Are A/V receivers specs expressed in peak or RMS??

[Daffypuck]

I have searched the internet high and low for the answer to this. WHen you buy an A/V receiver and it says 140wpc into 7 channels, is that peak or RMS? If not RMS, then what is its rated RMS wattage? Im in the market to upgrade and buy a power amp and then a prepro, but If the receiver I have is rated at 140 wpc and its RMS, then Im not really gonna notice any audible difference between iit and a 200 watt rms power amp.

[Msabot1]

RMS=.707P. Most manufacturers use rms watts in their specs cause that is continuous before clipping begins past a point on the wave. Any doubt use that form to get rms rating.

[nhhiep]

in term of watt, you're not going to hear much of a difference between 140w vs 200w, assume everything else equal. general rule is you need to double it just to gain 3db in volume. and if it's an AVR that rated 140WPC x7, then for sure it's peak for 2 channels only. I haven't seen one that can do a real 140wpc x7 from 20hz-20khz.

[tonyb]

Receiver power ratings are somewhat dubious at best. A seperate applifier, even at lower wattage will more times than not produce better sound quality due to it's ability to deliver higher amounts of current than an AVR can.

[cnh]

You have to be careful with AVR power ratings. They are ALL over the place. And usually if RMS figures are actually given they are almost NEVER for more than the L/R channels with no other channels running. Sometimes, manufacturers even use ONLY ONE channel to list their MAX wattage ratings.

With that in mind. A High Current power amp of 200 watts x 2 @ 8 ohms RMS continuous will probably give you a difference that you can actually hear in most cases!

cnh

[pdxfj]

Usually with an AVR it's the wattage into 2 channels. If you have the ablity to add an external amp you're best off doing so. If it's a small HT with bookshelf speakers you'd likely be fine with just the AVR powering everything but of you're running towers for your L-R, plus a center, side and back surrounds an amp would be of great benefit. Even if it was just a 2ch to run your L-R speakers.

Some of the higher end AVRs will have separate power supplies for the Video, Pre-amp and amplifier sections and can reach their rated wattage. The Onkyo 5010 has 4 separate power supplies, where the 818 has only one.

Here's an example from the specs of a 7.2ch AVR.

Amplifier Section

Power Output -
All Channels 140 W (8 ohms, 20 Hz-20 kHz, 0.05%, 2 channels driven, FTC)

Dynamic Power
320 W (3 ohms, 1 ch)
270 W (4 ohms, 1 ch)
160 W (8 ohms, 1 ch)

[jon s]

It all depends on the power supply... Light weight receivers have smaller power supplies which cannot supply the current demanded by high power. For example, a typical Yamaha or Sony receiver weighs about 30 lbs... It is rated about 120wpc with two channels driven. With all channels driven, the power usually drops to 35-50wpc. An Onkyo 5010 (which weighs 50+ lbs) is rated at 140wpc, with all channels driven, it can supply about 90-100 wpc.

Pioneer's class D amps in their top line Elite receivers are another story. Class D amps are digital, more efficient and are lighter. Even with all channels driven, they should be able to drive 100wpc easily with all channels driven. It's just that some people do not like the sound from class D.

Another factor to be aware is to see if the receivers can be used with 4-ohm speakers which put a higher strain on power supplies. Many AVRs cannot be used with 4-ohm speakers.