More speakers, less watts?

[Rayharrison]

I recon see how you go. If it struggles then I don’t think you can go wrong if you amplify the LCR channels with a power amp and let the receiver power the surrounds as they aren’t constantly active like the fronts which the avr should handle easily. I have noticed the avr still gets pretty hot with any amps active so cooling might be a good option. It is said that the Denon 3600 and 3700 are basically the cheapest processors you can buy when in pre out mode. I eventually plan to run all 11 channels of seperate amps which is optimal if in reality if a little expensive.

 

[beagleman]

Well intuitively I would agree, since at very low frequencies speakers are generally inefficient unless absolutely huge. However that is a different thing from what I was re-quoting.
- Clipping is not really "running out of power" - it is actually running out of voltage swing when the power supply cannot supply enough current (at least usually).
- The highpass filtering causes additional peak voltage swing.
- So removing the bass reduces some voltage swing, the highpass filters put it back, and your AVRs clips just as easily.
- Of course that depends on umpteen factors, but the point is cutting out the bass does not necessarily give more peak headroom at all. Long term power maybe, however it's the peaks that we don't want to clip.

I have no idea what you are talking about. I have been in audio and electronics for over 35 years.
Highpass filters "put it back"???

 

[Persik]

My LCR speakers are rated at 4 Ohms, 2 surrounds - 8 Ohms. SVS3000 sub crossed at 60Hz for fronts and 80Hz for center, as recommended by SVS speaker matching tool. Unfortunately, X3700H does not specify power output to 4 Ohms,. Also, the best practice seems to keep 8 Ohm AVR setting regarddless of speaker rating.
Any insight, on max power available without significant distortion to fronts rated 4 Ohm?
How would I know if the speakers underpowered? Do they sound different when underpowered?
Also, shall I have ECO ON/OFF/AUTO for my setup?

 

[sigbergaudio]

My LCR speakers are rated at 4 Ohms, 2 surrounds - 8 Ohms. SVS3000 sub crossed at 60Hz for fronts and 80Hz for center, as recommended by SVS speaker matching tool. Unfortunately, X3700H does not specify power output to 4 Ohms,. Also, the best practice seems to keep 8 Ohm AVR setting regarddless of speaker rating.
Any insight, on max power available without significant distortion to fronts rated 4 Ohm?
How would I know if the speakers underpowered? Do they sound different when underpowered?
Also, shall I have ECO ON/OFF/AUTO for my setup?

There's a review on this forum that measures the 3700 in 4 ohms. Which speakers do you have? Also you should cross your main speakers at 80hz too

 

[jgiannakas]

My LCR speakers are rated at 4 Ohms, 2 surrounds - 8 Ohms. SVS3000 sub crossed at 60Hz for fronts and 80Hz for center, as recommended by SVS speaker matching tool. Unfortunately, X3700H does not specify power output to 4 Ohms,. Also, the best practice seems to keep 8 Ohm AVR setting regarddless of speaker rating.
Any insight, on max power available without significant distortion to fronts rated 4 Ohm?
How would I know if the speakers underpowered? Do they sound different when underpowered?
Also, shall I have ECO ON/OFF/AUTO for my setup?

power measurements at 4&8 ohms can be found here: https://www.audiosciencereview.com/forum/index.php?threads/denon-avr-x3700h-avr-review.15031/

leave eco on auto, as it helps save power when at low volumes and gives you full power when needed. Don’t leave it at eco on as it cuts power to something ridiculously low which defeats the purpose of the amp.

 

[Mr Wolf]

How would I know if the speakers underpowered? Do they sound different when underpowered?

You're only ever at risk of running out of power on dynamic peaks which, being up to 20dB above the average soundtrack level, can require up to 100x the amount of power. Overdriving an amp can result in increased distortion and compression which will effect sound quality and may damage your speakers.

The maximum amount of power needed is a function of the source material's mastering level, listening level (i.e. volume setting) and the speakers' effective sensitivity at the listening position, taking account of in-room dispersion losses due to distance/room gain. In large rooms where the dispersion loss is typically about 7dB, for reference source material (i.e. 85dB average) I estimate the X3700 should be safe for volume settings up to about your LCR speaker's sensitivity rating (i.e. @[email protected]) minus 97. So if your LCR speakers are rated at 89dB, you should be good for volume settings at or below -8dB. This assumes the 0dB volume setting has been calibrated to 85dB reference level.

 

[jgiannakas]

You're only ever at risk of running out of power on dynamic peaks which, being up to 20dB above the average soundtrack level, can require up to 100x the amount of power. Overdriving an amp can result in increased distortion and compression which will effect sound quality and may damage your speakers.

The maximum amount of power needed is a function of the source material's mastering level, listening level (i.e. volume setting) and the speakers' effective sensitivity at the listening position, taking account of in-room dispersion losses due to distance/room gain. In large rooms where the dispersion loss is typically about 7dB, for reference source material (i.e. 85dB average) I estimate the X3700 should be safe for volume settings up to about your LCR speaker's sensitivity rating (i.e. @[email protected]) minus 97. So if your LCR speakers are rated at 89dB, you should be good for volume settings at or below -8dB. This assumes the 0dB volume setting has been calibrated to 85dB reference level.

