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How much amplifier power do you really need?
#61
(12-Jul-2019, 10:01)thumb5 Wrote: @David A Maybe you're thinking of @Confused's original post in this thread?


Quote:It also reminds me of the day at Oxford Audio, when Mathieu Pernot stated that his perfect amplifier design would have "infinite power".  This seamed slightly absurd to me at the time and I was talking to him about this later in the day.

Yes, that's where I saw the comment. Many thanks for finding it


(12-Jul-2019, 10:46)thumb5 Wrote: @David A's comment in an earlier post got me doing some background reading:

Quote:It would be interesting to know how crest factor relates to the dynamic range measurement Roon uses. From reading what Roon have written about the dynamic range measurement in their user guide and other documents, it defines the range in which something like 95% of the music occurs, excluding the loudest peaks and the softest passages. It's not a measure of the range from silence to maximum peak level of the recording.

While not touching specifically on what Roon uses as an indication of dynamic range, this article from Sound on Sound has a lot of interesting observations on measures of loudness, dynamic range and crest factor, in the context of looking at the effects of the so-called "loudness war".  It's quite technical but a good read for anyone so inclined.  Incidentally it includes a range of measured crest factors for a body of 4500 music tracks which more or less agrees with the figures mentioned earlier in the thread.  (Notwithstanding @David A's observation in his recent post, this is still relevant to the topic in general.)

Interesting article. I need to spend a bit more time going over it if I'm going to get a good grasp of everything it says. You're right that it is quite technical.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
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#62
Roon is using the loudness range in compliance to the EBU R128 spec and not the dynamic range nor the crest factor.

The loudness range calculate ratio of RMS power between certain normalized quantiles of the RMS power distribution.

Jean-Marie
MacBook Air M2 -> RAAT/Air -> WiFi -> PLC -> Ethernet -> Devialet 220pro with Core Infinity (upgraded from 120) -> AperturA Armonia
France
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#63
Some fascinating posts in this thread this week, it has certainly got me thinking about a few things. Although one thing I would say is that the thread has drifted a little onto how much power does a Devialet produce and how does it do it, and a little away from the "How much power do you really need" question.

This takes me back to the original video. One thing that is a fact is that the CI Precision amplifiers were routinely showing 400 to 750w peaks. OK - RebelMan was quick to dismiss the validity of the video, making the point that SPL reading were not measured. I can only agree that the video would have been more informative if this data was included, but personally I take more of an "it is what it is" view, we have the video, what can we make of it? If anyone finds something better, then please post it, meanwhile I will try to make the best of what we have. One point here is that we do not really know how accurate the CI Precision amp power readings are, but they are a serious audio company, and the CI Precisions are very expensive, this is not some gimmick on a toy. I do not know for sure, but I suspect that they are probably reasonably accurate. Does anyone know for sure?

So how loud were they playing in the video? Obviously this was not measured, but there are some clues. From 5:50 to 7:00 minutes you can clearly hear the voices of the attendees in the room over the music, furthermore, in the same time frame you can see three people approaching to within a foot of the speakers, so this does give us an idea,

For a bit of fun, I tried the "Laptev Sea" track at home, armed with a probably not very accurate iPhone app. At a loud but almost comfortable level, I was getting an average of 90dB, with peaks of about 97dB. I am sure that if recorded, you could hear me speak over the music at this level. As a guestimate, I would say the music in the video is at about this level, if anything a little quieter. I tried pushing the volume higher, and did get peaks of about 103dB. I did this for maybe two seconds. Trust me, I would NOT want to listen to this track at this kind of volume. I know about hearing damage due to sustained SPL levels, and even a couple of seconds at that volume was too much. It is a guess I know, but I am 99% as certain as I can be that the volumes in the video demo room were much lower. I would not have stuck my head one foot away from the Blades with that volume level, not a chance. For the record, I briefly ran the amps to about -7dB, and the clipping indicator was not activating. So how much power did this need? I do not know, but if someone knows a cleaver way of measuring this I am all ears. (If now maybe suffering temporary hearing loss)

So I am happy to speculate at maybe 90 to 95dB in the room with peaks, and defeatedly not significantly higher, that just would not be credible. Running as loud as I did for a very brief moment, people would have been leaving the room, I would not have stayed in there for more than a second.

