Limited current, limited electricity.

[Music is life]

You need music in a remote area and it needs to be loud.
Let's say you have very limited power like Car batteries (and so inverter) or generator.
Number 1 consideration would seem to be very efficient speakers like Bill Fitzmaurice's horns both top and bottom.

But what type of amplifiers would be the best for this application?
Any other considerations?

[Sydney]

Re: Limited current, limited electricity.

Know people who live too far to be hooked up the grid; as a result used a 12V based system.
Car amps and speakers that provide the most SPL out per watt in.
Home or Party?

[Music is life]

Re: Limited current, limited electricity.

I'm thinking in terms of a possible future rental business for parties mostly. And some of the areas are remote. Generator is the usual answer there. So might need this type of option. (Also the current there will be 220 volts)

[Sydney]

Re: Limited current, limited electricity.

I'm thinking in terms of a possible future rental business for parties mostly. And some of the areas are remote. Generator is the usual answer there. So might need this type of option.

While I've gotten sufficient SPL with a rolling rig ( parade float ) using 12V - you want a generator.
Probably a quiet Honda.
Around here ( with off-the-grid people who have free natural gas ) N.G, generators are popular.

[wg_ski]

Re: Limited current, limited electricity.

You need music in a remote area and it needs to be loud.
Let's say you have very limited power like Car batteries (and so inverter) or generator.
Number 1 consideration would seem to be very efficient speakers like Bill Fitzmaurice's horns both top and bottom.

But what type of amplifiers would be the best for this application?
Any other considerations?

Speakers - Highest efficiency wins. Not necessarily the highest sensitivity. May have to settle for 50 Hz bass. Can debate all day about what kind of horns, but they will be horns nonetheless.

Amps - Class D or class H, with a standard core-coil transformer power suppy or a universal 90-260V with PFC. Do not use a cheap unregulated switcher on a generator unless you can rebuild them and have a spare. Bad power will kill a cheap switchmode supply in a heartbeat. Transformer supplies absorb surges. A univesral voltage input with PFC would likely tolerate what a gas generator spits out, but try finding that on an entry level amplifier. If you use batteries, class D car amps are advised, for both subs and mids. Highs ok on class AB - especially if you use a 113dB/W 2" HF driver.

[Sydney]

Re: Limited current, limited electricity.

I'm thinking in terms of a possible future rental business for parties mostly. ...

If you don't supervise the operation of the gear being rented out - I would STRONGLY advise that safeguards are installed to prevent the abuse of the sound system. Most I know that rent gear - operate it as well, otherwise they install devices to keep blown drivers.

[Music is life]

Re: Limited current, limited electricity.

Safeguards for rental gear sounds like a great new thread starter too.
But while I got your attention.

Thinking:
Passive crossover in two way PA tops.

Proprietary wiring for tops and subs so they cannot be confused.

Maybe this:

http://www.parts-express.com/eminence-d-fend-sa300-loudspeaker-protection--290-683

[billfitzmaurice]

Re: Limited current, limited electricity.

Speakers - Highest efficiency wins. Not necessarily the highest sensitivity.

Huh?
FWIW sensitivity is decibels out for watts or voltage in, efficiency is acoustical watts out for electrical watts in. They're essentially the same thing, but the former is expressed as db/w or dB/v, the latter as a percentage.
OP, ask on my forum. Some users there have noted that some Class D and/or amps with switching supplies can have issues when powered by generators, especially inexpensive generators.

[Sydney]

Re: Limited current, limited electricity.

...Thinking:
Passive crossover in two way PA tops.

Proprietary wiring for tops and subs so they cannot be confused. ...

Should work - while I use ( or at least prefer ) only active in a live/outdoor situation; this is a case of unsupervised rental; make it simple, foolproof and robust.

[Brian Steele]

Re: Limited current, limited electricity.

You need music in a remote area and it needs to be loud.
Let's say you have very limited power like Car batteries (and so inverter) or generator.
Number 1 consideration would seem to be very efficient speakers like Bill Fitzmaurice's horns both top and bottom.

