This is topic Why Dolby EX seems to be going nowhere in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Bobby Henderson (Member # 840) on 06-04-2002, 10:58 PM:
 
I was going to post this in response to another comment in the "article about digital projection" thread, but it is too far off topic --but an interesting topic on its own.

Dolby Digital, DTS and even SDDS have all been used on many hundreds of films in just the last ten years. In a single year any of these formats will be featured on more than 120 major releases in North America alone.

Dolby Digital Surround EX on the other hand seems to be getting less use than 70mm mag did during the 1980's. Why? I don't think it is really a knock against George Lucas, THX or Dolby Labs. It is just that the marketing on this is TERRIBLE. C'mon, how confusing can a group of people possibly make one format?

First, you have the movie release advertising. It is never clear a film is a Dolby EX enhanced title until you see the logo crawl up the screen on the end credits (if it is even used). But you built up your newspaper ads a few days ago and may already have the morning paper while you are checking the print you just built. The one sheets rarely ever carry the EX logo. The poster art on stack seems to add it in a week or so after the film has already been released (if it is ever done at all).

Even if you know a film is going to be Surround EX enhanced, can you really use the logo? What is proper use of the DD-EX logo? Dolby seems to say it is OK for a DTS equipped theater running a SA-10 processor to pop in that DD-EX logo. But if you have a CP-500 with a DTS-ES unit hooked up to it (or even a Smart unit), you can't use the tag. So that's kind of silly for both DTS-ES and DD-EX formats.

The mistake Dolby and THX made was in not coming up with a totally separated "Surround EX" logo that had nothing to do with the Dolby Digital icon. DD-EX implies the show is playing an enhanced Dolby Digital audio track (not DTS or SDDS which may actually be the case).

A generic Surround EX term would have also been able to work as an umbrella for all the extended surround systems and their various combinations of digital sound formats they are enhancing. In the end, the whole thing is a totally confusing mess. And with the newspapers seemingly unable to get regular digital sound notifiers right in the ads, how are they going to work Surround EX into that?

The situation is just as maddening in home theater --if not more so. Dolby's marketing rules do not allow for any use of the Dolby Digital Surround EX logo on any home theater hardware or DVD release packaging. But they will allow items like "Dolby Surround EX 5.1" to be spelled out in regular type on the box. That just doesn't make much sense.

Instead, we have "THX Surround EX" emblazoned on high priced THX receivers (which now have the tinge of Creative Labs Soundblaster computer speaker association). So many theater workers try to explain to movie fans that THX is not a sound recording format. But this baloney makes it sound like that. Let's see, my DVD has in tiny print "Dolby EX 5.1" but my receiver has "THX Surround EX" ---I don't think I have the right format! I bought the wrong DVD! Well, you get the point.

Even though DTS seems to be doing something more sensible, such as allowing the DTS-ES logo to be used in movie end credits (finally) as well as appearing on home theater hardware and some software (the DVDs themselves), things have not been very consistent. First, some of the DVDs carrying DTS-ES 5.1 matrix audio don't list it. Then there are way too few DTS-ES 6.1 Discrete DVDs.

The real bone I have to pick regarding DTS-ES is in audio video receivers and surround controllers. I've talked to people who have been screwed by salespeople who basically lied in saying the receiver did full 6.1 when it only did 5.1 matrix Center Surround. Pioneer Electronics is very culpable in some of their decidedly misleading ads. There's too many phoney-baloney claims coming from manufacturers stating "6.1" or even "7.1" when it is really only 5.1 Matrix CS.

What should be done? In theaters the Dolby Digital Surround EX logo should only be used when an SA-10 processor is enhancing real Dolby Digital playback. DTS-ES should only be listed when their processor is enhancing a DTS track. All other odd combinations mixing formats and ES/EX processors should use a generic Surround EX term. Well, I think just going with the fully generic "Extended Surround" would be good enough.

