Regression: Bass synthesizer and bass guitar create popping sounds

• May 6, 2017 - 22:51
Reported version
S4 - Minor

Playing back bass synthesizer 1 notes too quickly makes popping sounds that get louder the lower the notes are (Windows 10). Popping sounds remain even in exported mp3 and when using a different soundfont.

Attachment Size
testingpops.mscz 17 KB


Title Bass synthesizer 1 creates popping sounds Regression: Bass synthesizer 1 creates popping sounds

This bug seems to be triggered by samples in instruments that have the following in common:
1. Low base filter cutoff (usually around 100-400 Hz)
2. Filter-to-cutoff set to high value (e.g. 6000).
3. Modulation envelope has fastest attack (0.001 sec.) and slower decay. Combined with #1 and #2 above, this causes the filter to start open and then close as the sample plays.

In the FluidGM "Synth Bass 1" preset, this technique is used to give the sawtooth wave sample a "bowwww" sound. This is also the method I used in the GeneralUser GS "Synth Bass 1", which also triggers this bug, as does the low C kick drum in the standard drum kit.

I made a video demonstrating all of this:

This bug was not present in MuseScore 2.0.3, so I am marking it as a regression.

FWIW, this change does seem to do what it is supposed to do, eliminating pops in all examples I was able to reproduce using 2.1. No idea if it introduces new issues.

However, there is something else going on that could still be troubling. The score attached to demonstrates a possibly related but apparently different problem. You can actually hear the different just entering a single quarter note on middle C (or just about any note) for vibraphone using the the default soundfont. As you enter the note, it sounds fine. It also sounds fine as you click the note (in normal mode). But when actually playing back, it gets noticeably more harsh, using 2.1 - but not with 2.0.3. So somehow something different happens during playback as compared to single note playback. Could be related to effects, I don't know - the compressor, maybe? Others have reported a harsher sound overall for some drums, and I think this may be a similar phenomenon.

Anyhow, probably not related to this code since it is a much subtler thing than the loud pop in the bass synth, but worth looking into further I think.

About the last comment #13: "for vibraphone [...] when actually playing back, it gets noticeably more harsh, using 2.1 - but not with 2.0.3." :
I locate a change at the beginning of April 2017.

With this nightly: 2026e09, the sound result is identical to that of the 2.0.3.
With this one: 417af1e, we get this sound more harsh, acid.

- I see, on April 3, a few commits related to sound: one to "fix a click-sound", two for "Volumes for envelopes", and another for "fluidsynth optimization"

In reply to by Jojo-Schmitz

I know from nothing about recent development builds, but I was looking to get some functionality with lute tabs, so I downloaded the latest 2.1 version. While the lute tabs are looking great, I quickly remembered why I was using an old version of your program. That pestilential, never to be tolerated, damnable whip crack sound. I get it on about a third of my projects (I mostly write transcriptions and arrangements of Elizabethan music and I'm up in the 7 hundreds) and the same exact files work great on 2.0 and start whip cracking on 2.1 when I move the file over to that machine. (I'm now using 2.1 to do lute tabs, and 2.0 for everything else.) The attached file is from 1597, for lute. It's one that works on 2.0 and whip cracks on 2.1 when I migrate it. A Study.mscz There is no apparent rhyme or reason, pitch, timbre, volume, SoundFont (I use TimGM6mb.sf2), or any other commonality that I can see to what works and what doesn't, other than the version of MuseScore. I notice random whip cracks from the lute solo at the beginning, then rhythmic ones when the drums come in.
Thanks for listening!

C. A. Powers
AKA Charric Van der Vliet