Arduino controlled mute switch


I’m trying to make a box that can pass audio from a DAC with XLR outputs to a monitor controller with XLR inputs. I want to be able to have a push button that can run a series of keyboard shortcuts while also cutting the signal from the XLR cables going to the monitor controller. I need to have the signal remain as transparent as possible. I have no real issues with the push button, but I’m not sure the best way to go about the audio path portion. Thanks anyone that can help out.

Here’s a good thread about muting XLR audio. Instead of a switch, you could use a relais.

lg, couka


Yeah I was thinking of using relays to make the switch. That thread helped to give a better idea of the connections. Now, what are some really good relays that can pass audio without any signal degradation?

"Now, what are some really good relays that can pass audio without any signal degradation?"
That's a loaded question. Electrically, audio is very low frequency. Cabling capacitance an length resistance is likely to play a larger roll in upper or lower frequency loss than a closed relay contact. Check on an audiophile forum and see what they recommend for relays and wiring/shielding/oxygen-free monster cable!

yeah I’ve definitely run around in circles with cable length, material, etc. Lately I’ve stuck with the tried and true standards and have been fine with cables.

The more I’ve been reading about relays, the more confused I get. I’m sort of stuck at the idea of whether to use a transistor and diode in the circuit. If I’m not using the relay to control any higher voltage devices, would the transistor and diode be necessary to keep from frying the arduino? Would it be safe to directly power a 5v relay from the vcc pin of the arduino?

I was looking at the diagram attached below that is using a switch to either short pins 2 and 3 together to mute, or leave the switch open and allow the input to pass to the xlr output. Would this make sense to use for a relay?

Would it be safe to directly power a 5v relay from the vcc pin of the arduino?

No. An arduino is not suited to deliver enough current and without a flyback diode, the coil will fry the arduino sooner or later.

The voltage on the switch side of the relay doesn't matter, since it is completely isolated anyways.

lg, couka

OK Thanks a lot I think I have a grasp on most of this now. So If I'm walking through this, would it make sense to use two relays per XLR connection? So for each relay I would go from an output pin of the arduino to a transistor to the relay with a diode strapped across the coil. The switch section of each relay would cut the hot and cold pins of the xlr. Is there a better way to do this?

Also, for a quick test to make sure I understand how this relay works, can I use the arduino to power the relay while simultaneously using it to power an led? If I connect the relay from an output pin to transistor to relay with a diode, write output pin high, switch closes. On the switch side can I run from the vcc pin of the arduino to one terminal of the relay, other terminal of the relay to the led, led to ground? I've only seen people use separate power supplies, but I'm assuming that's because relays are typically used to control higher voltage circuits?