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Re: Bi-Amping with Atma-Spheres

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Posted by mark on February 2, 2001 at 07:11:05

In Reply to: Re: Bi-Amping with Atma-Spheres posted by Dennis Ketterer on January 31, 2001 at 11:46:34:

This is just opinion, based on actual experience over the years and a smattering of theory - nothing more. The last thing I want to do is stir serious controversy, but perhaps that can't be helped. IMHO, in most all cases, bi-amping isn't necessary and will yield no sonic benefits. There are limited occasions where a given woofer will exhibit very low impedance and our relatively high impedance output amps are not a good match. It's also possible that you're speaker's crossover is so very poor that separate amps and an active crossover can be a real improvement. In your case these scenarios are not in question. The MA-1 can do fine job with your woofers. As unpopular as this sounds, the bi-amping craze is a perfect way to separate you from your money very quickly, while yielding no sonic benefits.

So please let me clarify one thing. Speakers do not have dampening factors. Amplifiers do. It's the ratio of the amps output impedance to the speaker's impedance. But, that's not what I want to talk about and that's not the thrust of Tomcik's article. A woofer is a motor. It must accelerate and decelerate. If your amp has too low an output impedance, it will not allow the motor to move - too much control. If the amp's impedance it too high, the amp won't exercise enough control over the woofer. The former will have thin bass and the later will have mushy bass. If you happen to know your woofer's critical dampening impedance and match that to your amps output impedance, you'll have the best possible bass. Most solid-state amps have output impedance that are too low, resulting in thin bass. Many tubes amps have output impedances that are too high, resulting in flabby bass.

I won't bore you with more theory now. I've oversimplified the concept a good bit. Spend some quiet time with Tomcik's article if you're so inclined. I've only introduced the tip of the iceberg. I hope this helps a bit.

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Kimber Kable

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