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Author Topic: Starting off with stereo sound Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 05-17-2006 03:51 PM                        Going back to your original question: Yes the CP-45 is plenty good enough, even with the 222sra card. I also would hope you buy good speakers and most certainly bi-amp. Later you could add subs & digital when the budget allows. Louis  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 05-17-2006 07:36 PM                     If on a budget I would go for a used USL JSX with the 1/3 octave eq as it can accept a dts or srd adpater also I don't know any second run theatres in canada that currently have issues getting disks on time  |  IP: Logged David Ingalsbe Film Handler Posts: 31 From: Eagan, MN, USA Registered: May 2004 posted 05-18-2006 04:17 AM                     Well this is a crazy thought I know but a cp500sr would be another way to start. they have been hooking up to everything that we can though at it and the prologic decoder is as good as the dma8. Downside is every option requires an add on board.  |  IP: Logged Paul Gordon Jedi Master Film Handler Posts: 580 From: Ottawa, Ontario, Canada Registered: Aug 2005 posted 05-18-2006 07:06 AM                        Our theatre (second run/art) has trouble getting DTS disks. Lots of times the main projectionist has to run around and find a theatre with the disks and copy them. Or when we complain to the distributor about it (like Alliance Atlantis) they get pissed off at us for asking about the disks. Smaller distributors are even worse, I think sometimes they just don't buy the rights to DTS, the prints may have the code but they don't come with the disks.  |  IP: Logged Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 09-06-2006 05:35 PM                        Thanks for all the feedback. So, just out of curiousity (because I don't really understand lenses, although I'm getting better, and not too much about sound systems besides the basics), is a stereo system a left channel behind the screen and a right channel? So, as far as my understanding works: Soundhead to processor processor to left and right amps left and right amps to left and right screen systems (respectfully). Now, this is just a work in progress (you know how I am), but I've been working on a business plan, layout, equipment, where to finance, yada yada yada. The rooms would be wired for expansion to digital.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 09-06-2006 06:40 PM                        You need to add a center channel with amps. And yet another amp for the subwoofer channel. Don't go without a sub. (Two is better.)  |  IP: Logged Caleb Johnstone-Cowan Jedi Master Film Handler Posts: 593 From: London, UK Registered: Mar 2006 posted 09-06-2006 08:32 PM                     I would invest now in decent sound. Fact is a lot of your potential customers could have 5.1 sound in their home theatres and after coming to watch a film in stereo never come back.  |  IP: Logged Cameron Glendinning Jedi Master Film Handler Posts: 845 From: West Ryde, Sydney, NSW Australia Registered: Dec 2005 posted 09-06-2006 08:41 PM                     Dolby stereo is really just stereo but played back through 4 channels, left, centre, right and surrounds, in the real world you must sit aproximatly in the middle of the two speakers (stereo)to get a true sound stage, from that position a phantom center and surround is created. If you move away from the center listening position the effect is lost. In a cinema this translates to a very small number of seats that would get acceptable sound. the further you sit from the middle the more unballanced the sound becomes, ultimately creating the situation that if you sit on the left of the auditorium, the dialogue will apear to be coming from the left of screen! Dolby bought and adapted the Sansui home quadraphonic system for cinema, so that quality stereo sound could be enjoyed in the majority of the seats in a cinema. Now Quality of sound is most dependant on the speaker system! and how they are installed to interact with the unique room acoustics. Most electronics/ amps / modern processors have almost no recordable distortion. The speakers though are the proverbial tin can on a string. High quality sound can be achieved through a simple 2 way passive speaker system. If you create a quiet place for the speakers to operate from by lining the back stage with fiberglass or polyester will also create a dramatic improvement to dialogue intelligibility / natural sound of the cinema. Angling the Horn to minimize echo / getting that right is also a key to great sound. Quality surround speakers that simply sound good especially in the midrange! these speakers point directly into the ears of the audience and color the sound. the number of cinemas with crap sounding surrounds still surprises me. Bi amping / 3 & 4 way systems / genuine SR Cards / can then add to this. but are to some degree subtle compared to the basics. Dolby with cat280 cards and Panastereo are to me the finest sounding analoge processers. My relivent experience to this is that my company Cinepro has custom built several complete cinema speaker systems and have modified many more in Sydney, Australia. Companies who have purchased my products include, Hayden, Dendy, Hoyts, Valhalla, Chauvel, United, Palace and John Wilsons GALAXY traveling cinema. Also Wings on your speakers can help control the air and help the formation of a perfect bass wave and deepen the bass response, think 1"mdf timber wings that are crossbraced with 2x4 that are 4 ft wide, this will dramatically increase your sub bass response from your conventinal speaker system beware of non solid surfaces or materials in the cinema, thin materials can shake / absorb the bass and even create rattles. Left and right only configeration is extremly rare in cinemas, cut down systems usually are centre only with surround, I do not recomend this though! [ 09-06-2006, 11:18 PM: Message edited by: Cameron Glendinning ]  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 09-09-2006 10:30 PM                     quote: Andrew McCrea So, as far as my understanding works: Soundhead to processor processor to left and right amps left and right amps to left and right screen systems (respectfully). If you really really just want a left channel and a right channel, then you don't need a processor, you just need to connect the soundhead to the amps. (somehow) there is no processing needed to get a left and right signal from 25mm film, it is recorded right on the film that way. However, trust me and what the others have said - You really don't want to do it like that. In the year 2006, you need to install Dolby SR, with a nice basic Dolby processor as the others have mentioned above. That will give you left, center & right screen channels and a mono surround channel, and an all over better sound quality because you have the dolby processing.