Makeshift Radio Broadcast Mixer

[TomHoward]

I have to put a makeshift radio broadcast studio together for an RSL studio.

I don't have a proper broadcast mixer, although I could buy one it's probably overkill.

 

The feature I'd ideally like would be monitor mute on mic channel being raised, pretty standard on broadcast desks I've used, and possibly the 'mic live' light.

 

I have a standard selection of small analogue desks eg Behringers and small Soundcrafts, and X32 consoles.

Is there an easy X32 configuration setting to do this at all? I don't think it's a software feature I've seen.

 

Alternatively I guess I could do it modifying a small desk and adding a sense relay or something, or is there an easy way on an analogue desk to confirm if a fader is up?

 

Thanks, Tom

[alistermorton]

In the good old days (some) DJ mixers had microswitches on the sliders to start the turntable motors when they were raised. Could you bodge something like that onto onto the faders for the mics?

[Brian]

In the good old days (some) DJ mixers had microswitches on the sliders to start the turntable motors when they were raised. Could you bodge something like that onto onto the faders for the mics?

 

In the old days that pretty much how it worked. Penny and Giles faders had microswitches built into them.

[DrV]

Some of the DJ desks I've repaired, which do fader-start on the decks, have an opto switch mounted on the PCB beside the fader and a little plastic paddle pushed onto the shaft. I think the Xone:XX range do for example. Would require some mechanical work but if you have access to a 3d printer it's probably not a big job.

[kitlane]

Probably a ridiculously complex way to do it but I can imagine a piece of software listening out for the OSC message sent when the fader is moved and sending an OSC message to mute the monitor channel in response.

 

*Edit. I was assuming an X32 was being used.

Edited March 25, 2020 by kitlane

[sandall]

The cheap'n cheerful way with a small analogue mixer would be to use Ch.1 (to give more space) & glue a microswitch below the fader-cap (if it's for a one-off event you might even get away with blutak or gaffer). That way you can switch as many things as you like. There is unlikely to be enough clearance between the fader body & the top-panel to mount anything under the top panel (though I have come across microswitches with long thin wire actuators)..

[TomHoward]

Thanks all, I might open an old Behringer desk and see what space is inside.

We have a Soundcraft EPM but I'd rather but butcher it for the sake of this.

 

I was wondering about Arduino measuring the fader values and then switching a relay on another output but my programming isn't that good. I might break a few wires out from the desk to a case outside of the desk and go from there rather than trying to fit it inside the desk.

 

On the one hand I don't really want to cut the EPM desk, but on the other hand it has much better PFL than the Behringer.

On the third hand, the X32 has much more onboard processing that might help with radio production.

 

Is there an off-the-shelf program that would be easy to do the OSC on? I guess I could use QLab but it might be easier just to sack off this off and buy an old Broadcast desk once I've spent a while on it.

[Peter F]

Replace a fader with a switched one?

 

Alps Fader K-type

 

Edit: Having reminded myself what the inside of an EPM looks like I accept this may not have be my most useful suggestion ever.

 

Cheers,

 

Peter

Edited March 25, 2020 by Peter F

[Dave m]

Could you use a side chain compressor between the monitor out and mic? Effectively the mic causes the monitor feed to duck?

[alistermorton]

Penny and Giles faders had microswitches built into them.

 

Penny and Giles - there's a blast from the past!

 

One small problem I can see with trying to measure the fader position electronically (by somehow reading the resistance/wiper voltage, perhaps) is that it will probably not have a DC wiper voltage. On an analogue mixer there's the signal it self, on a digital mixer I can imagine the faders (if they're resistive rather than linear encoders) being multiplexed so there could be digital noise on the signal too.

Edited March 25, 2020 by alistermorton

[TomHoward]

I’d only do that on the analogue, on the digital mixer I’d use the OSC route maybe, sounds quite viable but would tie up another computer maybe. I’m going to have a quick go metering a fader out to see if I can take a reliable DC reading off it which audio is passing through without affecting the audio signal as well.

[DrV]

According to the x32 schematics the faders produce a steady D.C. voltage (a proportion of Vref which is 3V3) which could be tapped off and buffered to do anything you like. It would be a faff but there's lots of room inside to put an extra PCB. Fun project though, during all this enforced downtime!

[timsabre]

X32 you can read the fader position over the network or even by midi, you don't need to bodge it

[DrV]

X32 you can read the fader position over the network or even by midi, you don't need to bodge it

MUCH better!

[IRW]

If you are interested in going down the OSC route, I could have a look into whizzing up a basic 'If this command comes in, send this command out' jobbie that could run in the background of a computer that's already involved on the network?