Film-Tech Forum ARCHIVE: Renting Pink Noise Generator ?

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Posted by Randy Stankey (Member # 64) on 05-13-2010, 09:55 AM:

We will be doing some upgrades to our sound system this summer. Of course, this will require rechecking the A-Chain and B-Chain but I don't have all of the equipment to do the job.

I have the oscilloscope and test films for the A-Chain.
I can probably rent or borrow an analyzer from the local company who does other sound system work for us.
I do not have the pink noise generator for our cinema processor. (Smart Mod II-B) It would not be economical for us to buy one.

Is there any chance we can rent one for the job?
Anybody out there have one they can loan out. (For pay.)

Posted by Jarret Chessell (Member # 5077) on 05-13-2010, 06:30 PM:

Do you have DTS installed?? You can use the pink noise off the test discs.

Posted by Randy Stankey (Member # 64) on 05-13-2010, 06:52 PM:

Nope. No digital. The cinema processor is a Smart MOD II-B.
You can sort of hook digital inputs up to it but it really wasn't designed for it.

I suppose I could hook an external PNG up to the discrete channel inputs but I'd really like to use the genuine article. This system hasn't had a good tune up in years. It's high time it was done right... or as close to right as I can get under the conditions I have to work under. [Roll Eyes]

Posted by Jarret Chessell (Member # 5077) on 05-13-2010, 07:28 PM:

The manual says you can hook up a different pink noise source to digital input, but to make sure it's at .55 volts RMS before you plug her in...

Now remember kids: if a 707 hits a peek you get a real mess.
.707 X Vppk = Vrms
(if you're using your scope to set it anyways...) lol sorry, being silly

Posted by Jonathan Bodge (Member # 4072) on 05-13-2010, 09:14 PM:

Here's my 2 cents which is worth 2 cents. I've done many houses with pink noise and analyzer. All of the time I readjust by using my ear. Not to mention EVERY movie is mixed (EQ) differently. I'll never forget working along side a sound company that produced great sound in a live venue. I asked, "Did you pink noise the room?" he said "Oh that can get you in more trouble than it's worth"

Posted by Gordon McLeod (Member # 33) on 05-13-2010, 09:21 PM:

the buss level in the mod 2b is 707 at 50%

Posted by Randy Stankey (Member # 64) on 05-13-2010, 10:01 PM:

The story on this theater's sound system is a long and sad one. It needs to be EQed with pink noise.

When the theater was installed, 15 years ago, they used EAW speakers. The LA325. http://www.eaw.com/products/la325.html

I told them these weren't going to work but this is what I got anyway. When they didn't work, they asked me why. I told them there are supposed to be three speakers across the screen. So they bought a JBL. Oh, I forget the model. It is the one with the long HF horn on top.

So, now they have one theater speaker and two concert speakers. What's more the center speaker had to be bi-amped and the others were full-range.
That still didn't work. So, after much fussing around, they bought two more JBLs. This time the 4675C. http://www.jblpro.com/catalog/General/Product.aspx?PId=77&MId=1

What's more the center speaker was being re-routed to the house sound system's Media Matrix to split the signal into HF and LF for the bi-amp.

Years go by. People complain that they can't hear the dialogue. Nothing really gets done but some minor fussing around. Finally, somebody drops some scenery on the long horn of the center JBL. It tears the whole top of the speaker cabinet off... Horn, mount and all.

So I patched that back up with plywood and gaffer's tape. That keeps for another two or three years, even though I told them that the thing needed to be replaced. They just didn't want to pay for it.

More time goes by. More complaints. More questions. I keep giving the same answer: The sound system was messed up from the start.

Finally, through some stroke of magic, enough people complained and enough of the higher-ups heard about it that something "had to be done."

That's why we're getting a new center speaker. A 4675C to match the other two.

So, now I am going to install that speaker. Hook it up to the Smart cinema processor the way it should have been done all those years ago, then perform a complete A-Chain and B-Chain on the system.

I have done A-Chains on the system about once per year but it has never had a B-chain done since it was installed. At least not correctly. I know that more than one of the various and sundry "consultants" who were called in to look at the system made some adjustments to it. I am sure that the levels and the EQ settings are all over the map.

I am certain that replacing the center speaker and retuning the system the way it should be tuned will make 100% difference. I know that it won't be perfect but it will be better than what we've been doing.

Once this has been done I would like to put a baffle wall behind the screen. (Remember, we are a live performance theater.) I can hang it on one of the fly lines and fly it in when we need it. Currently, we fly in the mid-stage curtains behind the speakers.

After that, I would like to get a new cinema processor but that is going to have to wait.