But what type of amplifiers would be the best for this application?
Any other considerations?

I would plan for both 12V and 220V options. Or, maybe go for a 12V system with a trickle charger. You know, like the car that the battery's installed in, LOL. Go for the deep-cycle type and run one or more in parallel to get a longer running time. I'd say go for two batteries at least and some sort of isolator switch. That way you can run the PA off of one of the batteries, and if the voltage starts to dip more than you like, you can start the car and switch the car's other battery into operation without cutting off the music.

Good class-D car amps are fine for the entire spectrum. In fact, that's exactly what I use my Alpine PDX amps for from time to time . They use plugs instead of screw terminals for the speaker outputs, so it's very easy to switch them from powering the car's audio system to my little PA.

I think another issue you're probably going to run into is powering the processing and the mixer (if there's a mixer involved). You really want to avoid using an inverter if you can, and that may require a bit more planning. Fortunately there's lots of car audio processers available now that can give you almost everything you can get from a pro audio one (the one big feature that seems to be missing from almost all of them is compression / limiting).

As for cabling, I like the idea of using "idiot-proof" connections. Very easy to do this with SpeakON terminals, e.g. use 4-pole speakon connectors and wire the subs using the 1-2 connections and the main speakers using the 3-4 connections.

[Mipsconsult]

Re: Limited current, limited electricity.

Your very best option is to make the A/C power supply the responsibility of the service buyer. Make it part of the contract.
All contracts SHOULD/MUST include a "buyer provides:" provision with required voltage/wattage/amperage specifications. That's simply a CYA provision.
If your needs require you to eventually buy an appropriate generator, be sure to upcharge for it if required.

[wg_ski]

Re: Limited current, limited electricity.

I think another issue you're probably going to run into is powering the processing and the mixer (if there's a mixer involved). You really want to avoid using an inverter if you can, and that may require a bit more planning. Fortunately there's lots of car audio processers available now that can give you almost everything you can get from a pro audio one (the one big feature that seems to be missing from almost all of them is compression / limiting).

Someone was making a conversion kit specifically for the DCX2496 to run on 12V (was it Envisionelectroics, and are they still around?). The appropriate power brick module form Digi-key or whatever would probably work as well. Of course, that means modifying a unit but that's really the way to go to use one of these processors.

[1100xxben]

Re: Limited current, limited electricity.

If you don't mind forking over the cash, a Crown ITech amplifier is about as bullet proof as they come, and I've run an ITech 9000 amplifier on a generator, putting out about 4000 watts into the speakers and it never missed a beat. I've also used an ITech 12000 as a variable AC power supply to do some brown-out testing with a 2kw+ load (output 80-120 VAC @ 60 Hz to power AC equipment). I don't know if they still do, but I know Crown used to plug in power tools, such as circuilar saws, to their ITech amplifiers at trade shows to show how ridiculously awesome they are!

Another huge benefit to an ITech amplifier is the sharc DSP. You can set voltage limiters for each channel as well as thermal limiters in an attempt to minimize damage to the speakers.

[wg_ski]

Re: Limited current, limited electricity.

Huge difference between an Itech and a typical QSC, XLS or PV amp with a switching supply. Those are touring grade amps and are supposed to work reliably on questionable power. You get what you pay for.

Even if I had a rack full of these, I'm not sure I'd commit one (or two) to my 'take it out to the woods and party' rig.

[Sydney]

Re: Limited current, limited electricity.

Valid points: Renting gear ( without the owner's supervision is very risky ), it will turn friends into enemies quickly.
And some amps are know for their tolerance to supply voltage issues and some aren't.
I know of a sound system that had 22 Crown amps that worked without fail for years and a half dozen other amps that failed.

Using my experience with a parade float sound system as reference: Started out using an inverter to power 120V audio systems off the vehicle 12 V. Too much conversion loss and extraneous noise.
Went to car amps and a total 12VDC sound system - the setup evolved to allow for a hookup directly to the battery of a vehicle within 15 minutes. A platform was setup in the bed of a pickup which held and elevated speakers. Amp and controlling electronics were in the cab - placed below the AC duct.