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Mix-minus setup: Cannot send computer sound from USB to the caller

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Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Mon Mar 08, 2021 3:52 pm

Hi,

I have a Yamaha MG12XU mixer. I am using FX1 aux to send out my signal to the outside.

I call the other person over the phone. The person I call is able to hear my input channels except, except the USB input.

- I playback music from my computer and I have a USB switch ON for Channel 11/12. I hear the music played from my computer and the PFL meter shows around 0dbFS when I play it.
- I have the Aux 1 knob on the USB input channel (11/12) all the way clockwise to the end! The channel is ON and its PFL is off.


What other settings I should check, please?

Any help would be much appreciated.

CS
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Sam Spoons » Mon Mar 08, 2021 3:58 pm

As far as I can tell for a brief glance at the manual the Yamaha MG12XU only routes USB returns to the main L/R bus.

edit :- that is wrong I think, just trying to puzzle it out, it would be so much easier if I had the mixer in front of me :headbang:
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Sam Spoons » Mon Mar 08, 2021 4:11 pm

Ok, can you press two or more of the routing [1-2] [3-4] [L-R] buttons, if so then I'd try sending the stream from a pair of groups rather than the aux send but, that said your aux send method should work so check the attenuator function and the [Line/USB] button as well as the channel [ON] button on the USB channel.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Kwackman » Mon Mar 08, 2021 4:21 pm

As Sam says, the "Attenuation Function" button (page 22,28 of manual) are worth checking out.
Also, from what I can see, Aux 1 is only Pre-fader?
If that is so, it might not be the best for a mix-minus as contributors will hear stuff even if you've faded it out.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Hugh Robjohns » Mon Mar 08, 2021 4:23 pm

If your phone called can hear other channels via Aux 1, then it should work on the USB input channel too.

First thing I'd try is listening to the FX1 output to make sure it's actually coming out of the desk. If your USB source was, for example, polarity inverted on one channel for some reason you'd hear it in stereo on the main mix out and monitoring speakers, but the (summed mono) Aux 1 output would cancel to silence.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Mon Mar 08, 2021 7:50 pm

Kwackman wrote:As Sam says, the "Attenuation Function" button (page 22,28 of manual) are worth checking out.
Also, from what I can see, Aux 1 is only Pre-fader?
If that is so, it might not be the best for a mix-minus as contributors will hear stuff even if you've faded it out.

I think the attenuator, would make the input from USB even softer! wouldn't it?
I suppose Aux 1 and Aux 2 are both post fader. But I will check that. Thank you.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Mon Mar 08, 2021 7:55 pm

Hugh Robjohns wrote:If your phone called can hear other channels via Aux 1, then it should work on the USB input channel too.

First thing I'd try is listening to the FX1 output to make sure it's actually coming out of the desk. If your USB source was, for example, polarity inverted on one channel for some reason you'd hear it in stereo on the main mix out and monitoring speakers, but the (summed mono) Aux 1 output would cancel to silence.

I am testing this with ""Echo / Sound Test Service" of Skype.

It seems my mics can only send signals to Aux 1 and the "Echo / Sound Test Service" records them just find.

It seems beside the USB, even when I insert my synth outputs ( stereo) to

1) any input including Mono: Ch 4 ( just one of the cables), or
2) both cables into stereos: 5/6,7/8,9/10,11/12,

I don't hear anything out of them recorded with I try "Echo / Sound Test Service.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Hugh Robjohns » Mon Mar 08, 2021 8:55 pm

csarami@ncsu.edu wrote:I am testing this with ""Echo / Sound Test Service" of Skype.

As I said, it would be a lot more helpful to check the actual Aux signal coming out of the console, just so you're testing one thing at a time.

It seems my mics can only send signals to Aux 1 and the "Echo / Sound Test Service" records them just find.

Looking at the manual, the only obvious difference between the mic channels and the stereo channels is the mono summing to feed the Aux buses. So I can't see any obvious reason why those channels shouldn't make it to the Aux output (assuming the channels are turned on, of course).

It seems beside the USB, even when I insert my synth outputs ( stereo) to
1) any input including Mono: Ch 4 ( just one of the cables), or
2) both cables into stereos: 5/6,7/8,9/10,11/12,
I don't hear anything out of them recorded with I try "Echo / Sound Test Service.

