Film-Tech Forum ARCHIVE: Wiring into sound system

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Posted by Brandon Lokesak (Member # 2280) on 10-15-2004, 10:17 PM:

We are going to be running a film that requires a dvd projector I belive that it is the XL100 from Christie the unit has rca cables. The sound system for that side runs off a dolby cp55. The amps that we use have no rca inputs its some kins of 3 pronged round plug. The amps i belive as Ashly amps not sure of the model number I was wondering if anyone knew of a way to wire this to run atleast on the front main speakers through the amps? Thanks

Posted by Brad Miller (Member # 2) on 10-15-2004, 11:13 PM:

Take your DVD left and right output and go into the non-sync inputs of the CP55. You don't wanna mess with them freaky 3 pronged thingamajigs!

Posted by Chris Hipp (Member # 1788) on 10-15-2004, 11:14 PM:

There is probably a better way but you could always hook up the DVD player to the Non-sync on your CP.

Brad and I must have been typing at the same time. [Smile]

Posted by Richard Hamilton (Member # 321) on 10-16-2004, 06:48 AM:

How do you run film through a DVD player?

Rick

Posted by Brandon Lokesak (Member # 2280) on 10-16-2004, 12:09 PM:

Its not film its a dvd disc. We are trying to keep the non sync music for before the show. Is there anyway possible to use say the magnetic sound inputs?

Posted by Gordon McLeod (Member # 33) on 10-16-2004, 12:36 PM:

It could be wired to either the aux or the mag inputs
If the dvd is just a L and R out then connect to those channels if you have a 5.1 out then connect to appropriate inputs
Is there by chance a SRA5 connected to the cp55?

Posted by Brandon Lokesak (Member # 2280) on 10-16-2004, 01:55 PM:

No I dont believe that there is a SRA5 connected to the CP55. If I do wire into the mag. input will it run off the amps then? I dont know if you can answer that with out seeing the setup here. Thanks for all the help guys.

Posted by Gordon McLeod (Member # 33) on 10-16-2004, 02:07 PM:

If you connect to the mag input it will feed the poweramps as labled
remmeber that the input level must be set internally on the cp55 as there are 2 gain settings for the mag sensitivity
The aux inputs if unused are true line level

Posted by Brad Miller (Member # 2) on 10-16-2004, 02:18 PM:

Brandon, do you know how to connect an RCA audio cable to the CP55? I'm going to guess you don't since you are not familiar with XLR jacks, so rather than to have this keep going and going, here is the simple answer in the most basic description.

Go to Radio Shack and buy a generic "RCA stereo patch cord". Cut one end off. Strip about 1.5 inches of the shielding from one of the wires. Inside you will find tiny wires surrounding another wire inside it, in it's own shield. Pull the surrounding wires together and away from the internal wire. Now strip about 1/2 inch from that internal wire. Repeat for the other wire.

Connect the left inside wire (on Radio Shack cables this is denoted by the white connector) to the AUX L screw terminal. Connect the right inside wire (red) to the AUX R screw terminal. Assuming you are only feeding the system left and right, you are done. If you have a 5.1 output, then get another stereo wire and use one side of it to connect the center output of the DVD player to AUX C and the other side to pick one of the surround channels from the DVD player and connect it to the AUX S terminal. Now you're not done yet...connect all of the outer wires and tie them to the screw terminal that looks like an upside down triangle made up of 3 horizontal lines. NOW you are done. (No subwoofer or split surrounds can be easily had from a generic CP55 unless it has been modified.)

Don't use the MAG input. It will only complicate things more. Just use the AUX inputs.

I am recommending you follow this procedure, because although you could run the signal through the non-sync inputs to achieve matrix decoding, you may find that you have distortion in the sound or have to make internal adjustments to the cards, and then you could end up having to make more adjustments to get your normal non-sync back. This is the simplest way without fear of screwing things up.

Posted by Michael Schaffer (Member # 1204) on 10-16-2004, 05:39 PM:

Why pick only one surround channel? You could also tie the 2 together to go into the one S input of the CP55, provided you are in stereo surround mode. That wouldn't give you stereo surround either, but at least nothing is "missing". Easier of course would be to play the disc in "Dolby Surround" and just use one of the 2 then identical outputs.

