| MagnetoSound wrote |
Like I said (about three posts up) phase shift is subtractive. You do all know what 'notch' means, right?
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Oh yessindeedie... I was confirming/summing up.
| MagnetoSound wrote |
| bob ebeling wrote |
For real phasing the double has to get in front of the origional
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Huh??
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That's 'Tape phasing' also known as 'flanging'.
Time for some definitions here, methinks...
"FLANGING" requires TWO signals, one of which is delayed. The re-combination produces COMB-filtering, which sweeps the mathematically-related notch frequencies up and down together, as the delay time is modulated.
"TAPE PHASING", -also known as "THROUGH-ZERO FLANGING" requires two signals, BOTH of which are delayed. This allows the two delayed signals to "swap" in terms of which 'arrives' first. (I believe that this is what Bob is referring to) This (after re-combining) sweeps the mathematically-related notch frequencies up and down together, as the delay time is modulated, passing through ZERO cancellation (when ALL combs meet at 'infinite' frequency, thus momentarily all 'shooting' outside the audio band, giving a most satisfying result)
"PHASING" as in a guitar "phaser" pedal requires two signals, one of which is PHASE-SHIFTED. -this causes a notch to sweep up and down, but does NOT produce comb-filtering, which is characteristic of flanging or "tape-phasing".
I'm sure that we all know this, but the casual use of the terminology often gets people talking at cross-purposes. This is merely an attempt on my part to clarify.
Through-zero flanging is also sometimes abbreviated to "TZF" by effects builders, incidentally.
Keith
