When to know it's time to add external amplification to a Denon 8500?

[Stephen Novosel]

if you watch a dynamic scene in a movie at the loudest level you like

Matthew, any chance you (or anyone else) has/have a scene(s) in mind that I could test out?

 

[Matthew J Poes]

You made some good points, but let's look at some facts:

1. The OP said "Using a laser measuring device, my MLP does not exceed 106" from the furthermost speaker location (most are far shorter than that). " Based on 89 dB/1W/1m, that is 92 dB/2.83 V/1m, he only needs 150 W to achieve 105 dB sitting 9 feet, that's 108".

2. That calculator HD linked calculate peaks, so the calculated 150 W is peak, or 75 W average. That means the 150 W rated AVR-X8500H will have at least 3 dB of headroom when delivering reference level at his mlp.

3. The 150 W rating is for 8 ohms, if you look at Denon's bench test data (Audioholics.com, soundandvision.com etc.) based on their past flag ship models, we can expect the AVR-X8500H to manage at least 200 WPC into 4 ohms, two channel driven.

According to Audiovision.de's test bench:

"With a terrific 161 watts per box in 5-channel operation (4 ohms),140 watts in 7-channel mode (4 ohms) and lush 260 watts in stereo (4 ohms),the Denon AVC-X8500H is master of any situation."

4. Audiovision probably measured output at 1% THD, so to be conservative, I would discount their figures by about 10-15% to project output at the more stringent THD of 0.1%.

5. The OP also said "Part of the attraction of the 8500 was to consolidate amplification" So while more power than needed never hurts, I would hesitate to tell him he needs to keep those amps, after paying a fortune for a 52 lbs Denon.

6. Power consumption specs can only get you in the ball park and can be used to compare models by the same manufacturers, in this case, Denon and Marantz only. Power consumption spec does not equal power supply rating spec. If the AVR-X8500H's power consumption is 900 W then I am comfortable to assume it has a stronger power supply than the Marantz SR8012 and Denon AVR-X6500H that has their power consumption specified 780 W and 750 W respectively, but I wouldn't speculate the power supply rating of any of them. My educated guess is that their continuous duty would likely be much less, while their short term rating would likely be much higher, because such small power transformer typically have very good short term overload capability. If severe overload condition is prolonged, they would fail, or shutdown on thermal protection.

I think HD is right, if he doesn't typically exceed -10 when watching movies, he should be fine, assuming the level settings are at 0 or within +/- a few dB post Audyssey.

all true. Like I said when I corrected my statenents, I misread the situation and contended that he isn't far short of ok but rather probably ok but at the limit. He indicate d powering a lot of speakers off this single receiver. I'm sure it's still a rare and unusual scenario but I do think a peak in a movie would still probably limit this thing to under 100 watts to the front speakers if powering 10- 13 speakers.

 

[Matthew J Poes]

Matthew, any chance you (or anyone else) has/have a scene(s) in mind that I could test out?

I'm terrible about keeping up on the best dynamic action movies. I'm sure these guys are a better bet. The last review I did references a 3 year old action movie.

 

[Stephen Novosel]

Would it make sense to stress my system (turn it up louder than -10) to find out where it will ultimately distort? I know it's not apples to apples but I do that all the time on PC processors -- stress them to failure to determine the highest overclock speed I can attain.

 

[Stephen Novosel]

Then I could add in the XPA5 to see how its addition affects things and try to distort the system with the 5 in play. I guess I'd then know what my tolerance levels are?

 

[Stephen Novosel]

He indicate d powering a lot of speakers off this single receiver.

The other variable (I think but correct me) is that even with an Atmos or Auro or DTS.xxx encoded disk, the various upmixers do not always upmix content to every channel that's in play for any given surround format (unfortunately as I have learned).

 

[Matthew J Poes]

Well I think you are comparing an engineering test to what really amounts to a human pain threshold test. In all seriousness the proper way to test this would be to measure. I really want to do this with my reviews but as my friend @shady likes to point out, that is risky.

I say just do a couple listening tests and see if it think you hear a difference. You could also download an APP logger app and compare. As long as everything is level matched then if you see a big difference, might imply you were limited by the amps. I don't expect that to show a big reliable difference though as it's a crude test. I think it's safe to trust your ears here.

 

[Matthew J Poes]

The other variable (I think but correct me) is that even with a DAtmos or Auro or DTS.xxx encoded disk, the various upmixers do not always upmix content to every channel (unfortunately as I have learned).

For sure. I was just making a worst case scenario. I've never examined the way atmos is mixed. I have done that with prior 7.1 mixed and found they seem to make loud scenes loud by mixing heavily into all channels. I assume atmos continues this trend but suspect the bandwidth I atmos effect speakers is much more limjted, which helps.

 

[PENG]

Yeah, thanks, I'm becoming resigned to thinking that the quickest way to even begin to sort this out is to haul in the XPA5 for "testing". My fear is that I won't be able to discern via hearing whether or not the "5" would be of any benefit or just dead weight (and as you know, it's weighty and not something I want to be bringing in/out if I don't have a reason).

Matthew, does it make any difference in your calculations to know that the most sensitive (per ML spec) is actually 94 dB for the entire system. Only the R/L towers are 92 dB.

Also, I've noticed that since I moved from a Yamaha 3040 to the Denon 8500, the Denon requires me to go closer to -10 than with the Yammy which I would drive down to about -17 to -22 (depending on how content was recorded). Or, not having previously owned a Denon, are they calibrated that way which would explain the minor difference? (I had a LX901 Elite in here two weeks ago and I wish I would have paid closer attention to its performance settings in-use for comparison purposes).

I do have a miniDSP UMIK and REW on a laptop. I just haven't had the time to do a deep dive to learn how to use them, but I could if you think that would answer my questions.

I've read references to "distortion" and "clipping" but I don't recall ever hearing either in any of my system setups over the years. Maybe it's been there and I was simply too ignorant to know what to listen for? Would I be out of line if I were to use this YouTuber's examples as a gauge:

.

Is it fair to say that even if distortion/clipping surfaces albeit rarely and only under atypical "demanding" scene-cases (1:100 films), that it's too risky for either or both amp and speakers to take a chance and leave it unaddressed? Or is that too extreme a position?

7 dB different between the 3040 and 8500 seems like a lot but it is hard to compare a Denon to a Yamaha. The Denon's relative scale typically goes from -80 to +18, the Yamaha's likely different. Their amplification gains may also be different, it should be about 29 dB door the Denon, may be the 3040 has a higher gain?