Denon AVR-X3100 Amplification calculations including scope of ECO mode

D

Deleted member 901590

Guest
@Mr Wolf I’d like to know please an update on my peak power figures, not sure on the specific data you need so just supplied lots.

This is to explore where I am now with available headroom but also, considering my AVR is powered on normally about 12-14 hours a day, thinking about that our gas and electric bill is now £190 a month set to rise more and more... so a specific question about ECO mode too please.

1. Max. listening level (to reference):

Up to a maximum special film of -20dB.
Normal multi-channel dramas and 2 channel TV -25dB.
Daytime news or Mr Tumble -30dB.

2. Speaker data, distances and crossovers:

FL and FR
MLP 4.5m
8 Ohms, 87 dB
Crossover 80Hz

C
MLP 4.9m
8 Ohms, 91 dB
Crossover 150Hz

SL and SR
MLP 2.5m
8 Ohms, 91 dB
Crossover 80Hz

3. Amplifier power per channel on 2 channel and (if known) 5 channel basis:

Denon AVR-X3100
2 channels 105 Watts 8 Ohms 20-20,000Hz 0.08% THD
2 channels (into 4 Ohms) 154 Watts
5 channels ACD at 1% THD 88.4 Watts

4. Audyssey level set results for channels:

FL/FR: -1.5dB
C: -3dB
SL/SR: -6.5dB

5. Specific question of interest…

Online lab tests reported the following, “With Eco mode engaged, it limited power on the bench to 20 watts/ch no matter how many channels were driven.”

Running the AVR in ECO mode reduces power consumption, what is the approximate maximum MV that can be used in my system where 20 Watts per channel is adequate? Thinking more for general viewing here, not special Saturday night lights off for The Conjuring.

Thank you.
 

Jase

Distinguished Member
@AEIOU

Just leave ECO on Auto and it'll sort itself out. On the Info screen you should see the power consumption bar increase/decrease as you turn the volume up/down.
 

Mr Wolf

Well-known Member
This is your system modelled at -20dB. Based on my recent experience using external Dolby Digital test tones (on a disc) to calibrate my system, I highly doubt that your maximum listening level is really -20dB as that really is not very loud at all.

I've assumed 5-Ohm dips on all speakers and that your centre is 2dB less sensitive due to being off axis as you mount it high up. This brings its in-room sensitivity in line with what the trim levels indicate is going on relative to the L/R.

The model shows estimated maximum peak power on front L/R channels of 3.1W. The tipping point for using more than 20W/channel is -12dB which shows 19.5W peak power on the L/R channels. If these peak power requirement figures look low to you just remember that -20dB only requires 1% of the power of reference level so that 3.1W would be 310W/channel for reference which is a sensible looking figure for a 87dB speaker that's 4.5M from the seats.

1645697591380.png
 
D

Deleted member 901590

Guest
Firstly, thank you, it is much appreciated. And interesting!

I highly doubt that your maximum listening level is really -20dB as that really is not very loud at all.

I agree. Because I am rubbish and have no useful sound (or voltage at speaker terminal) measuring tools, the only subjective way I can get any relativity on that figure is to ask if someone else has Supernatural Series 6 to 8 and if they too think -28dB is a plenty loud and immersive viewing experience. If they, for example, say they can't even hear speech then I know that (for some reason) what this Denon (and the other two Denons too) say is reference is a load of monkey balls.

I've assumed 5-Ohm dips on all speakers and that your centre is 2dB less sensitive due to being off axis as you mount it high up. This brings its in-room sensitivity in line with what the trim levels indicate is going on relative to the L/R.

Good assumptions, centre's tweeters is 5cm upwards from "nominal MLP" and FL/FR about 8cm. MLP better aligns with FL/FR bass reflex ports :)

The tipping point for using more than 20W/channel is -12dB which shows 19.5W peak power on the L/R channels.