In home theater, Dolby and THX need to hammer out a singular Surround EX logo and go with that alone, especially if the Dolby Digital Surround EX logo is only going to be allowed for use in theaters. Any use of "6.1" in association with a Dolby Digital based EX track needs to be banned outright in all advertising. Even Dolby says it is just 5.1. The THX Surround EX logo needs to be canned. DTS needs to crack down on manufacturers making "6.1" claims when their products don't support full DTS-ES Discrete 6.1 decoding.

Well, crap. I think I've lost all hope. My explanation of the problem and "solution" is just to long winded for any lay-persons to fathom. With that, we may see 5.1-EX and Discrete 6.1 disappear.
 


Posted by Ron Lacheur (Member # 1126) on 06-05-2002, 01:34 AM:
 
Some High-End Receivers such as the Denon 5802 have their own " 7.1 " processing according to their specs.

Sony is one for stating " 6.1 " when there receivers are 5.1. But you have to read the " fine print " and all is explained. Sony's version of 6.1 as stated on the front panel as a " Virtual Matrix ". But if you didn't see the " Virtual Matrix " underneath the 6.1, one could easily be fooled to think it was a true 6.1 receiver.
 


Posted by Joe Redifer (Member # 3) on 06-05-2002, 02:47 AM:
 
How can you get 7.1 when all of the source material is mostly 5.1 and 6.1 at the very best? You cannot add a discrete channel and matrixing simply does not count. I guess I will just never trust Denon, then. Thanks to your post, I will now never ever buy a Denon product!

Bobby, I agree with what you have written. I think the situation is simply this:

Dolby EX is an afterthought. DTS-ES was quickly created as an answer to Dolby EX. The home versions were offered as a marketing ploy to sell receivers since it was a simple technology to bring to consumers. I believe that neither Dolby nor DTS really care much about the format. It is hardly revolutionary and therefore not worth the marketing dollars and effort it would take to really educate people about it. And if the format died, would you really miss it? It's just Pro-Logic, dude!


 


Posted by Mark Lucas (Member # 791) on 06-05-2002, 03:06 AM:
 
How many theaters are actually set up for EX anyway?
 
Posted by Brad Miller (Member # 2) on 06-05-2002, 03:37 AM:
 
I've set up a few theaters with CP200s and CP55s as EX processors (coupled onto the outputs of a CP65) and with a cat150E card and cat 64B EQ cards, I feel that combination is a MUCH better solution technically than the SA10. CP50s can be had for next to nothing on the used market and would also work fine and dandy for the purpose (fine and dandy meaning better than the SA10).


 


Posted by Michael Brown (Member # 890) on 06-05-2002, 06:41 AM:
 
And please if you have what is advertised as an all SRD multiplex and you install a couple of DTS units in a few houses. Advertise to your customers in some way that you have DTS!! Else it is a waste of money since no one knows you have them.

And make sure that the box office staff know what they are doing. If someone rings up and asks what sound format the performace of blah blah at 6pm is playing in, the box office should know.


 


Posted by Charles Everett (Member # 889) on 06-05-2002, 09:31 AM:
 
The Reading Cinemas in Manville NJ opened for Star Wars Episode 1 with Dolby EX in the 2 giant-size halls. That's how I saw Star Wars Episode 2 last weekend.
 
Posted by Evans A Criswell (Member # 381) on 06-05-2002, 10:01 AM:
 
quote:
And make sure that the box office staff know what they are doing. If someone rings up and asks what sound format the performace of blah blah at 6pm is playing in, the box office should know.

Fortunately, most theatres have something in the box office that lets the people working there know that movies are in which auditoriums, and which sound format each is in. One time, though, that must have not been the case:

There is one 8-plex (Carmike 8, Decatur) in my area that has only one auditorium with DTS and all others have pretty crummy (sometimes very crummy) sounding analog systems. When I went to see Tarzan back on June 18, 1999, Tarzan was showing in two different auditoriums. When I bought my ticket, I asked if the 5:15 showing was in the DTS auditorium and the girl selling the tickets had no idea what DTS was, so I asked if it were in auditorium 2, and she didn't know. Sigh. I bought a ticket for the 5:15 and it was the one in the DTS auditorium.

