subtractive phase technique for crossovers?

[mossie23]

hello,

rhythm in mind, the guy who started the whole 'digital eq myth' thread has on his page some frequency divider plugins which use a technique called subtractive phase. he claims it's 100% transparent and some tests i ran indeed show this.

what he does is for instance lowpass filtering a signal, and mixing a phase inverted copy of the lowpass filtered signal with the unfiltered signal. the first signal yields the signal below the filter frequency, the second signal yields the rest of the signal. combining them gives you the total signal, which can be nulled with the original signal.

this is indeed transparant, and i think it is quite brilliant. so why doesn't every manufacturer use this technique? having a transparent crossover is every marketing department's wet dream. or are there disadvantages with this technique? or advantages to having non-transparent crossovers?

thnx,
michel

[Alexey Lukin]

This is indeed used in several products, like Digital and Hybrid crossovers in Ozone 4. They are transparent.

[mossie23]

Originally Posted by Alexey Lukin

This is indeed used in several products, like Digital and Hybrid crossovers in Ozone 4. They are transparent.

excellent! especially since i own ozone 4.

thnx for clearing that one up.

[bmanic]

Apparently this kind of filtering is transparent, until you start modulating the amplitude of one of the bands. So, it's transparent in it's steady state but not while amplitude has been changed.

Anyhow, I do still seem to prefer this kind of filtering to the typical cross overs.

Cheers!
bManic