Voicemeeter frequency response of virtual outputs

[stoepie]

Hi Vincent,

I heard that the high notes seemed a bit attenuated, so I decided to measure the frequency response from Voicemeeter.

Using Arta sending PN Pink noise into Virtual input "VAIO", and routing that audio to B1 and using that is Arta input, I notice the following frequency response:

VM FR RESP.jpeg (155.28 KiB) Viewed 5926 times

This is -3dB at 15kHz.

Samplerate in VM 48, same as in Arta. Selecting higher sample rates does not seem to improve anything.

When I do something similar, going into Virtual input "VAIO" but then routing to my ASIO connected XR 18 air, and going from there directly to Arta using ASIO, I see the following response:

VM XR18 FR RESP.jpeg (134.57 KiB) Viewed 5926 times

Flat as can be!

To me, this suggests that the virtual input into VM is fine, but the virtual output has some kind of filtering in it, losing 3dB at 15kHz.

Any ideas?

-David

[Vincent Burel]

This can happen if you have a SRC in the path (Sample Rate Conversion).

[stoepie]

Good SRC's are flat. To be honest I don't know if the SRC's in Windows are good or not.

But, I had everything at 48kHz, so I don't expect SRC's in the path.

[Vincent Burel]

if your response curve is not flat, you have surely an SRC somewhere (SRC cannot be good, because they must be fast).
so you may check the output path point by point:
1- Voicemeeter main stream samplerate
2- Voicemeeter VAIO output default format (in Sound Dialog box -> properties -> advanced thumbnail)
3- Arta samplerate and audio interface used

[stoepie]

You nailed it!

The B1 output was set to 44.1kHz in Windows, while everything else was set to 48kHz.

I sometimes really hate Windows.

Thanks for educating me, Vincent!

-David

PS from professional audio equipment I am used to SRCs that do work and have a flat frequency response, I guess I was expecting this from Windos as well (or is this SRC part of your code?).