USB mic latency increasing by itself during audio session

[gemada]

Hi,
I'm trying to record some songs (acoustic guitar and voice) using a mackie em91-cu condenser mic with an acer ryzen 5 laptop, windows 11, wasapi mode inside cakewalk or reaper or any other compatible daw, and monitoring audio trough realtek onboard headphones out. I'm experiencing a weird problem with latency...When I start a new recording session, latency is ok (256 samples, less than 20ms roundtrip latency and no perceptible latency in my headphones) but after a few minutes I start to hear an increasing delay in my guitar and voice, that disturbs the recording...It seems latency starts to increase by itself in the background even though latency values in the daw window are constant (with no change, as expected).

I've tried asio4all and all the optimizations for audio recording (updated drivers, energy plan for best performance, disabling devices in device manager, disabled core parking, etc...) but nothing seems to solve the problem...

Anyone can help me?
Thanks!

[Gavincoolguy]

This is a issue that comes up a lot with USB mics and Windows. I personally couldn't cure my computer of the problem using a couple different blu mics. It's a weird issue that you don't notice exists if you monitor directly from the mic which I assume you are bypassing because you are doing something in daw and you want to hear the result. The descending order of chaos is update your realtek drivers, try a USB soundcard, throw the USB mic away and get an audio interface. The windows audio stack is that bad.

[Pictus]

Some tweaks may help
viewtopic.php?p=8667750#p8667750

[BertKoor]

The Mackie EM-91CU large diaphragm USB condenser microphone is perfect for streaming, online meetings, and more.

... but (like all USB mics) not fit for usage by musicians that need non-direct monitoring.

[gemada]

Thanks a lot for the replies! Very appreciated!
I´ll try all suggestions to solve the problem before I'll put the mic away for home decor hehehe.
If I can solve the problem I'll update here.
Best regards

[jackoo]

The USB mike is a "soundcard" with an input.
Whatever outputs the sound to your speakers is another soundcard.

Therefore you need to create a so called aggregate device, in order to use both in an application.
Asio4All can do that but it's not perfect.

Having two audio devices agregatted, can be a problem because they might not share the same clock. That means that their sense of time drifts apart with time, which can cause issues with filling and unloading the same buffer.

[gemada]

Thanks for the reply. That makes a lot of sense to me
Meanwhile I´ve done all the tweaks suggested and I've been trying also some different "drivers" and/or settings...
In case it's useful for someone, here are my results until now:
- Wasapi exclusive mode and Asio4all have the same issue: latency starts good but increases by itself along recording session and it becomes impossible to record audio within time;
- With Wasapi shared mode I have total roundtrip latency higher than in exclusive mode, as expected, (25ms acording to Reaper) but it seems latency doesn't change along recording time;
- I've tried KoordAsio (a clone of FlexAsio) with different results: in exclusive mode I hear a lot of pops no matter what buffer size I choose; in shared mode I can use 32 buffer size and it seems the sound is a little bit less delayed than with Windows Wasapi shared mode, although Reaper is reading a total roundtrip latency of 31ms.

I'll test a little bit more before I give up...