• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Merit in measuring @ 1 watt (first watt performance)?

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
I've seen this idea thrown around at times - is there merit in including a measurement of how clean an amp can produce sound at very low levels, such as some of the transients in music or when listening at low volume?

Also, I have a Denon X4500H and a Hypex NC252MP if anyone has specific info about those.
 

Matias

Master Contributor
Forum Donor
Joined
Jan 1, 2019
Messages
5,029
Likes
10,796
Location
São Paulo, Brazil
The current 5W in 4 ohms is very good, very representative. Most people would be surprised how little power is needed to play reasonably loud in most systems.
 

Foxxy

Member
Forum Donor
Joined
Jul 31, 2020
Messages
24
Likes
43
Location
Austria
The first Watt is actually the most important Watt in any amp. Just take a SPLmeter an measure how loud you actually listen most of the time. Often it's not even 80dB average which means you aren't even using much more than a Watt to listen to stuff. Turn it down just a few dB more and not even your transients will use a full Watt.
A Watt is a lot more than most people think, and that's when dealing with lower efficiency speakers.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,386
Location
Seattle Area
Most amps have more noise at 1 watt than distortion. So the measurement becomes that of noise. By going up to 5 watt, then there is enough signal to push the noise down and let the distortion contribute as well.

In this day and age, speakers are using small enclosures, making them pretty inefficient. One watt as a result is not an indicator of real life usage.
 
OP
Chromatischism

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
The current 5W in 4 ohms is very good, very representative. Most people would be surprised how little power is needed to play reasonably loud in most systems.
5 watts gets me 85 dB with only 88 dB sensitive speakers. That's pretty loud. I'm talking about what an amp does when it's asked to produce sounds that require only 1 watt. That would be about 80 dB for me, which is music listening level. That assumes the amp has no headroom, so subtract 3 dB to assume you're maintaining some headroom.

https://www.crownaudio.com/en/tools/calculators

That becomes a fraction of a watt if someone uses higher sensitivity speakers.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,522
Likes
37,053
If you listen at reference levels averaging mid 80 db spl, you may be averaging around a watt or two, but 20 db headroom means some momentary amounts of 100 watts or so.
 
OP
Chromatischism

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
Right. I'm definitely using more than a watt for movies. But most music doesn't have me going from 85 dB to 105 dB. I'd turn that down or run out of the room :)
 

NTK

Major Contributor
Forum Donor
Joined
Aug 11, 2019
Messages
2,656
Likes
5,819
Location
US East
The issue is a little bit more subtle. There is a "problem" with measuring power amp output using single tone sine waves. Music is not a single tone sine wave. The important difference is in the crest factor. Single tone sine waves has a crest factor of 3 dB, which means the V_peak is 1.414 * V_rms. Music typically has a crest factor of >12 dB (see below), which means when outputting the same average power, V_peak is >4 * V_rms.

The implication is that, if you are listening to music at the 80 dB SPL at 1 W average power (as in your earlier example), your amplifier will need to have the voltage output capability to produce an equivalent of >8 W when tested with a single tone sine wave. Add another 10 dB headroom for program peaks, and you will need an amplifier capable of delivery unclipped power of >80 W (as measured with single tone sine waves) when your listening level only requires an average power of 1 W.

CF.JPG
 
Last edited:

MaxBuck

Major Contributor
Forum Donor
Joined
May 22, 2021
Messages
1,515
Likes
2,117
Location
SoCal, Baby!
I continue to believe that there are superb low-SPL systems that I wouldn't care to listen to above, say, 85 dB, that are nonetheless outstanding in providing clarity, soundstage and imaging at those low levels. And that many systems that are tremendous at 85-90 dB (my current system being a prime example) are muddy and indistinct at lower SPLs.

My old Paradigm Atoms were perhaps the best low-SPL speakers I've ever heard (to my preferences). Just don't try to get them much above 85 dB. They're terrific background music speakers, and that's about it.

Obviously the distortion and noise produced by an amplifier are functions of many parameters, including frequency, output impedance and power. Matching speakers, listening preferences and amplifier characteristics to find the perfect match is probably a lot more complicated than simply selecting the lowest SINAD at some arbitrary frequency, wattage and output impedance.
 

