Audio Mixer Issue

[arseal]

Hi. Let me start by saying I have very little understanding of OBS and audio mixing, but I was put in a role where I have no option but to figure it out. I'm not even 100% on the setup, but this is what I have gathered.

I have a pan/tilt camera that plugs into a laptop via ethernet to USB-C. It delivers the sound and audio. I also have a peavey unity dr16 wifi mixer. For the audio feeding into OBS, it is a podium mic and a lapel mic (only one is turned on at a time). This goes through the mixer and out over the ethernet to usb-c.

These audio sources are mainly controlled through the peavey app for ipad, but can also be tweaked in OBS.

My issue at the moment is when all audio sources are muted, the audio mixer source will "jitter" back and forth between -60 and -45 dB. I don't like this, because it makes it look like an audio source is active and being picked up by obs, when in fact it is not.

The only way I've found to fix this is to lower the volume slider on the obs slider and/or the wifi mixer app BUT then the volume on the stream is too low.

Any suggestions?

 

[AaronD]

According to Sweetwater, that mixer can do Dante by swapping an expansion card, from the default 4x analog inputs, to a different one with Ethernet. The built-in Ethernet is probably control-only with no audio whatsoever. Is that what you're doing? Dante over Ethernet with that expansion card?

Or are you running analog out of the mixer and into something else? Like maybe the camera? Dedicated wire for one or two channels of audio, and nothing else.

If you're running analog, then what you're seeing in OBS could very well be analog noise. The mixer itself is indeed silent, but that noise gets into the wire *after* the mixer. There are ways to reduce that noise pickup while staying analog - 100dB of isolation is difficult but possible, compared to your 45 to 60 - but it can never be eliminated. The details get technical in a hurry, and depend a lot on what you actually specifically have.

 

[AaronD]

The only way I've found to fix this is to lower the volume slider on the obs slider and/or the wifi mixer app BUT then the volume on the stream is too low.

*That* suggests that the mixer is not silent when you want it to be. If turning *that* down fixes it, then everything after that point is okay.

So what comes *before* that point? Do you have some analog noise on the mixer's *inputs*, perhaps? Not necessarily enough to hear in the PA over the normal room noise, but it does show up on a sensitive meter? And you're not muting things when they're not being used at the moment?

There are several things that professional audio engineers perpetually disagree on. One of them is muting discipline:

• Some are sticklers for never having anything on that isn't being used in that exact moment. Dedicated engineer, stick to your post, pay attention, and always enforce that. This produces the least noise and has the least chance for the system to misbehave, but it requires constant dedicated attention.
• Some keep everything on, and just pull the faders back a little bit. Still on, but not going to feed back. If someone grabs a mic and starts talking while the engineer is doing something else, (s)he can hear it, snap back to the desk to see which one it is, and push that fader up.
• Some keep everything on, and even leave the faders up. This doesn't sound any different at all at first, if someone grabs a mic without warning - compared to the previous one that is quiet at first and then turns up - but it does allow the most noise through, and depends on the system being relatively immune to feedback. (the annoying tone that increases in volume all by itself)

 

[Lawrence_SoCal]

Aaron knows WAY more than I do... but in case these questions/comments help

I have a pan/tilt camera that plugs into a laptop via ethernet to USB-C. It delivers the sound and audio. I also have a peavey unity dr16 wifi mixer. For the audio feeding into OBS, it is a podium mic and a lapel mic (only one is turned on at a time). This goes through the mixer and out over the ethernet to usb-c.

please clarify over ethernet to USB-C???
- is that the pan/tilt camera is networked... and your laptop has a USB-C ethernet adapter to connect to network switch?
- and as Arron asked, is that mixer using Dante for audio output over Ethernet?

My issue at the moment is when all audio sources are muted, the audio mixer source will "jitter" back and forth between -60 and -45 dB. I don't like this, because it makes it look like an audio source is active and being picked up by obs, when in fact it is not.

Where, exactly, are the audio sources 'muted'.. .sorry, yes, it can make a difference. At the mic themselves, at the mixer, or ??
And is that Mic source your show an image of ONLY the Mixer, or does it also include the camera mic?

Personally, I disabled Desktop Audio globally, and only have device specific Audio Sources in my scenes

Assuming Mic (your image) is ONLY the Mixer
- On the mixer, do you have a Main mix (for in-house speakers) and a sub-mix for your output to OBS Studio. (ideally you would) If yes, a Mixer Mute, depending on exactly with one, how configured, etc, may NOT be muting the sub-mix output
I wouldn't be surprised if iPad app is 'Mute'ing Main out, but not touching (or at least not the way you expect) the sub/aux-out? or something along those lines ?? Or if there is maybe another audio source hooked up to the mixer you aren't aware of? lots of possibilities

 

[AaronD]

Where, exactly, are the audio sources 'muted'.. .sorry, yes, it can make a difference. At the mic themselves, at the mixer, or ??

It's *probably* okay, regardless of which of those it is. Not guaranteed, but probably. Normally, you'd think that turning a mic off *at the mic* would allow the high-gain preamp to pick up a ton of noise...until you take one of those mics apart and see that the mute switch actually shorts it out instead of disconnecting it. That allows even less electronic noise than it does when the mic is "on".

(It's okay to short it out at that point, because it's a direct physical conversion with hardly any energy involved and no active electronics yet. It also makes the physical diaphragm stiffer, which nobody will notice. For an active mic that requires a battery or phantom power to run an internal pre-preamp, you probably don't want to do that...but they have their own methods anyway, if at all.)

My guess is that the "noise" is actually environmental acoustics being picked up by a mic that is not used at the moment but still open.

- On the mixer, do you have a Main mix (for in-house speakers) and a sub-mix for your output to OBS Studio. (ideally you would) If yes, a Mixer Mute, depending on exactly with one, how configured, etc, may NOT be muting the sub-mix output
I wouldn't be surprised if iPad app is 'Mute'ing Main out, but not touching (or at least not the way you expect) the sub/aux-out? or something along those lines ?? Or if there is maybe another audio source hooked up to the mixer you aren't aware of? lots of possibilities

That is absolutely possible! See this settings page from a different brand of digital mixer (Behringer X-Air):

Notice that each tap point also has an option for whether it respects the Mute or not. Not respecting the Mute is nice for in-ear monitors, so that the musicians can be comfortable as they set up, before they're ready to send to the PA. But for the application in this thread, they probably *should* respect the Mute.

 

[Lawrence_SoCal]

In our case, we use a Sub/Aux mix as certain audio sources (Pipe Organ, Piano, and Choir) should NOT be amplified in-house, but are required for livestream audience... see we have multiple mics with the main Slide Faders set to 0 for Main Output, but normal output for sub-/aux-mix, which is for livestream. [Main and Sub/Aux mix all controlled via physical dials on panel]

Our older, analog (with USB out option) mixer isn't sophisticated enough to run compression on sub/Aux mix only... otherwise, I probably would ... but other discussion regarding use of Audio Compression for non-HiFi livestream audio