Thank you. The ECO mode switches between two different transformer windings, delivering different rail voltages. Whilst there's any indication of how this relates to RMS on the bench (from that quote) we don't have a clear picture of relation to peak power spikes. So, I think I will stick with anything multi-channel "proper" source will be ECO OFF and all the rest of TV ECO ON. Yes, it may miss the odd LCR peak in Emmerdale - but I'll get over it with therapy :)

The model shows estimated maximum peak power on front L/R channels of 3.1W

Yes, so the chart adds to this a total of 9w for all channels at -20dB. This is where I get suspicious as mentioned above, that Supernatural at -28dB for two episodes in a row (ECO OFF obviously) there's proper heat coming from the AVR. And I don't mean the good old Denon's 4k board, as this one isn't 4k! The main heat is a considerable heat spot exactly over the transformer.
And I simply cannot believe if that was the RMS power it was drawing that it would do that. So, I am not entirely tool-less (oo-er missus), I do have a socket power monitor and I'm going to be interested to see how that compares with "proper viewing".

Just leave ECO on Auto and it'll sort itself out.

Problem is that the AUTO isn't very clever, it just switches ECO off over relative volume 45 (which is reference volume -35dB). We may have the Teletubbies on over that volume and, obviously I love my grandkids but they don't fully appreciate the dynamic abilities of the system.🤣

So, I need to use it manually.

Which is easy, most days routine, it's set in ECO ON as start up default. At some point in the day, decide we want ooomph and switch it off. Then can leave it like that.
 
D

Deleted member 901590

Guest
Power consumption findings for those interested. Denon AVR-X3100.

Powered off, in standby, but with no network standby on and no HDMI passthrough on (which means it also switches off the front LED):

0.2w

Powered on, HDMI picture passthrough, video processing on (for OSD), but sound off:

ECO ON: 49w

ECO OFF: 84w

So, the below is findings of additional power used when sound is switched on:


Normal TV (e.g. Richard Osman's House of Games, BBC News or Teletubbies) at -27dB MV:

Additional (maximum peaks) 3w.

Either watching Supernatural BR disc in DTS-HD at -28dB MV or streaming the film 13 Minutes from Netflix (DD+) at -20dB MV:

Additional (maximum peaks) 9w.

(Interesting point, that film and Supernatural sound roughly the same amplitude at those MVs, which shows difference in soundtrack levels).

Then, maybe @Mr Wolf this may interest you...

Either watching Supernatural BR disc in DTS-HD at -28dB MV or streaming the film 13 Minutes from Netflix (DD+) at -20dB MV but with FL/FR changed from 80hz crossover to 60hz and SL/SR changed from 80hz crossover to 40hz:

Additional (maximum peaks) 20w.

All measurements for "additional power" were with ECO OFF viewing.

For the interest of anyone really geeky, like me, I also tried the BR player. When it span the disc up to maximum it used 10w. So, more or less, the power required to make the peak sounds in the 5 floor level speakers is the same as that required to turn a plastic disc around 🤣
 

Mr Wolf

Well-known Member
Interesting, that just shows how conservative my power estimates were as at that level of utilisation Class A/B amps will be less than 10% energy efficient.

1646041946402.png

So that maximum 20W peak additional power need will be less than 2W of amplifier power in total. Much less than the 9W maximum peak estimated above but that is a theoretical worse case scenario (simultaneous maximum possible peaks on all 5 channels at the lowest impedance point of all speakers).

None of this surprises me. Based on actual power measurements (not estimates) at a speaker channel level using a True RMS voltage meter, my own 7.2 system would use no more than 1W of amplifier power in total at -20dB volume.
 
D

Deleted member 901590

Guest
but that is a theoretical worse case scenario (simultaneous maximum possible peaks on all 5 channels at the lowest impedance point of all speakers).

Indeed, and the further worst case being no inclusion of crossovers. Hence, why I tried that changed. It would've been interesting to change to no subwoofers, all speakers large.

None of this surprises me. Based on actual power measurements (not estimates) at a speaker channel level using a True RMS voltage meter, my own 7.2 system would use no more than 1W of amplifier power in total at -20dB volume.

So, in summary, AVRs appear to be either:

(a) Massively unnecessarily over powered compared to typical use or

(b) What are the very immediate short term peaks and do these require tiny power spikes that actually utilise some of that headroom?