Beershaun

Major Contributor
Forum Donor
Joined
Oct 3, 2019
Messages
1,864
Likes
1,910
Some examples of real world usage. TLDR; it's all about the bass.

 

Ata

Senior Member
Forum Donor
Joined
May 6, 2021
Messages
388
Likes
333
Location
Adelaide, Australia
The issue is a little bit more subtle. There is a "problem" with measuring power amp output using single tone sine waves. Music is not a single tone sine wave. The important difference is in the crest factor. Single tone sine waves has a crest factor of 3 dB, which means the V_peak is 1.414 * V_rms. Music typically has a crest factor of >12 dB (see below), which means when outputting the same average power, V_peak is >4 * V_rms.

The implication is that, if you are listening to music at the 80 dB SPL at 1 W average power (as in your earlier example), your amplifier will need to have the voltage output capability to produce an equivalent of >8 W when tested with a single tone sine wave. Add another 10 dB headroom for program peaks, and you will need an amplifier capable of delivery unclipped power of >80 W (as measured with single tone sine waves) when your listening level only requires an average power of 1 W.

View attachment 76423

Thank you for bringing this consideration up! I had heard the term but was not clear what is stands for.

Could this be the answer why we need 80+W amplification even if, for people like me, normal listening levels are around 70-75db? To avoid small distortion/compression at the dynamic peaks? This could add to the perception of clarity and dynamism. In theory it could also be an argument against using smaller speakers, even at moderate listening levels.
 

LiquidSound

Member
Joined
Aug 27, 2022
Messages
7
Likes
2
The first Watt is actually the most important Watt in any amp. Just take a SPLmeter an measure how loud you actually listen most of the time. Often it's not even 80dB average which means you aren't even using much more than a Watt to listen to stuff. Turn it down just a few dB more and not even your transients will use a full Watt.
A Watt is a lot more than most people think, and that's when dealing with lower efficiency speakers.
Agreed ! It's my belief that if the amp's first-watt doesn't sound really good, how can anything above that sound any better ! ? Also, if it measures good and sounds good, it's good. If it measures good but sounds bad, it's bad. If it measures bad but sounds good, perhaps you've measured the wrong things !
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
Thank you for bringing this consideration up! I had heard the term but was not clear what is stands for.

Could this be the answer why we need 80+W amplification even if, for people like me, normal listening levels are around 70-75db? To avoid small distortion/compression at the dynamic peaks? This could add to the perception of clarity and dynamism. In theory it could also be an argument against using smaller speakers, even at moderate listening levels.
Yes. The peaks can be 20dB higher than the average, or more, depending on the recording. 20dB is 100x the power.
 

GXAlan

Major Contributor
Forum Donor
Joined
Jan 15, 2020
Messages
3,868
Likes
5,954
Most amps have more noise at 1 watt than distortion. So the measurement becomes that of noise. By going up to 5 watt, then there is enough signal to push the noise down and let the distortion contribute as well.

In this day and age, speakers are using small enclosures, making them pretty inefficient. One watt as a result is not an indicator of real life usage.

To add to this comment (to the readership and not Amir), in the dream world, we'd wave a magic wand and we'd have measurements at 0.05, 0.5, 5 and 50 watts for every amplifier that's tested. It'd give us a lot of information about the amplifier in a wide range of conditions. The reality is that it'd be impossible to get through any meaningful number of tests, so picking 5W is the ideal "single" measurement for the amp if that's what you have.

I would respectfully add more commentary to Amir's second comment given the wide range of differences in size of the "average real-life" listening environment. Millionaires living in New York City are going to have a different listening environment that a "blue collar, middle class worker" in the US midwest.

