Under-Powering a sub? Dangerous?

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Under-Powering a sub? Dangerous?

Postby Zyros » Wed Dec 28, 2005 9:30 pm

Hey, i have a pioneer 400 rms Sub (100 W max, 12" ) and my amp is not big enough to power it fully, (giving out 150 rms if that to the sub )

If i continue running the sub? (brand new) on this amp, will it damage it at all? As i do plan to get a new one in january..
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Postby 86_rolla » Wed Dec 28, 2005 10:22 pm

Im no expert but isnt there like a minmum rquired input rating on the box or something???? And i THINK underpowering is worse than overpowering but dont relie on this adivce, not 100%
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Postby gt-trainer » Wed Dec 28, 2005 10:31 pm

Just don't drive it to clipping point and you should be sweet. :D Oh and get more power :lol:
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Postby igor » Wed Dec 28, 2005 10:38 pm

gt-trainer wrote:Just don't drive it to clipping point and you should be sweet. :D Oh and get more power :lol:


^^ What he said. :)

I have run a pair of 150W rms subs off 88W rms for a long time, and the subs still work. :)
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Postby Zyros » Wed Dec 28, 2005 11:02 pm

gt-trainer wrote:Just don't drive it to clipping point and you should be sweet. :D Oh and get more power :lol:


What do you mean by clipping point?

The sub seems to work fine.. yea, i need more power.. anyone know of any with a budget of $200 :D
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Postby deaf_rattle » Wed Dec 28, 2005 11:10 pm

underpowering? i have heard that from a few people but i think its a load of shite.

if it was bad, wouldnt having the music turned down be underpowering the speakers?

as long as you arent giving the speakers/sub distortion/clipping she'll be right

providing your sub can handle what you are giving it.

but from my experience subs can handle more than the specs on the box, as long as you treat them right.
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Postby Fenix » Thu Dec 29, 2005 5:23 am

Zyros wrote:
gt-trainer wrote:Just don't drive it to clipping point and you should be sweet. :D Oh and get more power :lol:


What do you mean by clipping point?

The sub seems to work fine.. yea, i need more power.. anyone know of any with a budget of $200 :D


"Clipping point" is where the amp is told to provide more power than it's capable of. This is more an issue about the source unit (headunit in most cases, or processor/eq in others) and the amp than the speakers themselves.


Let's say your source unit has 4V preouts, and your amp has an adjustable gain from 0.2V to 16V. When your headunit is playing at max volume, it's sound signal is +4V. Hence, you want to set your gain for 4V, so when the headunit is saying "100%", the amp is hearing "100%". Clipping occours when the gain on the amp is set for a value below the preamp level, i.e. 4V preouts on the h/u and the amp set for 0.5V input. When this happens, the amp sends a clipped signal to the speaker.

A clipped signal is the equivilant of flooring your car for 100 meters, then slamming the breaks, then as soon as you come to a stop flooring it, and doing so untill your car dies.

An unclipped signal is like accelerating gradually over 50 meters, then slowing down over the next 50, then accelerating over the next 50 and so on. It's a nicer ride, and your car doesn't explode.


People's subs dieing due to underpower happen when people set the gain really low to get "louder" sound. I.e., the input signal is at 100% (and usually over 100% in the clipping area) more of the time. If your sub really doesn't sound loud enough when your amp is running at 100%, then get a new amp. Maxing the gain will just end up meaning you have to buy a new sub as well.
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Postby vvega » Thu Dec 29, 2005 6:57 pm

hmmm
were i come from clipping is sending a square wave to ya speakers
witch in essance is a dc signal......
dc kills speakers very fast

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Postby Zyros » Thu Dec 29, 2005 10:00 pm

So, to sum this up.. should i take my sub out untill i get a bigger amp?
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Postby DeeCee » Thu Dec 29, 2005 10:39 pm

no - just don't set your gains on your current amplifier high and dont' clip your sub by trying to go loud
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Postby vvega » Thu Dec 29, 2005 10:41 pm

i was jusr defining what clipping wise :D
not giving advice :D

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Postby Zyros » Thu Dec 29, 2005 11:41 pm

Okay, yea, i turned my sub gainz up when i got it.. only had it in for a few dayz tho.. shouldnt of done any damage.. ill put it back down..
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Postby Alex B » Thu Dec 29, 2005 11:43 pm

evey one loves there gain controls dont they :lol:
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Postby Fenix » Fri Dec 30, 2005 5:31 pm

vvega, effectively you're right about the square wave. It's not "entirely true", but it's close enough. I just thought cars would be easier than explaining waves. :P

A clipped wave resembled a square wave because most of it (i.e. 7/8ths from my example) is cut off so there's only a very small amount of rounding, then it just plataeus till the input gives it a signal in-range again. The effect is slamming things around till they break.

Zyros, try and find out what the preouts on your headunit are, and set the gains appropriately. Should be around 2-4V depending on the model/brand. But yeah, if that's not loud enough, look for a more suitable amp because really driving your amp into clipping isn't going to make your system any louder, it's just going to make your system run as loud for more of the time, and end up destroying your sub. Oh yeah, and remember, the LOWER the gain is set, the MORE sensitive it is! 0.2V is BAD.
Last edited by Fenix on Fri Dec 30, 2005 5:40 pm, edited 1 time in total.
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Postby vvega » Fri Dec 30, 2005 5:38 pm

Fenix wrote:vvega, effectively you're right about the square wave. It's not "entirely true", but it's close enough. I just thought cars would be easier than explaining waves. :P

A clipped wave resembled a square wave because most of it (i.e. 7/8ths from my example) is cut off so there's only a very small amount of rounding, then it just plataeus till the input gives it a signal in-range again. The effect is slamming things around till they break.


i was making it very simple
the effect is a build up heat cause by the length of time the voltage is dc for

even 10watts of square wave input will cook most speakers and it will not be slamming anything around

having a distored or clipped input will also kill your speakers ..... so a overdriven amp is not the only reason for clipped signals :D

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Postby Fenix » Fri Dec 30, 2005 5:42 pm

You'd hope the source unit was capable of providing a non-clipped signal. >.> That's a scary thought.
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Postby BZG Wagon » Fri Dec 30, 2005 7:11 pm

I would be more worried about damaging the amp than the sub?!?
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Postby vvega » Fri Dec 30, 2005 7:21 pm

Fenix wrote:You'd hope the source unit was capable of providing a non-clipped signal. >.> That's a scary thought.


most preamps are more than capable of creating a clipped signal
mp'3 back in the old days used to have a certain amount of distortion "encoded" into them
as well as the base signal often been higher than most prerecored cd's
it was not uncomon when mp3 players first cam out in cars for speakers to be blown at relatively low levels and quite often it seamed to be the left side that suffered the most
thnakfull peaple have lernt that 128k (barrel scrappings)is the absolute lowest encoding you should allowed to be played back though any stereo gear you care about
and that 192k+ is really what you should be looking to keep as your base for music colection :D

personally im of the opinion that only genuine wave format disc's shoul be used on hi fidelity equipment but there are very few car stereo's in the country that would hold a candle to a proper home hifi setup(30k+ system)
and most of owners of the top gear will only use records .........

just some observations made on past experiance :)

your personal experiances may differ from mine :D but do feel free to express them


whoohoo what a ramble
man it must be close to the end of the year :d

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