How did you calculate the -97 figure? That’s really handy!

 

[Mr Wolf]

How did you calculate the -97 figure? That’s really handy!

I actually calculated the maximum AVR volume settings which in effect represent the maximum amplifier gain that the AVR can deploy while maintaining 3dB of headroom at the target listening level. As every 1dB of extra speaker sensitivity provides an extra 1dB of SPL headroom the 97dB is simply reverse calculated from that.

Using this logic I created a spreadsheet model to estimate maximum safe volume settings for the Denon range. The example I highlighted above is circled in red.

In practice most source material isn't mastered higher than 83dB (i.e. 103dB peaks) in which case all these estimated maximum volume levels would all be 2dB higher.

 

[jgiannakas]

I actually calculated the maximum AVR volume settings which in effect represent the maximum amplifier gain that the AVR can deploy while maintaining 3dB of headroom at the target listening level. As every 1dB of extra speaker sensitivity provides an extra 1dB of SPL headroom the 97dB is simply reverse calculated from that.

Using this logic I created a spreadsheet model to estimate maximum safe volume settings for the Denon range. The example I highlighted above is circled in red.

View attachment 142163

In practice most source material isn't mastered higher than 83dB (i.e. 103dB peaks) in which case all these estimated maximum volume levels would all be 2dB higher.

Love it! Would you mind sharing the spreadsheet?

 

[Mr Wolf]

Love it! Would you mind sharing the spreadsheet?

I don't mind at all but Excel files cannot be uploaded to threads so you'll have to PM me your email address so I can send it to you.

 

[tifune]

Sorry for possibly hijacking this thread, but I've had a Q about this for awhile. It's largely accepted that passive bi-amping w AVR is pretty much pointless because there's only 1 power supply. However looking at above, if we oversimplify and accept this power supply can output 500W with 5ch driven then clearly there's some limiter in place per channel, otherwise above graph would conversely show 500W at 1 channel driven.

What is causing that? in my particular use case, I'm curious if the same limitation apply to the Monolith 9/11 100W channels? or could I simply not use one of the taps and still get 200W

 

[Persik]

There's a review on this forum that measures the 3700 in 4 ohms. Which speakers do you have? Also you should cross your main speakers at 80hz too

Thank you, I somehow missed the 4ohm chart in Amir's review, now found it. The speakers are Emotiva T2+ and C2+, 60Hz and 80Hz crossover respectively are recommended values by SVS matching tool. Crossing mains at 80Hz, would probably reduce power requirements for mains, but might not be as accurate and directional, T2+ FR spec goes as low as 35Hz. Let me know if there are other considerations for crossing mains at 80Hz.

power measurements at 4&8 ohms can be found here: https://www.audiosciencereview.com/forum/index.php?threads/denon-avr-x3700h-avr-review.15031/

leave eco on auto, as it helps save power when at low volumes and gives you full power when needed. Don’t leave it at eco on as it cuts power to something ridiculously low which defeats the purpose of the amp.

Thank you that helps!

You're only ever at risk of running out of power on dynamic peaks which, being up to 20dB above the average soundtrack level, can require up to 100x the amount of power. Overdriving an amp can result in increased distortion and compression which will effect sound quality and may damage your speakers.

The maximum amount of power needed is a function of the source material's mastering level, listening level (i.e. volume setting) and the speakers' effective sensitivity at the listening position, taking account of in-room dispersion losses due to distance/room gain. In large rooms where the dispersion loss is typically about 7dB, for reference source material (i.e. 85dB average) I estimate the X3700 should be safe for volume settings up to about your LCR speaker's sensitivity rating (i.e. @[email protected]) minus 97. So if your LCR speakers are rated at 89dB, you should be good for volume settings at or below -8dB. This assumes the 0dB volume setting has been calibrated to 85dB reference level.

Thank you, not sure how can I calibrate the volume at 0db to reference level, out of the box the AVR value is not id dB...
Mains Efficiency: 91 dB (2.83V/1m), not sure if that helps in estimating safe volumes.

 

[Mr Wolf]

Thank you, not sure how can I calibrate the volume at 0db to reference level, out of the box the AVR value is not id dB...
Mains Efficiency: 91 dB (2.83V/1m), not sure if that helps in estimating safe volumes.

You need to change your volume scale from the default one to the relative to reference one in the settings menu.

https://manuals.denon.com/AVRX3700H/NA/EN/GFNFSYwrfimgdw.php

If the internal (channel setting) test tones measure 75dB at MLP then you should be calibrated to reference level at 0dB. If that’s the case then under my rule of thumb calcs, 91dB speakers should be safe up to about -6dB. That’s extremely loud, much louder than most would want to listen at.

 

[jgiannakas]

Audyssey calibrates to reference levels (85db) at 0 volume. Run it and let it adjust the channel levels and you should be pretty close to 85db at 0.