If I remember correctly, the actual conversation went like this:

Me: Is the 5:15 Tarzan in the DTS auditorium?
Her: DTS? (with a very confused look).
Me: OK, well, is the 5:15 in auditorium 2?
Her: I don't know.
Her (after a pause): We still have the 5:15. (????)
Me: OK, I'll take one for the 5:15.

If it hadn't been the right one, I would have just waited 30 minutes and gone into the other one.

How can a person working in a theatre be so dumb?


------------------
Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site


 


Posted by Ron Lacheur (Member # 1126) on 06-05-2002, 12:20 PM:
 
Joe,

I think in the Denon unit, that it takes the 6.1 and basically amplifies it so there is 2 rear speakers instead of one, making it a marketable " 7.1 ".
 


Posted by Jesse Skeen (Member # 586) on 06-05-2002, 01:21 PM:
 
Overall they've done a lousy job with this format- Several films that used it didn't come with anything at all letting us know that it was mixed in EX. Theaters aren't promoting it either; one theater I worked at got it installed for "Phantom Menace" but never advertised it, and other theaters in the area advertised it when that was playing but don't for anything that's out now so it's anyone's guess as to what's playing with it.
 
Posted by Joe Redifer (Member # 3) on 06-05-2002, 06:08 PM:
 
Ron,

That's the way theatrical EX works, since there are actually 4 zones of surrounds hooked up to the amps. But it is not all discrete, that's for sure. Denon is lying in their ads. That's like saying that since you have different amps pumping out the high and low end of each stage speaker and four subwoofer amps that you have a 16 channel sound system in an SDDS-8 house. Thanks to your second post, I will now stand outside high end audio stores all day every day and warn entering customers not to fall prey to Denon's lies!


 


Posted by Bobby Henderson (Member # 840) on 06-05-2002, 06:09 PM:
 
Joe, I agree with your judgment that Surround EX is just a workaround. It is a pretty jerry-rigged workaround at that. At least what DTS offers in ES 6.1 Discrete is a real improvement, if it is only a small one.

I would not call Denon's extra speaker outputs and signal manipulations "marketable" 7.1. It is just blown up 5.1 (or 6.1 in the case of an authentic DTS-ES receiver playing a real DTS-ES 6.1 disc).

It is the same laughable hooey the electronics companies tried making everyone swallow years ago when they were claiming their Pro-Logic Surround receivers were 4-channel or 5-channel when they were really only 2-channel matrix.

I would also say Dolby Labs is opening up a different can of worms when it comes to Dolby Pro-Logic II, which features two slightly different logos where the Dolby Digital and Dolby Surround icons are included. Both marks look essentially the same but have very different results.

I've beat the drum about 10.2 Surround before. For any real "next generation" improvement in movie theater sound to happen, new formats are required with more than just the regular 5.1 to 7.1 channels. It may not have to be full 10.2. It could be 9-track or 10-track. But all channels of sound must be discrete and mastered at lower levels of data compression (if any compression is used at all). And if such a system is developed, I really hope they think carefully about how to market it.
 


Posted by Michael Brown (Member # 890) on 06-05-2002, 06:30 PM:
 
quote:
That's the way theatrical EX works, since there are actually 4 zones of surrounds

Isn't it 3. Left Surround, Right Surround, Back Surround

what's the fourth?
 


Posted by Joe Redifer (Member # 3) on 06-05-2002, 07:40 PM:
 
Glad you asked.

There is left surround, left surround rear, right surround rear, and right surround. They are not all independent/discrete channels, however. That's just they way they are hooked up to the amps. The left rear and right rear become part of the left and right surrounds in non-EX mode. Then the left surround rear and the right surround rear become one "back surround" channel in EX mode.


