let's work backwards for a bit...

you want your system to do 85db SPL (that is reference level, normal listening is usually some way below that, like 75db SPL)

so 85db SPL output, and you are sitting what, 3m away from the front.

now, JBL Northridges are fairly efficient, about 90db/w/m

then we plug these figures into this calculator (http://www.crownaudio.com/apps_htm/designt...ect-pwr-req.htm) and give it 3db headroom,

it turns out you only need about 6W steady output, really.

Even if you up the headroom to 9db (meaning when there's a explosion or something, it goes to 94db SPL) you will only need 23W per channel.

So the Onkyo, rating at 185 W (6Ω, 1 kHz, 1 channel driven, JEITA) probably translates to max 60W 6Ω 20Hz - 20kHz all channels driven has more than enough power.

This post has been edited by SiriuslyCold: Oct 23 2009, 09:50 AM

Its more like testing with limited parameters and publishing the results of that. I'm sure Onkyo and JEITA can verify 185W per channel but the fine print says its 1kHz one channel driven.

so, feed a 1kHz signal to one channel of the amp and test output, sure can get 185W. But a video / music programme is never a steady 1kHz, and never 1 channel only.

So its 20Hz - 20kHz to 8 channels ... nobody publishes those results.

to be fair, all manufacturers do this with the AV receivers. Partly because consumers WHAT to see a lot of power output even when they don't really need it. For example, people have had good sound from stereo integrated amplifiers putting out only 20W or 40W maciimum

(I also forgot to mention that into 8Ω the output will be even lower..

105db is for the LFE channel, IIRC so you need a sub with >300W (if all other things remain the same)