#26 Convolution during pre-mix results in garbage output

[Markus Linseisen]

When I attempt to apply convolution during pre-mix I get a loud buzzing as output. This buzzing does not appear to change based on the impulse response used.

The following results in garbage output:

Stage: pre-mix
Channel: L R
Convolution: <my impulse response>

The following works as expected:

Stage: post-mix
Channel: L R
Convolution: <my impulse response>

Is this is expected behavior? If yes, how would I go about applying convolution during the pre-mix stage properly?

[Jonas Thedering]

No, this is of course not expected. I just tried it and there was no difference when switching between pre-mix and post-mix so there must be something else that causes your problem.

Does the problem still occur if you just have the lines that you posted here in your config.txt? Is your audio device set to two channels and also the audio application?

You could maybe enable trace messages and attach the logfile E-APO generates. (instructions)

[Erik Swan]

I'm having this issue as well. Convolution in the pre-mix stage simply does not seem to work. Someone else reported the same thing here, as well.

Here's what's in my config.txt.

Works:

Stage: post-mix
Convolution: ir1.wav

Doesn't work: (buzzing output, seems to be correlated to when an application starts playing sound, then silence)

Stage: pre-mix
Convolution: ir1.wav

I'm playing a two-channel audio file. Application does not seem to matter - any audio through Spotify, foobar2000, MPC-HC results in the same thing. Configuring my output as either two-channel or 7.1 in Windows doesn't make a difference.

I've attached the log files with tracing enabled and the ir1.wav file I am using as the impulse response, for when the config is set to using pre-mix and when it is set to using post-mix.

System details:
Windows 10 Pro 64-bit, version 1709, build 16299.248
EqAPO installed on motherboard sound, Realtek ALC1150

Thanks!