If we were to get a new processor we would have to get that new speaker anyway. Therefore, I am hoping (praying) that this improvement will be a lead-in to further improvements.

I will set it according to the RTA but once that is done, we will have to make adjustments by ear. Being a live performance venue it has very live walls. I know that there will have to be adjustments to account for that but I will have to cross that bridge when we come to it. (I don't remember what the adjustments will have to be. It's been too long. I will just have to look them up and do some studying.)

But first, the B-Chain....

[Smile]

Posted by Richard Hamilton (Member # 321) on 05-14-2010, 08:52 AM:

Randy, is the Smart II-B going thru the Media Matrix?

Posted by Sean McKinnon (Member # 612) on 05-14-2010, 09:07 AM:

quote: Jonathan Bodge
Here's my 2 cents which is worth 2 cents. I've done many houses with pink noise and analyzer. All of the time I readjust by using my ear. Not to mention EVERY movie is mixed (EQ) differently. I'll never forget working along side a sound company that produced great sound in a live venue. I asked, "Did you pink noise the room?" he said "Oh that can get you in more trouble than it's worth"

The thing is John is that yeah every soundtrack is mixed differently but (theoretically) every mixing studio (for motion picture soundtracks) is eq'd to the same standard theatres are eq'd to (ISO 2969 if I remember correctl) so in order for the mix to sound as it was intended to sound pink noise must be used and the proper response curve applied. Final minor adjustment by ear is an important part of the process but without the solid foundation the content being played back will not sound like it was intended to. Pink noise is also required to set proper SPL's.

Now live sound is a completely different animal from cinema sound same as broadcast and other pro-audio is completely different. Different standards, signal levels, etc... Remember in a cinema sound system we do not have to worry so much about mic feedback so we do not have to isolate the frequencies that cause feedback in a particular room. We are free to have a perceived even power level for most of the audible frequencies which is ideal.

Posted by Randy Stankey (Member # 64) on 05-14-2010, 09:25 AM:

Richard;

Yes. It goes through the Media Matrix.

The left and right screen channels go directly to the speakers on the stage. The center speaker is routed through the Media Matrix.

From the Media Matrix there are four outputs:

1 output goes to the main, center cluster for the auditorium sound system.
1 output goes to the under balcony speakers.
1 output goes to the hearing impaired system.
1 output goes to the center stage speaker, full range. Then that goes into a Rane electronic crossover which splits the high and the low and, finally, that goes out to the amps & speakers. The Rane crossover also splits out the low freq. for the subwoofers.

It's a Mongolian cluster fuck. (As opposed to the standard cluster fuck.) [Roll Eyes]

I want all of that to basically be torn out.

I want all the screen channels to go direct to the speakers with nothing in between.

Then I will throw them a line for the hearing impaired system.
If they want to route that signal to the under balcony speakers they can do that but I'm not really digging the idea.

Posted by Richard Hamilton (Member # 321) on 05-14-2010, 09:55 AM:

Randy, can you look at the veiw file for the Media Matrix? Is it a main frame or x-frame? I always wrote my programs with a built in pink noise generator.

Posted by Randy Stankey (Member # 64) on 05-14-2010, 10:15 AM:

I know there is no PNG in the Media Matrix program.

This thing is OLD. The computer runs on Windows 3.1.
It was put in 15 years ago and hasn't been updated since. New programs were written and rewritten. It's all a patchwork quilt of junk on top of junk.

I generally like the Media Matrix but I really want to get the cinema system untangled from the house system before I do anything else. Then, once the cinema system works in some semblance of the way it is supposed to work, we can think about integrating the two.

But, right now, with two channels going direct to the stage and one channel being split up four ways before being directed to five different locations, I think I have to untangle all that crap before doing anything else.

Posted by Richard Hamilton (Member # 321) on 05-14-2010, 10:45 AM:

Randy, It could be as simple as adding a BoB and re-writing the veiw file. Or....do you have spare inputs and outputs on the BoBs that are in the rack?

It's been a few years since I wrote a veiw file, but your case doesn't sound that bad.

Posted by Demetris Thoupis (Member # 833) on 05-14-2010, 11:39 AM:

Randy it would be WISER and much better going for a JSD80 unit instead from USL Pink noise built in, RTA built in! Nothing can go wrong and it does emulate SR Excellent. Also their monitor has built in crossover if you wish for (again an excellent addition and not that costly) Price also is not restrictive at all. Force them. Tell them IT HAS TO BE DONE. Or you can go with the Dolby unit and get urself some DD as well [Smile]

If you stick with the Smart died obsolete thing, you will be stuck with it and complains for more than 20 more years to come. Also note that the JSD unit is D-Cinema ready.

