Help choosing sub

[sqcomp]

Originally Posted by Damo

Its a silly statement to make though. We dont listen to power at all, and power is no guarantee of volume.

If my calculations are correct, speakers with a sensitivity rating of 88db would be outputting around 107dB at 100W (which is still very loud), whereas speakers rated at 91dB would be putting out that same volume at only around 43W.

You are absolutely right! Power is not a guarantee of volume. Look at the statement again, we're in agreement. Sensitivity is not an indicator of loudness either. They are both contributing factors to the outcome of the signal. The enclosure will change the sensitivity of the woofer as well. See the difference in sealed versus ported.

...and yes, you don't listen to power, you listen to signal. The statement of fact is really saying that one isn't going to use all that available power if the signal chain is more efficient. Who cares how much power you use? Don't we care about the cleanliness of the signal, how much distortion is being pumped through it?

As for underpowering a woofer...What happens when someone with a 400 Watt amplifier powers a woofer that can only handle 500 Watts? Nothing...unless the person is STUPID with the juice. He's sitting at a light in his 97 Civic Hatch with a crappy prefab bandpass box and some 1000 Watt amplifier on a stock charging system trying to outduel some SUV with 592578738 subwoofers in the back (yeah I know, that was silly, but the point is there)? He's going to crank it up past what the amplifier can offer. The amplifier is setup incorrectly 95% of the time anyway...he clips the signal. He doesn't give two $hits...he's dB dragging!

Taln can tell us what happens when a signal clips. He can also tell us how much output happens. I can tell you what happens to your batteries and stock alternator. We can both tell you what happens to the woofer on a clipped signal.

I will venture to say that it isn't the clipping that kills the woofer. When that square wave signal stops the woofer at the top and bottom of it's throw...what happens? The woofer stops moving at the top and bottom of the wave. It's still being powered though. Those voice coils rely on cool air to keep from frying. Hmmm...what happens to an air cooled machine when it's worked hard and not cooled?

Heat is what kills our woofers. Clipping is the cause...heat is the effect.

I digress, properly level setting your signal chain will assure that nothing in that chain will produce a potentially damaging square waveform. You become more efficient. You can rail on all day (if your charging system is adequate) and not worry.

AM and Damo,

I'm going to disagree with your statement on how smaller woofers tend to be more tight simply because they're smaller. I'd refer to the enclosure to make the woofer more accurate(tight) or being able to provide more low end extension(boominess). The enclosure will dictate the performance of the woofer. We've all heard plenty of woofers in our time. What exactly about a woofer tells you that it's going to sound good? The specs? Seriously? We all know that one can polish a turd. We've seen it.

Why exactly can I not use a 15" woofer for example to play the 1812 overature? Why? Especially when there's a recording of it with real carbide cannons and huge kettle drums! That sounds like big woofer territory to me all the way....low frequency. Even then, one can make an enclosure that will have the 12" woofer playing as low (to a point).