Quote:
Originally posted by Stealth
Yeah but Luc, what about the big class A/B or D for subs debate? Obviously we know the advantage of D class amps is that we get more efficient power, therefore putting less strain on our electrical systems, however, with an A/B set up, we'd be getting "cleaner" power. Can we actually hear the difference? probably not.
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It's all about efficiency. Why there are more upper range speaker types, like coaxial, component, etc., compared to subs? When you are listening to the upper frequency spectrum, say 1000-Hz - up, music reproduction can be very selective and you can really hear the difference between something that's OEM to mid-level to high-level. Our ears are very susceptible to those pitch changes, as there are three parts of the ear: outer, middle, and inner. Each part has its functions. But when you are talking about 200-Hz and below, you don't "hear" the music because the wavelength is long and not much frequency changes. Why do some subs sound louder than others? It's because their construction alters the
amplitude of the waveform, the
frequency doesn't change, if you were comparing subs together. In addition, the box dimension plays a very large part. Thus, we always "feel" the subs, we don't "hear" the subs.
Class A/B amps are full-range type amplifiers, so any speakers (subs, coaxial, component) can be used. Class D amps only serve one purpose, to play a limited range, typically, 200-Hz and below. But when you are talking about efficiency, Class A/B is only 50%, whereas the other 50% is dissipated as
heat, compared to Class D, at least 80% efficient. The bigger the speaker, the more electrical energy is needed to be converted to mechanical energy to move the speaker. Think of how large that electric field is around that magnet!!
There's no law saying that you can't use Class A/B to run subs through a LP filter, but you are wasting the other 90% of amplifier's capabilities. If you were to compare Class A/B and Class D amplifiers to run same subs with the same power, 95% (may be more) of the time, you will not hear a difference. You are getting clean power from either class designs, it just depends which design is more efficient.
In all my work projects, we are always aiming for efficiency, less heat dissipation, lower costs, etc. However, not every factor can be satisfied at one time, there will be compromises.
