quote: Carsten Kurz

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E.g. Mackie Thump TH-15A.

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Please tell me you're not serious?
 

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Posted by Carsten Kurz (Member # 5396) on 08-26-2011, 11:43 AM:
 
I'm completely serious. There is NO center speaker at all currently. ANY speaker there should to be taken serious.

- Carsten
 

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Posted by Monte L Fullmer (Member # 2797) on 08-26-2011, 12:32 PM:
 
I knew of a twin (converted from a single) that had just that: L/R/S with no center, and Center was mixed in with the L/R.

They had old USL JS 95/195 processors.
 

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Posted by Pete Naples (Member # 761) on 08-26-2011, 01:18 PM:
 
It's called 'phantom centre' Monte, it can work very well.

Without knowing or better still, hearing Williams room, none of us are qualified to state that a dedicated centre speaker is essential.

And in any case, I'd rather have phantom centre between two decent boxes, than anything involving Mackie, 'Thump' or otherwise.
 

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Posted by Chris Slycord (Member # 4239) on 08-26-2011, 03:46 PM:
 
I understand the whole "having little-to-no budget" thing but I think you should consider if adding the center will actually cost that much more than adding in mixers and such.
 

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Posted by Eric Robinson (Member # 2966) on 08-26-2011, 09:37 PM:
 
I have noticed with 2 speaker systems that have the center mixed into both that the closer you sit to either speaker, the sound becomes very pronounced from that one speaker and you notice little sound from the other. So, all the dialog will appear to come from the left speaker if you are sitting close to the left speaker.
 

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Posted by Monte L Fullmer (Member # 2797) on 08-27-2011, 03:24 AM:
 
..why, when you do the "phantom center" channel adjustments, that the L/R attenuations has to be perfectly balanced so it's not obvious if sitting close.

Ya gotta make that 'sweet spot' happen in the right spot ...
 

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Posted by Pete Naples (Member # 761) on 08-27-2011, 04:08 AM:
 
Eric/Monte, that's spot on observation/information.

William has already stated he doesn't have a perforated screen, perhaps there is no where that a centre speaker could go, either above or below the TPL?
I have in the past when faced with a non perf or even solid (Gyproc) screen, phantom centred top to bottom, ie one box above and below the TPL, on the centre line. Both driven by the centre channel output and very carefully balanced.
He's already stated he has a suitable mixer available, so down mixing is a no-cost option to him.

I'm not saying this is an ideal thing, however he has what facilities he has, let him get on with it. As I said before, none of us keyboard experts here have seen or heard the room in question, so we are not qualified to make sweeping judgements about it
 

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Posted by William F Green (Member # 3192) on 08-27-2011, 07:27 AM:
 
Unfortunately a centre speaker under the screen (which has been considered and tried before) is not a viable solution. Sound-wise we have to cover the main part of the auditorium and a balcony as well.
After a lot of experimenting years ago we discovered that there was absolutely no way that a speaker placed below the screen could cover the balcony - it's just too low-down. So the compromise solution to get decent coverage of ground floor AND balcony was to feed all sound info to left and right only. These speakers are then positioned about 6-8ft above stage level. From this position the speaker horns have just enough dispersion (60 degrees) to cover all seats including balcony.
Whatever we tried, speakers under the screen at the level of the stage just would not deliver intelligible dialogue to the balcony due to reflections off the back wall - the auditorium is stepped in shape with the ground floor area being forward of the balcony rather than under it.
Above the screen can't be done either as it's a large roll-down type and rolls down from above and behind the (very tall) proscenium arch.

This is a 'difficult' venue both acoustically and logistically and the current speaker positioning is the best compromise we've found to-date. If we were setting up our own venue from scratch there is no way on earth we would do it like this - but we have to use what we have in the building and for now at least that means we are stuck with non-perf screen and no surrounds. In fact in an ideal world we wouldn't even use the speakers we are using but we had to select something that was capable of projecting dialogue clearly in a reverberant space (which they do very well) - albeit at the expense of some smoothness.

As somebody mentioned, one of the consequences of not having a discrete centre speaker is that the sound always appears to come more from the right or left depending on which side of the centre-line you sit. In all the years of running this way we have never had a single comment about this though.

Regarding the mis-match between installing digital projection and connecting it to a less-than-perfect audio system - there is really no choice on that, 35mm will become scarce and so having digital projection will be an essential rather than a choice.

