Audio Mixing Causing Combinational Tone
I've recently tried to listen to 2 tones of different frequencies simultaneously. I've written about it on this forum. To summarise, I've tried to listen to 4 kHz and 6 kHz sine wave tones with the same audio encoding settings and heard an overpowering 2 kHz tone over the 2 other tones, making it really difficult to pick out the individual tones. Same was experienced with 250 Hz and 300 Hz (but the sound of them together causes a strange fax-like tone at a lower frequency).
As in the forum post above, it seems as though this is the effect of the mixing formula (with clamping of the amplitude) (more on this on the forum)
uname -a: (too short to be worth a file)
Linux LINUX 4.18.0-18-generic #19~18.04.1-Ubuntu SMP Fri Apr 5 10:22:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
arecord -l: (too short to be worth a file)
**** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC892 Analog [ALC892 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0
pulseaudio --version: (too short to be worth a file)
Steps to reproduce
What is the current bug behavior?
A tone is heard overpowering the original 2 tones
What is the expected correct behavior?
Both tones should be heard separately with the 3rd tone being barely audible and not overpowering the original requested 2 tones. This is what happens on Windows under the same conditions and on the only Mac I tested with (obviously different hardware, but the hardware is not the reason from what I've seen, it seems the issue is actually just the mixing formula used - including clamping)