This is topic Dolby Surround EX in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Michael Harlow (Member # 1353) on 12-08-2003, 01:24 PM:
 
How many amp channels does surround EX use? at present i have 3 amps - left, center, right, sub bass, left surround, right surround. If i had EX will i need another amplifier? Ta
 

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Posted by Pete Naples (Member # 761) on 12-08-2003, 02:05 PM:
 
Yes. And you might need to consider extra surrounds on the rear wall.
 

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Posted by John McConnel (Member # 2000) on 12-08-2003, 02:07 PM:
 
Yes. You'll need two more channels -- One for Back Surround Left, and one for Back Surround Right.

We use 8 surround speakers on the back wall, in a 50-ft auditorium. 4 are Bsl and 4 are Bsr.

It's likely your customers will really like EX.
 

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Posted by Michael Harlow (Member # 1353) on 12-08-2003, 02:16 PM:
 
Many thanks, we have 4 surround on the rear wall, currently wired as left surround and right surround on our CP55. I think we are a way from Surround EX yet, maybe Father Christmas will bring me a DA20 or a CP650 for Christmas
 

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Posted by John McConnel (Member # 2000) on 12-08-2003, 02:34 PM:
 
Let's hope you've been good this year, and Santa remembers you. You'll love Dolby Digital.

If it's a DA20 that Santa brings you, you'll need to remind him to bring an SA10 so you'll have EX. If he brings the 650, he can get it equipped in advance for EX.
 

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Posted by Ron Lacheur (Member # 1126) on 12-08-2003, 03:54 PM:
 
It is also possible to use DTS's ES decoder for EX as well. It's a bit cheaper if you are working with a budget.

EDIT:

Wasn't there a review for the DTS ES unit in the reviews section?
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 12-08-2003, 04:14 PM:
 
No review that I know of.

If I'm not mistaken, the Panastereo SP23 Digital Surround Adapter would probably be even less expensive.
 

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Posted by Steve Guttag (Member # 268) on 12-08-2003, 04:34 PM:
 
The Panastereo SP-23 is the EX decoder. It is 1-U tall, available with 1/3-octave EQ on the surrounds and has calibration meters right on the front. Each of the four surround channels are separately level balanced on the unit. There is also a hard relay bypass. The logic circuit allows one to assign any of the formats as EX or non-EX...so if you have a CP-500 with internal Dolby Digital and a DTS with external digital, the SP-23 would understand that SK4 and SK5 are potential EX formats (or SK 8 if you want a separate EX button for Dolby Digital).

You can have the factory modify the unit so that the "bypass" button functions as an EX/Non-EX button too. Very fast and easy installation.

Steve
 

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Posted by Aaron Sisemore (Member # 145) on 12-08-2003, 04:35 PM:
 
The Smart CSEX/CS3X is another lower-cost way of adding EX, and you can get away with a single amplifier channel for the rear wall (EX) speakers, or wire it as a conventional EXL/EXR (stereo) rear wall configuration.

-Aaron
 

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Posted by John McConnel (Member # 2000) on 12-09-2003, 11:05 AM:
 
With the Smart unit using a single-channel amp for the rear speakers, how does it handle a non-EX soundtrack?
 

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Posted by Aaron Sisemore (Member # 145) on 12-09-2003, 12:22 PM:
 

quote:

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With the Smart unit using a single-channel amp for the rear speakers, how does it handle a non-EX soundtrack?

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With the Smart unit using a single-channel amp for the rear speakers, how does it handle a non-EX soundtrack?
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In 'non-EX' and 'bypass' modes, it sums the LS and RS signals into the single rear EX channel. (LS and RS side wall channels retain their stereo separation) Not 'perfect', but if you have only one extra channel of amplification available for the rear wall it gets the job done.

-Aaron

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Posted by Gordon McLeod (Member # 33) on 12-10-2003, 09:26 AM:
 
Which was what was often done anyway on many CP200's in very wide theatres made use of the 3rd surround eq slot in the aux rack for a summed rear wall surround
 

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Posted by John McConnel (Member # 2000) on 12-10-2003, 10:26 PM:
 
Are we talking about 35mm optical? If so, where did the CP200 get two surround tracks to sum with?
 

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Posted by Aaron Sisemore (Member # 145) on 12-11-2003, 03:08 AM:
 
I think we ventured into split surround Mag territory when Gordon brought up the subject of the CP200.

-Aaron
 

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Posted by Steve Guttag (Member # 268) on 12-11-2003, 07:47 AM:
 
To bring it full circle...The CP-200, if you pay attention to the wonderful signal diagram in the back of the manual, always had the provision for the never released, Optical Stereo Surround.

Steve
 

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Posted by John McConnel (Member # 2000) on 12-11-2003, 01:27 PM:
 
What was the configuration for the Optical Stereo Surround that was never released?
 

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Posted by Gordon McLeod (Member # 33) on 12-11-2003, 04:54 PM:
 
The movie TOMMY had split surrounds on the optical track using the QS matrix scheme
The Lb and Rb vectors were summed for a standard 4:2:4 matrix yet on that film it was encoded with the LB and Rb like the mag prints and the first CP100 was configured for it
 

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Posted by John McConnel (Member # 2000) on 12-11-2003, 09:32 PM:
 
So what did the TOMMY optical sound track have?
Stage Left
Stage Right
Left Surround
Right Surround

or what?
 

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Posted by Gordon McLeod (Member # 33) on 12-11-2003, 09:39 PM:
 
Left Centre Right P and Q
 

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Posted by John McConnel (Member # 2000) on 12-12-2003, 01:04 PM:
 
5 channels from optical? How is this done?

Also, P and Q is unfamiliar terminology to me. What is it?
 

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Posted by Gordon McLeod (Member # 33) on 12-12-2003, 01:15 PM:
 
John said"5 channels from optical? How is this done?

Also, P and Q is unfamiliar terminology to me. What is it?"

I would sugest that you take the time to download and read in this order from the manuals on line
Dolby CP100
Dolby SA5
Dolby CP200

After reading that most of your questions will be awnsered
The twin surround outputs are possible because a matrix is in effect a circle of vectors and all one needs to do is extract the correct vector.
If you look up the history that has been discussed on the site of the various methods of matrixing then the awnsers will become self evident
 

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Posted by John McConnel (Member # 2000) on 12-12-2003, 05:18 PM:
 
Thank you for the sources. I'll have to start reading. I've missed earlier discusions on the issue, but after getting into it recently, I started wondering if perhaps there could be sub-encoding in the encoded channels. The "circle of vectors" is a new expression to me.

Initially, I was thinking "inside the box", which for me was four channels derivable from two optical tracks.
 

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Posted by Bill Gabel (Member # 1105) on 12-12-2003, 05:55 PM:
 
The sound format "Tommy" used was called Quintaphonic Sound . There was another decoder unit that you needed to use with the CP-100. My friend has the decoder from the Fox Wilshire Theatre engagement in Beverly Hills.
 

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Posted by Gordon McLeod (Member # 33) on 12-12-2003, 06:42 PM:
 
The quintaphonic decoder was for using DBX nr and Qs matrixed 4 track mag print
The original CP100 in London installed for Tommy was fitted for 4 track mag with Dolby a on the print and also the option of SVA with split surround using the QS matrix
The 116 surround card (used in the early surround adapters with teh cp50 and 100) took the left back and the right back and summed them for a surround output. Tommy did contain the Lb and Rb tracks
which normally could be used as summed into a mono surround or standalone by iteself
The big problem is if one does the vector diagram the centre back (monosurround) has the greatest distance from the left and right and centre channels than one drawn to the left and right back position
since matrixs and logic steering was in its infancy the better the seperation you could get the less the time delay was critical for the haas effect to cancel out bleeding dialogue
 

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Posted by John McConnel (Member # 2000) on 12-12-2003, 08:59 PM:
 
Bill, I saw TOMMY at the Ziegfeld in New York, in Quintaphonic Sound, which was aurally spectacular. And a good movie, too. I presumed it was a 70mm 6-track print. But was it something else?

When I played TOMMY in my own theatre in 4-track magnetic, the sound was also really good. But could a 5th channel have been derived?
 

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Posted by Gordon McLeod (Member # 33) on 12-12-2003, 09:07 PM:
 
All the mag prints had matrixed surrounds left (surround) back (P) and right (surround) back (q) are matrixed onto left and right tracks
also it would have either DBX or Dolby NR on it
 

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