Soncoz LA-QXD1 not playing with the correct sampling frequency (44098Hz) and has no amixer support

[alekksander]

Hello there. Last 7 years i've been using Objective DAC with various speaker/amp combinations. Never experienced any problems regarding that device. Whatever i fed to it was converted properly. Years passed and i decided to move to something performing even better — the la-qxd1. Received it just today. It's a pretty nice and heavy box. There was a flyer inside with manual dated October 2020. After configuring ALSA for new device i decided to check it and to my surprise it couldn't play even 44100Hz, giving me 44099Hz instead! And it's 95996 for 96kHz files. Bit values are also not right. It plays at alset 1 no matter the format – 16 or 24 bit. Alset 1 says 32bit, alset 2 is 24 (never used), and alset 3 (for dsd) is again 32bit.

Here is exact output of „cat /proc/asound/card1/stream0” while playing 24/96:

Later on i tried something less refined (lossy 44.1kHz) and i was even more surprised:

Apparently momentary frequency is not consistent despite cat commands were made with no more than 3 second interval.
This does not look the way it should. I re-checked it on bootable debian (ofc decapitated pulseaudio) but results were wrong as well – this eliminates my specific system configuration.

Running amixer doesn't give any result, it just doesn't start and so kmix has no control over this unit volume. Volume can be changed only with hardware buttons. What gives? Is this normal for this unit? I knew it has hardware vol. control, but thought alsa one would be there as well. Xmos specifics? (Regarding sound i'm also not 100% satisfied. Higher frequencies cut off faster than i expected despite filter n.3 (but need some more testing on this one)). Is anyone able to verify this information for me? I'm sad to report i'm currently disappointed with la-qxd1.

 

[gvl]

I'm not an expert in ALSA, but 16 bit samples can be happily sent to the DAC as 24 or 32 bits with 0-padding, same goes for 24 bit samples in 32 bit words. As for sampling frequency being off my guess this is due to the DAC clock spinning a bit faster than the system clock on your Linux box, 1/44100 is 0.002% deviation, this is immaterial.

 

[alekksander]

I'm not an expert in ALSA, but 16 bit samples can be happily sent to the DAC as 24 or 32 bits with 0-padding

could You elaborate a bit more? how is it possible from technical point of view? isn't this „upsampling”?

new issue:
after setting filter to desired one it is not remember on power re–plug, but what's worse leds are not going back to input+power state, but remain indicating filter. when i change volume now the first led is for some reason blinking instead of the one above volume controls.

 

[gvl]

This is most definitely not upsampling, the sampling rate remains the same. 0s added in lower bits are benign.

Afaik the LA-QXD1 has some rough edges, it not persisting its settings is one of them, perhaps the only one.

 

[alekksander]

@Sophia Ann , @Ben1987 would it be possible to fix described problems in firmware update? and what's more important to me – would it be possible to have back software volume control for this dac? i'd expect that to be separated from hardware one. (edit: ) or controlled via usb.

currently:„amixer: Control default element write error: Operation not permitted”

 

[Sophia Ann]

@Sophia Ann , @Ben1987 would it be possible to fix described problems in firmware update? and what's more important to me – would it be possible to have back software volume control for this dac? i'd expect that to be separated from hardware one.

currently:„amixer: Control default element write error: Operation not permitted”

Don't worry Alex, and wait for a while, Ben will reply

 

[Pluto]

If you have an asynchronous USB connection between the computer and DAC, how do you know the exact sample rate at which the DAC is running? The flow control inherent in the USB interface might create all kinds of apparent inconsistencies in the transfer while the buffering internal to the DAC smooths it all out before the data hit the actual converter chip.

This is far more likely to be a measurement or experimental error than a flaw in the DAC.

 

[somebodyelse]

I don't think I've seen a DAC with an async USB interface where the 'Momentary freq' doesn't change in the last digit every time you check. I'm pretty sure what you're seeing is an artifact of the way alsa is calculating that value, but can't see it documented in the kernel docs and haven't gone digging in the source to check.
Similarly other DACs use S32_LE when playing 16 or 24 bit - this isn't unusual.
The volume/mute via USB was mentioned in the original thread - I don't know if it was actually added to later firmware versions or not.

 

[Ben1987]

would it be possible to fix described problems in firmware update?

Check this and try our new firmwar which supported hardware volume control.

Download DFU files from HERE and after unzipping, you'll find two files“LA-QXD1 Maximum Volume with Hardware Control DFU_V502.bin” and “LA-QXD1 Minimum Volume DFU_V501.bin”.

Change log：2020-11-11
Fixed DSD playback reverses problem.
Notice:
1. "LA-QXD1 Minimum Volume DFU_V501.bin" is default factory firmware version and without hardware volume control；
2. “LA-QXD1 Maximum Volume with Hardware Control DFU_V502.bin” is max volume output firmware with hardware volume control；

 

[alekksander]

Check this and try our new firmwar which supported hardware volume control.

Download DFU files from HERE and after unzipping, you'll find two files“LA-QXD1 Maximum Volume with Hardware Control DFU_V502.bin” and “LA-QXD1 Minimum Volume DFU_V501.bin”.

Change log：2020-11-11
Fixed DSD playback reverses problem.
Notice:
1. "LA-QXD1 Minimum Volume DFU_V501.bin" is default factory firmware version and without hardware volume control；
2. “LA-QXD1 Maximum Volume with Hardware Control DFU_V502.bin” is max volume output firmware with hardware volume control；

Thank You very much @Ben1987 . Would it be possible to get minimum volume output with hardware volume control firmware?

Going to update once I have access to windows controlled pc.

leds are not going back to input+power state, but remain indicating filter. when i change volume now the first led is for some reason blinking instead of the one above volume controls.

It's not the big issue, but would it be possible to fix this at some point?