Would I be better off using professional PA amplifiers for a home theater setup?

[Sinterklaas]

I'm looking to invest in a high quality home theater system in the near future. Instead of using the built-in amplifier of an audio receiver, I want to connect all of the pre-outs to a DBX Driverack, which would then connect to several PA amplifiers that would power each of my speakers and my subwoofer(s). I could fine-tune the crossover and equalizer levels on the Driverack and prevent damage to my speakers caused by clipping, which is why I want to use PA amplifiers.

This kind of setup may use a lot of electricity unless I manage to find amplifiers that don't take up a lot of power (for example, my QSC Model 1400 amplifier uses 1200w of power and pushes 200w per channel at an 8 ohm load and pushes 600 watts in bridge mono, so it's not very efficient).

As far as the subwoofer(s) go, I'm thinking of finding some good passive home theater subwoofers that I can power with a PA amplifier (again, to keep an eye on clipping). If I can't find any good passive subwoofers, I might consider buying powered subwoofers, whether new or used, and bypassing the amplifier altogether. I'd run a cable directly from the woofer to a PA amplifier, and the Driverack can handle the crossover frequencies.

What do you think? As long as I find some good quality RCA to XLR or RCA to 1/4" adapters and/or cables, I'm thinking this would be the ideal setup. The power amps would take up more space, but I figure it would be worth it, and if I want my music (or movies) loud, I don't have to wonder if the signal is clipping and I'm slowly causing damage to my speakers.

 

[DanielK]

PA amps will work just fine except for one possible problem - if the amps are installed in the room, they may have excessive fan noise because PA amps are fan cooled. You will need to experiment with that. Most home amps are not fan cooled for this reason. Other than that they will work fine and you will save money. If you can install the amps in a nearby closet, that may fix that problem.

 

[Maniac]

You could do that, the QSC amps are a lot of watts for the money but I personally wouldn't use them for home audio. Emotiva makes some low cost (not low cost compared to QSC however) amplifiers that sound very good. http://shop.emotiva.com/collections/amplifiers These are going to sound a lot better than QSC but don't give you the kind of clip monitoring you're looking for.

I looked at the Driverack, it doesn't appear to have much crossover capability. Are you planning on using passive for everything but the cross from subwoofers to mains? What kind of speakers are you planning to use, commercial cinema? If you're really wanting a top notch home theatre, active crossovers for everything would be better.

Personally I'm a big fan of large line arrays for home theatre due to the extreme dynamic impact they can be capable of. My theatre mains... http://www.mfk-projects.com/theatre_main_speakers.htm and curved line array center... http://www.mfk-projects.com/center_speaker.htm You're going to need a lot of DSP crossover capability for something like this however. I use four Behringer DCX 2496 crossovers but I'm looking at the miniDSP stuff and will probably go that route eventually using high quality external DACs on everything.

For subwoofers if you really want a lot of capability using external pro or other amplifiers you definitely need to go custom. DIY your subwoofers! Parts Express Dayton Reference drivers are very quiet low distortion woofers and are inexpensive. I use twenty four of these... http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-468 They also have an 18" version now... http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-472 You can do a lot better on subwoofers by building custom subs than you can possibly come close to with commercial options.

mk

 

[KevinL]

Not that you cant get good sound from professional audio equipment, for home theater if you choose carefully you can have a nice sounding system, but honestly higher end home audio gear will sound better. Certainly using separate amplifiers over a receiver is a much better way of going, receivers just don't use very good quality parts, and are very limited dynamic headroom and sound quality. You can certainly use the receiver strictly as a pre-amplifier processor as long as it has the preamplifier outputs for all channels.

I like the sound and build quality of the QSC amplifiers as far as professional amplifiers go, and I wouldn't look at the QSC as being in-efficient, its a amplifier that is capable of providing good dynamic power, has lots of headroom, and that's a sign of a well built amplifier. It really depends on the efficiency of the speakers how much power you really need, and of course the sound pressure levels your hoping to achieve. You can use allot of power very quickly in a home theater system, and having more power than you will use is not a issue, as this also puts less of a strain on the amplifier, and less of a chance of damaging your speakers. Its when the amplifier runs out of power and sends a distorted signal to the speakers that puts them at risk of damaging them.

I would also recommend keeping all the same amplifiers for all the speakers to assure you have the same tonal balance and sound through out the system.

Kevin
40 years high end audio video specialist

 

[michaeljhuman]

I tried to stay quiet, but I couldn't do it.

While some people do feel pro audio amps are not as good as consumer amps, that's an unproven assumption.

Many people are very happy with pro audio amps in their home systems. Some blind listening tests have shown that people could not tell when a high end consumer amp was swapped with a budget pro amp. Due to the people not being able to see the switch, there was no bias.

Of course, some audiophiles will never agree that pro amps sound as good. I leave it up to you to decide if that's a bias in their thinking.

As someone said, fan noise could be very annoying. Crown's XLS series uses cool running class D amp technology, and variable speed fans. I use an XLS 1000 for my surrounds, and never have the fans come on.

I use an Emotiva for my front three speakers, but if I did it over, I would probably have gotten three XLS 1500 amps. They are MUCH lighter.