USB DAC direct or over USB Hub


maybe someone here can give me a hint how to get closer to my problem:
I use a USB DAC (digital/analog converter) in my setup. For this I have now bought the Sound Blaster X5 from Creative, but with this I have a “bandwidth problem” or at least I suspect that.
When I connect this DAC via USB to my notebook (Lenovo X1), I have clear sound.
I also use an eGPU (external Graficcard), which I connect to the notebook via Thunderbold. The eGPU also has USB where I would like to connect the DAC. However, I have there very bad sound, with scratching und crackling.
Could this be a bandwidth issue? Can I analyze this further. Does anyone have any ideas on what I should check to find or even solve the cause of the bad sound?

Many Thanks

welcome to the forum.
A bandwidth problem is very unlikely for a DAC, because audio does not need much. A DAC should work fine on a legacy USB port speed.

IMO it is more likely that your eGPU has high frequency occilation in operation which disturb the DAC output (similar to a radio antenna next to a disturbing electric source). One idea to test is to add a USB-extension cable to the eGPU USB port and insert the DAC a meter away into it. If the distortions continue, it’s something else USB related (for example you can watch kernel messages to see if errors occur with sudo dmesg -w).

Hello Ion,

thank you for your hint.

this is the output from dmesg:

[ 6700.061784] usb 3-2: USB disconnect, device number 8
[ 6719.477129] usb 3-2: new high-speed USB device number 35 using xhci_hcd
[ 6719.617810] usb 3-2: config 1 interface 2 altsetting 0 bulk endpoint 0x82 has invalid maxpacket 256
[ 6719.618227] usb 3-2: New USB device found, idVendor=041e, idProduct=3265, bcdDevice=10.00
[ 6719.618243] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=7
[ 6719.618252] usb 3-2: Product: Sound Blaster X5
[ 6719.618258] usb 3-2: Manufacturer: Creative Technology Ltd
[ 6719.618264] usb 3-2: SerialNumber: 9352489D23931D48
[ 6719.629339] input: Creative Technology Ltd Sound Blaster X5 as /devices/pci0000:00/0000:00:1d.0/0000:05:00.0/0000:06:01.0/0000:08:00.0/0000:09:04.0/0000:0b:00.0/0000:0c:01.0/0000:0e:00.0/usb3/3-2/3-2:1.0/0003:041E:3265.001F/input/input57
[ 6719.683601] hid-generic 0003:041E:3265.001F: input,hidraw0: USB HID v1.10 Device [Creative Technology Ltd Sound Blaster X5] on usb-0000:0e:00.0-2/input0
[ 6719.683856] cdc_acm 3-2:1.1: ttyACM0: USB ACM device

Music (Spotify native App) sound good
Gaming Sound (Steam) is crackling with this messages:

[ 6998.424749] xhci_hcd 0000:0e:00.0: WARN Event TRB for slot 9 ep 6 with no TDs queued?
[ 6998.431777] xhci_hcd 0000:0e:00.0: WARN Event TRB for slot 9 ep 6 with no TDs queued?
[ 6998.466178] xhci_hcd 0000:0e:00.0: WARN Event TRB for slot 9 ep 6 with no TDs queued?
[ 7005.360710] xhci_hcd 0000:0e:00.0: WARN Event TRB for slot 9 ep 6 with no TDs queued?
[ 7006.579613] xhci_hcd 0000:0e:00.0: WARN Event TRB for slot 9 ep 6 with no TDs queued?

However, that seems to be a GPU issue.

I know this isn’t your model but In general it’s not recommended to run audio interfaces on hubs, some manufacturers (Tascam) explicitly state that their products will not work on hubs. If you do make sure you’re using a powered hub.

The error message must not necessarily relate to the GPU, but may indeed be a warning related to USB hub.
Now that spotify appears to work suggests it may be related to setup. For example, in this issue case, the same warning apparently went away when changing sampling rate away from 48Khz. You should be able to test that within steam.

Hello 6x12,

Thank you. Both Hubs (in eGPU from Sonnet and in Monitor from Dell) has Power Supply. Both has the same Problem.

Hello Ion, after many hours with pipewire configs, changing samplerate, change cable oder switching from thunderbolt dock to usbc dock … nothing works. The DAC is crackling.
Only if i connect the dac directly to my Notebook USB ports, the sound is good.

So i would close this post, because i send the DAC back. I think it’s a pity, because I was looking forward to great sound.

Thanks to you all.

Pity, but understandable that you want it to work in a stationary setup and not plug it in/out all the time. That DAC is an expensive piece of specialised hardware, but there is plenty choice of established manufacturers in that segment. Good luck on your next try.