Axiom Home Page Forums General Discussion Home Theater AV receivers/multi-channel amps What the diff?

Ok, I know this is a silly question to everyone, but I am still kinda confussed on this. What is the difference between an av receiver and a multi-channel amp? I own a yamaha 5790 that is running my 7.1 system of axioms. Is there any difference other than the reciever has a tuner for radio and some video connections? Is one better than the other? What advantages are there to separates? I am lost as too this difference? If you have a reciever that is rated 110 x 7 would I ever have a need for a separate amp? Confussed?????

jhunt17, it's not a silly question and in fact is more of a debatable one, the board is mixed on the usage and need for amps, so I'll just explain why I use one.
I use a 5 channel amp to drive a 7.1 system in a large room, my Denon only powers my rear surround thus relieving
it of the load to drive my 80's, center and side surrounds. My amp provides 200w in 8 ohms and around 300 something in 4ohms for my 80's giving me the ability to really blast my speakers and fill most my house with sound when needed. Your reciever is likely to have as much power as you will need, some of us just enjoy more power

To answer your initial question, a receiver integrates a tuner, preamp/processor, and multi-channel amplifier. You cannot use just an amplifier, you need a preamp/processor to adjust volume, decode digital signals, switch between channels, etc. Separates generally allow more flexibility with upgrades, etc, and standalone power amps can often handle and output more power than receivers.

Hi Jhunt17,

Getting a separate multichannel power amplifier will usually get you a lot more real power output (from 200 to 400 watts per channel into 4 ohm loads) than an AV receiver is capable of, and for lots of enthusiasts with big rooms, large low-impedance tower speakers like the M80s and an appetite for very loud, clean playback levels, the separate multi-channel power amplifier will deliver the goods.

By contrast, an AV receiver's power output is typically measured with only a couple of channels running at full rated output while the others run at 1/8th power output whereas multichannel power amplifiers will generally deliver their full rated power output with all channels running.

It's really a matter of cooling. It's impossible to stuff five or seven high-power amplifiers with huge power supplies onto one receiver chassis and keep the thing running cool enough, so compromises have to be made. Lots of AV receivers won't even drive low-impedance (4 ohm) main speakers like the M80s without overheating or shutting down. The protection circuitry of those models do that to prevent the output sections from burning out.

thanks for the replies everyone. So in other words in my room of 24x10.5x7.5 the yamaha should do without any problems other than being a little hot. When I watch movies I notice it can get very warm. I never have it turned any louder than -15 which usually on my spl meter runs around 75 dbl for normal secenes and spikes of 95 of more durring a battle scene or explosion of sorts. That wouldn't be considered dangerous to my ear would it?? Isn't that about how the theaters are setup??

Sounds pretty normal to me jhunt17!

You can always add a very quiet fan to facilitate ventilation.

Hi jhunt,

Your M60s are 8 ohms so the Yamaha should be quite comfortable driving them cleanly without breaking a sweat in that size of room. And you're fine at 75 dB SPL. It's also a matter of duration and giving your ears a rest.

Long-term hearing damage starts to occur if you are subjected to levels of 85 dB SPL for 8 hours a day or more. That's also the rationale for THX specifying cinema playback levels averaging 85 dB SPL in the middle of the auditorium. It's quite loud, but it's only for a couple of hours, so you don't get long-term exposure.

I would add, however, that some THX movie theaters greatly exceed that specification, notably the Ziegfeld theater in Manhattan. I attended a press screening of a Star Wars movie (the third one, I think) where the levels were well above 100 dB SPL. I left after 30 minutes. It was deafeningly loud. The screening was sponsored by a big electronics company and I think they suggested to the cinema operator to crank the levels, which was stupid.

You can safely run your system to occasional peaks of 100 dB SPL without danger, so long as you give your ears a rest after the movie.

Thanks Alan, I thought what I was doing was ok.

Alan,

If you were to get amps for M80s to run with on Yamaha 2500 for a room of 20'x 25' with vaulted ceilings (I do like listening at loud levels at times) which amps would you buy?

Are the outlaw 2200 m-block(s) the way to go? Or?

I presently have M60s in a smaller room and I'm happy with them, but I'll be moving someday with eyes on a larger dedicated home theater room.