Looking at 3 highly-rated passive speakers here, we can see different levels of efficiency.
  1. Revel PerformaBe F328Be - 91 dB/2.83V
  2. Focal Aria 906 - 87 dB/2.83V
  3. Elac Uni-Fi 2.0 UB52 83 dB/2.83V
Then looking at the US, France, and Germany (for those speaker brands) and China (picked due to the popularity of Topping and because it's got a smaller average home size), we can see the average home size is very different which also translates into the average "living room" or "bedroom" [Ref: https://www.homedit.com/average-bedroom-size/]
  • United States: 2163 sq ft
  • France: 1205 sq ft
  • Germany: 1173 sq ft
  • China: 645 sq ft
We need to pick listening distances. I have chosen 5 feet and 15 feet. 5 feet because that's the Dolby Atmos "minimum" distance for those upfiring home speakers. I've chosen 15 feet since that's my own listening distance in my biggest room in the United States. The 3x spread is pretty close to what we see in size difference between China and the US so it seems reasonable on face value.

Now the question is "what is the average listening level?" THX Reference Movies are 85 dB average. That's pretty loud because that's the upper limit of what you'd be allowed to listen all day/every day without injury. Then, I'll pick 65 dB for the lower level since that's the typical volume of someone sitting and playing the piano normally:
[Ref https://music.eku.edu/sites/music.eku.edu/files/ekuhealthandsafety.pdf]

Now we do math. I will assume 2 speakers, near a wall.


SpeakerdB at 0.05W (5 vs 15 ft)dB at 0.5W (5 vs 15 ft)dB at 5W (5 vs 15 ft)dB at 50W (5 vs 15 ft)
Revel PerformaBe F328Be80.3 / 70.8 90.3 / 80.8100.3 / 90.8110.3 / 100.8
Focal Aria 90676.3 / 66.886.3 / 76.896.3 / 86.8106.3 / 96.8
Elac Uni-Fi 2.0 UB5272.3 / 62.882.3 / 72.892.3 / 82.8102.3 / 92.8

Peak advertised power handling
SpeakerPeak Advertised Power HandlingIn room Peak SPL (5 vs 15 ft)
Revel PerformaBe F328Be300 watts118.1 / 108.6
Focal Aria 906120 watts110.1 / 100.6
Elac Uni-Fi 2.0 UB52140 watts106.8 / 97.3


The detail that's missing from this is the concept of bass needing power. If we look at the Revel PerformaBe F328Be, the 30-50Hz region is ~81 dB/2.83V and impedance is about 6 ohms. At 50 Hz exactly, it's 84 dB/2.83V and 8 ohms. If you wanted your bass to hit 105 dB peaks at 15 foot listening distance, you need ~1300 watts into 6 ohms or ~650 watts into 8 ohms using those assumptions. (Hence, the value of a subwoofer even with full-range speakers.)
 

LiquidSound

Member
Joined
Aug 27, 2022
Messages
7
Likes
2
To add to this comment (to the readership and not Amir), in the dream world, we'd wave a magic wand and we'd have measurements at 0.05, 0.5, 5 and 50 watts for every amplifier that's tested. It'd give us a lot of information about the amplifier in a wide range of conditions. The reality is that it'd be impossible to get through any meaningful number of tests, so picking 5W is the ideal "single" measurement for the amp if that's what you have.

I would respectfully add more commentary to Amir's second comment given the wide range of differences in size of the "average real-life" listening environment. Millionaires living in New York City are going to have a different listening environment that a "blue collar, middle class worker" in the US midwest.

Looking at 3 highly-rated passive speakers here, we can see different levels of efficiency.
  1. Revel PerformaBe F328Be - 91 dB/2.83V
  2. Focal Aria 906 - 87 dB/2.83V
  3. Elac Uni-Fi 2.0 UB52 83 dB/2.83V
Then looking at the US, France, and Germany (for those speaker brands) and China (picked due to the popularity of Topping and because it's got a smaller average home size), we can see the average home size is very different which also translates into the average "living room" or "bedroom" [Ref: https://www.homedit.com/average-bedroom-size/]
  • United States: 2163 sq ft
  • France: 1205 sq ft
  • Germany: 1173 sq ft
  • China: 645 sq ft
We need to pick listening distances. I have chosen 5 feet and 15 feet. 5 feet because that's the Dolby Atmos "minimum" distance for those upfiring home speakers. I've chosen 15 feet since that's my own listening distance in my biggest room in the United States. The 3x spread is pretty close to what we see in size difference between China and the US so it seems reasonable on face value.