It would be worth trying the stereo channels with only one input connected.

It would also be worth checking that the output level From Aux 1 is roughly the same for both mic signals and line sources.

It's an intriguing problem.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Sam Spoons » Mon Mar 08, 2021 9:41 pm

csarami@ncsu.edu wrote:
Kwackman wrote:As Sam says, the "Attenuation Function" button (page 22,28 of manual) are worth checking out.
Also, from what I can see, Aux 1 is only Pre-fader?
If that is so, it might not be the best for a mix-minus as contributors will hear stuff even if you've faded it out.

I think the attenuator, would make the input from USB even softer! wouldn't it?

Not if it is set to max attenuation, make sure it is set to off.

I suppose Aux 1 and Aux 2 are both post fader. But I will check that. Thank you

Aux 1 is pre-fade, aux 2 is switchable. It is normal for the low numbered aux sends to be pre and high numbered post, sometimes with some of the others switchable between pre and post, A post-fade aux will depend on the channel fader as well as the aux knob for it's live, pre-fade will only be affected by it's aux knob.

Next step is definitely to follow Hugh's advice and work through the system logically. If you are using your phone as a streaming device does Skype have a background sounds cancel option (zoom does I believe)?
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Tue Mar 09, 2021 2:33 am

Hugh Robjohns wrote:
csarami@ncsu.edu wrote:I am testing this with ""Echo / Sound Test Service" of Skype.

As I said, it would be a lot more helpful to check the actual Aux signal coming out of the console, just so you're testing one thing at a time.

I have checked it!

I hooked up my small speaker to Aux 1 out and played back from the computer and also from Synth. I can hear both fine. It seems they don't make it to my iPhones microphone/input device.

Here is what I have purchased and my setup:

A) I have an Apple Lightning to 3.5 mm Headphone Jack Adapter
B) l have connected to that a Sennheiser PCV 05 Combo Audio Adapter
C) the microphone end is connected to Aux 1, and the headphones' end is connected to Channel 5/6 with a TRS 1/8inch to dual mono unbalanced TRS 1/4 inch.
D) I have the aux 1 knob on 5/6 channel off so it doesn't feedback to itself.
E) On the master section I have Aux 1 on 0 ( nominal).
Image
I desperately need help with this!
Thank you very much.

Any help would be much appreciated.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Tue Mar 09, 2021 2:36 am

Sam Spoons wrote:Aux 1 is pre-fade, aux 2 is switchable. It is normal for the low numbered aux sends to be pre and high numbered post, sometimes with some of the others switchable between pre and post, A post-fade aux will depend on the channel fader as well as the aux knob for it's live, pre-fade will only be affected by it's aux knob.
Thank you. As you see in my image above, Aux 1 is switchable pre/post. So I suppose Aux 2 is sent effect it also adjust the built-in effects of the MG unit.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Kwackman » Tue Mar 09, 2021 9:52 am

csarami@ncsu.edu wrote:I hooked up my small speaker to Aux 1 out and played back from the computer and also from Synth. I can hear both fine. It seems they don't make it to my iPhones microphone/input device.

Can I double check something- I'm easily confused!
You have checked that audio sources in your mono channels do make it to the iPhone's input, but the USB/synth don't?
Silly question, how do you know what the iPhone is receiving?
I thought the iPhone input would be looking for mic level rather than line level, but if you say the mono channels DO make it to the input of the iPhone...I'm wrong...again!


csarami@ncsu.edu wrote:Aux 1 is switchable pre/post
My fault for bringing that red herring up. The manual confused me as it only shows the bigger models where Aux1 is only PRE. But, in the signal flow diagrams, it shows the MG12-XU with the Pre/Post option. Apologies.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby Hugh Robjohns » Tue Mar 09, 2021 12:31 pm

So... it seems we now know for sure that the USB/stereo channel signals are reaching the Aux 1 output, along with the mic channel signals.

Is it also safe to presume that these are all at roughly similar levels? I ask because if the USB channels were substantially louder that could trigger some kind of AGC/limiter that might give the impression of low level...

