zynaddsubfx

commit 3dfdeb8f954a2f3235ebc28cf49a1da398282538
parent 50b9f1ac4ee9ae3809b8724dbfd7ad62a5454268
Author: Friedolino <mkirchn@freenet.de>
Date:   Thu, 24 Jun 2021 17:28:33 +0200

try better Q mapping

Diffstat:
M
src/DSP/MoogFilter.cpp
 | 
4
+++-

1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/DSP/MoogFilter.cpp b/src/DSP/MoogFilter.cpp
@@ -136,7 +136,9 @@ void MoogFilter::setfreq(float ff)
 void MoogFilter::setq(float q)
 {
     // flattening the Q input
-    feedbackGain = cbrtf(q/1000.0f)*4.15f + 0.1f;
+    // self oscillation begins around 4.0
+    // mapped to match the ANALOG filter class
+    feedbackGain = cbrtf(q/1000.0f)*4.0f + 0.3f;
     // compensation factor for passband reduction by the negative feedback
     passbandCompensation = 1.0f + limit(feedbackGain, 0.0f, 1.0f);
 }