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 09-10-2006 06:24 AM                     Cameron said "Dolby stereo is really just stereo but played back through 4 channels, left, centre, right and surrounds, in the real world you must sit aproximatly in the middle of the two speakers (stereo)to get a true sound stage, from that position a phantom center and surround is created. If you move away from the center listening position the effect is lost" Not true Dolby stereo optical is a 4 channel encoded matrix system. It is not a two channel with a improved stereo image  |  IP: Logged Cameron Glendinning Jedi Master Film Handler Posts: 845 From: West Ryde, Sydney, NSW Australia Registered: Dec 2005 posted 09-10-2006 08:03 AM                     Ok Gordon, yes there are 4 channels derived from a stereo source. On a regular stereo amp it is also possible to create a surround channel simply hook up a speaker from the amp pos of the right and the negitive from the speaker to the pos of the left and presto a surround channel 85% as acurite as a Dolby one (no delay) Early cheap cinema processers like eprad combined l + r for the centre Now why if I am wrong? how can you play a regular CD mixed only for stereo through a prologic decoder and get a centre and surround channel even though the recording was not mixed for it?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 09-10-2006 08:22 AM                     actually a cd played back through a prologic decoder doesn't "decode" it properly and the L-R channel is not actually the surround channel persay but the source of the surround control As for Eprad they did use the L+R as the centre channel as did the early dolby units I would recomend that you read the wilcox patent for the 4:2:4 matrix as used by Dolby that is the most current patent on the encoding process that follows on after the patents of schriber and tate the original concept for center channel was a 3db gain riding (cat 110 for the cp50 and the pentoptical module for the cp100) enhancement of the original phantom center channel described back in the 50's in a SMPTE journal artical on a 3 channel optical system The surround channel was originaly as you mentioned a adaptation of the Sansui QS system and was a sum of the Lb and Rb channels this was the cat 116 To increase the channel seperation they quickly adopted the tate set of chips that were adapted from the schriber SQ matrix that CBS had used (I think if memory serves it was the New Orleans Matrix was the mix parameters that were used There are many other decoders that work all are based on the core of sum and difference but even in the sweet spot of a room the logic gain riding is still needed  |  IP: Logged Cameron Glendinning Jedi Master Film Handler Posts: 845 From: West Ryde, Sydney, NSW Australia Registered: Dec 2005 posted 09-10-2006 09:40 PM                     Gordon is totally correct of course!!! I was trying to simlify it a little too much to put it in context of this tread so that a cinema would not have only a left and right speaker backstage. When you play a regular cd through a prologic the stereo effect is sort of crushed to centre ect. amp output Surround positive> + L - - R + <surround neg my original post is too confusing, try above sometime for a cheap surround channel, yes you do wire up the left and right channel off the same amp. Please only at home, the effect isnt for the big screen [ 09-12-2006, 04:15 AM: Message edited by: Cameron Glendinning ]  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 09-13-2006 01:04 AM                        I've got a similar situation to the OP. We are an analog stereo house, that is real stereo not "cinema stereo", just one pair of speakers behind the screen, one stereo amp, a pair of ASR-40s (we run changeovers), and a mixer the readers are both plugged into. The audio is switched using the power supplies for the LED readers. At a leisurly pace (ie several years) we'd like to upgrade this system to something more standard, L/C/R + surround(s) + sub, but wont be able to do this in one go, but I'd figure a good place to start with would be installing a processor. If we got more speakers and/or amps then we'd have nothing to drive them with, whereas with a processor we'd at least get noise reduction as an opening gambit. What we be a sensible processor to go for? Its got to be available, affordable, and happy to generate just stereo so we dont lose the center and surround audio, and work with changeovers, ie two sync inputs and switching betwixt same. Ideally if it can then go L/C/R only as a step to surround(s) and sub that would be excellent. Old tech, ie repairable would be nice too  |  IP: Logged Paul Gordon Jedi Master Film Handler Posts: 580 From: Ottawa, Ontario, Canada Registered: Aug 2005 posted 09-13-2006 07:36 AM                        You have to have more then a left & right system now a days.... Buy yourself a used CP55 or 65 with split surrounds and get yourself setup for a good 5.1 analog system. A CP55 will run you around ($600.00) then buy a SRA5 w/ two CAT 280T cards ($500.00) you can find cheap CAT 280's on ebay and change them to 280T's. Put in some new red light readers ($800.00) and your off and running. Sound is in fact more important then picture!! people will accept an "ok" picture but not bad sound.  |  IP: Logged

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