OHM's puzzlement on my Onkyo 609


Standard Member
I've been reading through the settings for my new Onkyo 609 and came across the Ohms settings options.

In the managemnt screen I can switch between 4ohms and 6ohms, but I'm running a set of Mission 77 5.1's which all say they have a 'nominal impedence' of 8ohms.

What should I be running the Amp at? (4 or 6) and can I expect to notice any difference?



Active Member
good question, also the same on my 607, settings only for 4 or 6 ohms. who's got the answer.


Standard Member

i think i can answer this... :) in page 46 of the manual we can read...

Speaker Impedance
(European, Australian and Asian models)
Select if the impedance of any speaker is 4 ohms or
more but less than 6.
Select if the impedances of all speakers are between
6 and 16 ohms


Standard Member

Thanks, I'd ready that but wondered what impact that will have on the speakers.

I'll double check my settings.



Novice Member
What this setting does is place a resistance (generally in the form of a transistor) in series to each speaker output to limit the current draw from the amp's power supply - the idea here is to offer some protection (to amp and tweeters) when using generally low impedance speakers with the amp.

The "correct" setting is 6 .... practically always! ... choosing the other setting means you've mismatched the amp and the speakers, as low impedance speakers need good power-supplies. Don't kick yourself if you've made this mistake - I've seen "pros" (mags & shops) suggesting some very mismatched speaker/amp sets!


good question, also the same on my 607, settings only for 4 or 6 ohms. who's got the answer.
Well the manual has the answer for one - in several places, page 43 among others.

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