My 2cents

Demetris.

Posted by Randy Stankey (Member # 64) on 05-14-2010, 12:54 PM:

There are two BoBs. Only about 1-1/2 of them are used. There are extra ins and outs.

The contractor who does our house sound has worked on it, spradically, for years. There is little or no improvement. He really does not understand cinema sound and he makes little attempt to understand. Every time he does anything it's just a patchwork job.

The guy who is the TD for the center wants to get rid of the Media Matrix all together so it is likely to go away some time in the future. I don't want to invest time in something that is just going to get torn out again.

I really want a JSD-80. I have been telling them for years that they need a new processor. I have said it so much for so long that people get angry at me for the mere mention of it.

From the day this system was put in I have been telling them it is wrong. I have showed them the manuals and the tech specs that detail how it is supposed to be done. I have been in shouting matches about it yet they still insist on doing it this way.

For the amount of money they have spent on this broken sound system they could have bought two brand new Dolby CP-650s yet they still insist on ignoring me but, whenever there is a complaint, I am the first one who gets called.

The guy who is supposed to be our contractor convinced the director of the center to buy a pair of Rhenkus-Heniz 18 inch subwoofers and a pair of EV amps to power them because he had them sitting around his warehouse and he just wanted to get rid of them so he convinced my boss that he needed them.

He told me this in so many words: "I just want to sell them to somebody."

I know you guys think I'm just bellyaching but, if there is a word of this that is not true, may God strike me with a bolt of lighting!

This is what I want:

1) I want that new speaker to replace the broken one.
2) I want all three stage speakers hooked up direct to the processor and amps.
3) I want to completely disconnect the Media Matrix from the cinema sound system except for the aux. input for the hearing impaired emitters.
4) I want a complete A-Chain and B-Chain then to tweak the sound for the hall to compensate for the live walls. (I know that's a tall order.)

When this is done, I expect to hear a good improvement in the sound which will prove I was right all along.

Once we get that far, I hope to convince them to get either a Dolby processor or a USL processor.

We are slowly moving toward more digital projection content via satellite. Therefore, whatever the processor we use it is going to have to be able to accept the inputs from at least one or two aux. input sources. While we are at it, I would love to get Dolby Digital for the film sound.

Because of this, I think that the JSD-80 or the CP-650 would be the best choices because they are the most "future proof."

Right now, I have to concentrate on one thing at a time.
I used to do this kind of work every day but, for the last the last ten years I have done little more than monkey work. My skills are rusty, to say the least.

I think it's important to tackle this problem one step at a time.

Speaker first.
Tune-up second.
Suggest upgrades third.

Posted by Demetris Thoupis (Member # 833) on 05-14-2010, 01:03 PM:

Randy I am with you. I understand perfectly your position. YOU HAVE to insist that even what you try will not improve a SHIT processor. Bi amping all screen speakers (even just the centre is a great improvement) and a NEW processor with many of todays and future capabilities is the ONLY way to go. Don't tune the shit processor for nothing. You will only end up doing double the work with tripple the hustle with quadrouble the shit you have to go through! Convince them. Tell them is either this or you are better sticking with the crap you have because its not worth putting any cent for this type of processor NOW after all that has happened. First of all you need to tell them that Smart is long dead obsolete. Parts are rare, sounds like shit so long, why would it sound better afterwards?
Demetris

Posted by Scott Norwood (Member # 30) on 05-14-2010, 01:22 PM:

So, what are the issues with running film sound through a Media Matrix box?

I am tangentially involved with an opening-next-year multi-use facility that might be doing just this. I'm not familiar with the Media Matrix, but I have been told that it is essentially the same thing as an automated patch panel.

Is there something horribly wrong with this approach? The live stage people who are involved with this project seem to think that it is the greatest thing since sliced bread.

Posted by Demetris Thoupis (Member # 833) on 05-14-2010, 01:39 PM:

Media Matrix is not the only company out there. There are more DSP Matrix mixing companies e.g Symmetrix, even EAW makes, e.t.c. I had to spec a system relevant to what you are about to do. I DID use a DSP matrix mixing device for two reasons. First it provided me with enough inputs to be able to route from the main CINEMA processor towards the amplifiers (and crossover it via a preset) but keep the eq in this dsp matrix device flat since all eq was done from the Cinema processor side (beside the crossovering) and also give me two inputs so I could use the same speakers for live events as well (via a live mixing console) so the system basically is able to either route audio from the cinema processor unequed in the dsp except crossovering via a preset directly on the amps and into the theater, and using a Crestron TP the system switches the inputs to the mixing console and uses a complete different preset applying also feedback suppresion and other compression/limiter facilities used in live events. Its not a bad thing it just has to be configured correctly. What is really though impressive today is the steerable arrays various companies make, Renkus Heinz being top on my list, used for live events for very demanding places. Two speakers like that and you are done. Those speakers can direct the sound beam directly on the listeners ear so in live events you have CRISP sound at the listener no matter what.
Demetris

Posted by Richard Hamilton (Member # 321) on 05-14-2010, 01:47 PM:

Scott, The Media Matrix is fine for special Venues. When I took their training course about 10 years ago, I believe they said they had Media Matrixes in all of Disney's attractions.

