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Amplifier Power: How much do you really need and your system’s dynamic range.

hardisj

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During my chat with the The Daily HiFi guys this past Monday, the topic of higher sensitivity speakers having more dynamic range came up. I gave my condensed spiel about why I think it isn't the speakers but rather the system as a whole that when integrating higher sensitivity speakers that provide more dynamics.

In this video I address that a little bit more but with a focus on how to obtain a realistic number for how much amplifier power you need using three factors:
1) Speaker sensitivity
2) Distance from MLP to speaker
3) Dynamic range of the content you listen to

The third is key but never discussed when the topic of "how much power do I need" comes up on the forums. So, I spend some time on that aspect. If you're wanting to kill about 20 minutes listening to audio chat, I have provided the link below.




--------------------------------

To address a comment I already had from @MZKM:
* doubling of speakers = +3dB
* doubling of power = +3dB
* net gain of adding a speaker & its own amp channel = +6dB (theoretical)
* speaker in a room vs anechoic = +3-6dB (+3dB is the norm above the transition frequency)

I tested the +6dB doubling of speakers/power by simply using a single powered speaker and measured the FR via RTA. Then I connected the other powered speaker and measured the response. I got about +5dB from about 300Hz+. In the HF+ I noticed less overall gain, which I believe aligns with what Toole discusses in his book regarding the point where a speaker becomes more directional. In the LF the gain was anywhere from +3 to +6dB.


--------------------------------

I created a poll on AVSforum a year or two ago asking what the listening distance is for people from the MLP to the speakers. The poll showed 3-4m average listening distance.

I created a poll on my YT channel and my FB group asking who pays attention to the mfg spec for "recommended power". Over 80% said they pay it no mind.


--------------------------------


Links used:
https://dr.loudness-war.info/
https://www.crownaudio.com/how-much-amplifier-power
https://www.crownaudio.com/en-US/tools/calculators#amp_power_required
 
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Matias

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3) Dynamic range of the content you listen to

The third is key but never discussed. So, I spend some time on that aspect.

The Harbeth video demonstrates this very well between the bass heavy drum song and the string quartet, completely different power requirements for the same speaker in the same room at the same volume.

 

eddantes

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Ummmm - Spkr 85 > Spkr 92 = 7db...

But otherwise a lovely explanation! TY! Also - ty for pointing me to DRDB! What a great resource.
 

Hiten

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Thanks for doing this.
I am always interested in construction of music content and amp power/speakers relations. In following link I tried to learn peaks across all genres of music which lead to some discussion and links. Which I find interesting.

Average music transients across all genres.

best regards

addition : M-Noise test signal from Meyer sound is also interesting.
 
OP
hardisj

hardisj

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Ummmm - Spkr 85 > Spkr 92 = 7db...

LOL. Of course. But I think showing what it is rather than just stating the number helps with the understanding of the significance.



Also - ty for pointing me to DRDB! What a great resource.

No problem! Frankly, I'm surprised at how many people don't know about this website. I've been using it for a long time. It is my go-to when I am shopping for an album as it helps me determine which version might be best (since dynamic range isn't everything). Often times, you'll find newly remastered albums are just compressed versions of the original. The EQ may be different as well but in my experience, the original album(s) from decades ago are still better than the remasters.
 

Frank Dernie

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Excellent.
In the old saying "preaching to the choir" I am definitely the choir here :)
Over the years I have ended up with big efficient speakers and powerful amps probably because I listen to music with a very high dynamic range for the majority of my listening.
I have rejected numerous systems on audition simply because they may be fine on a lot of music but present them with a well recorded big orchestral work and the shortcomings in dynamics are obvious.
 

MattHooper

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During my chat with the The Daily HiFi guys this past Monday, the topic of higher sensitivity speakers having more dynamic range came up. I gave my condensed spiel about why I think it isn't the speakers but rather the system as a whole that when integrating higher sensitivity speakers that provide more dynamics.

In this video I address that a little bit more but with a focus on how to obtain a realistic number for how much amplifier power you need using three factors:
1) Speaker sensitivity
2) Distance from MLP to speaker
3) Dynamic range of the content you listen to

The third is key but never discussed when the topic of "how much power do I need" comes up on the forums. So, I spend some time on that aspect. If you're wanting to kill about 20 minutes listening to audio chat, I have provided the link below.




--------------------------------

To address a comment I already had from @MZKM:
* doubling of speakers = +3dB
* doubling of power = +3dB
* net gain of adding a speaker & its own amp channel = +6dB (theoretical)
* speaker in a room vs anechoic = +3-6dB (+3dB is the norm above the transition frequency)

I tested the +6dB doubling of speakers/power by simply using a single powered speaker and measured the FR via RTA. Then I connected the other powered speaker and measured the response. I got about +5dB from about 300Hz+. In the HF+ I noticed less overall gain, which I believe aligns with what Toole discusses in his book regarding the point where a speaker becomes more directional. In the LF the gain was anywhere from +3 to +6dB.