 


Posted by Paul Linfesty (Member # 214) on 06-05-2002, 08:18 PM:
 
Normally you would refer to Dolby's stereo optical format as 2-track, 4 channel, since there are 2 differential optical tracks on the film. The matrixing (for the surround) and deriving (for the surround) will create 4 channels, since all 4 channels as re-produced will carry somewhat unique (with bleed, of course) information. So 4 channel is an accurate term to describe the presentation, if not the actual track layout.

 
Posted by Gordon McLeod (Member # 33) on 06-05-2002, 10:12 PM:
 
Actuallytje proper term for a optical matrix print (SVA) is a 4:2:4
 
Posted by Bobby Henderson (Member # 840) on 06-06-2002, 05:56 PM:
 
It's still 2-channel to me. And I prefer any such nomenclature, especially on DVDs, to be "Dolby Stereo 2.0" or "Dolby Surround 2.0" (or PCM 2.0 if applicable). A 4-channel description should only apply to something like a DVD featuring a discrete Dolby Digital 4.0 audio track (and there are some out there).

Bobby Henderson
 


Posted by Michael Barry (Member # 237) on 06-10-2002, 09:48 AM:
 
...like 'Big Trouble In Little China', which I rented tonight. Not sure if the region 1 is the same, though.

My processor displays '3/1 - LFE' meaning 3 discrete front channels and 1 discrete rear channel plus a .1 LFE encoding.

The DVD for 'Sex, Lies and Videotape' was produced the same way, with an alternative 2.0 track as well. The discrete one has better separation (no surprises there).
 


Posted by Ron Lacheur (Member # 1126) on 06-10-2002, 04:14 PM:
 
The Region 1 DVD of " Big Trouble In Little China " is " 4.1 " as stated on the box.
 
Posted by Bobby Henderson (Member # 840) on 06-10-2002, 06:57 PM:
 
"Working Girl" on DVD is an odd one. Dolby Digital 3.0. Three fronts, no surround and no LFE.

I was kind of surprised to find the "Edward Scissorhands" DVD being released in discrete Dolby Digital 4.0. That makes me wonder if Fox simply blew up the discrete 4 channel master for optical Dolby Stereo 4:2:4 to Cinema Digital Sound on the tiny number of 70mm CDS prints that were made.

At least in terms of those two discs, their channel nomenclature is listed correctly, as are other previously mentioned discs like "Big Trouble in Little China" with its 4.1 mix. Others are inaccurate, such as "The Abyss" (4.1 instead of 5.1). I think "Die Hard" and "Tron" fall into the same category.

To get back onto the Surround EX thing, I'm not sure which is a worse practice: not listing the Surround EX capability at all on the disc or claiming it is "6.1" when it is really 5.1 using a matrixed center surround.
 


Posted by Manny Knowles (Member # 1171) on 06-11-2002, 05:43 PM:
 
I would suppose that the main reason for a format's demise (e.g. EX) would be that the cinemas didn't embrace it in the first place.

This might be due to the added expense of upgrading. As far as audiences are concerned 5.1 Digital is just fine and dandy. The average moviegoer hasn't been properly educated about what EX is. Chances are it wouldn't exactly make that much of a difference with the average moviegoer anyway.

Not too many movies coming out with EX and it's already a few years old. You'd think there'd have been more titles in the cinemas. This may be a case of the chicken and the egg: No movies because there are so few cinemas equipped or so few cinemas equipped because it's an underutilized gimmick that customers don't really know or care about.

The other problem is that there is/was some confusion when it came to identification on the prints & cans that a given movie was in EX. So the proper application of the technology was (and still is) bound to be a bit spotty.

------------------
~Manny.

"The brown acid that is circulating around is not specifically too good."

-- An announcement in the film, "Woodstock: 3 Days of Peace & Music."
 


Posted by Manny Knowles (Member # 1171) on 06-11-2002, 05:50 PM:
 
Bobby:

We could easily have 10.2 if a film was mixed with 2 sets of DTS discs, right?