 

[Mr Wolf]

Audyssey calibrates to reference levels (85db) at 0 volume. Run it and let it adjust the channel levels and you should be pretty close to 85db at 0.

That’s what I always thought but when I measured it found it to be a few dB less than 85dB. I then found this guidance which suggests Audyssey is calibrating to 81dB.

https://support.denon.com/app/answers/detail/a_id/337/~/receiver-volume

Could just be a typo of course but I’m aware of a few other cases where it came up with less than 85dB. I now set mine manually using the test tones and a UMIK-1 microphone.

 

[Persik]

That’s what I always thought but when I measured it found it to be a few dB less than 85dB. I then found this guidance which suggests Audyssey is calibrating to 81dB.

https://support.denon.com/app/answers/detail/a_id/337/~/receiver-volume

Could just be a typo of course but I’m aware of a few other cases where it came up with less than 85dB. I now set mine manually using the test tones and a UMIK-1 microphone.

If reference level calibrated to 81dB, does that mean that safe volume for my speakers is approx -12dB, instead of -6dB?
Just trying to understand how this relationship works. Thank you!

 

[Mr Wolf]

If reference level calibrated to 81dB, does that mean that safe volume for my speakers is approx -12dB, instead of -6dB?
Just trying to understand how this relationship works. Thank you!

No, it means that when fed a reference signal it will be playing 4dB lower than if the 0dB volume setting was calibrated to 85dB so the -6dB maximum safe level moves up 4dB to -2dB.

EDIT: If the source signal was 83dB (most Blu-rays are) then that increases safe level 2dB further to 0dB. So while it may say 0dB on the volume, in this case you would be listening at 79dB average volume i.e. 6dB below “85dB reference”. Does this make sense to you?

 

[Persik]

No, it means that when fed a reference signal it will be playing 4dB lower than if the 0dB volume setting was calibrated to 85dB so the -6dB maximum safe level moves up 4dB to -2dB.

EDIT: If the source signal was 83dB (most Blu-rays are) then that increases safe level 2dB further to 0dB. So while it may say 0dB on the volume, in this case you would be listening at 79dB average volume i.e. 6dB below “85dB reference”. Does this make sense to you?

It does make sense, thank you for clarifying!
Does that apply to Direct and Pure Direct sound modes too, or only when Audyssey corrections are in use?

 

[AdamG]

Sorry for possibly hijacking this thread, but I've had a Q about this for awhile. It's largely accepted that passive bi-amping w AVR is pretty much pointless because there's only 1 power supply. However looking at above, if we oversimplify and accept this power supply can output 500W with 5ch driven then clearly there's some limiter in place per channel, otherwise above graph would conversely show 500W at 1 channel driven.

What is causing that? in my particular use case, I'm curious if the same limitation apply to the Monolith 9/11 100W channels? or could I simply not use one of the taps and still get 200W

Good question. I have no clue, someone far knowledgeable about this particular amp design will have to provide the answer. Your specific question about the Monolith and if you can recover some of the available power by not using one channel is another great question. May I suggest you go post this question in the Monolith site here: https://www.monoprice.com/help?pn=contact

 

[Mr Wolf]

Sorry for possibly hijacking this thread, but I've had a Q about this for awhile. It's largely accepted that passive bi-amping w AVR is pretty much pointless because there's only 1 power supply. However looking at above, if we oversimplify and accept this power supply can output 500W with 5ch driven then clearly there's some limiter in place per channel, otherwise above graph would conversely show 500W at 1 channel driven.

What is causing that? in my particular use case, I'm curious if the same limitation apply to the Monolith 9/11 100W channels? or could I simply not use one of the taps and still get 200W

In saying it won't make any difference a presumption is being made that the PSU feeding the amps is maxed out current-wise which is unlikely to be the case. The reason it won't make a huge difference is because even if it current supply was unlimited (enabling available amp power to double) you're only picking up a theoretical maximum extra 3dB headroom anyway which is nice but not game changing. Depending on how close your system is to its limits, that may not make any difference at all to the playback.

Does that apply to Direct and Pure Direct sound modes too, or only when Audyssey corrections are in use?

I assume you're now talking about music playback. All my calcs above are for movies.

Running in a 2 channel mode (vs. multi-channel surround sound) will increase available amplifier gain per channel by about 1.5dB as no need to de-rate available power by 30%. The problem is that music is usually mastered hotter than movies as a result of the "loudness war" that kicked off in the 1980s - search that term and you'll get the background.

These are digital music signal source levels from Wikipedia:

Service Loudness (measured in LUFS)
Spotify -13 to -15 LUFS
Apple Music -16 LUFS
Amazon Music -9 to -13 LUFS
YouTube -13 to -15 LUFS
SoundCloud -8 to -13 LUFS
Tidal -14 LUFS

The loudest movie source signal is -20 LUFS (i.e. 85dB reference) and many are lower. LUFS is Loudness Unit reference to Full Scale - full scale being 105dB.

The bottom line is that music source signals can be 5-12dB hotter than movies so you need to be careful when cranking it up. This is why Denon AVR's Dynamic EQ feature has higher adjustment settings for music to an create equal loudness curve.