I guess, what I'm trying to get at is, if someone declares their typical listening levels as low (say below -10dB MV) and they don't have any bizarre high demand speakers to use then should our advice be that the power per channel from the AVR (or external power amp) is reasonably irrelevant and to purchase based on other features/performance.
 

Mr Wolf

Well-known Member
It's very easy to reach those conclusions based on your particular system and usage but power needs can change quite dramatically at higher listening levels, especially with less efficient speakers.

For example, if you listened at -10dB (which IMO is far more typical maximum than -20dB) and all your speakers were Arendal 1961 bookshelf speakers which are 84dB sensitivity, 4-ohm rated with 3.5-Ohm dips then your estimated power needs would be this and your AVR might be really struggling.

1646045586471.png


An 84dB sensitive speaker uses 4x the power of a 90dB one at the same volume (assuming they are the same impedance).

My view on all this is that if you want to listen relatively loudly then the choice is of speakers is the most important thing. Amping up inefficient speakers is not a smart way of going loud.
 
D

Deleted member 901590

Guest
And, in general, the more "over amped" someone's system is the more that they are paying to power up (idling) their transformer (or transformers if they use more external amplifiers).

Most people are looking at ~25p/unit in April. I estimate (as 12 hours usage a day) anyone comparing an approx. 90-100w per channel AVR (e.g. AVR-X3700) to using external power amplification are talking a unit more a day. So, in April that's £7.50 a month.

By April 2023 this could be more than £15 a month.

Anyway,

(a) I'll shut up now as people probably don't care. But I reckon there are a few people who do care and would think "hmmm, I'll think about my amplification running costs at my next AV change". And

(b) As you have just kindly checked for me, my system is over-amplified, so I should shut up as I am wasting money keeping an EI transformer powered up that doesn't need to be that big 🤣

Thank you again Mr Wolf. I've got some useful savings out of the known parameters with ECO mode.
 
D

Deleted member 901590

Guest
@Mr Wolf good old Sky Glass gets reasonable reviews of how "immersive" it is. And it uses naff tiny speakers firing from the top of the TV.
Just part experiment/part for a laugh as I have:
  • spare Minx
  • wiring provision mostly there (the difficult trunking bit done)
  • they would be invisible to the "Manager of Lounge Aesthetics"
I plan to see what two of them positioned similarly to Glass is like for effects.
If course, that's currently just PLIIx or DSX until I have an Atmos AVR again but really this is to just test the theory.
Anyway question... they're 85dB sensitivity will that matter? I assume so little content with mostly smaller peaks than even surrounds that it shouldn't cause juice issues? I'm talking even if I did have Atmos/DTS:X.
To be honest, unlike many AV changes people make, I'm expecting this one to be crap from the start. 🤣
 

rccarguy2

Distinguished Member
With my whole system on, 7ch ATI, 65" TV and one sub was about 350-550w during movie
 

Mr Wolf

Well-known Member
Anyway question... they're 85dB sensitivity will that matter? I assume so little content with mostly smaller peaks than even surrounds that it shouldn't cause juice issues? I'm talking even if I did have Atmos/DTS:X.
Even with Atmos channels with discrete content the maximum peaks are limited to 14dB. This is 6dB less than the maximum LCR peaks so, all other things being equal, using an 85dB speaker for these is like having a very sensitive 91dB speaker on the LCRs. This, coupled with the fact that they will have a very low duty cycle, means it won’t be an issue for you at all.
 
Last edited:
D

Deleted member 901590

Guest
Even with Atmos channels with discrete content the maximum peaks are limited to 14dB. This is 6dB more than the maximum LCR peaks so, all other things being equal, using an 85dB speaker for these is like having a very sensitive 91dB speaker on the LCRs. This, coupled with the fact that they will have a very low duty cycle, means it won’t be an issue for you at all.

Thanks Wolfy. My real expectation is that they may add a nice ambience to 2 channel TV sources... but likely switch back to 5.2.0 only for "proper sources".
Assumed you meant 6dB less BTW. 😁
 

The latest video from AVForums

Samsung QN800B 8K TV Review
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom