Distortion vs. excessive power

[GSteg 10+ year member]

what do you guys think blow speakers faster?

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[Randy Savage 5,000+ posts]

Originally posted by GSteg what do you guys think blow speakers faster?

Excessive power AND distortion!!!

 

[Mark_ab 5,000+ posts]

Depends on how much "excessive" means.

 

[MikeofTulsa Moderator]

distortion will never blow a speaker......but im assuming your talking about clipping......which can be interpreted as distortion........excessive power will blow the speakers tho

 

[xin 10+ year member]

I was told time after time again distortion can blow speakers. In the past I have blown 2 subs due to clipping. I have yet to blow a speaker with excessive power. Except the time when I was bored and hooked up a Radio Shack 8" to my Planet Audio 2250D.....//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[denim 5,000+ posts]

think about it, if you send a crappy signal to a sub with enough power it will blow

 

[Savant 10+ year member]

Originally posted by denim think about it, if you send a crappy signal to a sub with enough power it will blow

if you send a CLEAN signal with enough power it will blow..

sending an 'ugly' signal at reasonable power will NOT blow it...

 

[jlaine 10+ year member]

Thermal handling.

That's all it boils down to.

Clipped waves limit stroke, which in turn limit air cooling. Power is power.

 

[MikeofTulsa Moderator]

Originally posted by denim think about it, if you send a crappy signal to a sub with enough power it will blow

agreed however is it the distortion that is blowing the speakers or the extra power.....maybe josh or someone else can get on here and explain it a little better......

I was told time after time again distortion can blow speakers. In the past I have blown 2 subs due to clipping. I have yet to blow a speaker with excessive power.

well in essence clipping causeing the thermal limits of the sub to be exceded due to sending a square signal wave.....which alot of people perceive as distoriton.....

 

[denim 5,000+ posts]

Originally posted by Savant if you send a CLEAN signal with enough power it will blow..

 

sending an 'ugly' signal at reasonable power will NOT blow it...

I did not say resonable power, I said enough

 

[MikeofTulsa Moderator]

Originally posted by jlaine Thermal handling.

 

That's all it boils down to.

 

Clipped waves limit stroke, which in turn limit air cooling. Power is power.

speak of the devil...heh

 

[Alaxan 5,000+ posts]

Power is power. As Jlaine stated it is the thermal handeling of the sub. If it can not handle the heat being produced it blows. Wether that be from a clipped signal or not depends on the situation. In any case it is excessive anything to the subs handeling however that caue it to overheat and in turn blow.

 

[Wonderbread 5,000+ posts]

also, exceeding mechanical limits can mess it up good, lol.

such as playing below tuning frequency...

that can mess a driver up relaly well, lol.

the two ways to blwoa speaker, exceeding thermal limits, and exceeding the mechanical limits...

 

[GSteg 10+ year member]

whoever feels like arguing, come here

http://www.superhonda.com/forum/showthread.php?s=&threadid=101106

they are saying if a speaker can handle 150 watts RMS, and you send it 200 watts of "clean" power, it will not blow. send it 150 watts of "distorted" power and it will blow.//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif jlaine, enlighten me

 

[Wonderbread 5,000+ posts]

"Damaging Woofers:

When a woofer is driven with a high powered amplifier to high levels, there will be a significant amount of current flowing through the voice coil. Since the voice coil has resistance, there is a voltage drop across the speaker's voice coil (which the amplifier appreciates greatly . This means that there may be a great amount of power being dissipated (in the form of heat) in the voice coil. When a speaker is driven with lots of clean power, the cone moves a great deal (in proportion to the output voltage from the amplifier). For speakers with vented pole pieces (or other types of venting), this movement forces a lot of air to flow in the magnetic gap (area where the voice coil rides). When the woofer moves out of the basket, the chamber that's under the dust cap and around the voice coil expands (increases in volume) which pulls cool air into the magnetic gap. When the woofer moves the other direction, the chamber size is reduced and the hot air is forced out of the vent in the pole piece. This air flow cools the voice coil. If a relatively low powered amplifier is driven into clipping (to a full square wave for a lot of people), a relatively large portion of the time, the voltage delivered to the voice coil no longer resembles a sine wave as it would with an unclipped signal. While the amplifier's output is clipped, the voice coil is not being motivated to move as far as it should for the power that's being delivered to it and therefore is likely not being cooled sufficiently (since the speaker is driven by a linear motor, the voltage applied to the voice coil determines how far the voice coil moves from its point of rest). At points a, b, d, e, f and h the voltage is changing causing the voice coil to move in the gap and therefore pull in fresh cool air. At points c and g, the voice coil may still be moving a little due to momentum but may not be moving enough to cool properly. Remember that during the clipped portion of the waveform current is still flowing through the voice coil. Since the displacement of the voice coil (and therefore the airflow around the voice coil) is no longer proportional to the heat being generated, the voice coil can overheat. This excess heat may cause the voice coil former to be physically distorted and/or melt the insulation off of the voice coil wire and/or cause the adhesives to fail (especially if the speaker is rated to handle no more than the power that the amp can produce cleanly). If your speakers are rated (honestly) to handle the maximum 'clean' power that your amplifier can produce, slight clipping isn't generally a problem. Severe clipping is more likely to cause a problem. Severe Clipping (square wave):

It always amazes me when I hear some idiot driving down the road and the audio is clearly distorted (is that possible . Many people drive their amplifiers into what could be called a square wave output (white line below). When an amplifier is pushed that hard, it is actually possible to drive the speaker with twice as much power as the amplifier can cleanly produce into the speaker. As you can see below, the yellow sine wave is the maximum 'clean' output that the amp can produce. When an amplifier is pushed way too hard, the signal will eventually look like the white line. The effective voltage of the white line is ~1.414 x the yellow line. This means the the total power driven into the speaker by the clipped (square wave) signal is double the power delivered by the 'clean' signal (yellow line). This means that the power is double but the cooling of the voice coil will not increase in proportion with the power increase (since the voice coil isn't moving as much as it needs to be for the given power dissipation). This will lead to the voice coil overheating. If we compared the output of a 100 watt amp (the one that's clipping) to a 200 watt amp, the 200 watt amplifier would be able to push the speaker as much as 40% farther than the 100 watt amp (depending on the frequency of the signal). This extra travel (in each direction from its point of rest) would result in added airflow around the voice coil.

Note:

If your speakers are capable of handling significantly more than your amplifier can produce, driving them with a clipped signal will not likely hurt them.

If the speakers can handle 3 or 4 times the power that your amplifier can produce, there's virtually no way to damage your speakers (no matter how clipped the signal is).

If your speakers are rated for the same power handling as your amplifier is capable of producing cleanly, driving them with a clipped signal for extended periods of time may cause speaker damage and/or premature failure.

If your speakers are rated for the same power handling as your amplifier is capable of producing cleanly, driving them with a square wave signal for extended periods of time will likely cause speaker damage.

Thanks Eatel...