When I first saw the video, my thoughts went to the Harbeths, I know they are not the most efficient speaker, and I presumed they must be a hopelessly difficult load to drive. A quick check on the 'net shows this presumption to be wrong. Stereophile have tested the 40.1's, and the opposite is true, they have a very amplifier friendly looking impedance curve, see link below:

https://www.stereophile.com/content/harb...asurements

The review is also interesting in that Art Dudley ran the Harbeths with a selection of low powered amplifiers, and found a preference when using a 25wpc amp. Now I am sure that if the CI Precisions in the video were swapped for a 25wpc amp, playing the same track in the same room at the same volume, the result would sound very different. Much speculation I know, but whatever anyone says, those amps were showing 750w peaks.

So what about the Laptev Sea track itself? This I think is a factor. As it happens, I have a copy on CD. So I thought I would try it in my car. My car has the standard stereo as provided by the manufacturer. I actually really like how it sounds, it is pretty decent, but every now and again I might get a particular track at a particular volume where I feel the need to turn the volume down by one click, it is just on the edge of distortion. So it sounds good, but is clearly marginal on power. Playing the Latev Sea track, and it was really struggling. So out of thousands of pieces of recorded music that I have played in that car, the Laptev Sea track comes out on top as one of the hardest to reproduce.

Checking in Roon, the album has a DR of +/- 11, the Laptev Sea track is +/- 3. (which shows you how album DR's can be misleading) iTunes indicates a volume compensation value, which for the Laptev Sea track is -0.9dB. What this tells anyone I am not sure.

For me, the exceptional thing about the track (subjectively) is the power and extent of very low bass. At the very lowest frequencies the Harbeths have an impedance of about 8 ohms. Others have mentioned that the Devialet in dual mono can run +/- 55v, giving 110v. If we assume say 100v (or running almost flat chat, as it otherwise might be known) and using ohms law, this gives a current of 100/8 = 12.5amps. Volts x amps = watts, so this is 100 x 12.5 = 1250 watts. OK, that is a lot, too big a number, but the Blades are a touch more efficient than the Harbeths, so for me the 750w number, as a transient peak looks entirely credible. In other words, I could not stay in the Room with the Blades at almost full volume, with the slightly less efficient Harbeth's and a bigger room, I might get nearer to full volume, but on balance, the 750w figure does look credible, and indeed it is the number on the front of the amp. OK, a lot of assumptions here and the "math" is crude compared to what is a very complex and dynamic system, but it is starting to make some sense to me, maybe in some situations you might need a touch more power than you might think.

As a bit of trivia, listening on the Blades to the recording of the Harbeths playing Laptev Sea, everything sounded clear, no obvious distortions, and the low bass comes through nicely. Obviously the track sounds better played direct on the Blades and the Harbeth's would undoubtedly sound much better listening to them direct in the room, but those Harbeths still sound decent when recorded, I am guessing they are impressive when heard for real. (I have heard other Harbeths, but never the 40.1)

As a final point, I remain fascinated by all this. It is easy do some simple calculations, I want to listen at a maximum of 95dB, my speakers produce 93dB for 1w/m, 10 watts is fine etc., but there is a lot more going on here I think, and to be honest, I think I need to learn more to fully understand all this. I mean, Mr Art Dudley was happy running his 40.1's with a 25 wpc amp, and I am sure they sounded great, the video I think does show a real world situation, albeit a rather extreme one, and the speakers are taking fully 30 times that much power, it boggles the mind.
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#64
Please read the following review in the german fidelity-magazin. If you have problems with the german language I recommend google translate:
https://www.fidelity-magazin.de/2017/02/...messungen/
Especially the figures 8 and 9 give interesting results about the RMS power and the peak power with different crest factors. In the article it is also mentioned that no clipping appears below a volume setting of +3dB on the Devialet.
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#65
@Confused

Interesting comments.

You said: "Although one thing I would say is that the thread has drifted a little onto how much power does a Devialet produce and how does it do it, and a little away from the "How much power do you really need" question". Yes, it has in some ways but it's hard to separate the question of how much power you need from the questions of how much power a Devialet produces and how it does it. We usually ask how much power we need in the context of deciding whether we have enough power for our needs and answering that often involves issues of how much power our amp actually produces in real life situations and how it does that.

You commented on the levels the music played at in the video and the fact that people could be heard speaking during the music. My background isn't in electronics or audio or recording. I worked in health and safety before I retired and things like hearing protection were part of what I studied to get my professional qualification though I never worked in that area. At one stage, however, I was involved in some issues around the design of a telephone call centre and was asked for an assessment/explanation of the acoustic design of the sound absorption characteristics of the dividers between the workstations. That was something that hadn't been covered in anything I'd been taught, we're speaking here of sound pressure levels well below the kind of levels which trigger hearing protection issues, but I found the bit of research I did interesting because at that time I was starting to get interested in acoustic treatment for home listening rooms since I was starting to read reviews in magazines of some early room treatment products and I was wondering whether or not I would get any benefit from them in my room.

