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z5kb

Member

Registered: 2025-10-09

Posts: 16

[SOLVED] Significant bluetooth audio latency

I bought the CMF Buds 2 Plus recently and they have very high latency on my PC. I am using pipewire + pulse and SBC as a codec. I have the Archer TX20E bluetooth + wifi "adapter" attached to my motherboard (PCIe). I noticed a couple of things:
1. the latency seems to be ~370 ms when measured with this website . I used the microphone of my Logitech G Pro X wired headphones which, at least when outputting sound, seem to have no noticeable latency.
2. the latency gets noticeably higher when using LDAC instead of SBC. Also, there is almost no noticeable latency when using mSBC
3. disabling (inside the app provided by the earbuds' manufacturer) noise cancellation, custom sound profile, etc. doesn't seem to improve things
4. since the PC has a combined bluetooth + WiFi "adapter" (Archer TX20E) I tried switching the WiFi to a 5G network so the 2.4 GHz frequency is solely reserved for the bluetooth earbuds. This didn't improve anything.
5. I tried this fix but nothing changed.
6. I also tried lowering the buffer size to 32 by setting the clock.force-quantum variable with pw-metadata (see this ). The latency seemed like 40-50% better but when I measured it again it was only reduced to ~350ms.

I find it very hard to believe that 400ms audio delay is normal for bluetooth haedphones/earbuds. Is it actually normal? Could there be another problem?

Last edited by z5kb (2026-02-06 01:37:32)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,074

Re: [SOLVED] Significant bluetooth audio latency

Absolutely normal for bluetooth in the vast majority of cases. One of the main reasons why wireless "gaming" headsets will ship with their own dongles that don't do bluetooth.

There might be some newer BT standard that improves on this, but your entire chain needs to support that. So in the general case you can assume that it's "normal".

z5kb

Member

Registered: 2025-10-09

Posts: 16

Re: [SOLVED] Significant bluetooth audio latency

Thanks for responding.

I looked at the manufacturer's website and apparently these earbuds are capable to get to 105 ms latency over bluetooth when using their phones (nothing phone) with the "low lag" mode enabled. I tried enabling this mode from the mobile app before connecting the earbuds to the computer and it seemed to improve the latency - it dropped from 370 ms to 300 ms.

I don't see why the latency would be this high when it can get to 105 ms on their phones. I would guess that:
1. there is a problem with my bluetooth "adapter" mentioned above (e.g. bad drivers, bad "low lag mode" implementation, etc.);
2. there is some problem in the way I have configured bluetooth or audio in general to work on my system

I'd like to get the earbuds at least close to the latency they can apparently achieve on a phone. I don't see why this shouldn't be possible so I appreciate any additional input anyone might have.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,074

Re: [SOLVED] Significant bluetooth audio latency

These are often "selling points" that have a proprietary implementation, similar like Apple airpods are "technically" Bluetooth but you can't use most of their more advanced functionality unless you have an iPhone.

Do you have anyone other phone that isn't a nothing phone where you could test what happens? Yes this situation sucks but can sadly be very common.

z5kb

Member

Registered: 2025-10-09

Posts: 16

Re: [SOLVED] Significant bluetooth audio latency

I disabled all of the earbuds' settings and got a small improvement - 250 ms (measured with the microphone attached to my wired headset). My guess is that the functionality which allows them to be connected to 2 devices at the same time is the one which was lowering the latency but I haven't verified this. Also, tried the test on 2 other devices - one is a 2025 Google Pixel and another is a 2022 budget Samsung phone (I used the devices' built-in microphones for both tests). The latency to the Pixel was ~300 ms and the latency to the Samsung phone was ~400 ms. Furthermore, I run the test on my wired headset connected to my PC as well (it's a Logitech G Pro X) - 80 ms.

It seems to me like the testing app is far from ideal and it doesn't detect the latency very well. Combined with the fact that the wired microphone also has to have some latency, I think it's realistic to say that the earbuds' latency on my PC may be below 200 ms. It's not ideal but it got noticeably better after disabling the "connect to 2 devices at a time" functionality. Guess I'll just have to use them like this.

Thanks for the help.

Last edited by z5kb (2025-12-03 21:20:13)