Could 1 timecode reader supply data to two DTS units or would we have to stack 2 readers and just have 2 different offsets?

We could have it tomorrow!


 


Posted by Bobby Henderson (Member # 840) on 06-11-2002, 07:22 PM:
 
Yes, two different sets of DTS discs (each holding their own 5.1 half of a full 10.2 surround track) could very easily be played back on a specially equipped movie theater featuring essentially what amounts to two sound racks.

One single time code reader could be split to two DTS machines for the playback. It is not very much different from the two machine setup DTS recommends for 70mm (one for playback and one for backup).

It would take a little more work for Dolby Digital to be made into a 10.2 Surround setup. Dolby Digital data would have to be printed along both left and right sproket areas of the print. That would require at least some degree of customization on the film printer. And then you would have the situation regarding the film reader. With those two issues tackled, two DD sound racks could play back a 10.2 track as well.

If we ever see 10.2 Surround, the media used may either be DVD-based discs (ROM/R/RW) or even a removable hard disc.
 


Posted by Karen Hultgren (Member # 395) on 06-12-2002, 11:28 AM:
 
Yes, DTS can playback in more than 6 channels if more than one player was used. We've done this many times for special venue or special presentations. The configuration is one reader and two players.

Karen at DTS
khultgren@dtsonline.com


 


Posted by System Notices (Member # 2357) on 04-10-2007, 05:54 PM:
 

It has been 1763 days since the last post.


 
Posted by Ken Lackner (Member # 1002) on 04-10-2007, 05:54 PM:
 
Way back in the day, the Grand Pooh-Bah had this to say:

quote:
I've set up a few theaters with CP200s and CP55s as EX processors (coupled onto the outputs of a CP65) and with a cat150E card and cat 64B EQ cards, I feel that combination is a MUCH better solution technically than the SA10. CP50s can be had for next to nothing on the used market and would also work fine and dandy for the purpose (fine and dandy meaning better than the SA10).
Well I'm glad I stumbled on to this thread and found someone who knows about this setup. I have a theater that has about half a dozen houses where this was done. Some with CP55's, some with CP50's. Frankly I don't quite understand how it works. If you are using the optical input on the CP55 to matrix the surrounds, then what happens when there is totally different LS and RS information? Wouldn't the audio be steered to the LS and RS, resulting in no sound coming out of the back surrounds? So how do you get BSL and BSR? I believe the back planes of the CP50's and 55's have been somehow modified, but I don't know the details. Anyone who can clearly explain to me how this setup works will be my bestest friend!
 
Posted by Cory Isemann (Member # 2517) on 04-10-2007, 06:17 PM:
 
quote: Ken Lackner
Anyone who can clearly explain to me how this setup works will be my bestest friend!
Or the proud new owner of some Smart Afterburners [Wink]
 
Posted by Joel N. Weber II (Member # 3530) on 04-10-2007, 07:26 PM:
 
I believe the way EX works is that the LS and RS output of the 5.1 digital sound goes into the EX decoder, and the EX decoder then dematrixes the sound into left surround, back center surround, and right surround. (I'm not sure what's supposed to happen with the surround output of the cat150 card; maybe you're supposed to use a version of the cat150 that lets you turn decoding of the fourth, ``surround'' channel off. Though I think one of the processor manufacturers advocates sending the surround output of this decoder to an overhead speaker; but I'm not aware of any movies that ever expected this speaker to exist.)

It seems like if you wanted to wire a sound rack to play non-EX movies the way they'd been played before you got the EX decoder, you'd need a total of four amplifiers for the surround speakers (assuming you aren't biamplifying) and a relay. In non-EX mode, the LS output of the 5.1 digital sound player goes to the LS and BLS amplifiers, and the RS output from the 5.1 decoder goes to the RS and BRS amplifiers; in EX mode, the left output of the EX decoder goes to LS, and center output of the EX decoder goes to both BLS and BRS, and the right output of the EX decoder goes to the RS amplifier.

