posted 31 March 2001 02:40            

triglpf.kym

I got my first real analog filter today and it inspired the attached patch...

This is a stereo, resonant, low-pass filter that is triggered by incoming audio from a sidechain fed through a bandpass filter. The trigger is sampled by a sample & hold module that is retriggerable at some BPM rate. The sample and hold then triggers (or not) an ADSR envelope that controls the left and right filters.

The neat thing about this version (although, I wouldn't be too surprised if SSC has already done this too...) is that it is self tracking and needs no threshold to be set for establishing the trigger. It uses a pair of amplitude followers; one with a short time constant (settable from the VCS), and the other ten times longer as a threshold reference. When the short time constant follower exceeds the long time constant follower's output value then the trigger is true. Otherwise, for this sampling cycle, the trigger is false.

With the bandpass filters in the side chain, it is possible to trigger on only the bass, or the drums, and have the low-pass filter affect the entire sound. There is no wet/dry mix in this version, and you might want to add that.

My analaog filter is pretty neat, but it isn't 2-channels like this one, and it isn't as controllable as a Kyma. I think I'll keep both of them...

Cheers!

posted 02 April 2001 18:53            

In some of your early sounds there was a little bit of the VCS on-screen - enough to grab and drag - but I can't see the VCS for either "Triggered LPF" or "AuralExciter".

posted 02 April 2001 20:57            

auralexciter.kym triglpf.kym

I have uploaded versions of these sounds that have the VCS in the upper left corner.

I am a little surprised that the Smalltalk environment doesn't take care of this for us. What other system is insensitive to the screen size? I can't think of any. My understanding is that SSC uses a fairly old 16-bit version of the language environment. Any chance of modernizing? I am also a bit disconcerted to see the memory usage always in the red when I have 256 MBytes available.