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Overpowering subs. 

 

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 Post subject: Overpowering subs.
Posted: Mon Jun 23, 2008 2:46 pm 
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What's the deal with overpowering subs? Is it dangerous to the sub? My mates been running 800 watts RMS through a 400 watt RMS 1000 watt peak 12" Pioneer sub and it puts out more bass than 2 12" type R's running at their RMS power of 500.

My system is SQ so I'm not interested in huge bass but I am curious as to how they run at that.

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Tyler

 

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Posted: Mon Jun 23, 2008 2:50 pm 
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What do you mean? Having too much power running through a individual sub? i think there is a fine line between too much and not enough.

but i have forgotten most of the sub / sound related s**t i used to know back when i was 18 lapping the streets

 

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Posted: Mon Jun 23, 2008 2:58 pm 
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Maybe it's just me, but I can't really see a Pioneer coping with twice it's RMS for very long... You sure your mates got the numbers right?
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Posted: Mon Jun 23, 2008 3:01 pm 
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Well as I see it, the sub isn't overpowered if the amp is running at 800W RMS since the sub has a peak of 1000W. If he was running 800W RMS into a 500W Peak, then I'd be worried about overheating and killing the sub.

I'd be more concerned about under powering subs since the amp stresses more to keep up with demand.

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Posted: Mon Jun 23, 2008 3:09 pm 
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timmay_73 wrote:
Maybe it's just me, but I can't really see a Pioneer coping with twice it's RMS for very long... You sure your mates got the numbers right?


I don't know. I have 2 x Pioneer free-air subs. both are rated at 250W RMS with peak power of 500W. They are running in parallel at 2ohm powered by a 800W RMS 2ohm stable amplifier...I've pushed my subs a fair bit...now I am only running the amp at half of its potential until i can afford better ones.

Pioneer subs can handle a fair bit of power.

phong =P~

 

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Posted: Mon Jun 23, 2008 3:20 pm 
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You see, just because the amp is rated at 800rms @ 2ohms it does not mean that it is always running at that.
It will only put out that much power on a certain note, at a certain volume level, with a certain gains tuning, with a certain input voltage (normally 13.8 or 14.4v), and probably more things.


All things being equal, his sub is probably only receiving 400-600rms when its being cranked.
It also depends on the they size and design of the box. A ported box will deliver louder bass and achieve a higher db reading than a sealed one, but will generally not sound as musical.
Having a custom built box specific to the specs of the sub also has a massive impact on how the sound and how low they can go. Most prefab boxes are way too small to get any decent output.


I'm running 1000rms into my 750rms (1500w max) Clarion from my Alpine amp. It handles it fine, doesnt stink up, or barely even heat up.

I would happily run 1500rms into my 750rms sub, as long as I set the gains correctly and had the rest of the system correctly tuned.

Another plus side to 'overpowering' subs is that if you have the amp properly tuned it will not be working anywhere near as hard as a smaller amp.

 

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Posted: Mon Jun 23, 2008 6:59 pm 
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^ agreed.

There's lots of variables to determine how much power a sub can take, vs. how loud it is etc.

 

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Posted: Wed Jun 25, 2008 2:42 pm 
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Ahh okay. Well thanks for the explainations. I assumed that the peak was only sustainable in short bursts and running 700-800rms @2ohms would surely overheat but he's been doing it for a while so obviously not.

What about life span of the sub? Shorten it at all?

 

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Posted: Wed Jun 25, 2008 3:24 pm 
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Feeding a sub a lot of good 'clean' power wont shorten its lifespan much at all. Sending a sub a 'clipped' signal is far more damaging, even if you match the RMS of the amp to the sub.

 

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Posted: Wed Jun 25, 2008 10:03 pm 
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How do you avoid sending clipped signals?

 

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Wheels and lowering to come next, then exhaust.

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Posted: Wed Jun 25, 2008 10:27 pm 
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Don't turn the gain on the amp to maximum. Cause when it is, and you turn the head unit up, the amp is trying to amplify an already 'big' signal. Doing so can exceed the amps capabilities, leading to clipped signals - effectively DC current than quickly heats up the voice coils in speakers, leading to melting/burning them.

Overworking the amp (resulting in clipped signal) is more dangerous to speakers than overpowering the speakers with a clean signal.

I always overspec amps, so they can be run at mid range gain, so no possibility of them clipping.

 

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Posted: Sat Jun 28, 2008 12:22 am 
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Posted: Sat Jun 28, 2008 1:04 am 
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^ good point (what I was getting at), but rather useless for those not 'into' sound as it's not well explained (IMHO).


This one explains clipping (and pics!) http://en.wikipedia.org/wiki/Clipping_(audio)

The flat parts of the signal is what rapidly heats the voice coils, possibly leading to failure of the speaker/sub.

A more powerful amp (or the same one with the gain turned down a bit), would have the headroom, to cope with the larger signal (wouldn't clip).

Hint: the gain control on an amp, is NOT a volume knob (it'd be labelled volume if it was). It's purpose is to tune the amount of amplification the amp does to the input signal. It is optimally set so that the maximum input signal recevied from the head unit (i.e. it's volume up to max, and a CD playing a loud track) won't result in clipping of the amps output.

Generally once found, you turn it back a smidge to provide more headroom for when things really get heavy, i.e. low battery voltage, hot amp components etc. which can induce clipping at a lower level.

 

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Posted: Sat Jun 28, 2008 2:41 pm 
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yeah subs can take a fair bit as long as its clean power...i have an 863wrms at birthsheet amp running rated 500wrms sub...sounds better and gain can be much lower

depends on what amp your mate has too, not all amps put out their rated power....

 

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