This is topic Speakers & Amps recommended for small cinema? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Amanda Mundin (Member # 3386) on 10-08-2005, 07:48 AM:
 
Hi all, i'm looking to open a small single screen cinema in the UK and i'm looking for speaker & amp recommendations, the auditorium is 14metres wide x 13.5metres long (46ft wide x 44ft long), so roughly 200metre square with a stepped stadium seat rake to seat approx 140. We plan to have Dolby SR to start with (CP55/SRA5) and upgrade to digital at a later date.
Any thoughts/ideas would be appreciated for both new & second hand options, thanks.
 

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Posted by Joshua Waaland (Member # 287) on 10-08-2005, 04:44 PM:
 
I can't tell you which models to use, but QSC makes a good amplifier. I am sure someone else who has more experience will chime in soon. Also you could search the archives for topics like this that may help.
 

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Posted by Samuel Hynds (Member # 2610) on 10-10-2005, 10:21 AM:
 
I would recommend getting a sound system that can handle digital now - than later. It's easier turning DOWN a system than to turn it UP.
 

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Posted by Gordon McLeod (Member # 33) on 10-10-2005, 11:19 AM:
 
I would tend to use the equipment your service engineer likes to work with and is familiar with since they will have to work on it
QSC is my usual amp of choice but there are several UK amps that appear quite good
 

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Posted by Mark Gulbrandsen (Member # 72) on 10-10-2005, 05:27 PM:
 
Gord,
What about all those Pyramyd amps you were putting in... are they holding up?

As for QSC I like certain models... the ones that don't use the class H circuit. If you look at the distortion content of them comminng out of the aalyzer there is considerable added distortion content when the higher voltage rails switch on....

Mark
 

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Posted by Steve Scott (Member # 630) on 10-10-2005, 08:10 PM:
 
QSC's DCA series amps work quite well in a variety of situations, although the four-channel models really do benefit from the higher powered amps in the series. The low power models are quite underwhelming when it comes to driving screen systems in an auditorium of roughly the same dimensions as yours, Amanda.

Although, the CP-65 at St. Anthony does perform remarkably well with QSC's USA series amps, although I've heard that some have had their troubles with the USA series.
 

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Posted by John Walsh (Member # 168) on 10-11-2005, 07:23 AM:
 
I think that what Amanda was looking for was suggested amp wattage ratings and such.
 

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Posted by Steve Guttag (Member # 268) on 10-11-2005, 08:56 AM:
 
Amanda...and S. Scott for that matter...

Look at the Technical Guidelines by Dolby (in the manuals section on this web site)...

Figure 2.2 shows a nomograph...for a 200-watt amp (the little QSC DCA1222) can work playing digital sound on a stage speaker in a 44-foot deep room so long as the efficientcy of the speaker is 99 or better. Just as an example, the JBL 4675 fits that description and there are many others.

If you are using an efficent speaker, like the Altec A-5, that 200-watt amp will work in a room 70-feet deep. You are good out to 120-feet with the 200-watt amp if you plunk some A-4s back there.

But back to the original question...the problem is that speakers and to some degree amplifiers are personal preference items. Some may like the sound of one but not everyone is going to agree...otherwise, there would just be the one speaker/amp since everyone would agree it is the best.

Some equipment is more reliable than others and I do tend to put reliability above features...it has to work, first. We have had great luck with the reliability of QSC amplifiers and JBL speakers. They certainly do not have the lock on reliability though.

As to getting the right match, you do need to ensure you have enough power for your theatre and using the Dolby Technical Guidelines will ensure that you don't underpower your system, which leads back to reliability.
 

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Posted by Amanda Mundin (Member # 3386) on 10-12-2005, 12:13 PM:
 
Thanks for that, i've looked at the Dolby Tech guidelines and using Martin Audio speakers as a bench mark, the Screen 4 for stage speakers, Sub 1a for subwoofer and Effect 3R for surround I worked out the power requirements needed would be 125watt per screen channel (or 85w+85w for Bi-Amp), 1300watt for a single sub and 400watt for each surround channel, does this sound correct, LCR stage channels don't seem very high?

Also what does anyone think of Martin Audio speakers?
 

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Posted by Steve Guttag (Member # 268) on 10-12-2005, 05:07 PM:
 
Amanda...I only checked the stage speaker (100dB @1W/1m) and came up with 160-watts. The nomogragh isn't going to be precise but it is getting you into the right ball park. I don't take the 2/3rds for biamp discount...it presumes too much in my opinion and one can never have too much power. Dolby also only calculates to 103dB, not 105dB.

However, with all of the above said, if you bought 125-watt amps and ran bi-amped, you would probably do just fine. I would recommend 160-watts or better though. In this power range, things are not getting too pricy for the power...as you climb above 400-watts/channel things get a bit more pricey, geometrically.

Bringing this back to another discussion...even QSC's little DCA-1222 amplifier will suffice for your stage speakers given the speakers you've chosen and given the theatre size.

You should triple check the other speakers/power and make sure you have them right (you might, I haven't checked) and also ensure that the speakers you've chosen can also handle the power that is required...especially that 1300-watt single sub...my guess is that it won't cut it (you want the continious pink noise or "AES" power rating." I know of very few drivers that can handle 800 or more watts of continious pink noise (JBL's 2242 is one). If you add another sub, you will reduce your power requirement by half and most likely your amplifier will be able to handle a 4-ohm load (you said it was a single sub so I presume it is 8-Ohms)...as such, your amplifier could provide as much as double the power. It is very rare when a single driver is sufficient as a subwoofer in a digitally equipped theatre.
 

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Posted by Brian Guckian (Member # 1678) on 10-12-2005, 06:30 PM:
 
Martin Audio speakers are very well thought of and seen as a good competitor to JBL. You can't go wrong with JBL or Martin speakers, nor with QSC nor indeed Crown amps.

Also - what are your acoustics like? Do you have an acoustic consultant on board?

Pity you can't get a CP65 with SR cards...I ran a setup with same and JBL speaker / QSC amp combination. With good acoustics to boot, the SR sounded FANTASTIC!
 

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Posted by Amanda Mundin (Member # 3386) on 10-15-2005, 06:08 AM:
 
Thanks for the help
No acoustic consultant onboard but will be applying a fabric covered mineral fibre to 3 visible walls above dado level and covering the screen wall in a black faced rockwool or equivalent to prevent reverb etc
 

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Posted by Andy Summers (Member # 3207) on 10-15-2005, 07:06 PM:
 
Armanda’

Hears a site in based in the U.K. called "Future Projections" and I’ve but together some hot links

35mm projectors
http://www.fproj.com/35mm.htm

Amplification
http://www.fproj.com/amps.htm

Dolby A SR-D dts-ES and oddly there’s no SDDS processors
http://www.fproj.com/processors.htm

Second hand equipment
http://www.fproj.com/used.htm

Enjoy unless you have all ready visited the site with the crazy music, cool…

Future projections also do installations including some THX screens as well. http://www.fproj.com/thx.htm
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 10-15-2005, 10:21 PM:
 

quote: Andy Summers

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oddly there’s no SDDS processors

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