Posted by Rich Ferrando (Member # 2056) on 10-16-2004, 07:44 PM:

This brings up a question that I can't seem to find an answer to in the Smart processor manuals. I've had to rig our system for input from DVD players several times in the past, and usually I just force the renters to bring a mixer, and I hook the master outs directly to the XLR-ins on our Left-Right amp, but there has been the occasion (usually with my own stuff, just because I like to be difficult) where I've wired the amps to receive a 6-channel mix. This is usually done in my jury-rigged way (I own one 4-channel mixer and one stereo compressor/limiter with level controls, and have a complicated rigging that routes the 5.1 analog outputs from the DVD player through these devices and to the amps, just so I can control the output level- I always have great fear of blowing the speakers) which is a big pain in the vrump.

It would, of course, be much easier if I hooked it up to the Digital input barrier strip terminal on our Smart Mod V, but I have no idea what the maximum input voltage is, as this information is not in the manual we have. I know that the DVD player I have (and most others if I'm not mistaken) output at 2-volts line level.

Anybody know what the input voltage needs to be in order to avoid overloading the processor?

Posted by Michael Schaffer (Member # 1204) on 10-16-2004, 08:03 PM:

Oscar is the man to ask.
There is one little detail problem with your custom hookup though: you bypass the house EQ in the sound processor if you go directly into the amps.

Posted by Rich Ferrando (Member # 2056) on 10-16-2004, 08:22 PM:

I know- I usually make my own (limited) EQ adjustments via the mixer, though even when turning the low end all the way down, the sound in the house still has way too much bass, which, naturally, limits the level I can set it at.

Posted by Gordon McLeod (Member # 33) on 10-16-2004, 09:40 PM:

The mod v is about 300-700mv close to standard comercial home audio depending on the digital/mag input card individual channel trims

Posted by Randy Stankey (Member # 64) on 10-16-2004, 09:45 PM:

Many good mixing boards that have Lo-Z/balanced inputs don't care if the connections to it are balanced or not.

Just make sure your connections are solid, your shield is grounded and the phantom power is OFF.

I have hooked many external devices into my Mod II B. If you take the time to do things right, I dont' see why it wouldn't work.

Posted by Oscar Neundorfer (Member # 458) on 10-16-2004, 10:00 PM:

Rich,

You should have no problem running a typical dvd player's multichannel outputs directly into the MOD V Digital inputs. I use a Toshiba dvd doing exactly the same thing to check the digital inputs on our processors for our listening tests.

I am not sure of the nominal output voltage levels of dvd players, but 2V seems a bit on the high side. Maybe 2 V peak to peak, but not rms. In any event the MOD V will handle it OK, although you may have to turn the master fader on the MOD V down a bit more than usual if the voltage level is as high as you say.

Give it a go. You will not hurt anything. Just set your MOD V master fader a good bit lower to start, just to make sure you are not overdriving anything, and then crank it up as needed.

Posted by Rich Ferrando (Member # 2056) on 10-16-2004, 10:41 PM:

The manual for my Sony DVP-S560D says specifically: 5.1 Channel Output: 2 Vrms / 10 kilohms. Same specs go for the stereo line outs.

I was worried that I'd have to build a complicated box with step-down transformers. But if the processor can take it, I can certainly dish it out.

Thanks a lot!

EDIT----
One more question, which I think Brad answered already, but I just want to confirm....

With the outer ground wires in the RCA cable, those can all be routed to the same ground terminal, correct?

[ 10-17-2004, 12:09 AM: Message edited by: Rich Ferrando ]

Posted by Jason M Miller (Member # 2597) on 10-17-2004, 12:10 AM:

Try this XLR to RCA

[Edit]

Sorry I had a brain fart when I posted this.....DO NOT go directly from the dvd player to the amp use a mixer....there are some cheap mixers out there. They are mostly used for live sound applications such as concerts but will work fine for you application. http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/631236/ This is a good example... And sorry again for my stupidness

[ 10-21-2004, 10:19 AM: Message edited by: Jason M Miller ]

Posted by Rich Ferrando (Member # 2056) on 10-17-2004, 12:42 AM:

The only problem with going from the RCA outs on the DVD player directly to the XLR ins on the amps is that you have little control over the level in the house and, as Michael stated, you bypass the House EQ settings. And when dealing with most rentals involving video projection from DVD (usually first-timers or fiercely independent filmmakers), you're not necessarily dealing with people who know how to monitor their levels, or who know that "Red Means Bad" as far as VU metering is concerned.

Now, one more question for the brain trust.... I'm sorry, but I'm getting weird ideas late at night....

