quote: Michael Schaffer

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My question mainly aims at whether this formula should be modified, depending on the the relation of the actual number of speakers in each group.

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4x2 vs. 4x3?

No.


 

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Posted by Steve Guttag (Member # 268) on 04-17-2005, 01:14 AM:
 
I always make my own cables. Dsubs are just too quick and easy to make.

We generally stock 6, 8 and 12 pair snake (Belden), 4-pair digital snake (110-Ohm cable) and such.

In fact, Michael, we also custom make our digital reader cables (even did a couple of SDDS 3000 series since Sony only had 10m and 50m cables...who needs that much length?). Our Dolby Digital cables run in metalic tubing and flex all of the way to the soundhead. it is much easier to pull in cable without ends on them. No wasted cable either and no wasted video level or signal degredation going through extra cable. I much prefer Belden's cable over Carol's for Dolby Digital...not as stiff.
 

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Posted by Robbie Hidalgo (Member # 2090) on 04-17-2005, 01:55 AM:
 
Dr. Guttag,

"Dsubs are just to quick and easy to make"... Wow, wish I heard that more often than "what were you idiots thinking!" (Then again, did you mean crimp or solder?)

You know, the 3k's SDI I/F runs about 100Mhz. Tell me you actually found a supplier for those connectors and didn't splice the ends of the stock 10m cables...?

On the other hand, a 2k cable, now there's a fun thing to make...

Oops. Sorry Michael. Clearly this is now utterly off-topic.
In that case...I'll just ditto what Mark said.
 

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Posted by Steve Guttag (Member # 268) on 04-17-2005, 03:38 PM:
 
Robbie,

We crimp our cables. Use high-grade stuff (AMP and gold crimps) so it goes about as fast, if not faster than properly dressing a phoenix connector. What I fault Sony for in their Dsubs are the 2.6mm jack screws...that was just plain BS...4-40 is the standard dsub screw...2.6mm is Japan only...very arrogant...I don't see Sony forcing 2.6mm on their laptops...they seem to have 4-40 for them. When we made the SCIv2...we make sure that we supplied the 2.6mm hardware on our Dsubs to ensure any remotes would be able to plug in afterwards without changing any hardware.

With respect to the SDDS 3000 cables...yes we found the "5W4" dsub connector (amphenol) but we did a test on splicing the ends of a standard cable and the test proved to be sufficient. Why was Sony wigging out on that one?

The cable we use is 3GHz swept rated (HD-SDI RG-6). We crimped on BNC connectors to the ends, used true 75-Ohm barrel connectors to splice in. The cable we used between the ends was of higher grade than Sony used. The only potential problems would be at the barrel connectors but again...no problems were found and I doubt you could see any ringing at the connectors at 100MHz. I guess having made many video cables (both compression and traditional hex-crimp) making a video extension cable just didn't seem like any big deal. Again, the power cable was a larger gauge than Sony used (and probably at least as high a grade)...less loss there.

This was done on a Kinoton projector where the cable is routed out of the front of the column and connects up to the reader without a bunch of dangly crap. All of the cables on this installation came up from the floor into the column so it appears to be wireless.

So just what problems have you encountered by splcing the cable? Do people just solder on more cable? Use CATV cable or what?
 

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Posted by Robbie Hidalgo (Member # 2090) on 04-18-2005, 05:01 PM:
 
Hi Steve,

There had been several initial installs during the beta period where the reader cables had to be installed in conduit too small to fit the 3000 connector ends. So of course, being molded on, several integrators just cut off an end to fish the cable through the conduit, then tack soldered the end back on. In the handful of episodes I heard about, there was no SDDS decoding at all (as if the reader weren't there). Not to say that there weren't loads of successful efforts at this, but of course I'd never hear about it when/if it worked...My guess has always been a shielding or poor workmanship issue, but it's an indefinitive conclusion. Somwhere around here we've got a victim cable from years ago, I'll try to dig it up and look at it more closely just for curiosity's sake.

The metric D-Sub screws are an inconvenience to say the least. But I'm certain no malice was intended; Japanese-standard-issue became the default. Once their parts-order cycle starts for production, it's a major undertaking to change - the QA process is time, function, and cost intensive, and nothing, not even a screw post, gets modified without an entire by-the-book product re-evaluation by QA. Needless to say, the design groups over there practically hold office parties for QA approvals, but I imagine are also more reluctant than not to revisit the process, unless of course a safety or operational issue is at stake. You'd also probably be surprised how much they have to pay for standard (non-metric) hardware there. That's how we ended up sourcing the metric equivalents here.

