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| Re: Battery Powered "Biggish" PA System [message #320946 is a reply to message #320933 ] |
Thu, 08 May 2008 14:57   |
 Rory Buszka
Messages: 27
Registered: May 2006
Location: Oblivion |
Should Get Out More |
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I'm not completely sorry to say it, but the EV ZX5 boxes are your problem. If you're trying to cover stadium seating from a rig that's still easily transportable, you'll need as much sensitivity as you can get, and that means horns. The easily-set-up solution would be two or four Danley SH-100B (8" coaxial on 100-degree horn, quad 8" drivers on tapped horns providing low end). Put the Danleys on the 30 yard lines and face them straight ahead. If you want, you could take a pair of field carts and rig up a tilting system that would allow the boxes to be laid flat for transportation. If this system were going to be used for marching competitions (where the pit has to be off the field by the time the last row of the marchers has passed the goal line), the ZX5 approach would be a real killer. I'd hate to be the guy responsible for taking down the six ZX5 boxes, breaking down the six tripod stands, and coiling the how-many-feet of cable you'd need. The Danley SH-100Bs, by comparison, will offer up the "percussive" low end you want -- but don't expect the same from the ZX5s. You can get by with WAY less amplifier power than you'll need for the six ZX5.
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| Re: Battery Powered "Biggish" PA System [message #320982 is a reply to message #320839 ] |
Thu, 08 May 2008 17:00 |
Alex Cipriani
Messages: 160
Registered: April 2004
Location: Monitor Beach, UK |
Has No Life |
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We have a van fitted out for this kind of thing. A 6kW inverter powered by 440Ah worth of 24v lead-acid batteries gives us just under 2 hours of music with a 2400W front-of-house system and 3x600W of monitors.
Two things to be aware of:
- Most UPS systems (unless you spend a lot of money) are quasi-sine wave supplies. That is, they produce an approximation of a smooth mains supply containing varying levels of harmonics which will almost certainly induce noise (think dimmer buzz) into the system. Whether this noise can be controlled and kept to an acceptable minimum depends on all the components of the system.
- Be careful with power supply sag. Since UPS systems aren't really designed to power amplifiers with a very variable load, the low voltage wiring might not be up to the job. By way of example, our system can draw over 800 amps peak from the batteries, and that needs some really thick cabling to avoid huge line losses.
In summary, I don't think a UPS is the way to go, and while an inverter certainly can work, it's not going to be particularly small when you include the size and weight of batteries, and there are a few things to be thought about in designing the system. We certainly had some interesting experiences when designing our van.
It's taken me almost an hour to type almost nothing, and I'm about to start rambling, so I'll stop now.
HTH,
Alex
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| Re: Battery Powered "Biggish" PA System [message #320997 is a reply to message #320973 ] |
Thu, 08 May 2008 17:53 |
Dave Bjornson
Messages: 83
Registered: July 2005
Location: Pittsburgh Pa. |
Nothing Better To Do |
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| Mac Kerr wrote on Thu, 08 May 2008 22:34 |
| Marty McCann wrote on Thu, 08 May 2008 17:25 |
Tim wrote:
>>>
My question, though, is "Aren't marching bands already loud enough?"
<<<
Not any longer.
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Blast! was a drum and bugle corp with about 60 members, indoors, with a wireless mic on every mobile instrument. There were also 5 "percussion cubes" that had wired mic setups. FOH was a PM1D, mons a PM3500M doing 12 mixes. The show was loud. Did I say the show was loud?
Mac
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I pulled the Blast DVD out of the dumpster at my local library.
Once I got past the goofy flag/pole corp....
Holy Crap what playing!
Great set too...
DVD sounded pretty damn good too.
Were you on that gig Mac?
[Updated on: Thu, 08 May 2008 17:54]
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| Re: Battery Powered "Biggish" PA System [message #321007 is a reply to message #321003 ] |
Thu, 08 May 2008 19:12 |
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At my college, the marching band (~400 Members) would play a yearly concert in one of our auditoriums. No amplification (they did set up the band shell though.) One of the loudest *things* I've ever heard!
Oh, and +1 for the little quiet Honda generator.
-JB
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| Re: Battery Powered "Biggish" PA System [message #321070 is a reply to message #320839 ] |
Thu, 08 May 2008 22:31 |
David Buckley
Messages: 486
Registered: January 2005
Location: New Zealand |
Has No Life |
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Give these guys a ring: http://www.50hz.com
Don't be fooled by the name; the do 60Hz as well. Their static converters can have battery packs fitted to enable them to run off batteries, and they can handle your power requirements without difficulty.
For this sort of application the batteries are in series to produce a highish DC voltage, for a 120V AC supply the DC voltage will probably be 180V, which is 15 x 12v batteries. So much more efficient than inverting up 12V, with much lower current handling problems.
A genset will probably be cheaper though; a film set standard silenced generator will make less noise than the fans on the back of the QSCs...
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| Re: Battery Powered "Biggish" PA System [message #321137 is a reply to message #321070 ] |
Fri, 09 May 2008 07:42 |
Charlie Zureki
Messages: 843
Registered: April 2008
Location: Detroit Area |
Has No Life |
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Genset is the way to go... smaller, cheaper, less weight, less maintenance.
Hammer
Be prepared, you'll need it!
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