nanook
Addicted to Fun and Learning
There are a few interesting points to consider regarding acoustic perception.
I’d like to address two of them:
1) The “distortions” caused by signal delay, as mentioned by @levimax. In a multi-way loudspeaker and the associated (minimum-phase) filters, a broadband sound event does not emerge simultaneously from the participating drivers, but rather sequentially (very clearly visible in the frequently plotted impulse responses; first the steep transient of the tweeter, then the midrange driver, and eventually the bass).
With some musical material, this is audible. Filtering using FIR filters is capable of influencing time delays and amplitude response separately, ensuring that the broadband sound is reproduced in the same temporal sequence as it is contained in the source material.
However, our hearing is surprisingly tolerant of these “incorrect time delays.”
2) Absolute Phase of the Speakers
It is commonly believed that absolute phase is inaudible, meaning it is impossible to distinguish whether both speakers are correctly or incorrectly phased.
It is audible with critical material in the bass (bass drum, plucked bass); the bass sounds crisper, with more punch, when the first half-wave reaches our ear as a pressure rise.
The reason for this apparently lies in the nonlinear behavior of our cochlear mechanics.
I’d like to address two of them:
1) The “distortions” caused by signal delay, as mentioned by @levimax. In a multi-way loudspeaker and the associated (minimum-phase) filters, a broadband sound event does not emerge simultaneously from the participating drivers, but rather sequentially (very clearly visible in the frequently plotted impulse responses; first the steep transient of the tweeter, then the midrange driver, and eventually the bass).
With some musical material, this is audible. Filtering using FIR filters is capable of influencing time delays and amplitude response separately, ensuring that the broadband sound is reproduced in the same temporal sequence as it is contained in the source material.
However, our hearing is surprisingly tolerant of these “incorrect time delays.”
2) Absolute Phase of the Speakers
It is commonly believed that absolute phase is inaudible, meaning it is impossible to distinguish whether both speakers are correctly or incorrectly phased.
It is audible with critical material in the bass (bass drum, plucked bass); the bass sounds crisper, with more punch, when the first half-wave reaches our ear as a pressure rise.
The reason for this apparently lies in the nonlinear behavior of our cochlear mechanics.