Hence, the eventual inclusion of the infamous "connector kit" with the metric screws thrown in during the 3000 era...

As for crimps, well...OK. (Not a fan).
But the BNC with adapter idea seems reasonable. It's good to hear that something other than the OEM cable is actually working!
 

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Posted by Steve Guttag (Member # 268) on 04-18-2005, 10:29 PM:
 
Ya know...I went up against a Mil-spec guy on an installation where he soldered and I crimped...my connectors went together faster and had no reliability issues. Again, it is in the quality of the components and the crimper that makes the difference.

With a solder on Dsub...you have the quality of the solder job, the shrink-back of the wire that are potential pit falls...with a crimp you get a molecular bond. How many BNCs have you seen that are soldered on versus crimp? Those connection typically have much more critical connections for successful operation.

As to cutting the ends..I've seen the results from even a Dolby Digital installation where a tech cut the ends, and then spliced what he had...some sort of 15-conductor cable (not even paired or shielded (maybe an overall shield)...he ran the Dolby digital signal and I think even analog in the same cable. The net result was as system that didn't work very well.

I'm curious...just where have you had problems with cimped on Dsubs? I vary rarely use solder cup Dsubs anymore because I have not found any advantage.

As to the cable that wouldn't work after it was butchered...I suspect that putting a scope on the cable and with appropriate test signals, the cause for the signal failure could be quickly identified.
 

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Posted by Mark Gulbrandsen (Member # 72) on 04-18-2005, 10:39 PM:
 

quote: Steve Guttag

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The cable we use is 3GHz swept rated (HD-SDI RG-6).

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Now thats a bit of a statement for any cable company to make. Even though a slight trace of 3ghz signal might be detectable its gotta be down quite a lot at that frequency and the cable would be very temperatuire and humidity dependant! The only real reliable way to get signals around that high in frequency in to use solid waveguide transmission line designed for a specific use frequency. The loss at that frequency in even the best cable would be astromonical, ditto for even nitrogen or argon pressurized Heliax. Today computer manufacturers are etching in place waveguides as traces on motherboards for todays high speed CPU's to operate properly!!

Mark
 

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Posted by Robbie Hidalgo (Member # 2090) on 04-19-2005, 02:39 AM:
 
Steve, no question about the speed of crimp vs. solder I will admit. Indeed it is predominantly a quality issue as you pointed out.

Ironically, there's a site now with an intermittant, and I remember cringing while I was watching the crimping crew on the floor when that (remaining unnamed) theater was installed. Albeit, it may have nothing to do with the crimps, but because they are crimped, the possibility of them playing a role has crossed my mind out of necessity...and that's because surely, even you must have seen a squirrly interconnect due to crimps along the line somewhere.

Broken "wings", bent (cheap) pins, poor mating, my favorites are the pins which push back out of the hole when the connector is being reinserted. This is even more fun when the shell is back on and you have no idea what could be wrong with the connection that you just checked!

So OK, in semi-permanent installs, you are correct: fast integration, using high quality components makes the crimp vs. solder-cup consideration nearly moot. However, certainly, anywhere that the connectors will see a reasonable amount of in and out in their lives, I'll take solder over crimp every time. It's just that one extra potential that I prefer to leave out of the system equation whenever possible (IMHO).

Not that I haven't seen plenty of...er...less-than-ideal solder D-Sub jobs in my life...(but they're still not as "iffy"...again IMHO).

Mark, what the hell! The guy down at the local CB shop told me that RG-6 is flat from DC to light!

Although I suppose none of this is helping Michael with his 650 EX installation...
 

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Posted by Steve Guttag (Member # 268) on 04-19-2005, 08:17 AM:
 
Mark 3GHz cable is the standard for HD-SDI and is generally good, if the signal conforms to ANSI/SMPTE 292 for up to about 300-feet.

The reference standard cable is Belden 1694A (1695A for plenum)

It is certainly not "no-loss", hence the maximum length before a repeater for the signal. When one is running these signals...you do have to consider things like "bend-radius" and anything that is going to compromise the cable's capacitance properties...think making a really neat rack with the cable formed just perfectly? Think again...keep the bends to a minimum and gradual when they are needed.

Robbie...clearly you've had bad experiences with some cheap Dsub crimps...I've NEVER (and I do a whole lot of cable manufacturing) had one of my crimp pins push out...again, I use AMP brand crimps, shells and hoods exclusively as well as AMP brand crimper. I'll put my connectors up to frequent use as much as I've seen other people's solder.