Our other two houses, which our DM also wants wired for "easy external audio hookup" use a CP200 and an Ultra Stereo JS-200. I figure on the CP200, I'd use the Mag inputs (100 mV or 1V level at 50k ohms), and on the JS-200, I'd use the Aux inputs (775 mV at 30k ohms)- this way I can still get LCRS, and don't have to disturb the DB25 connection from the DA20 in each case. Since the DVD player we'd be using is 10k ohms, there shouldn't be an impedance issue, but I still worry about that 2-volt output level from the DVD player. In your far-more-expert-than-I opinions, will I fry anything, or should I just try it and see?

Posted by Daryl C. W. O'Shea (Member # 1303) on 10-17-2004, 12:43 AM:

quote: Jason M Miller
Try this XLR to RCA

Or don't, if you want to avoid blowing things up.

Posted by John Hegel (Member # 628) on 10-17-2004, 03:13 AM:

You might also run into problems if your speakers ar bi-amped. From what I understand most bi/tri amped speaker setups don't have a x-over in line.

So, if you hook into the XLR imput on the amp without knowing what that amp is driving, you might end up sending low end to the horns which will fry them.

Posted by David Stambaugh (Member # 1102) on 10-17-2004, 01:02 PM:

Not that you're likely to run out and buy one of these, but is something like this what you really need?

Rane Balance Buddy

Posted by Steve Guttag (Member # 268) on 10-17-2004, 02:18 PM:

The Rane balance buddy does two things...it provides a transformer to isolate the two devices, and second its windings are such that a -10dB consumer piece is matched to a +4db professional piece IF the professional piece as a 20K input impedance. If the pro piece has an input impedance of 15K or less...you won't achieve the right level.

Given the information provided by Brad...why would you want a Balance Buddy?

Steve

Posted by David Stambaugh (Member # 1102) on 10-17-2004, 06:58 PM:

I didn't say that. And I guess I didn't realize there was only one possible answer permitted per question asked. Must be a new rule. Guess I should bone-up on the FAQ.

Posted by Steve Guttag (Member # 268) on 10-17-2004, 09:22 PM:

There isn't just one possible right answer...Gordy expanded on the choices...however, going directly to the amplifiers is a poor choice...one has zero volume control except for the amplifiers themselves.

Your choice of the BB44x is a poor one...all it would allow is one to connect directly to the amps and provide some amount of fixed level shift. Furthermore, it is a poor choice even from the Rane Line up...the BB 22 BB22 is a much better choice in that it does the specific thing needed (consumer unbal to pro bal) and costs less but again that only helps in this situaiton if one insists on connecting the DVD player directly to the amps. Again, the Rane BB products depend on the pro unit having a high input impedance...that is 20K...which I've found to be a bit higher than in real life. A different product to consider is FP-UBC2 It is an active solution but it is not load dependant and it provides level control.

But back to my statemnet about Brad's solution...it is clearly a superior choice...one isn't rewiring the main system to accomplish one task. The Non-Sync inputs are already unbalanced and provide level adjustment to balance the DVD in with the rest of the system.

Once that solution was offered...why would one consider a different one unless there was something to be gained by it? That is, perhaps the Non-Sync input is taken already...but Gord has shown the AUX inputs or the Mag inputs (with level information).

This isn't a FAQ situation but one of good or poor advice.

Steve

Posted by David Stambaugh (Member # 1102) on 10-17-2004, 10:11 PM:

Having never worked in a booth, I would be the last person to give advice to professionals. I was taking advantage of a rare opportunity to maybe share a tiny little factoid that might be of interest. So I threw out the Balance Buddy out as a possible option. I expected someone with more knowledge than me would either validate it or shoot it down. It's been shot down. I can live with it. [beer]

Don't mind me -- I'm in a pissy defensive mood tonight. [Wink]

Posted by Brandon Lokesak (Member # 2280) on 10-28-2004, 08:23 PM:

Well I got the sound going on the dvd player but now any film that runs on that side cant properly be ran on DTS the voices on the other movies from the front speakers are way too low to be heard while the rest of the movie is at normal level...

Posted by Brad Miller (Member # 2) on 10-28-2004, 09:04 PM:

Can you please reword that last post? I can interpret that in a few different ways.

Posted by Aaron Sisemore (Member # 145) on 10-28-2004, 10:49 PM:

quote: Brandon Lokesak
but now any film that runs on that side cant properly be ran on DTS the voices on the other movies from the front speakers are way too low to be heard while the rest of the movie is at normal level...

Disconnect the DVD player when running films; leaving the DVD connected apparently is loading down the outputs of the cinema processor.

-Aaron

Posted by Eli Blasingame (Member # 1052) on 11-01-2004, 10:57 PM:

Aaron, thx for the sound work. the show came out great. there was lots of [sex]

, give me a call when u get the time. thx for the help. [beer]