Re-Connecting Speakers to Sound Processor

[Jake Sinn]

John,

I don't think each actual wire coming from each amp is labeled (on the wire), I think each amp is labeled on the front with a sharpie by where the power switch is. I'm assuming it wouldn't be too hard to figure out from there? Just follow which wire is coming out of each amp, the connect to the Odyssey board.

Edit: I'm reading the processor manual, and it talks about the processor being grounded, is that necessary, and how is that done properly?

[Dave Macaulay]

What amplifiers do you have? Cinema grade will have "balanced" terminal block or Phoenix connector input, many non pro amps are "unbalanced" with RCA input connectors.
With balanced input you want shielded pair cable like Belden 8451 and all 3 conductors connected at both the amp and Odyssey card end - "+", "-", and shield.
Unbalanced RCA, same cable but connect shield and "-" to the outer ground and "+" to the inner, and do not connect shield at the Odyssey card. Unbalanced connection does tend to have hum problems.
The card terminals are super small and devilish to get wires into, connect the easier bottom row first so they aren't blocked by the top wires.

[Jake Sinn]

There are no shields. Just the + and -. I'm not sure of the amplifiers that are there, I don't have access to them right now.

[Carsten Kurz]

Jake - you wrote these amps are labeled somewhere near the On/Off Switch? Can you send pictures of these labels?

There are channel test DCPs. They play an identifying voice through each channel. Such a DCP would be useful after you finished your work to check wether everything is okay.

Whatever - we need to see where the other end of these red/black wires go to. There is not much you can damage, however, you should make sure processor and amps are powered down while you connect, and when you play test signals, that the volume on the processor is set really low.


Why didn't you just unplug the Odyssey board when you removed the processor?

- Carsten

[Jake Sinn]

Jake - you wrote these amps are labeled somewhere near the On/Off Switch? Can you send pictures of these labels?


- Carsten

I don't have any photos of them and don't have access to them right now.

Well, wouldn't the other ends of each cable go into its appropriate amp, they are untouched. The only thing that happened was the wires being cut from the processor, and the processor took out.

I did not personally remove it.

[Carsten Kurz]

If the amps are labeled e.g. with Left, Right, Center, Subwoofer, Surround, etc., it is probably easy to reestablish the proper wiring. Am I right that there are only 5 cables? So, no LFE/Subwoofer, or no Stereo Surrounds?

[Marcel Birgelen]

The original breakout board indeed only has 5 cables (2 x 5 wires) connected.

Jake: Is it possible to share pictures of the back and front of the amplifiers or, since you don't have access, ask someone to take those pictures for you? This would make clear if those amps have balanced or unbalanced inputs, how many channels there are per amp and maybe there is some labeling left what channels map to what amplifiers.

Without pictures or a clear description of the amps, it's just a bunch of guesswork.

[Jake Sinn]

Carsten: Yes, only five channels. Center, Right, Right Surround, Left, and Left Surround.

[Carsten Kurz]

Well, if you get there, I would first trace every cable/wire pair to the front (or whereever they are connected at the amp) and replicate it's label to the rear end near the Odyssey board. So you can easily see which cable you are dealing with there. Then the labeling on the Odyssey board will tell you what goes where. We also need to know/see the cable connection at the amp, or at least the amp type. However, if you can tell from your photos the exact location where a single wire goes to, that may not be necessary. There are two different ways how to wire amp inputs, and the Odyssey board has connectors for both methods - single ended/ground referenced, and balanced. The photos as I can see them are slightly blurry. I can see though that from the top right, 1+2 and 4+5 are wired, so, that tells us enough. At least if your amps are all wired the same.

Top right 4+5 are Left Surround, 1+2 Right Surround. The lower row carries Left, Center and Right. Your are using the red wire for each + signal, and the black for each neg. Indeed, SW/LFE is not connected.

The cable with the residual tape (if still present) is easiest, it goes to Right + and -

https://static.wixstatic.com/media/0...d3e182~mv2.jpg



- Carsten

[Jake Sinn]

I’ll attach the only photo I have of the front of the audio rack (it is a bit blurry and dark). I just realized this - the audio rack from the theater we are dealing with has 6 amplifiers, but the other theater, which is bigger, has 5 amplifiers, but on the back of the Odyssey boards for both theaters have 5 wires. I guess one of the amplifiers is out of commission and just wasn’t removed?

I didn’t know that that tape had anything to do with going to a certain channel. Why is that? That the cable with tape goes to the Right channel? Because that is only the case in the theater we are trying to reconnect. The tape may have been cut, if that is the case, does the tape need to be there, or can it be connected just like the other ones?

The amps were never unwired. The only thing that happened was the processor being taken out, and the cables coming from each amp being cut from the Odyssey board.

[Carsten Kurz]

The photo of the amp rack is useless, one can not even guess the type of amp. There are stereo and mono amps. Sometimes, channels are paired, sometimes channels or entire amps are not used. Follow the wires!
The tape bit is just an easy way to recognise where this cable needs to be reconnected. Solved for one channel, four to go.
Well, you could connect the wires arbitrarily, play a channel test DCP, then go to the auditorium and check and note where they came out, then correct it. Again, if the cables go straight to the amps, and the amps have channel labels, it should be easy.

[Jake Sinn]

Is putting tape on the right channel a common thing? I didn’t realize that - so thank you for pointing that out.

Question that doesn’t relate to this - how were the speakers being connected to the projector? I see the Non-Sync RCA cables, but those were connected to the DVD player. And I see those two Ethernet RJ45 cables, but I thought those were for automation. Those are the only options.

Also - any thought on why there are 5 cables going into the Odyssey board but there are 6 amps?

[Harold Hallikainen]

The AES/EBU input on the JSD-60 is on an RJ45. You should have a cable going to the server driving this.

Harold

[John Thomas]

It's not like there's a tape standard or something. He just noticed from your first pictures that the wire connected to the Right channel terminal has a band of tape on it.

As has been stated a few times: once you have ID'd all of the channels you should absolutely label them with masking tape to save you or the next guy the hassle next time.


In that picture I see three amplifiers with two channels apiece, which is a pretty common setup for a 5- or 6-channel system.



When do you think you'll be on site to take a look at this?

[Marcel Birgelen]

Is putting tape on the right channel a common thing? I didn’t realize that - so thank you for pointing that out.

It's normal to mark cables either with a color code or with some more descriptive labels, but "putting tape on the right channel" isn't some kind of standard.

Question that doesn’t relate to this - how were the speakers being connected to the projector? I see the Non-Sync RCA cables, but those were connected to the DVD player. And I see those two Ethernet RJ45 cables, but I thought those were for automation. Those are the only options.

Like Harold indicated, the AES/EBU channels used for digital cinema sound are on the upper RJ45 connector on the JSD-60, the lower is the Ethernet connection used for automation and configuration purposes. If you follow the upper RJ45 cable, you should eventually arrive at your server. Your server can be a stand-alone, rackmounted affair or if it is a more modern setup, it can also be integrated into your projector. The server is responsible for the audio and video playback, not the projector itself.

Also - any thought on why there are 5 cables going into the Odyssey board but there are 6 amps?

It could be one or more of the following:

- You didn't correctly identify the number of amps.
- For whatever reason, not all channels were previously connected.
- Those are spare amplifiers.

Like Carsten indicated, the picture is useless to identify anything correctly. I don't count 6 amps in that picture. The top device clearly is the JSD-60, the device below could be a booth monitor and I guess the three devices below that are amplifiers. The bottom device could be anything, but in this picture, it doesn't seem to be switched on.