All-pass filter colorlessness only holds when delay is under the ear’s integration time
Evidence
It is usually assumed that all-pass filters do not introduce colouration in the input sound. However, this assumption is valid from a perceptual point of view only if the delay line is much shorter than the integration time of the ear, which is about 50–100 ms. If this is not the case, the time-domain effects become much more relevant, and the timbre of the incoming signal is significantly affected. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1964
Categorization
Category: Contrarian or Surprising Claims
Related
- An all-pass filter alters phase and timing but not amplitude (similarity 0.86)