Volume collapses on a loud bit of Beethoven

[grischard]

The volume pops like a foam bubble during a loud bit of Beethoven's fifth piano concerto.

How to reproduce:

1. Run lcc_audio on macOS, to internal speakers, rate 96k:

/lcc_audio
./lcc_audio {inputgain} {centergain} {endgain} {LCC_Decaygain} {LCC_Delay_in_microseconds}
./lcc_audio {inputdevice_num} {outputdevice_num} {sample_rate} {inputgain} {centergain} {endgain} {LCC_Decaygain} {LCC_Delay_in_microseconds}
version 0.8
Did not receive 6 arguments. Using defaults: ./lcc -3 -3 3 -2.5 32
0:Apple Inc.: Built-in Microphone, rates:44100,48000,88200,96000
1:Apple Inc.: Built-in Output, rates:44100,48000,96000
2:ma++ ingalls for Cycling '74: Soundflower (2ch), rates:44100,48000,88200,96000,176400,192000
3:ma++ ingalls for Cycling '74: Soundflower (64ch), rates:44100,48000,88200,96000,176400,192000
Select Input Device: 2
Select Output Device: 1
Select Sample Rate: 96000
input gain: 0.700000
center channel gain: 0.700000
LCC decay gain: 0.749894
LCC delay in us: 32.000000
LCC delay in samples: 3.072000
Debug only: bufferframes: 2048

LCC ON... press 1 to turn LCC on, 2 to turn LCC off, 3 to change settings, 4 to quit.

2. Turn the volume all the way up, or the problem won't happen.
3. Play https://open.spotify.com/track/39d3Plk1T28MjuR9gYPu1h . If classical isn't your thing, you can skip to 3:00.
4. Wait until 3:12.

Expected result:

Music keeps playing at a constant volume

Actual result:

Volume collapses in the middle of a loud note

Workaround:

Turning the volume down a bit seems to prevent this. Is this some kind of saturation?