ZED10FX High Pitched Noise or Hiss with USB connection

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21

That sounds like digital noise on the USB cable ground making it’s way into the analogue signal than anything to do with drivers/software.

The main places to check would be:
Different grounding between the connected equipment - you mention the laptop was running on battery, but is it disconnected from the mains? is there anything else connected to the USB bus? How are the cameras powered? What are all the connections to the ZED? Is all connected equipment (including the speakers) earthed correctly?
The cable - are you using the supplied cable? Does it have a ferrite bead?
The ZED itself - Do you have any gains turned up? Are you using DI inputs (which use a different circuit and have 26dB boost switches on the rear)?

If there is an issue with the ZED though, then getting the unit to your distributor (AM&S) after you have looked at everything else will mean they can check it over fully and ensure it is working correctly/to spec.

22

@Mike

Like Keith just said, and I thought that I had pointed too earlier, interactions between all the things you have connected with grounding and direct connections could well be the issue.
Although I do not see how digital noise could be involved.
I do see how analog noise might get into the USB data stream.
Whilst it might turn out to be the Z10, I would still focus on the other items and their interactions first.

23

Hi Keith, thank you, really appreciate getting a reply directly from A&H about this issue. I’ll try to answer your questions to the best of my level of knowledge as I’m not a guru:

Different grounding between the connected equipment – you mention the laptop was running on battery, but is it disconnected from the mains?
For the troubleshooting, I disconnected everything from the laptop, including the power, and I brought it close to the mixer and plugged in a few USB cables to test, including the one I use on the desktop machine.

Is there anything else connected to the USB bus?
What do you mean when you say “USB bus” If you mean are there any other devices in the chain, then no, the USB goes directly from the mixer to the computer, or laptop in the case of the troubleshooting.

How are the cameras powered?
The camera, when in use is connected to its power supply, not battery, but again, the noise is present when there is no camera.

What are all the connections to the ZED?
See attached photo. Mic in M1, Guitar in M3, MIDI player in ST1, Laptop in ST2, USB to computer, AUX out to peavey power head to speakers, Main XLR outs to video camera, Phones to headphones

Is all connected equipment (including the speakers) earthed correctly?
I don’t understand about this question

The cable – are you using the supplied cable?
No, I do not have the supplied cable. I’m using a longer USB cable that is able to reach from the rack to the desktop machine. But the noise also happens with shorter USB cables (when I tested with the laptop)

Does it have a ferrite bead?
Had no idea what that was until I googled it just now. The long USB cable does not have one, don’t recall if any of the short ones did, but I’ll go back and look. If I find one with a ferrite bead, I’ll try testing with the laptop and report back.

The ZED itself – Do you have any gains turned up?
See the attached photo.

Are you using DI inputs (which use a different circuit and have 26dB boost switches on the rear)?
Not sure what you mean here. On the guitar input, depending on the output level of the guitar being used, sometimes I use the boost switch on that channel, and sometimes I don’t.

zed10fx.jpg
zed10fx.jpg1920×1080 304 KB

24

What is the other end of the cables connected to that are plugged into ST2?

You said ST2 is laptop in, is that cable plugged into the headphone jack on the
laptop?

Plugging into ST2 disconnects the USB from sending audio to the ST2 channel.

25

Yes, that’s correct, the headphone out from the laptop.

Why would I want the USB to send audio to the ST2 channel? Not following what you’re saying here. I want audio from ST2 (and the other channels) to be sent from the USB to the computer (which they are).

26

Instead of the using the headphone output to send audio to mixer you can use the
USB connection to send audio from the computer to the mixer on the ST2 input at the same time you are sending audio from the mixer to the computer on the USB.

You just need to change the audio output routing setting in the computer.

The noise clip you posted is what I heard many times when directly connecting a computer headphone jack to a sound system input.
Sometimes using a DI box / transformer isolation between the headphone output and the mixer input will work to get rid of the noise.

I asked about the headphone jack connection earlier.
I didn’t know or I missed it in an earlier post that you were using the headphone
connection.

27

wow you completely lost me there… The audio comes from the laptop (which is a separate computer from where Zoom is running) I only use the laptop to play backing tracks to the mixer, and the mixer sends that audio via the USB to the other computer that has Zoom.

Are you saying to connect a USB cable from the laptop to the mixer? How does audio go from the USB into the mixer? and then if the mixer’s USB port is occupied by that connection, how does it get sent to the other computer?

But more importantly, it’s not the laptop’s connection to the mixer that is causing the noise because again, the noise is present even when the laptop isn’t plugged into ST2, so it seems like a moot point from my perspective.

28

Then why mention the laptop at all.
Just give us ONE complete clear accurate use case that has the problem and do not conflate a bunch of use cases.
I interpreted your posts to mean you had the laptop and video camera and Z10 and other stuff all working at the same time.

29

Well yes that is true, I do use them all at the same time when shooting.
However, and I did say this, the noise is present when nothing is connected to the mixer except the USB, hence the reason I know the noise is related to the USB.

