YASE employs two strategies for expanding the stereo field without making it overly obvious.

The first is that a transient detector on the Middle channel triggers some increased gain on the Side channel with a duration of about 50 ms. The transient detector uses a thresholded difference between a fast acting peak follower and a slow acting peak follower. The fast follower uses attack and release times of 10 ms, while the slow follower uses attack and release times of 50 ms. The output of the threshold detector is used to trigger an AR Envelope to ensure smooth gain transitions.

The second approach adds some decorrelated Side channel information to the signal by sending the Side channel through a delay of around 50 ms and a high-pass filter to avoid the more correlated lower frequencies. The HPF cutoff is nominally around 200 Hz or so.

There is nothing special about any of these time constants and gain settings. I just winged this with what seemed about correct. There is an Oscilloscope display in the VCS to help with setting the threshold level. A Bypass toggle allows A/B comparisons between dry and wet sounds.

-- DavidMcClain - 25 Aug 2005