Making the audio desk send low signal always

[Kurt]

So I'm in a pickle. The audio rig I'm working on was previously somewhat controlled by a Crestron system, but after it bit us too many times we pulled all the Crestron out of the system. We have D&B D10, D30, and D80 amplifiers. The audio desk is a CL5, in between all of it is a redundant Dante network and Symmetrix DSPs to feed audio to the amps.

I'm interested in the autostandby and wakeup function because Crestron was our way of turning the amps on and off, and without it my only other option is to do it through the R1 software, which is not exactly a streamline process.

Does anyone know if there's a good way to get the CL5 to send a slightly higher signal to the outputs? I'm finding there isn't any difference in noise on the line between the console being on and off, so the amps currently don't have anything to work off that will ensure the amps are on as long as the console is on.

 

[Kurt]

@Kurt Since no one else has replied to your query, let's try a couple of things:

1; Consider sending a LOW LEVEL low frequency sub audible tone whose frequency is below the output capability of your woofers and sub woofers.
Alternately send a LOW LEVEL high frequency tone above the output capability of your tweeters and super treeters.

That was the direction I was going. I attempted to assign the oscillator to all of my outputs and setting it to a low level sinewave, but I quickly found out that it will not default to output on startup, so that was out.

Additionally I've been thinking I could put a tone generator in one of the DSPs, route it to an open Dante channel on the board, and have the channel on and sending to all the amps in our rep scene, and it should come on and off with the board. Additionally I've been thinking I could EQ the tone out on the amp to further ensure it isn't being sent to anything.

 

[FMEng]

Using tone is going to gets messy very quickly, because a single frequency would get filtered out by crossovers and other filters in the DSP, and not activate all of the amplifiers.

Looking at the manual for a 10D, I see something to try. Set a very low audio trigger threshold, like -80 dBu, with a long time to standby, such as 2 hours. Then, upon turning on the console, fade up an unterminated mic channel to apply some white noise to the amps for 10 seconds. No need to maintain the noise, since the long time out will keep the amp from going to sleep until well after the show is over. The threshold can be quite low, but setting it too low might allow circuit noise from the DSP to trigger them, so you'll have to experiment.

Another option is that the amps have GPIO contol inputs that can be configured to turn the amp on when 24 V DC is applied. That would be the simplest way to remotely turn them on and off. The only wrinkle could be whether you can turn all of them on at the same instant without having inrush current trip a circuit breaker. The only way to know that is to try it, or wire separate controls to smaller groups of amps.

A last option is to use a power sequencer to control power to the amp line cords. A Furman M-8S is one example, but there are a bunch out there. The sequencer(s) can be remotely controlled by a low voltage switch.

 

[MNicolai]

d&b amps are pretty well behaved in their auto standby mode. I wouldn't worry about cycling them on/off -- I certainly wouldn't hard-cycle the power with an outboard power sequencer because it forces the amps to reconnect to the network and reinitialize each time.

If anything, I would look at muting the outputs of the Symetrix, which you could set up pretty easily through Symetrix's web app and control through a phone/PC/tablet, or you could add an ARC or WX wall station near the console. You can probably also do it simply with an on/off switch near your console that opens and closes a GPIO contact on your Symetrix and/or your d&b amps.

Symetrix web app:

ARC-WEB - Symetrix

ARC-WEB Virtual User Interface for End-User Control of Presets / Volume / Mute / Source Series Features Virtual User Interface for Symetrix DSPsUser Control of Presets / Volume / Mute / SourceAccess Via Smartphones / Tablets / PCsUsed With Radius / Edge / Prism / Solus NX / Jupiter / Zone Mix...

www.symetrix.co