I would have thought you wouldn't want the optical preamp card changing the frequency response of the signal as it finds its way into the cat150 card that's doing EX decoding, and it's not obvious to me how you make that part work correctly.
 
Posted by Darryl Spicer (Member # 711) on 04-11-2007, 12:49 AM:
 
the way I understand it and the way that I did it at home with home 5.1 before they started incorporating it into stereo units was this. The EX is an EXpander that is all it is. You take the left and right surround signal and feed it into a system that has a matrix decoding capability. For home it was simple. I had another pro logic decoder unit that I sent the left and right surround to. So long as you are feeding a stereo surround signal to the unit it will put mono signals in the back surround channel and the stereo left and right signals in the left and right side surrounds. Note for that I had a 5.1 decoder that sent each channel at line level to the main processor for the front channels. The two line level surround outputs went to a left and right input on the second pro logic processor. With films recorded in EX supposedly there is a flag that will turn the EX processor on but I must assume that it only turns the back on when needed. For home anything with stereo surrounds sounds good playing with a matrix surround being processed.
 
Posted by Brad Miller (Member # 2) on 04-11-2007, 04:18 AM:
 
All the SA10 (or internal CP650 EX decoder) is, is a fancy cat 150 matrix card with some crappy 1/3 octave equalization.

Don't use the optical inputs on a CP50/55/etc. Use some form of auxiliary input that will not alter the frequency response like the optical preamp card will.

By inputing the LS into the LEFT channel and the RS into the RIGHT channel of a CP50/whatever, you then take the LEFT channel output and route to the LS speakers, the RIGHT channel output then gets routed to the RS speakers, and the CENTER channel output gets routed to the LSrear and RSrear speakers. Any sound mixed into the LS and RS tracks as a "mono" sound (recorded equally between the two channels) will play out of the rear wall speakers. Anything panned hard left, hard right or recorded out of phase gets properly steered to the LS and RS side wall speakers.

Does that make sense?
 
Posted by Ken Lackner (Member # 1002) on 04-11-2007, 06:52 AM:
 
That does make sense. I know that's not exactly how it's set up at this theater. They are using the optical input. Should this system be engaged (so that it's playing in "EX") all the time, or only for films recorded in EX? If you're not using EX, then I still don't understand how you would get the LSback to become part of the LS and the RSback to become part of the RS. Isn't that what an SA10 does when you turn EX off?

Should the EQ on the center channel in the CP50/whatever be flat, since you are EQing in the original processor?

All that being said, is this really worth it? What if the CP50 fails? Can you even get parts for it any more?
 
Posted by Brad Miller (Member # 2) on 04-11-2007, 01:24 PM:
 
It should only be engaged when playing an EX film. The secondary processor needs to be modified to let a L+R sum pass through the C channel for non-EX films. This is why the CP200 is the easiest processor to make an EX box out of.

The main processor should not have any EQ on the surrounds and all of the EQing should be done on your CP50 or whatever you are using for EX via the LCR cat64 cards.

I would say a CP50 has about the same chance of dying as an SA10. There are plenty of used cards on the market. Ideally, just get a friggin' CP650.
 
Posted by Louis Bornwasser (Member # 3063) on 04-11-2007, 01:49 PM:
 
Brad is right about the eq. Any eq or for that matter anything that affects phase or level that occurs before the matrix will cause falses; bad steering. After the matrix you can do anything or nothing. Louis
 
Posted by Ken Lackner (Member # 1002) on 04-11-2007, 04:44 PM:
 
After reading your posts over a couple times, I have to say your method makes sense. I know that's not exactly the way it's set up at my theater. They are using the optical inputs and the CP50's only have one EQ card in them. Next time I'm there I'll try to take some good notes on how it's wired and see if I can understand it a little better.