--------------------------------

I created a poll on AVSforum a year or two ago asking what the listening distance is for people from the MLP to the speakers. The poll showed 3-4m average listening distance.

I created a poll on my YT channel and my FB group asking who pays attention to the mfg spec for "recommended power". Over 80% said they pay it no mind.


--------------------------------


Links used:
https://dr.loudness-war.info/
https://www.crownaudio.com/how-much-amplifier-power
https://www.crownaudio.com/en-US/tools/calculators#amp_power_required

Nice video. Very well explained! (Also, you are clearly getting better and better as a presenter on camera!).

Not exactly sure how this anecdote figures in to this, but:

I've often, due to some room limitations, used a closer listening distance than most. It can range between 7 1/2' to 6 or even 5 feet, depending on the speakers I have set up (or how I'm experimenting).

On one hand I love how nearer-field listening removes some of the room influence, and the sound because particularly smooth and tonally nuanced (losing some of the room reflection hash). Also the imaging becomes more immersive.

On the other hand, I find it becomes more of a "headphone effect" where the music seems to sound a bit less punchy and dynamic. And the thing is this isn't strictly because I'm turning the sound down to listen closer. If I have the sound at the same volume and I sit on my sofa 7 1/2 feet away, and then move my head to 6 feet or under, the same thing happens. It doesn't even subjectively *seem* to get louder, but it does seem to lose a sense of density, aliveness and punch.

This is why I always search for a seating/speaker orientation that optimizes (or splits the difference) to get some of both characteristics.
 

Vovgan

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To address a comment I already had from @MZKM:
* doubling of speakers = +3dB
* doubling of power = +3dB

What about bi-amping? Can it improve the dynamic range / amplifier headroom for a given listening volume? What about bi-amping without removing connectors between two pairs of terminals on speakers? Thanks!
 
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eddantes

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On bi amping - my understanding is that it relieves one amp (tweeters) of heavy load (woofers). But if that actually contributes sonically, I'm not sure. Other than, I suppose, the high frequencies will not trigger clipping. So... maybe you'll lessen your chance of clipping?
 

Pdxwayne

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Hmm, how about achieving 90db at 20 Hz vs something higher like at 500 Hz?
 

Kegemusha

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Great video, thanks.
I always thought electronic music, like Aphex Twins would have some higher DR but seems like it is not, the 80s albums I listen have more DR (Joy division, The Cure and many of those pot punk bands), there were some very good recorded albums from those years.
 

Ingenieur

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None scientific using my McIntosh meters, not sure of response rate.
Typical volume
Quite passage, ~ 0.01 W, peaks 10 W
30 dBW
 

Gorgonzola

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Interesting. Based on the 1st video my amp power requirements are quite modest, viz.
  • 3 meter distance
  • 75 dB "average" listening volume -- lower than most people
  • 84 dB speaker sensitivity
  • 18 dB headroom (for Classical music)\
  • = 71 watts required power
-- And that would be a single speaker in an anechoic room. Of course I have two speaker in an echoic albeit fairly dead room.. This suggests perhaps a 6 dB lower requirement or 18 watts per channel -- lower that I suspected.

I wonder if a lot of people get the opposite result, i.e. a higher power requirement than they suspected? In my case it's the low "average" listening volume that makes the difference.
 

Ingenieur

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My speaker is rated 87 dB (2.83 V into 8 Ohm = 1 W)
I listen LAeq -70 with Lpeaks 95-100
LMax is 80
Based on the NIOSH app
So headroom ~ 25-30 SPL

IF 1 W = 87 dBSPL
10 W = 97
Makes sense
So 70 dB SPL 0.02 W or so

jives with the meters
 

AdamG247

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A possible error in this equation is unquestionably going by Manufacturers specs. Don’t a lot of manufacturers play loose and fast in reporting the real efficiency rating of their speakers?
 

Ingenieur

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A possible error in this equation is unquestionably going by Manufacturers specs. Don’t a lot of manufacturers play loose and fast in reporting the real efficiency rating of their speakers?
Perhaps some, but I guess some use a standardized DIN method.
The KEF R3 is spec'ed at 87
It was tested here, I'll see if it was measured.
Looks like 86 here.
 

ShadowFiend

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And efficiency of speaker is related also to the impedance of speaker. And both amplitude and phase of impedance is varied with frequency. So, you need to calculate the needed power when your speaker approaches the lowest level of impedance, not the vague "nominal impedance"
 
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