
06-28-2005, 05:15 PM
hehe, that's good, at least you tried.

if you want to learn more about it, there's a sticky here. "get some education, people" at the top of the audio subforum. links to probably the best audio site on the internet. that's where i learned what i have.

halxi
06-28-2005, 05:55 PM
yea, for the most part i know what im talking about. Sometimes i kind of stumble around the centeral idea and miss the point though :uh:

Hash_man_Se_i
06-28-2005, 08:12 PM
z :uh: :pc: :slap:

88accordhb
06-28-2005, 09:04 PM
I quit.
hahahaha!!! classical.

Drache713
06-29-2005, 04:56 PM
okay then, well do you guys think that I should move only to a single 12" sub then instead of 2? My friend's dad is a sound engineer and told me basiclly that since bass is omnidirectional, you really only need one sub, which makes sense because for stereo imaging you have speakers on each side of the car, but especially with low bass frequencies, bass is bass, doesn't really matter where it comes from. I know having two 12" subs has it's purpose, but i'm not looking to win SPL competitions here, and I don't want the bass to drown out the rest of the music, I just want a nice deep lower thumping sound, enough to still kick your ass but not enough to go deaf or have a bowel movement. So perhaps I should just go to one 12" sub and get a 300-400 watt amp perhaps?

hytro
07-03-2005, 12:20 PM
if you have 2 subs that means more air space your moving so infact its sometimes better to have 2 subs than one but if you tight on money one sub can still provide some serious bass when joined with the right amp but if your still looking for an amp that can push your subs i recommend going with the new kenwood monoblock amp 500 watts rms @ 4 ohms and 850 watts @ 2 ohms so thats plenty of power for your subs here is the link if you want to see the amp kenwood (http://www.bestbuy.com/site/olspage.jsp?navLevel=5&type=category&navHistory=cat00000%2Bcat03000%2Bcat03064%2Bcat030 84&id=cat03087)
2 channel amps are great but they dont realy provided the power that mono blocks give out and some are even 1 ohm stable so it realy also depends if you have the cash to spend it on but if you still cant decide its best you go to crutchfield they have a good selection of amps here is the link in case your intrested crutchfield (http://www.crutchfield.com/)

POS carb
07-07-2005, 05:17 PM
you should always have more power than you need. If you like the volume of 200 watts you should still get a 300 watt amp b/c amps sound like shit when they are reaching their peaks and can cause speaker and/or amp damage if driven past these limits. This is also why people recommend getting an amp for your surround speakers but another plus is that you can cut the bass notes from the little speakers and they can play louder & cleaner.

I quit too.

bobafett
07-07-2005, 05:36 PM
hahahaha!!! classical.

now that is classic

i quit as well. ;-)

HaShfIeNd
07-22-2005, 01:00 PM
hMMM.

i have 2 subs. powerd at lower power. i've said this before.. but.

i have two kicker comp series speakers. they are like 300 rms each.. i have a 150 watt rms phoenix gold octane r 2 channel amp powering them. its somewhere about 75 watts a piece but i dont believe they are hooked up paralell @ 2ohms. but anyway.. those things rattle the shit out of my car and hit hard.. the bass is nice.. anyways.. my plans are to get a mono amp.. probably a phoenix gold the xenon series 400 wattrms.. and then use my 2 channel phoenix gold amp to get some crossover and component speakers for that.. anyways..

those kenwood amps are pretty decent.. but i like quality over quanitity, kenwoods actually not that bad.. definately worse.. but you dont need a ton of power to have a great sounding system.

and listening to the difference between only having one sub, compared to having them both pushing.. has a big difference.

oh yeah, and your deck wrms of course is going to be low that 4 channel 25watt is that peak? lol or rms.. hope its not peak i bet your deck does more than that.. anyway if your going to use an amp on your inside speakers which is a very nice thing to do, you had better get some nice speakers that are rated for whatever your pushing them at.. yah know? basically the same thing for your sub. for example i guess

my amp is 2 channel can handle 2 ohms at like 50 watts and 75 watt peak.. so i'll probably get some 6x9's that around around 50 watts or whatever 2 ohm speakers.. and hookthem up to my octane-r amp and that will sound a lot better than my 25wrms 6x9 walmart speakers i'm sure! (which poop out on me WAY WAY WAY WAY before anything else does imagine that)
anyways... get a plan stan, just run them offa your deck until you figureout what you wanna do..

and hmm
i think my friend had one 12" pioneer 500rms speaker that he had hooked up to that nice 800w kenwood amp.. that thing mooooooooooooooved.. hit really hard to sounded great.. but that thing was moving daaamn.

but i like my kickers :D

gp02a0083
07-24-2005, 06:20 PM
is it annoying that i got a 1200 watt LA sound amp with 2 12' subs that fit nicely into my hatch