Just read Demetris's response, and that sounds like he could help you.

Posted by Kenneth Wuepper (Member # 1174) on 05-14-2010, 03:56 PM:

Randy,

I have heard this sound argument for many years with regard to the organ sound in auditoriums and churches. Basically the live sound system should be entirely separate from the other discrete sound systems in the room.

Since you are having trouble with the dialog channel of the cinema system, just look at the multiple sources for the sound in the room. The cinema center speaker. (this as it should be) Then there is the main PA cluster, the (hopefully delayed) under balcony speakers. All of these producing the same sound. While it is pretty good for music it makes understanding film dialog difficult.

If you could look at the delay in the system between the cinema center speaker and the main PA cluster you might identify the problem you are experiencing. Since the cinema signal goes through several processing steps more than the PA, there is possibly enough time difference to destroy articulation in the room.

Mentioning the "live" room, it is critical that the direct sound from the center speaker does not hit the side walls as the reflections will definitely destroy articulation. It is possible to use a laser pointer on the inside of the horn to show approximately where the sound is being directed. Aim the horn carefully to avoid the walls as much as possible. You can also minimize the slap from the back wall by pointing the horn downward using the laser as a guide. The sound needs to end just above the last row of seats.

Probably the only real asset from the PA system is your ability to use the hearing impaired feature. (That also needs to be properly delayed to work well)

Hope this is helpful.

KEN

Posted by Randy Stankey (Member # 64) on 05-14-2010, 04:03 PM:

It's not simply that the media matrix is bad. It is old and outdated, for sure, but the main problem is that one of the speakers is controlled by the Media Matrix and the others are not.

If it was hooked up correctly I don't think it would be a bad thing but this sound system is so badly bungled up that it hardly works for anything, let alone cinema sound. There are probably several upgrade cycles that would be needed to get it up to the place where it would be usable for cinema sound. The guy who fixes the system only does patchwork, at best.

Yes, I know that the Smart processor isn't very good but I guarantee that it will not be upgraded this year, even if I walked in with a machine gun and threatened to kill the boss's first born. If I could put in a brand new processor or even a used one I would do it in a heartbeat but it just ain't going to happen. I am damn lucky to be getting one stinking speaker at all!

So, what I have to do is to take what I have to work with and make it sound as good as possible.

When that works, even if the difference is small, I can use it as leverage to go to the next level.

Ken,

Thanks for your advice. When I get things rolling I will be sure to re-aim things to keep the sound off the walls.

I just got word that the speaker will be ordered soon and this project should be under way by the beginning of June.

Posted by Sean McKinnon (Member # 612) on 05-14-2010, 05:33 PM:

You know Randy those old smart are known to fail and if it happened to mysteriously fail one day they would have no option but to get a new processor [Wink]

Seriously though I agree that having the center channel come from more than one speaker system is a bad idea and could definately be a big factor to inaudible dialog. I bet that in effect both speaker systems are canceling each other's sound pressure out. What would you do if you had a show that wanted to speak over some type of low volume film or dvd sound? Having 2 seperate systems make this easy. Some speaker cable and a couple of JBL EON self powered speakers hung on the front side walls facing into the house is a cheap and effective way to get a totally independant PA system.

Posted by Monte L Fullmer (Member # 2797) on 05-14-2010, 06:05 PM:

Trick with large houses is to set the EQ for center channel with the LF's turned all the way down. Then start to run flat at 800hz up to 2kHz, then roll off the HF's.

This will help bring out the voice audio channel to be more clearer over the L and R channels.

Posted by Brad Miller (Member # 2) on 05-14-2010, 08:48 PM:

quote: Monte L Fullmer
Trick with large houses is to set the EQ for center channel with the LF's turned all the way down. Then start to run flat at 800hz up to 2kHz, then roll off the HF's.

Ummmm....NO. Seriously Monte, what the fuck? That is NOT how a room is tuned. If you need a "quick fix" for bad dialogue intelligibility and can't fix it properly, turn the center channel up a couple of db or something.

