Can't get Qu-24 to stream to/from PC

[enochho]

We’ve got several issues that we need help with, and the manuals are absolutely no help so far.

1. I’m trying to connect an A&H Qu-24 to a PC via USB. This used to work easily with a Mac desktop but I haven’t been able to get it to work on the PC. The PC does recognize that it’s connected to the Qu-24 (it says there are three connections, Qu-24 1, Qu-24 2 and Qu-24 3) but there’s no audio at all either coming in or going back to the mixer via USB. Is there a way to get the audio streamed via USB to/from the PC? I’ve updated the drivers on the PC to the latest version so I hope it’s all good on that front.

2. When we connect the Qu-24 to the PC via cables instead (using line in and line out on the computer) there is an awful hum and some crackling (not the nice porky kind) happening. If we plug the PC into another outlet far away (with a really long extension power cord) it does minimize the sound to an acceptable level but it’s still noticeable. Again, we didn’t have this issue with the Mac. Is this some kind of grounding or shielding issue? Using my Focusrite USB audio interface helps but I’d like to see if there was a more permanent fix to it rather than buying an additional piece of expensive equipment.

Please no snarky comments about Mac vs PC or anything like that. If we can resolve getting the Qu-24 to stream to and from the PC via USB then I don’t really care about getting the noise from the cables fixed.

[Mike C]

As for issue #2 that is ground loop noise.
I’m going to say 75% of the time you do an analog audio connection from a sound system to a computer you will need to use some form of transformer isolation between the two.

What outputs on the mixer are you using to feed the analog input on the computer?
Is the analog input on the computer truly a live level input and not mic level?

If the input is just an 1/8 inch mini TRS jack that will want to see a stereo input, left on tip, right on ring, ground on sleeve.
Feeding that input with a balanced line source will not work well.

Issue #1
What are you wanting to do with the USB feed to the computer, multitrack recording or just pull audio from a couple tracks to use for a recording or live stream feed?
What software are you using?

[SteffenR]

ASIO driver installed? the QU needs a driver to work for windows systems

[enochho]

Mike C,

Thanks for responding!

We are trying to get a USB feed to the computer to live stream our church services, and we’re using OBS as our streaming software. We’re also trying to play audio back to the mixing desk, like from Spotify / YouTube / Windows Media Player

As for the transformer isolation, would something like this do? https://www.swamp.net.au/ground-isolator

What we’re using is the ST1 in on the Qu-24 from the line out on the PC, and then 2TRK out to the line in on the computer.

It helps if I use my Focusrite Scarlett USB interface but it doesn’t completely eliminate the humming.

[SteffenR]

ok OBS is not able to use ASIO as far as I remember

but together with the ASIO driver there is an WASAPI driver installed that will be usable inside OBS
if I remember correctly OBS can only use the first two channels from the QU
you have to select the right device in OBS and you need to switch your driver to WASAPI mode

then you have to patch your outputs in the QU
use the I/O tab

much luck!

[enochho]

SteffenR

Thank you, I will try it!

[volounteer]

@enocho

We use a mix out from our Qu to feed OBS and the livestream.
And we use an audio interface into the PC not line in port.

Far easier than trying to get the usb working right.

[Mike C]

if I remember correctly OBS can only use the first two channels from the QU

Yes OBS only will see tracks/channels 1 & 2 off the multi track USB connection.

The ART iso transformer interface should work.
I would use fully balanced cabling between the mixer and transformer iso.

Were you using the Scarlett as an input or output on the computer.
Again use balanced line connections and if needed for more ground hum isolation lift
pin 1 the shield of the balanced lines at the interface end.

If using the Scarlett as an input make sure the 48v phantom power is turned off.

For a USB audio output this Peavey unit actually works well, about $60 most places on line.
Peavey USB DI Box

[enochho]

Thanks, everyone, I’ll try a few of the suggestions and see what works. Much appreciated!

[Author]

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