posted 10 November 2002 23:39            

stereo_field_correction.kym

It works as a pair (left/right) of broadband temporal dispersion controls. The input signal is sent through a channel splitter and then into identical parallel signal paths, the output of which is recombined to form a modified stereo field.

Each signal path splits the incoming channel into three spectral regions: Bass, sans-Bass, and high treble (typ. 1500+ Hz). The high treble region is selected by the !Cutoff parameter. This high treble signal is then delayed by some small fraction of 50 ms (typically 5 ms), and then boosted or attenuated, before being recombined with the sans-Bass signal.

Comb filtering will be present in the recombined signal, but at such high frequencies it will be largely unnoticed. Instead the effect is to add some high frequency definition to voices and instruments.

The recombined high-treble and sans-Bass signals are then delayed by the same amount before being recombined with a boosted Bass signal. In this case the bass is effectively advanced in time before being recombined with the rest of the signal. Comb filtering is minimized by separating the bass and sans-bass signals by means of complementary low-pass and high-pass filters.

I have read that the recording process can degrade the sound of a performance by causing progressive delays in the bass signal. I don't know if that is a true statement, but this Sound attempts to correct that effect, as well as boosting the bass level. Be sure to lower the input gain when you apply large amounts of bass boost, because most of the energy in the signal will be in the bass, and you will end up overloading the Kyma output drivers.

This sure sounds pretty!

- DM