No USB, no noise.
Add USB, activate USB as audio input in windows, get noise - it’s as simple as that.

30

Ok you did say in the first post that you are using two computers, the one playing back tracks is connected via headphone out to ST2 on the mixer and the computer feeding the ZOOM stream is connected using the USB.
I some how got to thinking you were using just one computer for everything.

So with the USB connected but not actually selected on the ZOOM computer as the audio input source you get no noise, as soon as you select the USB to be input audio source
the noise starts.

That just about tells me it’s not a physical ground connection issue.

31

@Mike

If what you just said is true then just do not connect the usb to a PC and activate audio through it.
I am still thinking your problem is the stuff you have attached to the Qu and not the Qu itself.
Are you connecting and activating the Qu USB to the PC using usb2.0? or does it have a later version??

32

I have to use the USB because the USB is what sends the mic, guitar and backing track audio to Zoom. In Zoom, I select the ZED as the “microphone”
What is a Qu ?

33

@Mike
Sorry for the typo.
Qu is a bigger version of mixer between Z and the SQs
so replace Qu with Z10 in the comment above and it will still apply.

You still did not tell us if the PC is usb2.0 or not.
USB2 is rock solid with AH mixers. usb3 has issues.

34

Sorry, missed that. I’m not actually sure. I know the desktop machine has both USB 2.0 and 3.0 ports so I don’t know what type of port it’s plugged into atm, but I will check that.
I believe however, the laptop I troubleshooted with is only USB 2.0, but I’ll double check shortly.

35

When I plug the (ferrite bead) USB into the laptop, there is no noise at all when USB is activated as an input. BUT, when I plug into ST2 (from the laptop’s headphone out), the noise appears. Additionally, the volume of the noise is controlled by the gain on ST2.

Next, I had to drag the audio rack over so that the ferrite bead USB cable would reach the computer. I plugged it into a USB (2.0) port, and the noise was present. ST2 had no effect whatsoever on the noise in this case like it did on the laptop. I could unplug ST2 altogether and the noise is still there.

SO, my conclusion, still without a resolution here:

USB to laptop = no noise
USB to laptop and laptop audio to ST2 = noise

USB to desktop = noise (whether or not laptop audio is plugged into ST2)

Also, USB 2.0 or 3.0 port made no difference.

36

@Mike

I see the data saying the laptop out is the problem, as is the desktop, as it works with laptop fine without headphone out to ST2.
There is a whole thread on usb noise. 20 pages of it.
https://community.allen-heath.com/forums/topic/digital-noise-when-streaming-audio-via-usb-b

You might find some clues there but I suspect that you will need to use an audio interface instead of usb.

37

@Mike -

The “Different grounding between the connected equipment” is a relative thing, i.e. it might require a combination of things to be connected for there to be a problem (as you have found with the laptop output). So try physically disconnecting everything except the USB ↔ computer/laptop first, then connecting things individually to figure out which two (or more) create the noise.

Once you have found where the difference is, you can either use a DI box if the guitar (or any pedals?) is causing the difference or a line level matching transformer (often referred to as a ‘hum eliminator’ or similar) for any line level signals such as that from the laptop analogue output. If you can’t have a common ground, the aim with this is to isolate everything electronically whilst still have an audio connection.

I noticed from the picture that you have around +15dB on the trim for both ST channels - this seems a lot, so make sure the outputs at the sources for those channels is actually line level and turned up!
Note also that although you can get away with it 90% of the time, a headphone output is not the same thing as a line level output. A headphone output from a laptop is intended for a ‘floating’ pair of headphones rather than connection to another piece of equipment like a (grounded) mixer.

You’re welcome to contact us about this directly using https://support.allen-heath.com too.

Thanks,
Keith.

38

@volounteer -

Unfortunately that link is to a discussion on Qu/SQ which uses a completely different USB connection and is not at all the same noise as being discussed here.
As already stated, this issue has nothing to do with software (or maybe even the ZED!) and is a case of digital noise making its way into the analogue circuitry.

Cheers,
Keith.

39

Keith, I had already isolated the noise directly to the USB. i.e., with only the USB connected to the mixer and to the desktop computer, the noise is heard (through speakers, or through the headphones)

It’s only when I connect the laptop (which is just for troubleshooting) to the USB and the ST2 from the laptop’s headphones out that the noise appears and is directly attributable to that ST2 from the laptop.

But with the desktop the same noise is heard with or without ST2 connected.

The first ST channel is audio output from a MIDI player. To get correct input signal level to the mixer, I have to raise it as shown, and yes they are both turned up at the sources.

As far as the headphone output on the laptop, there are no other audio outputs on the laptop, so I think I need to use that.

If I submit a ticket, I should just link to this thread I suppose?

40

@KeithJ A&H

Thanks for clarifying.
My bad for presuming that the Z10 had the same usb circuits at Qu and SQ.

I would still look at the pcs and other gear being the cause of the problem before the z10.

And I would still think that an audio interface would be easier than trying to find the usb related problems.