Now the question is "what is the average listening level?" THX Reference Movies are 85 dB average. That's pretty loud because that's the upper limit of what you'd be allowed to listen all day/every day without injury. Then, I'll pick 65 dB for the lower level since that's the typical volume of someone sitting and playing the piano normally:
[Ref https://music.eku.edu/sites/music.eku.edu/files/ekuhealthandsafety.pdf]

Now we do math. I will assume 2 speakers, near a wall.


SpeakerdB at 0.05W (5 vs 15 ft)dB at 0.5W (5 vs 15 ft)dB at 5W (5 vs 15 ft)dB at 50W (5 vs 15 ft)
Revel PerformaBe F328Be80.3 / 70.890.3 / 80.8100.3 / 90.8110.3 / 100.8
Focal Aria 90676.3 / 66.886.3 / 76.896.3 / 86.8106.3 / 96.8
Elac Uni-Fi 2.0 UB5272.3 / 62.882.3 / 72.892.3 / 82.8102.3 / 92.8

Peak advertised power handling
SpeakerPeak Advertised Power HandlingIn room Peak SPL (5 vs 15 ft)
Revel PerformaBe F328Be300 watts118.1 / 108.6
Focal Aria 906120 watts110.1 / 100.6
Elac Uni-Fi 2.0 UB52140 watts106.8 / 97.3


The detail that's missing from this is the concept of bass needing power. If we look at the Revel PerformaBe F328Be, the 30-50Hz region is ~81 dB/2.83V and impedance is about 6 ohms. At 50 Hz exactly, it's 84 dB/2.83V and 8 ohms. If you wanted your bass to hit 105 dB peaks at 15 foot listening distance, you need ~1300 watts into 6 ohms or ~650 watts into 8 ohms using those assumptions. (Hence, the value of a subwoofer even with full-range speakers.)
Thanks for the great information. With my soon coming 106-db speakers and my flea-watt amps, I should have plenty of power for most music which includes dynamic peaks.
 

mhardy6647

Grand Contributor
Joined
Dec 12, 2019
Messages
11,216
Likes
24,176
A bunch of opinions, albeit not uninformed ones. :)

1) I think that the first watt is important in real life even for modern, average reproduction chains (i.e., the glut of modern, low-sensitivity loudspeakers).
2) I think the trick is mostly noise down in the low-output
3) I think folks are even more noise-obsessed now than they were 20 years ago (which I find a bit ironic).
4) I think it is really unfortunate that the proliferation of RFI 'hash' from modern technology has led to both real and imagined noise issues in audio reproduction.
5) I think that the obsession with power conditioning and esoteric power and audio cables is driven, to a significant extent, by the added noise of RFI and digital signal processing artifacts (irrespective of the low level of particularly the latter).
6) I think that y'all'll likely disagree relatively vehemently with me on some, perhaps all of these items! ;)
(actually, I am pretty sure about number 6)

bonus opinion

7) For those of us troglodytes (mancave-dwellers, if you will ;) ) using (very) high-sensitivity loudspeakers, the first 100 mW is important (and, perhaps, even the most important)!
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
A bunch of opinions, albeit not uninformed ones. :)

1) I think that the first watt is important in real life even for modern, average reproduction chains (i.e., the glut of modern, low-sensitivity loudspeakers).
2) I think the trick is mostly noise down in the low-output
3) I think folks are even more noise-obsessed now than they were 20 years ago (which I find a bit ironic).
4) I think it is really unfortunate that the proliferation of RFI 'hash' from modern technology has led to both real and imagined noise issues in audio reproduction.
5) I think that the obsession with power conditioning and esoteric power and audio cables is driven, to a significant extent, by the added noise of RFI and digital signal processing artifacts (irrespective of the low level of particularly the latter).
6) I think that y'all'll likely disagree relatively vehemently with me on some, perhaps all of these items! ;)
(actually, I am pretty sure about number 6)

bonus opinion

7) For those of us troglodytes (mancave-dwellers, if you will ;) ) using (very) high-sensitivity loudspeakers, the first 100 mW is important (and, perhaps, even the most important)!
So profligate. I'm usually around 20mW. Go ahead, burn down the planet!!!
 
Top Bottom