Hello I have recently upgraded to M80s and vp180 with 4 qs8s with a denon 4311 receiver. I have wanted to upgrade to m80s for a whhile now but my old pioneer receiver I dont think was up to handling the 4 ohm loads of the m80s. The 4 ohm issue kept me on the fence for a while because upgrading to the m80 required a new receiver or a seperate amp to power the fronts. I now have a Denon 4311 receiver that from what I have read should easily handle the 4 ohm loads of the front three. Correct me if I am wrong I should leave the receiver set to 8 ohms as there is 4 qs8s to power also. I have noticed quite a few people use seperate amps to power the 4 ohm speakers even though their receivers shold be able to handle 4 ohm loads. Can you explain you decisions? I have been looking at an Emotiva XPA-3 to power the fronts if necessary. I listen to 60% movies 40% music -15db average on receiver average size room. This brings me to the issue I had. I have been trying to find the proper location for my subs and was moving them around trying different locations doing the subwoofer crawl (Thanks Alan) At each location I would rerun Audyssey XT32. Audyssey would always set my front speakers to large so I would manually set them to small and set the crossover to 80hz. (apparently this is normal for Audyssey) the movie I was using for testing my subs is How To Train Your Dragon the scene near the end where the dragon king smashes through the cave (really great lfe) On the 3rd time of going through this process right when the dragon smashes through the cave my denon shut down with the power light flashing red. OHOH this isnt good. Pressed the power buton and the receiver would power up normally. I go to the cave scene try again same thing happens denon shuts down power light flashing red. Look in the denon manual trouble shooting. flashing red light with 2 sec interval means amp over heated. mine is flashing .5 sec interval. Manual states if flashing in .5 sec intervals is either speaker wire short or set receiver to match proper ohm rating of speaker. Im quite sure I dont have a speaker short as I have been playing with the system for a couple of days. So thinking that I should change the receiver setting to 4 ohms by what the manual is saying. But I first go into the settings of the receiver check them out and I had forgotten to change the speaker size of the fronts to small after running Audyssey. DOH! Change speaker size to small go back to dragon cave scene at same volume level -15db and everything is fine Denon does not shut down.. Played scene several times infact with no probs at all. So by having the speakers set to large the low frequencies that were supposed to be sent to the subs went to the 4 ohm fronts and that was too much for the Denon to handle causing the circuit protection to kick in. Is this assumption correct? Now I am thinking of getting a seperate amp for the fronts to be on the safe side. Is my Denon warranty in jeopardy by running 4ohm speakers and having receiver set to 8 ohms?
Thank You
Dave
BTW the combination of the Denon 4311 and Axiom speakers does sound incredible.
Your assumption is correct. Having the M80's (VP180?) set to large is causing the shutdown with this certain scene. Speakers that have impedance dips in the low frequencies can be problematic with receivers because it causes the power demands to be greater. In this you are running a speaker that has impedance dips between 3-4 ohms in the low(er) frequencies played full range with content in the movie
How To Train Your Dragon which is VERY demanding in the low frequencies. There are waterfall plots of this movie posted over at avs and they are nasty. Your Denon is seeing this as a dangerous load and it is shutting down under those settings. Having them set to large you might only have issues with certain scenes, must of the time it will be O.K. Setting the M80's and VP180 to small with a crossover point of 80hz should solve this issue. Another receiver probably will not solve this issue either if you want to run them large however a robust external amplifier that can handle 3 and 4 ohm loads will or just a 4 ohm rated external amp for just the front 2 or 3.