I absolutely agree with you that on both, technique is key...either style can have excellent results or desastorous. One thing I will give the typical solder connector is that all pins are present...which makes for a more secure connection.

The least reliable Dsub connector I've come across is the IDC ribbon cable connectors. Dolby was issuing some with their SA-10s that were just dreadful. I do use IDC type ribbons when needed but they cost a fortune to get quality ones. And Mark G's trusty Arbor press does a fine job of assmebling them. I've found that cheap equipment and components normally are just not cheap in the end...in any one given year we must make thousands upon thousands of connections...how can you have any measurable percentage of them be questionable?

Hey Michael...I happened across a CP650 manual (issue 2 in this case)...page 4-13, section 4.7 clearly states that when setting up a CP650 for EX...set ALL surround channels to 82dB.

[edited to add Surround EX level information]

[ 04-19-2005, 09:52 AM: Message edited by: Steve Guttag ]
 

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Posted by Darren Briggs (Member # 1071) on 04-19-2005, 03:55 PM:
 
There are lots of references to EX on this website, and opinons differ alot. I think that if the film is made in EX it can sound very impresive, but yes not all films are in ex and EX if left on can spoil the surround sound field.

Back to the topic though, i find the SA10 manual very good and tells you everything you need to know to get all levels correct.
 

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Posted by Robbie Hidalgo (Member # 2090) on 04-20-2005, 01:29 AM:
 
Steve, agreed, agreed, and agreed. Ultimately, either method can shine or stink indeed...

As for those IDC connectors, you almost NEED Mark's arbor press to press those things together reliably! Booooo.

On the other hand, what really winds me up is racks full of ribbon (or other pre-fab computer) cables with audio running through them! Aarrgh.

And lastly, just for the thread's sake:

quote:

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Hey Michael...I happened across a CP650 manual (issue 2 in this case)...page 4-13, section 4.7 clearly states that when setting up a CP650 for EX...set ALL surround channels to 82dB.

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Just wanted to highlight that info from the rest of the chatter since it's dead-on topic, and extremely useful information. Time to get Issue 2 of the CP650 manual...!
 

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Posted by Michael Schaffer (Member # 1204) on 04-20-2005, 06:37 AM:
 
Roberta: thanks for highlighting that. I can never read Steve's posts - he always types so small. Normally I have to get somebody to read them to me. But thanks to you, I was actually able to read these lines without help!

Actually, the manual versions higher than 1a (which I looked up here on this website when I wrote the post because I was too lazy to get up and get the latest CD) contain that info. 1a doesn't. Neither does the EX upgrade kit manual.
I am still not completely satisfied with the information provided there. If you set all channels to 82dB, then you - theoretically - end up with 85dB or so blasting from the back when the back wall channels are active together. It also seems like a good idea to blow up speakers. Often, you only have 2 or 3 speakers in each group which would have to provide just as much air movement as 4, 5 or 6.
Also, it seems to be a contradiction to the procedure described in the SA10 manual where you set the side wall to 80dB and then bring the corresponding back section up to an overall 82dB.
Maybe it is one of those things that become obvious once you do it and carefully work your way to a good balanced setting.
 

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Posted by Steve Guttag (Member # 268) on 04-20-2005, 08:11 AM:
 
Michael,

You read too much into the CP650 setting...who says that it is in EX mode when you set levels?

If I were designing the processor...I would have everyone set the levels even more uniform...that is, 85dB per channel so only one number need be memorized and so that the room is properly excited while EQing. Then when the processor is acutally playing the film, it would adjust the surround levels appropriately. That kinda what Dolby is doing...though they chose 82dBc which is more the surround standard level.

The SA-TEN can't do that since it is working with a processed signal. You are sending your pink noise from your host processor and having it go through the SA-TEN as if it were the actual film. Note too the other limitations of the SA-10...you only have 3-EQ channels and three output level controls for 4-channels. As such, you have to set the levels between the four channels.

With the CP650, you don't have any of these restrictions, you have four independant EQs and four level controls so each of the four surround channels are treated on their own...then the CP650 can set the balance of the four channels as appropriate for the two modes.

As to blowing up speakers...that only happens in poorly designed systems. Surround-EX puts much greater demands (particulalry on the rear-wall) surround speakers. Each of the three sides needs to be able to handle what the entire system could handle before (level). Note too, that the rear wall often needs to be able to reach further since most auditoria are longer than they are wide (though that is certainly not always the case).

