Audio Source Switching

[David Ellis]

Hi. We are a drive-in. We play house music until the movie starts. I am trying to figure out how to automatically switch from house music to the projector audio when the movie starts. Any suggestions would be GREATLY appreciated.

Our setup is... NEC 3541 laser projector with audio converted to RCA. House music is played via RCA. We have a JNIOR as well, in case that is helpful.

Thanks in advance!

[Caleb Williams]

Can you provide a little more information about the audio system you're using? Inputs, outputs, and any automation capability could provide an answer to your question depending on the equipment.

[David Ellis]

Hi Caleb. Thank you for the reply. That is actually everything. Very simple setup...

Two Sources:
1) The projector's audio is converted to left/right RCA.
2) House music is played from a PC via left/right RCA.

One Output:
1) left/right RCA (this goes to our FM transmitter).

We have a JNIOR that is new in the box. We also have a Home Assistant running on a Pi. I am open to purchasing whatever maybe needed. Thanks!

[Caleb Williams]

This option allows a 12V trigger signal to control the output: https://www.bobwireaudio.com/rca1
I assume this is something like what you're looking for. It could be wired up with the jnior to trigger. Do you use a cinema server like Dolby or GDC to play the movie? It shouldn't be too hard to connect everything up so you have cues in an SPL trigger the audio change

[Lindsay Morris]

Its now well over 10 years since I payed with Digital projection and in my situation then I had a Dolby CP650 doing the sound and on the Playlist setup via the server (then a Dolby DSS 100) and I could set cues in the playlist to switch audio from background pre-show music to the output from the server as the movie stuff started..initially the screen ads.

I could set volume levels for each individual clip so that what came out in the auditorium was a CONSTANT level with no violent jumps up and down in sound levels as one often gets with trailers.

The server also controlled the lighting not only for the carpark but also the auditorium dimming down to half light for screen ads etc and then to OUT once the feature came on.It was easy peasy and made for good presentation.

As the movie ended the lights came back up and the sound went back to preshow feed which was just a MP3 player with hundreds of track on it running continually once the bio box was powered up..all on a micro SD card.

Each night I just powered up the bio box and walked away and left it to do "its" thing which it did night after night with never a glitch and I stood on the door doing the tickets .....projectionist no longer needed which was the best part moving to digital.

Surely you have a server on which to setup your playlist so I would imagine that on that you can set cues to do what you want it to do in controlling your audio processor.

[Ryan Gallagher]

Care to elaborate on the word "automatic"? Do you want just a couple faders you can move to cross fade or switch the two sources? A litteral toggle switch? Or do you want something that automation or the home assistant can trigger?

From your description it doesn't even sound like you have a stereo RCA mixer, switch, or combiner... are you just live swapping the RCAs to perform the switch?

The gamut of solutions (and relative costs) is pretty wide on what is possible here.

[David Ellis]

Care to elaborate on the word "automatic"? Do you want just a couple faders you can move to cross fade or switch the two sources? A litteral toggle switch? Or do you want something that automation or the home assistant can trigger?

From your description it doesn't even sound like you have a stereo RCA mixer, switch, or combiner... are you just live swapping the RCAs to perform the switch?

The gamut of solutions (and relative costs) is pretty wide on what is possible here.

"Automatic" meaning Automated, meaning the audio switches without additional human intervention. Currently we are doing this manually which is very cumbersome. I am willing to buy whatever is needed (within reason). Thanks!

[David Ellis]

Its now well over 10 years since I payed with Digital projection and in my situation then I had a Dolby CP650 doing the sound and on the Playlist setup via the server (then a Dolby DSS 100) and I could set cues in the playlist to switch audio from background pre-show music to the output from the server as the movie stuff started..initially the screen ads.

We have a Dolby IMS2000. I see the IMS2000 has cue capability, which is perfect. I just don't know what this "cues" to that actually controls everything.

[David Ellis]

This option allows a 12V trigger signal to control the output: https://www.bobwireaudio.com/rca1
I assume this is something like what you're looking for. It could be wired up with the jnior to trigger. Do you use a cinema server like Dolby or GDC to play the movie? It shouldn't be too hard to connect everything up so you have cues in an SPL trigger the audio change

Thanks so much for this! We use a Dolby IMS2000 (even open to changing that if something else is better).

The RCA1 you linked seems like a very easy solution. The auto sense alone may even work. But I am also excited that it has a 12v input to trigger the source switch.