I still have a few questions.

quote: Brad Miller
Don't use the optical inputs on a CP50/55/etc. Use some form of auxiliary input that will not alter the frequency response like the optical preamp card will.
If you have slit loss EQ turned all the way down, why would the optical input alter the frequency response in any way?

On a CP50 or CP55, I thought the only format that uses the matrix is optical, and that the auxillary input is discreet. Which input should I use?

quote: Brad Miller
It should only be engaged when playing an EX film.
So how do you engage and disengage it? The way it's set up right now with the optical inputs, Format 04 is "EX On." How would I turn it off?

quote: Brad Miller
The secondary processor needs to be modified to let a L+R sum pass through the C channel for non-EX films.
Am I to understand this to say that when not playing EX, the rear wall surrounds will ALL produce the LEFT surround AND the RIGHT surround information?

Brad, do you think you could come up with a block diagram and some simple instructions on this?
 
Posted by Demetris Thoupis (Member # 833) on 04-13-2007, 02:11 AM:
 
From what I understand and correct me if I am wrong:

1. Take the LS and RS output from your CP200 or whatever and rout it in the CP50 L/R Auxiliary or Music Input

2. Route the Front Left, Front Center, Front Right of the CP50 to the amplifiers for Surrounds

3. Do not EQ the surrounds on the CP200 but EQ them on the CP50 as "front screen channels".

Hopefully it will work!
 
Posted by Ken Lackner (Member # 1002) on 04-13-2007, 09:15 AM:
 
It seems that my understanding agrees with your understanding. But I am still waiting for someone to tackle my unanswered questions from my last post. Any takers? Brad?
 
Posted by Brad Miller (Member # 2) on 04-13-2007, 12:36 PM:
 
Demetris is basically correct.

To answer your other questions, you have to solder in some diodes to make custom formats on a CP55/200. I haven't done this on a 50, but I'm sure it can be done. Unfortunately you are asking me to remember something I did years ago and I don't know where my notes are.
 
Posted by Louis Bornwasser (Member # 3063) on 04-13-2007, 03:41 PM:
 
On the CP-50, remove the first 4 cards. Solder directly to the cat 150 stereo input. Observe the 500 mv level and you're finished! You will need eq cards in L-C-R channels. Louis
 
Posted by Steve Guttag (Member # 268) on 04-13-2007, 07:10 PM:
 
And then Louis remembers that the Cat 22s contain the line amps for the Left and Right channels....

There is more to it if you want to do it right so that you can switch between 5.1 and EX with all of the channels going in the right place and also match levels.

Steve
 
Posted by Ken Lackner (Member # 1002) on 04-13-2007, 09:16 PM:
 
quote: Steve Guttag
There is more to it if you want to do it right so that you can switch between 5.1 and EX with all of the channels going in the right place and also match levels
That's what I figured. That's the part I'm having a tough time understanding.
 
Posted by Demetris Thoupis (Member # 833) on 04-14-2007, 10:15 AM:
 
I guess you will be needing an isolated relay switching module where you will be able to route LS and RS to the BS channels! I would recommend tying on 2 three contact relays the following:

Relay 1 Common: To BS Left Amplifier
Relay 1 Normally Closed: From CP50 Front Left (Left Surround) channel
Relay 1 Normally Open: From CP50 Front Centre (Centre Surround) channel

Relay 2 Common: To BS Right Amplifier
Relay 2 Normally Closed: From CP50 Front Right (Right Surround) channel
Relay 2 Normally Open: From CP50 Front Centre (Centre Surround) channel.

The relay can be activated by a 12V DC Power Supply in order to do the switching and I am sure you can figure out a way of hooking up a switch to it! The basic concept is that when no 12V DC power is applied on the coil of the relay it will be Normally Closed thus the standard Left Surround and Right Surround will pass to the Back Surround Channels. When 12V DC power is applied on the coil of the relay then the back surrounds will operate as Back Surrounds. The only real issue you need to worry is that the relays are trully ISOLATED from the Coil otherwise humming bzzz e.t.c
Demetris
 




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