Posted by Lew on July 23, 2003 at 07:21:25:
In Reply to: Re: Not recommended? posted by Bob Ratner on July 22, 2003 at 16:51:19:
No argument from me that there is an inherent advantage having the components of your cross-over ahead of the amplifiers, rather than at the speaker. The biggest positive factor there may be the fact that one can use much less capacitance, so therefore higher quality capacitance is a lot cheaper to come by. One could even consider Teflons for that approach, which would be prohibitive in cost and size, if used at the speaker end. FYI, the normal factory components consist of an inductor for the lo-pass filter (or no inductor if you select the +3db option) and an RC network for the hi-pass filter, so 6db/octave on both sides, just as you suggest. However, the "hi-impedance" mod for the hi-pass filter adds a small inductor in parallel with the R in the RC network, thereby resulting in a 12db/octave slope. This allows the -3db point for the toroidal transformer to be moved down a whole octave. The results are stunning in terms of enhanced mid-bass and mid-range musicality, if you are using a tube amplifier, and I am not sure that I would want to give that up in favor of your approach, regardless of the theoretical effects on "phase distortion" related to the 12db/octave slope. (I'd have to audition the results both ways.) This does not mean that bi-amping per se is not a good idea, of course. Oh yes, and you reminded me, I think Dr. West's objection to removal of the hi-pass filter was related to the possibility of DC entering the toroid, not saturation as I earlier wrote. Sounds like you have NOT removed those components after all(?).