I appreciate that it's not easy to imagine my auditorium and I do appreciate all the suggestions here - even the ones we can't apply..
 

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Posted by Monte L Fullmer (Member # 2797) on 08-27-2011, 09:52 PM:
 
Okey, I'm going to throw a good one here and anybody can throw it out as a wacky idea. but give me a shot at this one...

Let's try the "BOSE" method: what he has is a non perfed screen. What we have then is a flat surface..

What about "reflecting sound" by mounting the speaker at a certain degree angle facing a flat and smooth section below the screen and let the sound reflect off of that surface out to the auditoria at the correct angle to create that line of path sound as if there were speakers behind the screen?

Then, one can easily drop a sub down below the screen since sound from a sub is muultidirectional anyway being a sub frequency and not full-range...

Okey, see how this one goes .... - Monte
 

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Posted by Manny Knowles (Member # 1171) on 08-28-2011, 12:03 AM:
 
The reason we have the center channel is because with a Left-Only/Right-Only (LoRo) setup, the phantom center only "exists" in the sweet spot, resulting in an inconsistent experience from seat to seat.

As noted, for persons who are not seated in the sweet spot, the sound appears to come from whichever speaker is nearest and, for them, the illusion falls apart.

This is known as the precedence effect, or the law of the first-arriving wavefront. The illusion falls apart fairly easily up-close, but I have seen where it is possible to tell whether a matrixed LCRS was being decoded from as far away as 50 feet.

The only way to ensure that the center-channel information appears to emanate from the center of the screen is to actually have a loudspeaker there.
 

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Posted by Pete Naples (Member # 761) on 08-28-2011, 04:46 AM:
 
Monte, I took over a site which uses that idea in two screens. Both of which are hard surface ie plasterboard.

I can tell you first hand it doesn't work. The sound disperses and intelligibility, as well as HF, dissapears.
I think what's happening is the sound is bouncing off the screen, then up towards the ceiling, then down to towards the audience. So they're hearing that reflected muddy sound plus whatever is bouncing direct off the screen, plus whatever is travelling direct. The installers tried touse this trick for left and right as well, it's impossible to distinguish much seperation, the stage channels are very inneficient and don't Eq well. It's about to be ripped out and re jigged with left and right situated, well left and right of the side masks, and the centre channel above the TPL. Not by the book but light years better than what's there presently.

Perhaps Bose have systems purpose designed to work this way, but with standard speakers, it's a stinker
 

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Posted by Kris Verhanneman (Member # 5562) on 08-28-2011, 05:34 AM:
 
I've had the pleasure to see and hear this in real.
http://www.showmaxcinema.com/
Sounds great and uses a non perf screen.
The speakers are behind the screen.
 

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Posted by Richard Fowler (Member # 893) on 08-28-2011, 10:19 AM:
 
Sounds like the polyplaner type of speaker set up using the screen as part of the speaker.....an idea that has recycled a couple of times...
 

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Posted by William F Green (Member # 3192) on 11-02-2011, 03:20 PM:
 
Just a little update on this ingesting into Doremi.. I've found a UK supplier of CRU cradles at a reasonable price and once I've got the total sorted and fitted all the bits I'll post here in case it's useful for somebody else.

Confirmed that via USB does indeed take around 2hrs to ingest a 2hr feature so not too good.

But, those little move-docks which come fitted to the rear of the drives (the bit with the power supply and USB) also have a SATA connector. So, for the time being we have an even cheaper solution for quick ingesting. We have run a SATA cable out of the back of the server and plugged into the SATA connector on the back of the drive and it works perfectly - around twice as quick as USB in fact. The SATA cable is just permanently plugged-in inside the server to a spare connector (SATA 4) on the motherboard - it worked straight away with no configuration needed.
It's just not quite so neat to have cables dangling all over the place so I will probably order a one-bay CRU unit for the long-term.
 

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Posted by Carsten Kurz (Member # 5396) on 11-02-2011, 08:05 PM:
 
Put something in the contract that

a.) makes the renter aware of possible legal issues, e.g. let him confirm that he owns the rights to any material he wants to show

b.) rent out auditorium and projection equipment, but do not act as the enity actually performing the projection/presentation. The specific media/title etc. should not even occur in the booking. That way, the person/company renting the auditorium and gear will be responsible for any legal issues arising from the showing.

- Carsten
 

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