Are the fronts the most power hungry?

[Threecats]

I have used every combo of search terms I can think of to get an idea and no luck. Here is my situation using a Yamaha RX-A3080 in 7.2.4. I recently added rear heights and had to use an old ancient 100W amp I had laying around to assign to the rear heights. On a couple Blu Rays with heavy action and LFE (the end of Top Gun was one) the receiver shuts down. I do have an Infinity fan atop it and the temp stays pretty stable.

My question is during scenes like this which channel is taxing the amp the most and would be best all around powering separately? My guess would be the fronts and if so would getting them on the seperate amp eliminate that rare shutdown, again only happening on a couple scenes in a couple films. I'll list what I am using to help with any suggestions. All SVS. Fronts are Ultra bookshelves and Ultra center, 4 heights and 2 rear surrounds are Prime elevations, side surrounds are 2 Prime sattelites, subs are two SB3000.

I see posts about amping fronts and center by themselves but I'm not sure I saw a way to do that and assign it that way. Also out of curiosity, what is activating the shut down? My guess is it's not heat or you could not restart and just roll along just by hitting the power button. Something would have to actually cool down. Seems more like whatever it is is acting more like a circuit breaker. It used to happen on my old Yamaha 5.1 as well under the same type of taxing condition.

 

[noiseboy72]

The 3 front channels will all be about equal in terms of power requirements.

The shutdown could be due to the impedance dropping below the level the amplifier can cope with at certain frequencies. A more powerful amplifier with better low impedance handling is probably the solution.

 

[SeanBrothers]

If you have preouts, a 2 or 3 channel amplifier for your fronts can take a fair bit of load of your AVR. @Mr Wolf is the power distribution guru!

P.S. You don't have Eco set to ON, or speaker impedance aet to 4 ohm, do you?

 

[Mark.Yudkin]

I agree that it's unlikely to be a heat issue. Since the problem started when you added a separate power amplifier to power rear height speakers, I also don't think it's a question of the AVR's power amplifier. Rather I guess it's a fault within the ancient 100W amp you had laying around unused that is causing the Yamaha to shut down due to a short circuit.

First off, check that all speakers are correctly and cleanly connected, with no free strands of copper anywhere.

Otherwise, to narrow this down, I suggest disconnecting the old power amplifier and test if the problem recurs. If it doesn't, it's time to get hold of a newer power amplifier for the additional speakers. It may be worth using the new power amplifier for the front left and right and powering the rear heights from the AVR (power amp assign: "7.2.4 (ext. Front)"). This is because the front left and right do indeed draw the most power, followed by the centre.

 

[Mr Wolf]

The RX-A3080 is a seriously beefy AVR and those SVS LCR speakers are all 8-Ohm, 87dB sensitivity rated so should not be particularly hard to drive. As suggested above, I suspect there is a fault some where.

In terms of power needs, by far the most demanding peaks are in the bass region so I would check that the speakers are set to "SMALL", an 80Hz (or higher) crossover is engaged and that the subwoofer mode is set to "LFE" and not "LFE+MAIN".

 

[Threecats]

No I do not have eco on or set to 4ohm but I'll double check.. This happened before I added the second amp and also happened with old Yamaha on the same rare occasions.
Mr. Wolf, yes it does only happen during heavy bass. The most recent times off the top of my head were near the end of Top Gun and I believe once during Hacksaw Ridge perhaps.
I did reset speakers to small after YPAO made them large. I'll check on the subwoofer mode and the coper strands issue.

I just checked manual and did not see any selection "LFE&MAIN" I have a look at the onscreen menu again in real time.

 

[dante01]

Yamaha AV receivers don't have an LFE + MAIN option and the closest you'd get to that if using a Yamaha model would be the EXTRA BASS feature. I'd disengage the EXTRA BASS option if engaged. THis feature can be accessed via the OPTIONS.

Anyway, ensure that all your passive speakers are designated as being SMALL in the speaker configurations and that you've set the associated crossovers no lower than 80Hz. This will reduce some of the strain being put upon the amplification driving your passive speakers by redirecting the harder to amplify lower frequencies away from the amplification and out to the active sub. The active sub's own integral amplification would be dealing with the harder to amplify lower

It would be strange for an A3080 to be struggling to power most speakers, even if low impedance in nature. If using an external amp to drive some of your speakers with, remove this and then see if the issues persists. If not then the issue is either with that external amp or an issue with the speakers you are using it to drive.

You'd need to be sat a considerable distance away from the speakers to be causing the AV receiver issues driving any of your speakers to reference, this or they are inordinately difficult to drive? AS said, the A3080 will drive 4ohm loads without issue and without having to use the imprdance switching feature. In fact, don't use that switching and leave the setting at 8ohm regardless of the actual impedance of your speakers. IMpedance switching is pointless and just starves you speakers of powr causing distortion.

 

[Mr Wolf]

Yamaha AV receivers don;t have an LFE + MAIN optyion and the closest you'd get to that if using a Yamaha model would be the EXTRA BASS feature.

On my much older Yamaha AVR the equivalent of "LFE+MAIN" is called "Front+SWFR" and is found in the "Bass out" menu settings.

Is that now called "EXTRA BASS"?

 

[dante01]

On the A3080 there's no such setting. As said, the closest you'd get would be the EXTRA BASS setting on Yamaha models.


The oldest model I have is an old RXV2065 and yes, this does have an "LFE / Bass Out" configuration. You can set this to either SUBWOOFER or BOTH. The BOTH setting would be the same as the MAIN + LFE option found on many AV receivers. The SUBWOOFER option is the same as setting such an AV receiver to just the LFE option.

 

[Threecats]

Thanks. As I said this happened on rare occasions even before I added that external amp for the rear ATMOS. I do not have Extra bass turned on. I will recheck what the crossovers are set at. I know YPAO sets them to large, which I had already set to small. I'll see what YPAO set the crossover at. That could be wrong too if they set speakers as large and I just didn't pay attention to it.

Update: I went in and saw that all speakers were at at 80Hz except the fronts were set at 60 and the center at 40. I changed the three fronts to 80. I wonder if that was the culprit because in the few scenes that the AVR shut down it was bass heavy explosions and action mostly in the direction of the front of the film scene viewing wise.

 

[noiseboy72]

The question is whether the AVR actually filters bass below the frequency - ie: is acting as a crossover, or just sends bass below the frequency to the sub as well. Both are methods are used, so worth checking if altering the frequency affects the mains. Try turning off the sub and see if changing the frequency makes any difference to the main speakers. If not, changing the frequency will make no difference to the power consumption or impedance of the speakers.

 

[dante01]

The AV receiver would redirect all frequencies at and below the crossover settings away from any speakers designated SMALL and redirect frequencies at and below the associated crossover configiurations to the active sub. The only exception to this would be if rhe PURE DIRECT mode is engaged. Bass management is not applicable while the AV receiver is in PURE DIRECT mode.

Regardless, I'd still find it strange for an A3080 ro have issues powering speakers even if regarding them as full range.

I'd start by double checking all the speaker wireung to ensure that there's no potential for shorts. I'd then look at the speakers and maybe even try swoppong them iut in order to ensure that they aren't the issue?

 

[Threecats]

Speaker wires are fine. I'm going to switch the front speakers to that amp instead of the rear heights and try it again.

I had this same thing happen with an older Yamaha 5.1 and Bose system a couple times under the same circumstance. Maybe I just had the volume too darn high.