I have two ideas with the 12v...
1) The JNIOR can send a 12v and that can be activated via a cue in the show playlist.
2) The JNIOR can send a signal via MQTT to Home Assistant and then Home Assistant can send a 12V to the RCA1 (via any number of zwave devices).
I really really wish MQTT was directly in the IMS. I know this is a little niche, but anyone know if any cinema server has MQTT built in?

Thanks again!

[Gordon McLeod]

what are you using to generate the analogue audio from the IMS 2000

[David Ellis]

what are you using to generate the analogue audio from the IMS 2000

The audio goes IMS2000 >> DAX602 >> Odyssey DA6-3 >> then via RCA to our FM transmitter.

Sidenote: It was set up like this about 15 years ago. I'm unsure why it takes 3 steps to go from digital to analogue. I’d love to update this because there’s A LOT of signal loss currently.

[Harold Hallikainen]

A JSD-60 would be nice here. IMS can send commands directly over Ethernet.

[Ryan Gallagher]

If you have an IMS2000 for cues, both approaches are probably valid. Either directly signaling via GPIO (might require a relay if there is a voltage expectation difference or you want to isolate better). Or over network to your JNIOR, which can then signal whatever devices need automating similarly.

Lots of people would recommend consolidating those automatable things to the JNIOR so you don't have to reinvent that wheel if your projector or IMS ever changes.

Of course as Harold suggested, a dedicated audio processor that is more suited to outputting what a drive-in typically needs might also be worth considering.

The device Caleb provided would suit the RCA switching bill. But if you have budget to work with you might consider other approaches such as the alternative cinema audio processor, or even just a "digital" mixer that has some fairly standard network controls. If you want to get really fancy get one that supports WIFI controls from a tablet so you can poke at it from anywhere in the venue.


Probably overkill for what you are asking for, but the Berringer X-Air 32 might suit that bill and give you lots of ways to expand your non-sync input needs for all kinds of events.
Behringer X32 Rack Digital Mixer Package with Rack Case | Sweetwater

[David Ellis]

If you have an IMS2000 for cues, both approaches are probably valid. Either directly signaling via GPIO (might require a relay if there is a voltage expectation difference or you want to isolate better). Or over network to your JNIOR, which can then signal whatever devices need automating similarly.

Lots of people would recommend consolidating those automatable things to the JNIOR so you don't have to reinvent that wheel if your projector or IMS ever changes.

Of course as Harold suggested, a dedicated audio processor that is more suited to outputting what a drive-in typically needs might also be worth considering.

The device Caleb provided would suit the RCA switching bill. But if you have budget to work with you might consider other approaches such as the alternative cinema audio processor, or even just a "digital" mixer that has some fairly standard network controls. If you want to get really fancy get one that supports WIFI controls from a tablet so you can poke at it from anywhere in the venue.


Probably overkill for what you are asking for, but the Berringer X-Air 32 might suit that bill and give you lots of ways to expand your non-sync input needs for all kinds of events.
Behringer X32 Rack Digital Mixer Package with Rack Case | Sweetwater

I can swing a little bit of a budget. With this solution, what would the flow be and/or what would this be eliminating? For instance, would this get rid of the DAX602 and Odyssey DA6-3?

[Tj Hopland]

You could look for a USL ECI-60, that would replace the DAX602. Those have been reliable and generally got replaced with other things for other reasons so there seem to be plenty of them around. Any other D cinema era gear is either going to cost more because its still good reliable stuff or its going cheap because they didn't age well and are no longer supported.

The ECI-60 has digtial in for the IMS2000 as well as the analog 2 channel you are looking for as well as stuff that could also maybe be useful like a optical and 2 coax and basically 2 6 channel analogs also. Its remote controllable from Ethernet so the IMS may be able to do it or the Jnior could do it over RS232 if the the network connection turned out to be too finicky.

I would have to look to confirm but I think all the pinouts are the same between the ECI and DAX so that part would be just a straight plug in and you could keep the DAX as a quick plug in backup if you were worried about a failure. The only slightly complicated thing depending on your skills and resources is the analog 2 channel input is shared in one of the 6 channel input jacks on a DB25 connector so you would need to make a custom DB25 to RCA cable if you want to use analog. If your house music source has a coax or optical out then you are set because those have the usual rca coax jacks and the usual square optical.

Dolby DMA8+ was similar but didn't have the 2 channel analog option but it did have the coax and optical. Coax was BNC so you would need an rca adapter to hook up consumer gear.