General Question about sample rate switching on USB/DAC combos.

[mdins1980]

I recently bought a Topping DX3 Pro+ and I am happy with it. However I mostly use it on Linux with pipewire, I have pipewire setup where the Topping will automatically switch the sample rate to match what ever the source is. This is working fine and the LCD screen confirms the sample rate does switch, but every time the sample rate switches there is a short 1/4 second delay that is extremely annoying. I contacted Topping and they said this is normal behavior and cannot be fixed. I now have it set at a static sample rate of 48000mhz. I know my naked caveman ears can't hear frequenices that high anyway so this is a non-issue. However it is extremely disappointing since my onbaord soundcard and my xonar dx can switch sample rates perfectly fine. My question is do all USB/DAC's have this audio delay on sample rate switching or can anyone confirm a DAC/AMP that doesn't have this problem?

 

[twsecrest]

My two cents, the Xonar DX is in a PCI-E slot and the slot only has to deals with the Xonar DX card.
USB interfaces with many devices, a more complicated situation, so might take it a little more time to process and switch sample rates on a device hooked up thru USB.
Best guess.

 

[radix]

I had the same problem with the DX3 Pro+ from my Macbook pro. I used the same workaround, fixing the sampling rate. I think it's a perfectly fine workaround and I doubt you're going to hear any difference.

I ended up selling the DX3 Pro+ and buying an RME ADI-2 DAC FS, mostly for the on-board EQ and headphone amp. It has no problems switching sampling rates.

 

[mdins1980]

Thanks for the replies. I at least give Topping credit for acknowledging that this is known and a hardware issue that cannot be fixed. And like radix said there is no way 99.9999999% of the population, myself included, is going to be able to pick apart that level of detail, even on super high end speakers. It is just frustrating that my onbard soundcard which probably cost the motherboard manufacturer $3 or less can do something my $200 DAC/AMP can't.

 

[twsecrest]

I recently bought a Topping DX3 Pro+ and I am happy with it. However I mostly use it on Linux with pipewire, I have pipewire setup where the Topping will automatically switch the sample rate to match what ever the source is. This is working fine and the LCD screen confirms the sample rate does switch, but every time the sample rate switches there is a short 1/4 second delay that is extremely annoying. I contacted Topping and they said this is normal behavior and cannot be fixed. I now have it set at a static sample rate of 48000mhz. I know my naked caveman ears can't hear frequenices that high anyway so this is a non-issue. However it is extremely disappointing since my onbaord soundcard and my xonar dx can switch sample rates perfectly fine. My question is do all USB/DAC's have this audio delay on sample rate switching or can anyone confirm a DAC/AMP that doesn't have this problem?

You could connect the the Topping, using optical, to go from the Xonar DX to the DX3 Pro +
So the switching is done by the DX and not the DX3 Pro plus.

But on the other hard, I think USB offers advantages, that optical does not.

 

[mdins1980]

Going that route you are limited to 192000mhz vs 384000mhz via USB. Again this is a pointless comparision considering I don't even have music that is sampled that high. All I really wanted to know from this post is if all DAC/AMP's have this resampeling issue or if this is something unique to the Topping or other specific units. And since radix confirmed his unit does not have this problem that tells me that there are units that don't do this. I like my Topping and I will keep it but I just feel that since Topping is aware of this they should fix it because if a cheap throw away sound card can do something a $200+ dac can't do, then there is a problem there that needs to be fixed IMO.

 

[Lambda]

Audiophile

This article covers configuring audio for optimal playback quality in Arch Linux. Table of contents: Changing sample rate Resampling quality USB DAC’s Recommended software Changing sample rat…

discovery.endeavouros.com

You could just up/over sample in software an always.

You also can prevent it to go to stendby to avoid the pop and delay

[Suggestion] S/PDIF keepalive (#705) · Issues · PipeWire / pipewire · GitLab

I've been experimenting with sound bars (a Bomaker Tapio 1 and a Samsung HW-T400) attached by optical S/PDIF as the machine's primary speakers. One thing I've noticed is...

gitlab.freedesktop.org

 

[bogi]

With delta sigma DACs I always upsample to the highest DSD rate DAC is capable to receive - regardless on sample rate of PCM or DSD content played.
You can do so in every better audio player. I tested it with foobar2000 and JRiver MC and I am using it with HQPlayer.

To avoid complains why to upsample in software: Every delta sigma DAC is oversampling DAC (with PCM input). If you don't upsample in software, DAC will do it. Your computer is able to perform this task better than resource constrained $10 chip.

 

[mdins1980]

Just thought I would report that I was able to get a Fiio E10K USB-C model as a loaner from a friend. I was able to test it and can confirm that the Fiio E10K USB-C has no issue whatsoever with sample rate switching. I had a feeling this would be the case. I am keeping my Topping and I am very happy with it. I just hope Topping fixes this in the future because its stupid that a product in that price range can't do a simple thing like sample rate switching correctly. Especially when they are aware of the problem.

 

[phofman]

Samplerate switching in UAC2 (which most modern USB DACs use) means sending a control message to the Sampling Frequency Control of the UAC2 clock entity. The device receives the message and acts accordingly. After confirmation the incoming data stream is considered as of the new samplerate.

Pipewire using alsa-lib will setup the device for the new samplerate first (and the snd-usb-audio driver will send the control message to the DAC), and then start writing data to the driver.

There is no standard technical reason for this operation to take so long. But of course implementations in the audio device receiver may vary. Details of the communication (e.g. how long the device takes to acknowledge the control transfer) could be viewed in USB packets captured e.g. by wireshark.

 

[HCT-5808]

Not sure this is a Topping issue. I have a Topping DX3 Pro+ as well. It is connected via USB to a Windows 10 PC. Using Roon I'm able to play files of various sample rates without a noticable pause. I did a quick test going from queing up three files: 44kHz 16 bit to 88kHz 24bit to 96kHz 24 without any noticable pause. To my ears it was exactly the same timing as when I play only 44kHz 16 bit files.

 

[Snoopy]

Not sure this is a Topping issue. I have a Topping DX3 Pro+ as well. It is connected via USB to a Windows 10 PC. Using Roon I'm able to play files of various sample rates without a noticable pause. I did a quick test going from queing up three files: 44kHz 16 bit to 88kHz 24bit to 96kHz 24 without any noticable pause. To my ears it was exactly the same timing as when I play only 44kHz 16 bit files.

Because you can adjust the delay in roon that the software uses a time delay when switching sample rates. In case the hardware needs time to perform that task. I think U can go as high as 4000-5000ms.

But If you go to high it's annoying with CDs that are designed to be played gapless.
I reduced that buffer delay to the minimum and have no issues at all.

But Im upsampling everything to DSD as well to avoid switching sampling rates and formats to begin with.

Pretty much a no-brainer for me. Offers better upsampling, takes annoying problems out of the equation (clicking, crackling, pops whatever when switching between pcm and dsd etc). And upsampling to DSD64/128 shouldn't even be a issue with older hardware.