Given all the above, it appears the problem lies somewhere in the phone or the streaming service you're using, rather than the console... so that's progress! ;)

Someone mentioned an auto-cancellation option in that system and it would definitely be worth looking into that.

Are you sure that your Aux1 mix-minus really is a 'clean feed' and doesn't contain anything coming back from the phone?
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Tue Mar 09, 2021 1:16 pm

Kwackman wrote:
Can I double check something- I'm easily confused!
You have checked that audio sources in your mono channels do make it to the iPhone's input, but the USB/synth don't?

That is a critical question indeed. "The mono channels make it to the iPhone input If and only if, the source is a Microphone ( dynamic or condenser)

Kwackman wrote:Silly question, how do you know what the iPhone is receiving?
Again a good question. I know it via Skype Echo/Sound test service


Kwackman wrote: I thought the iPhone input would be looking for mic level rather than line level, but if you say the mono channels DO make it to the input of the iPhone...I'm wrong...again!

The Aux1 knob has taken care of this I suppose. Please note I can monitor the signal in my headphones just fine.

Kwackman wrote:
csarami@ncsu.edu wrote:Aux 1 is switchable pre/post
My fault for bringing that red herring up. The manual confused me as it only shows the bigger models where Aux1 is only PRE. But, in the signal flow diagrams, it shows the MG12-XU with the Pre/Post option. Apologies.
Thank you for your time.
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Re: Mix-minus setup: Cannot send computer sound from USB to the caller

Postby csarami@ncsu.edu » Tue Mar 09, 2021 2:31 pm

Hugh Robjohns wrote:So... it seems we now know for sure that the USB/stereo channel signals are reaching the Aux 1 output, along with the mic channel signals.
Yes. They do reach Aux1 output. As I mentioned in my last post, only the microphone. I just did another experiment:

1. The stereo channel 7/8 have also an xlr microphone input aside from the 1/8" stereo dual unbalanced (line) inputs! When I connect a microphone to its XLR input, it gets recorded in the Skype test service. So I am guessing [b]the issue is with the signal levels of non-microphone sources.

Hugh Robjohns wrote:Is it also safe to presume that these are all at roughly similar levels? I ask because if the USB channels were substantially louder that could trigger some kind of AGC/limiter that might give the impression of low level...

At least when I monitor them with a microphone. I attenuated the USB input signal by -9 dB and raised the fader level to compensate here. The PFL meter when I play music from my computer is around 0dB. is how I check the signal levels:

Let say I want to check the signal level of the Channel fader 11/12 which is used for the USB input signal.
1. I turn off the channel fader by pressing the ON button.
2. I press the PFL button.
3. Play music to send signals to the channel.
As I said, the USB doesn't get recorded into my iPhone!

Hugh Robjohns wrote: Given all the above, it appears the problem lies somewhere in the phone or the streaming service you're using, rather than the console... so that's progress! ;)
I don't think this is about streaming sevice. I have tested it with Zoom and also Whatsapp. Same result.

Hugh Robjohns wrote:Someone mentioned an auto-cancellation option in that system and it would definitely be worth looking into that.
In fact, on Zoom there an option to set the "Echo cancellation". I set it to auto and also aggressive. Nothing changed!

Hugh Robjohns wrote:Are you sure that your Aux1 mix-minus really is a 'clean feed' and doesn't contain anything coming back from the phone?

I have the Aux 1 knob set to 0 (turned off) on channel 5/6 (iPhone's input channel).

Finally, I go something. I swapped my brand new "Sennheiser PCV 05 Combo Audio Adapter" with the "Movo TCB2 XLR Microphone to TRRS Smartphone Adapter with Headphone Jack". It seems all the signals microphone, USB and my synth reach the iPhone just fine. The female XLR end of the latter is connected to Aux 1 using XLR Male to 1/4-Inch TRS Male. I need to change this adaptor as the signal is not clean and is a bit noisy, but I cannot find it anywhere and as you see it is sold out

I guess the issue is the incompatibility of the Sennheiser audio adaptor for high voltage ( consumer level) signals! or maybe the seller send me a bad one. I will return it for sure.

Thank you very much, Hugh and everyone for the help! I learned quite a few things from you guys! Again Hardware is the trouble maker!
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