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This topic comprises 4 pages: 1 2 3 4
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Author
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Topic: JSD 60D crossover
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Harold Hallikainen
Jedi Master Film Handler
Posts: 906
From: Denver, CO, USA
Registered: Aug 2009
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posted 01-19-2015 11:37 AM
Thanks for the comments! There are, of course, several places in the signal chain the crossovers can go. As mentioned, the JSD-60 supports biamp of three screen channels. The manual at http://ftp.uslinc.com/?dir=ftp/Products/JSD-60/ provides a fairly extensive description. The GUI is also there for you to try. There's also a beta version available that adds support for AES/EBU outputs and BLU link outputs.
The USL monitors with crossovers has already been mentioned. There's now also a separate crossover that uses the same cards as the monitors. See the XTM-300A and XTM-300D at http://ftp.uslinc.com/?dir=ftp/Products .
Where to place crossovers is an interesting area for discussion. Some speakers include crossovers that are matched to the speakers, but these tend to be inefficient and may be overly simplified since power components are used. Next, many amplifiers include DSP crossovers. Crossovers can be moved back up the signal chain to between the processor and amplifiers, or back into the processor itself. Since the processor already has one or more DSPs, adding crossovers there is not overly complex or costly. It does add hardware in most cases. With the BLU link (or similar networked audio outputs), no additional hardware is needed.
Placing the crossovers in the processor is probably the lowest cost method since no additional devices or DSP-based amplifiers are required. This also keeps all the audio settings in one device simplifying setup and (heaven forbid) equipment swap outs.
THANKS!
Harold
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Carsten Kurz
Film God
Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009
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posted 01-19-2015 02:22 PM
I know a lot of cinemas using the cheap Behringer DCX2496. In a fixed installation and properly set up, they are not that bad. Good thing is, they have both analog and AES/EBU inputs. You can network them using RS232/RS422. If your cinema processor fails, you can actually bypass it and use your bunch of DCX2496 as your CP as long as your real box is under repair. You can actually control all centrally from a laptop, level, have analog Non-Sync options, etc.
Having a fail-safe option is sometimes more important than the highest level of audio fidelity, especially with Bi- or TriAmped systems where you can not simply throw in any other device.
These Behringers have been built for mobile/PA use. They may not be the most reliable under heavy use in that environment, but under stable cinema condition, I would consider them a decent choice. Plus, they come at a price where you can easily stock a spare.
- Carsten
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David Buckley
Jedi Master Film Handler
Posts: 525
From: Oxford, N. Canterbury, New Zealand
Registered: Aug 2004
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posted 01-19-2015 05:22 PM
quote: Steve Guttag Personally, I don't think enough consideration is given to the whole crossover and how the speakers are tuned, as a general statement.
I believe that to be a true statement, and with far wider applicability to cinema.
The discussion about the Berry DCX is all very well, but for a cinema you need a lot of them (assuming screen channels are identical) with a bunch of wiring. The Rane HAL system mentioned is one of the "drag n drop" DSP solutions that are just so much better than everything that went before them, others being Soundweb (where this paradigm started), Symnet, and there's more that I cant remember right now. These really come into their own where there are lots of inputs or outputs or both, and now that digital audio networking is commonplace, these solutions provide an especially great solution. The only problem is that they are relatively expensive. Perhaps more annoyingly, they expensive for what they are.
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Steve Guttag
We forgot the crackers Gromit!!!
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Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 01-20-2015 06:37 AM
I think the design emphasis is much different. No, there is no reason why the CP can't have a good crossover design. QSC makes their DCP line and the crossover in there is at least as good (actually better) than what is in their DCM and most any other cinema processor based crossover. It is still limited as compared to one of the various DSP boxes.
While it is true that if all you wanted from the DSP is a good crossover, the DSP solutions are a bit pricey...but when you factor in tuning as well as possible other channel routing, mixing, leveling...they become more economical. Also, one has to factor in cost/performance. If they do the job better and yield a consistently better result, then part of what you are paying for is quality. Why does a QSC SC-424 cost so much more than some cheap Peavey speaker? Well one does a MUCH better job than the other. I claim that crossover and EQ have a great affect on the outcome of the sound. As such, paying more for a better piece is a reasonable expense. For us, the RANE HAL3S offers quite a bit of bang for the buck (and rackspace). Out of the box, it is a 2x6 DSP (stereo 3-way) but adding two RAD-16s to it it becomes a 6x10 DSP so you can effectively set up an entire 5.1 system.
One thing most DSP based systems now get you are the ability to remotely locate your inputs/outputs where needed. This can also facility lowering the costs of big heavy copper runs.
I have discussed the concept of using a HAL1x system (with Rane) as the cinema processor as well as DSP. Cost wise, it is on par with a DCP300 system with similar ins/outs. What you miss out on generic DSP systems, typically, are "pro-logic" decode blocks. Since DCinema felt the need to issue "2.0" DCPs...including the home-made stuff...one really does need a "proper" pro-logic decoder in there somewhere. A simple L+R/L-R system really isn't sufficient. That is really a "better than nothing" solution. I know some that have used Basis as the Cinema processor but again without Pro-Logic capability.
The JSD60 has the pro logic decoder...BUT it, at the present time, doesn't work with the 1/2 input! I've considered using a passive splitter to send 1/2 to both the 1/2 input and the S/PDIF input (impedance matched) on this and other processors to get the pro-logic decoder. QSC promises to activate their decoder for the Digital inputs on the "next" release (they only have it on the other inputs).
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