When choosing surround speakers (or any speaker for that matter) you need to not only consider coverage but power handling. If you don't have the power handling with just 4 speakers on the back wall, then you must go to six and space them tighter...it is just that simple.

Often a better choice is to use a more efficient, though often a more expensive, speaker to deal with the power. There is a reason companies like JBL have speakers like the 8340A in addition to the 8330A...you go from 91dB @ 1W/1m to 96dB @ 1W/1m...that is a huge increase in sensitivity. In terms of wattage...that would take you from say 600-watts per surround side to say 190-watts.
 

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Posted by Michael Schaffer (Member # 1204) on 04-20-2005, 11:56 AM:
 

quote:

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You read too much into the CP650 setting...who says that it is in EX mode when you set levels?
...
With the CP650, you don't have any of these restrictions, you have four independant EQs and four level controls so each of the four surround channels are treated on their own...then the CP650 can set the balance of the four channels as appropriate for the two modes.

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That is probably what I missed - that the CP650 actually "knows" what mode it is in and that it can (and hopefully does) adjust the outputs accordingly. Thanks for pointing that out.
 

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Posted by Robbie Hidalgo (Member # 2090) on 04-20-2005, 05:59 PM:
 
Herr Shaffer,

I knew you would appreciate it. I know your vision tends to get a little blurry from time to time...


 

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Posted by Antonio Marcheselli (Member # 373) on 04-21-2005, 06:00 AM:
 
About EX levels...

I've checked the CP650 manual (the last online) and, really, there are no indications on how set the Back surround levels.

The SA10 does not consider the surround in quadrant so the level, I think, would be different than a CP650.

On DTS-ES the Surround are set 82dB LS and RS, 80dB BRS and BLR, so that Back Surround give 82dB. Has more sense to me.

Does CP650 with integrated EX card do the same? Is something official wrote from dolby?

Bye
A
 

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Posted by Christos Mitsakis (Member # 143) on 04-23-2005, 01:14 PM:
 
Antonio,
CP650s current manual, I think, is issue 4.
Quoting from it (Chapter 4, B-Chain Alignement, page 4-7)

"..setting the Ls and Rs channels
(Ls, Bsl, Bsr, and Rs channels if your unit is
equipped with Dolby Digital Surround EX) to 82
dB.
Ls and Rs = 82 dB or
Ls, Bsl, Bsr, Rs = 82 dB"

So what Steve wrote in his post above is correct.

Christos.
 

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Posted by Antonio Marcheselli (Member # 373) on 04-23-2005, 01:34 PM:
 
Christos

Thank you! Seems that I have only Issue 1A (the one that is available on MANUALS - Is there a way to download an updated one?)

AND, much important - Brad will punish me -, I didn't read carefully Steve's post, otherwise I didn't had made the question...

THANKS!

Bye
A
 

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Posted by Christos Mitsakis (Member # 143) on 04-24-2005, 02:47 AM:
 
Antonio you may try to download a manual here:

http://www.iceco.com/Technical.htm

There is a CP650 installation manual, unfortunatelly no time to dowload and see. I hope it is an updated edition.

C.
 

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Posted by Antonio Marcheselli (Member # 373) on 04-24-2005, 01:21 PM:
 
Thank you Christos,

It is Issue 2.

Bye
A
 

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Posted by Antonio Marcheselli (Member # 373) on 05-01-2005, 12:08 PM:
 
I made a search and I have a curiosity.

During EX playback does the Back Surround channel have a higher level? I understood that with Digital processor like CP650 you set all surround channels to 82dB. But what happen when EX is working with a film? Does the Back Surround operate at higher level?

In other words, if I cycle the same pink noise on LR, BS, RS (while the processor in EX mode) should I measure an higher SPL from the Back Surround?

I searched on Dolby.com but I found nothing.

Thank you!

Bye
Antonio
 

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Posted by Michael Schaffer (Member # 1204) on 05-01-2005, 01:08 PM:
 
I asked the same question, and Steve already answered it (see 6 or 7 posts above).
 

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Posted by Antonio Marcheselli (Member # 373) on 05-01-2005, 01:40 PM:
 
I understand that, so the "processed" Back Surround level is 3dB higher than Left and Right Surround? While in EX the surround levels are Ls:82 Bs:85 and Rs:82 and While NOT in EX Ls:82 and Rs:82?

Bye

Antonio
 

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