Continuously adjustable phase alignment (vs. phase invert)

[mhschmieder]

http://www.uaudio.com/products/software/ibp/index.html

Has anyone used this plug-in, or its hardware equivalent from the same vendor?

I didn't even know this existed, until coming upon it by accident while searching for eight-channel attenuation solutions between pre-amp and A/D (I prefer to avoid the bulk/weight of in-line attenuators, and recording loud metal drummers is challenging my ability to maintain proper headroom and avoid overs).

Anyway, this is what real phase alignment is about, as phase is rarely exactly 180 degrees off, so when we use phase invert functions such as the one in DP, we are just finding the position that is closest to the actual phase offset.

[bongo_x]

I've used the hardware, but only a little.

I've had it explained to me several times, but it hurts my head and goes away. It's an all-pass filter. I can't wrap my head around it, but it's not the same as delaying things.

bb

[mhschmieder]

Cool; that tells me a lot, as I develop all-pass filters in my day job.

[bongo_x]

Great, I've successfully explained something I don't understand.

bb

[mhschmieder]

I'll try to explain it, after reviewing how much of what I do is intellectual property of my employer.

[EMRR]

All pass filters have been used in audio processing since at least the 1940's, so I don't think there's much basic IP with a claim on it anymore.

[mhschmieder]

The Wiki page is quite accessible for those with a small amount of EE background:

http://en.wikipedia.org/wiki/All-pass_filter

Our custom use of All Pass Filters is hinted at in that article.

One use is publicized on our website, so I can mention it here:

Driver Protection Circuitry Low Frequency RMS limiters.

I don't have clearance yet on discussing our other, more recent use.