Posted by Gordon McLeod (Member # 33) on 05-14-2010, 09:25 PM:

first i doubt the mod2b is the source of the problem nor is the media matrix as they are very common and reliable
that said the interface is the issue then the alignment

Posted by Randy Stankey (Member # 64) on 05-14-2010, 10:22 PM:

I think the Mod II-B can produce "passable" sound. Not great but okay.

I think that this round of fix-ups will pave the way for future improvements. We show the Met Opera via satellite. We are generating some ticket sales (income) from these shows. I think that the desire for improvements to the Met Opera presentation will drive the boss's thinking in the next year or so.

I think that untangling the mess and retuning the system will prove to be the thing that gets the ball rolling toward more improvements.

The speakers are on wheeled carts. Aligning them is as simple as giving them a push in the right direction. There are spike marks nailed into the floor I use to position the speakers each time they are rolled out. To change the alignment all that is needed is to pound in new nails.

Posted by Louis Bornwasser (Member # 3063) on 05-15-2010, 07:15 AM:

The CP-650 is the only source for Dolby Digital. I suggest you use it as your main processor. It has a 6 channel analog input standard. A CP-750 or JSD80 could feed that input to allow more flexibility.

btw: I have NEVER seen a cinema sound system successfully integrated with a sound reinforcement system. Stand alone is the way to go. Cheaper, too. Louis

Posted by Sam D. Chavez (Member # 1841) on 05-15-2010, 10:35 AM:

I have been involved with multi-media sound systems where the cinema processor plays through the house system and they are always messy as Louis says. It can be done, but the operator needs to be well trained.

Posted by Steve Guttag (Member # 268) on 05-15-2010, 03:31 PM:

Okay...I'll chime in on this...I've done MANY "integrated" systems. Without fail, those that "integrate" the cinema with the "other" systems, result in some degree of failure. I've spend more time un-integrating systems than integrating them too.

The Media Matrix (or the sound web or the current Biamp wizbang thing....etc) can be great devices and give much flexibility but the cinema system should NOT go through them...they bring NOTHING to the system but a point of failure.

If you look at my AFI/Silver photos you will see a Media Matrix on every screen. It feeds the PA system which uses separate speakers, amps...etc. The Cinema systems (as well as the PA systems) stand unto themselves. Now BOTH systems CAN feed the other automatically or via a hard patch but 99.9999% of the time...never do they meet (sonically). Of the few times they have been integrated, it has been the PA system that feeds the cinema system.

Cinema systems are very specific, they don't need to be "helped" or fiddled with. As such, they tend to be more reliable than the systems that are subjected to the whims of various users.

If you MUST integrate...have the CINEMA PROCESSOR the last point in the food chain (that feeds the crossovers, amps, speakers). It will be MUCH more reliable.

Steve

Posted by Randy Stankey (Member # 64) on 05-15-2010, 05:02 PM:

That is exactly what I want to do. I want to sever the links between the Mod II-B and the Media Matrix. Then I want to tune up the M.M. the way it should be. Then I want to send an output to the media matrix in order to feed the hearing impaired system. That's it.

Posted by Richard Hamilton (Member # 321) on 05-17-2010, 08:55 AM:

Randy, I've done just a couple systems using a processor and a Media Matrix. One had a patchbay, the other I just fed the CP-650 into the Media Matrix (same thing basically). It can get complicated.

Another option is a drop in software program from MKPE. CinemaMatrix, it was designed for the media matrix. After the 2 installs I did that needed the CP-650, I wrote a similar view file, but never had the chance to test it, we never had to integrate a 35mm into a special venue again. Years ago, I believe the CinemaMatrix program was about $700. They don't have the price online.

If you have a copy of your view file, I could look at it and maybe give you some advice.

Rick

Posted by Randy Stankey (Member # 64) on 05-17-2010, 09:27 PM:

If I can find some double density floppy disks and a computer still capable of reading it I'll see if I can write-out the program and e-mail it to you. [Wink]

Posted by Sean McKinnon (Member # 612) on 05-18-2010, 02:41 PM:

At my venue we have seperate motion picture sound from a cp-650 either film based (Dolby Digital or SR/A) or Non-Sync fed from the AMX which sends one of the tape decks, dvd/blu-ray, or computer. PA sound is a seperate system with a mixer feeding outboard eq's and JBL Eon powered speakers. We send a mic level mono XLR out of our board into the pa mic input on the 650. We have this set up to come out surrounds only so if we want some extra "fill" to the room for a PA only (or seperate speaker and motion picture content) we can select format 4 on the 650. If we want to play sound from a computer or other source and allow a speaker to speak over it we keep the systems seperate. This works very well for us.