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Technical and scientific discussion of amps, cables and other topics.

RE: I find it sort of funny....

Klaus:

Those are the exact type of measurements that have my interest these days. I am using DSP IIR filters with phase correction as an alternative to FIR filters because I have not yet mastered how to get FIR filters summing up the way I would like.

The nice aspect about FIR filters, I suppose, would be that I could (perhaps) be able to incorporate crossover transfer functions and equalisation (amplitude/phase) in the same impulse, thus simplifying my digital chain. I assume you do not worry about the pre-ringing of FIR filters. I have yet to really hear this at work, although it is very easily measured with typical crossover development software tools.

I believe I have mastered the IIR approach using the Thuneau Allocator - it sounds very good - far better than other digital/active approaches that I have tried. These former methods lacked variable Q filters and phase correction despite having eq and time alignment capabilities. The Allocator/Arbitrator combo has filters, eq, time delay and phase correction rolled into one sleek package. It uses "forward/reverse" phase correction that is not dependent on mic location like digital room correction methods are. The opposite phase roll of the acoustic + electrical slopes (combined) are ADDED to the input signal. The actual phase roll then effectively cancels out with that imparted on the signal. All you need to do is match an even order target slope for it to work as designed. This can be done by combining electrical and acoustic slopes and adding in the necessary equalisation (6 or 12db) as required.

Anyways, I can appreciate the changes you are making are subtle because I believe those three systems are all very close to ideal.

What I was referring to, however, are systems that make a complete mess of phase, have no time alignment whatsoever and simply have a reasonably flat frequency response (if that). If comparing a properly dialed in system to what is commonly out there, I find the difference is not the loss of just the veil, but the entirety of her entire garb as well. And naked, I must say, she is all the more tantalizing - the music is.

I have just opened the door, really, on this stuff. I have years of work, study and trial and error ahead of me. Even if I end up putting all this DSP technology into the closet in exchange for passive crossovers and analog sourcesn, the fun of the journey alone even up to now would have been worth the effort.

Cheers,
Presto


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