87DXHatch
07-30-2005, 09:08 AM
Hey guys, I have 2 12" kenwood subs, and they are each rated at 400 watts rms each, 4 ohms. Right now I have em hooked up to a 2 channel pioneer amp giving each sub 75 watts. I would wire them in to parallel and bridge the amp but my amp isn't 2 ohm stable. Anyways, I was just curious for your guy's input on how many watts YOU think is enough. Like, I want more bass, but I don't want it to be super frickin gut tearing loud, I just need to know how many watts you guys consider to be enough ( i don't think i really need a 1000 or 1600 watta mp...). Also, as a side note, I've heard that it's beter to run your regular speakers off of an amp and not the deck's power, may i ask why this is? I found an old 4 channel 25 watts @ 4 ohms amp i might use for this purpose.
Hooookay... where do I start...

First, I would be willing to bet you're clipping the hell out of the amp, due to the small size of it. You generally want the most power you can get, if you can afford it. When your amp isn't big enough to suitably push your speakers/subs, you'll end up turning the gains up too high on it, causing distortion and other nasty stuff.

"How many watts to run" is a question that by itself is worthless. What sort of enclosure do you have the subs in? That will make a world of difference. I could build an enclosure that, off the 75 watts you're giving your subs, could annihilate a system with 300 watts going to each sub.

With subwoofers, there are three things that you have to make compromises between: Low-end extension, efficiency, and small box size. You can only have two of those at the most. The "400 watt" rating on your subs is going to be a THERMAL rating. That is the amount of power the coils can see for an extended period of time before they melt, blowing the sub. The MECHANICAL limits of the sub can vary greatly, depending on the box. Like I mentioned before, I could build a box that could send the subs to their MECHANICAL limits at 75 watts, eliminating the need for a more powerful amp... it would just be a huge-ass box :-P

Right now I have ~100 watts RMS going to each tweeter, and ~110 watts RMS going to each woofer in my Paseo. Are they actually seeing that much power any of the time? No. It's headroom. I don't have to worry about clipping my outputs and damaging my speakers by overpowering them because my gains are damn near minimized.


This is something i recently learned in amp/sub stuff while i was in missouri last week, if you have an amp that doesnt efficiently power your subs, youll fry one of your coils open. Why you ask? Lower wattage amps put out more DC power, bad for subs, you dont notice it when youre listening to music because of the changing notes but, the sub sticks at max excursion in (i cant remember the exact term he used) for a split second thus causing damage to your coil. On solid note songs for competitions you can hear it sticking, and its a horrid sound. The guy was showing us with my friends toasted Diamond 10, rather interesting.

Like Vanilla said (Hi!), it's mis-information like this that makes me sad. Putting DC on a sub won't do ANYTHING to it, unless you're putting it with more wattage than the coils can handle, or pushing the suspension beyond its limits. If you have a 400 watt RMS sub, and are giving it 75 watts RMS, but are clipping it to MAXIMUM, you're only putting out 150 watts to it, which will not do ANYTHING to coils, and will only damage the sub if you're pushing it beyond its mechanical limits.

The only time "underpowering" a sub or speaker gets you into trouble is if the amp is already putting out nearly the drivers RMS (such as a 250 watt RMS sub getting 200 watts RMS). Then when you overdrive the amp, and clip it, you're giving the driver way more power than it should be getting.

crazykamper
06-20-2006, 07:43 AM
sorry to bring back from dead,

so if i am underpowering the sub, i am only ruining the amp???
cause in my bros truck (2 speakers, 1 8'sub w/ tweeter...) he was runnin it all under the headunit, no amps, nuthin. would that be killin the head unit, or the sub??? (cause im taking his sub, speakers, and deck into my car....)

87DXHatch
06-20-2006, 08:52 AM
sorry to bring back from dead,

so if i am underpowering the sub, i am only ruining the amp???
cause in my bros truck (2 speakers, 1 8'sub w/ tweeter...) he was runnin it all under the headunit, no amps, nuthin. would that be killin the head unit, or the sub??? (cause im taking his sub, speakers, and deck into my car....)

If you're underpowering the sub, you're not necessary ruining anything. If you're underpowering the sub, but overdriving the amp to compensate for the lack of volume, then you have the potential to damage the amp, depending on the quality of the amp.

I don't think his set up would last very long as you described, unless the speakers, sub and (???) tweeter were all very efficient, like one of those $20 "Everything in one box" crap-tastic setups you can buy at Checker or NAPA.

crazykamper
06-20-2006, 09:50 AM
i took the sub / tweeter out a few weeks ago, cause he is getting an ENTIRE system for his truck, new speakers, deck, subs, everything, so im taking all of his old stuff, and throwin it in my 3g, (i already have speakers, but im just gonna upgrade, and put the extra speakers in box and throw them in car too! lol.