Re: ToneShiftEQ v0.3.0 — First public relea se

Il 04/07/26 19:36, Robin Gareus ha scritto:
> On 2026-07-04 1:04 PM, Fons Adriaensen wrote:
>> On a more philosophical note: almost all the math theory that
>> describes physical processes (e.g. differential equations)
>> requires complex numbers. In other words, numbers that combine
>> amplitude and phase into a single concept. There is in general
>> no reason to assume that any process would modify only one of
>> them and leave the other alone when not unnaturally contrived
>> to do so.
> 
> Except the human ear is does not perceive phase. Radio stations use[d] 
> all-pass filters to shift peaks so they could add more gain before 
> clipping. A few years ago I wrote a phase-rotate plugin [1] to 
> experiment with this. I found if fascinating to rotate the phase of a 
> square-wave, which results in vastly different waveform shapes without 
> my ear being able to hear any difference whatsoever.

I used to think that we don't perceive phase as well but, no, that's not 
true. Two examples: 1. Feed a Moog-like filter with a sawtooth wave and 
try again phase-inverting it. 2. Take a static waveform of your choice 
with a limited number of predominant harmonics and then resynthesize it 
keeping the magnitudes and randomizing the phases - most of the times 
you won't perceive a difference but sometimes you'll do.

Anyway, dynamic range reduction through allpass filters was also studied 
in [1] and [2].

Stefano D'Angelo

[1] J. Parker, V. Valimaki, "Linear Dynamic Range Reduction of Musical 
Audio Using an Allpass Filter Chain", 
https://ieeexplore.ieee.org/document/6516022