Axiom Home Page Forums General Discussion Home Theater Onkyo 875

Thanks for the reassurance ibmack. I have just pulled the trigger and bought the 875. I expected to see it tomorrow and can't wait to set it up!! Have you set your receiver impedance to 4, 6 or 8 Ohms? Your room size is about the same as mine. Now all I need to buy is a projector(most likely pana ae-3000) and a sub(thinking about SVS PB-13Ultra).

Always leave your receiver set to 8 Ohms. The other settings are there to make sure it passes the requirements for the Underwriter's Laboratory listing.

They basically say that a receiver designed for household use can not have an instantaneous current draw of more than some number of amps, and in theory running a less than 8 Ohm load could produce a draw that high.

Setting the receiver to 6 or 4, places an artificial limit on the receiver's current draw (a lower limit anyway, most amps are current limited even at their 8 Ohm setting, but to a more reasonable level). In the real world, sometimes you want to pull a little more amperage to provide that bass kick. Nothing bad will happen with a few loud thumps a minute, though a continuous draw that high will shut down the amp.

If you do happen to shut down an amp, just make a note not to play it that loud again (make sure it is a written note, not a voice annotation, because you're likely making yourself deaf playing that loud anyway).

This is a timely thread...

I'm shopping for a new AVR and the 876 has appeared on my radar. Really good to hear of at least one person running their M80's with it without incident.

Looks like a fantastic receiver. The specs are amazing.

For those with the 875/876, have you been happy with it? The "Official" TX-SR876 thread over on AVS has me given me slightly cold feet over it, as there seem to be a fair number of 'quirky' complaints.

Drewy1, I am no expert and so wouldn't argue with anyone here, but I have my receiver set at 4 ohms as per what the manual says. I get all the power I need so I don't intend to change it. Enjoy the unit!

Peter, I followed the 875 AVS thread from start to finish and inspite of all the negative comments (there were also many positive ones), I never had any issues with the 875 - no overheating or anything. I sold my 875 and bought the 876 because it had Audyssey dynamic EQ in addition to the MultEQ on the 875 and that feature alone was worth the upgrade for me. Other improvements have made the 876 a little better than the 875 but they are essentially the same unit.

Oh well I plan to run the receiver in the 6 ohm setting as the power is limited to only 55 watts per channel in 4 ohm mode. It will be interesting to see if the receiver shuts down as I give it a decent workout.

Do be sure to share your findings! Inquiring minds want to know the outcome!

D1, the object shouldn't be to give the receiver a "workout", but rather to see if it does the job at normally loud listening levels which don't cause permanent hearing loss. At those levels the 875 will certainly be fine, but if you keep increasing the volume level for a better "workout", the 875 or any other unit will eventually shut down to protect itself from such abuse.

Well I have just fired up the 875 with the M80's and I am reasonably happy. I need more time to test with good source material to make a more rounded view. I had the impedance set to 6 ohms and no probs with the reciever cutting out. I ran it pretty hard and it did get a bit hot but I understand that this is normal for this receiver. I did expect that I would have unbearably loud sound coming out at high volumes but this is not the case. I measured sound level at peaks of 108 db coming out of the M80's from 1 metre. From my calculations this means I am only putting less than 50 watts into the speakers at this spl.
Axiom M80 SPL in room = 95 db /1 w/1 m
= 98 db /2 w/1 m
= 101db /4 w/1 m
= 104db /8 w/1 m
= 107db /16w/1 m
= 110db /32w/1 m
= 113db /64w/1 m
= 116db /128w/1 m
= 119db /256w/1 m
= 122db /512w/1 m

I can hear the M80's start to distort at around 110db which only equates to an input power of 32watts. The 875 has plenty of headroom and I am sure that there could be no clipping at 32 watts. Interestingly when I set the impedance to 4 ohms on the 875 I still got about 110db out of the M80's before distortion occurred. In 4 ohm mode the 875 is limited to 55 watts per channel.

Does anyone know why the M80's don't seem to be handling much power? I am sure it is not my ears distorting as it sounds like the woofer cones are breaking up at around 110db. The excursion of the woofers at 110db seems large. With the 875 I should be getting peaks around 119db = 256 watts.

Was this in stereo..i.e., the two M80s only?

If not, there was just a recent thread showing some receivers are actually putting out closer to 30 w/c when all the channels were driven...

The M80s have been tested with (I believe) 1,000 watts....