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JLTD · 06-01-2005, 01:57 PM

You go find a 50 Watt RMS amp and connect it to a W7 and see what happens. That is if you can find one that can handle 3 ohms and the W7 motor (no chip amps).
Clipping is another issue and has nothing to do with the topic. The topic was #1 and Clipping was #2. I tried to nip it in the bud, but I guess the Myths are too deeply imbedded. So I guess I will go through it.

#2 "Clipping by producing harmonic distortion and/or DC blows speakers"

What is harmonic distortion?
Harmonic distortion is high frequency noise which is a by-product of clipping.

So high frequency noise blows a speaker? How?
The inductance of the voice coils and/or x-overs absorb high frequencies so no problem there.

Does DC blow speakers?
Sure it can. Hook up a speaker directly to a car battery and watch it cook.

But how much DC is coming out of an amp?
Some people seem to think that you can connect a DMM to the outputs of an amp to read DC. The reality is the actual DC content is very small even when driven into clipping. Any reading you would get with a DMM only prove that signal and output devices are not always in sync. The reading is the difference in potential.

So what does kill speakers?
Excessive average power over time.
Clipping dramatically increases average power over time. Amplifiers that are driven into severe clipping will produce average energy like an amp twice it's size. By the way, everyone drives their sytems into clipping....levels of 10dB are not uncommon.

Here is an example of a clipped signal and one that is not:

If the line on the top and bottom of the graph equals the maximum output of an amp, notice how little time the unclipped signal spends at max power. Now look at the clipped signal and notice how much more time we are spending at max power.
Keeping this in mind, lets go to your 50 Watt amp example. I have one connected to my 13W7 which is rated for 1000 Watts. If you're right, this subwoofer will fail because it's connected to too little power.
How?
Even if I railed the hell out of the amp, it would produce lots of harmonic distortion... the voice coil would laugh. It's unlikely that the suspension would be very stressed.
What about heat?
Well, if I did drive the amp into severe clipping and it produced 100 Watts worth of heat energy, the voice coil is rated for 1000 Watts. No problem there either.
Clipping is clipping. Everyone does it and they are not going to stop just because they get bigger amps. What does change is the amount of damage that can be caused (by getting bigger amps).
The only difference in performance between a 13W7-250/1 system and a 13W7-1000/1 system is 6 dB of potential. Both systems can (and will) be driven into clipping by the typical user.

The universe if ruled by the laws of physics not by the laws of man. It is my policy not to argue on the internet so there is a good chance this will be my last post on this topic.

06-01-2005, 01:57 PM	#11 (permalink)
JLTD Registered User iTrader: (0) Join Date: May 2005 Posts: 59 Thanks: 0 Thanked 0 Times in 0 Posts	You go find a 50 Watt RMS amp and connect it to a W7 and see what happens. That is if you can find one that can handle 3 ohms and the W7 motor (no chip amps). Clipping is another issue and has nothing to do with the topic. The topic was #1 and Clipping was #2. I tried to nip it in the bud, but I guess the Myths are too deeply imbedded. So I guess I will go through it. #2 "Clipping by producing harmonic distortion and/or DC blows speakers" What is harmonic distortion? Harmonic distortion is high frequency noise which is a by-product of clipping. So high frequency noise blows a speaker? How? The inductance of the voice coils and/or x-overs absorb high frequencies so no problem there. Does DC blow speakers? Sure it can. Hook up a speaker directly to a car battery and watch it cook. But how much DC is coming out of an amp? Some people seem to think that you can connect a DMM to the outputs of an amp to read DC. The reality is the actual DC content is very small even when driven into clipping. Any reading you would get with a DMM only prove that signal and output devices are not always in sync. The reading is the difference in potential. So what does kill speakers? Excessive average power over time. Clipping dramatically increases average power over time. Amplifiers that are driven into severe clipping will produce average energy like an amp twice it's size. By the way, everyone drives their sytems into clipping....levels of 10dB are not uncommon. Here is an example of a clipped signal and one that is not: If the line on the top and bottom of the graph equals the maximum output of an amp, notice how little time the unclipped signal spends at max power. Now look at the clipped signal and notice how much more time we are spending at max power. Keeping this in mind, lets go to your 50 Watt amp example. I have one connected to my 13W7 which is rated for 1000 Watts. If you're right, this subwoofer will fail because it's connected to too little power. How? Even if I railed the hell out of the amp, it would produce lots of harmonic distortion... the voice coil would laugh. It's unlikely that the suspension would be very stressed. What about heat? Well, if I did drive the amp into severe clipping and it produced 100 Watts worth of heat energy, the voice coil is rated for 1000 Watts. No problem there either. Clipping is clipping. Everyone does it and they are not going to stop just because they get bigger amps. What does change is the amount of damage that can be caused (by getting bigger amps). The only difference in performance between a 13W7-250/1 system and a 13W7-1000/1 system is 6 dB of potential. Both systems can (and will) be driven into clipping by the typical user. The universe if ruled by the laws of physics not by the laws of man. It is my policy not to argue on the internet so there is a good chance this will be my last post on this topic.