Film-Tech Forum ARCHIVE: Audio Cable Conduit Sizing

This is topic Audio Cable Conduit Sizing in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Barry Floyd (Member # 385) on 02-19-2013, 03:35 PM:

My install date for digital is set for February 27th, and I'm trying my best to make sure I've got everything in place before the techs get here.

We'll be installing GDC SX2000A servers and USL JSD-60 processors for sound. To connect those two pieces together, what type of cabling will they likely use and what size conduit should I provide for them? I've read that the USL can accept Cat5e for sound, but that almost seems too simple to me.

I don't have access to a wall mounted metal wire trough, so I figured I'd give them at least a 1 1/4" EMT conduit running from the wall in front of the projector across the wall and come up through the bottom of the wall mounted sound rack. If they use something pre-made with DB25 connectors - those won't fit in that.

Anyone care to guess?

Posted by Tony Bandiera Jr (Member # 2365) on 02-19-2013, 04:18 PM:

Barry, 1.25 to 1.5 inch conduit will be just fine.

Most DB25 cable assemblies have a removable shell which can be taken off and the cable CAREFULLY folded back on the connector and taped up to be pulled through the conduit.

Also, ask your installer or equipment vendor for recommended conduit sizes if you have any doubts. If they cannot give you an answer, be afraid...be very afraid.

Posted by Steve Guttag (Member # 268) on 02-19-2013, 04:46 PM:

Barry...it is true you can use CAT 5 or CAT 6 cable for AES audio. As luck would have it, the impedance of CAT 5E is proper for AES too.

GDC includes in their kit a DB25 to a dual RJ45 adapter too. GDC even includes the shielded CAT5 (and labeled it too). So...as for conduit...you need to pass one or two CAT 5s for audio, probably another CAT 5 for sound processor. The rest is a matter of how much automation you are putting in.

Posted by Frank Angel (Member # 248) on 02-19-2013, 06:07 PM:

And it never hurts to pull spares.

Posted by Dave Macaulay (Member # 813) on 02-19-2013, 08:26 PM:

There's no good reason to run DB-25 cables through a conduit these days. It makes sense to use CAT5 for digital audio, assuming you have an IMB or have the server in the projector base and need to run it to the sound rack. Just have your D-A (if your processor doesn't accept digital audio) in the sound rack. Some servers/IMBs come with RJ-45 digital outputs and a dongle for the processor/D-A but if not you can get pretty sweet RJ45-DB25 adapters from Odyssey - these can even do the 7.1 channel swapping using jumpers.
So the biggest connector you should be required to get through a conduit is a DVI, and you can cheat that a bit by using a cable with HDMI at one end and use an adapter if you need DVI on both ends. A 1.25" conduit should be plenty.

Posted by Steve Guttag (Member # 268) on 02-19-2013, 08:43 PM:

1.25" conduit for DVI would be problematic...particularly if there are any bends in it, particularly "90s".

I still "prefer" the proper AES cable...it is more durable than CAT cable, provides better shielding and allows one to route pairs better but CAT cable does work and is far more convenient, faster to make (and significantly cheaper).

Note, even for the DVI/HDMI thing...there are many CAT solutions out there too. Depending on the run, the cost can be similar to using a high quality HDMI/DVI cable.

Posted by Barry Floyd (Member # 385) on 02-20-2013, 08:36 AM:

Thanks everyone for your replies. Looks like we should be OK with running the Cat5 or Cat6 cabling thru the 1 1/4" conduit. I just wanted to be prepared ahead of time. Right now our projectors are nowhere to be found, and we're scheduled to open on Friday march 1st. I'm kinda praying for a miracle to happen here in Tennessee.