To cut to the chase, normal speech levels tend to run in the mid-60s dB range and it is basically accepted that background noise levels of around 65 dB interfere with speech comprehension. That doesn't mean that a background level of 65 dB means you won't be able to hear someone speaking to you at a normal level, it means that you will probably be having difficulty understanding what they're saying at least part of the time. As you know, the louder the background noise becomes, the more you raise your voice so that the person you're speaking to can understand you rather than so that they can hear you. There's a difference between being able to hear that someone is speaking to you and being able to understand what they're saying.

Things are a bit messier than that, however, because frequency plays a part. Music contains sounds at different frequencies and we can hear what a violin is doing in a string quartet and appreciate it's contribution to the music even if the violin is playing softly and the 'cello, which is playing a couple of octaves lower, is playing much louder and carrying the main musical message. There's a thing called "masking" also involved and louder sounds will mask other sounds in the same frequency range more than they mask other sounds in a different frequency range. That means that a background noise level of 65-70 dB will mask speech at a normal volume level and make it harder to understand if the background noise is in the same frequency range as the speech than if it is in a different frequency range and has little content in the speech range.

I didn't watch much of the video so I didn't see the section you mentioned but another factor is likely to the proximity of the people speaking to the camera and mic. They were probably a lot closer than the speakers were and that means that the level of the sound produced by the speakers is going to have dropped a lot more by the time it reached the mic than the level of the voices had. For the people actually speaking to each other, they would have been very close to each other, probably only 30-40 cm separating their heads if they were sitting next to each other in the demo room because they were probably leaning a bit towards each other given that there was music playing, and the speakers were probably 2-3 metres away. That means that there would have been a lot less difference in the levels of the speech they were hearing and the music from the speakers than you would think so they were probably having little difficulty understanding each other. At the greater distance from the people that the mic was placed at, the sound of the music would have been louder relative to that of the voices and the impact on speech intelligibility greater.

The take away from all of that is that when it comes to listening to music it's not only level that is important to how we hear what's going on and our assessment of how loud is loud enough (the main factor in deciding how much power you need) but also the frequency of the various elements of the music and room acoustics plays a big part there.

My room is acoustically treated and I've experimented with acoustic treatment of my room for around 25 years now in 2 different rooms (I don't move house often) starting with DIY treatments and ending up with commercial products. It's been a fascinating experience in many ways and it's taught me a few interesting things. One is that acoustic treatment only affects reflected sound, not the direct sound reaching your ears in a straight line from the speakers. That makes sense because acoustic treatment only affects the sound striking the treatments and you don't put acoustic treatment products in the path of the direct sound. The reflected sound arrives later and is lower in level than the direct sound (greater travel distance, absorption at the surfaces it reflects off along the way, scattering due to diffusion etc) and higher frequencies decay faster than lower frequencies (they're absorbed more easily and even increasingly absorbed by air at frequencies above 7-8 kHz or so). Acoustic treatment results in a greater difference in level between the direct sound and the reflected sound reaching your ears and music becomes clearer and more "understandable", just as speech is more understandable when background noise is lower. I listened, and still listen, at a higher level in a room without acoustic treatment than I do in a room which is well treated, simply because the music is clearer and it's easier to hear everything in the music. One of the reasons we turn the level up is because we can't hear something in the music as clearly as we want to hear it and turning the volume up tends to make it easier for us to hear elements we want to hear and usually the things we want to hear more clearly, the things we lump under the label of "detail", are at higher frequencies. Even with bass, the details of the sound of an acoustic or electric bass, tend to come with the tonal characteristics and those characteristics are linked to the overtone structure of the sound so they start an octave above the fundamental note. Detail holds up better than fundamentals because it occurs at higher frequencies and cleaning up lower frequencies which is one of the main purposes of treating a room makes detail easier to hear. There's less need to turn the volume up to enhance the "intelligibility" of the music in a well treated room and you end up listening at lower levels which need less amplifier power.

And finally there's your choice of music. If your main listening choices are, say, solo clavichord music and a clavichord probably struggles to produce a level of 65 dB on peaks (it's a very soft instrument) then you don't need much power at all to produce realistic levels. A string quartet takes a bit more power but doesn't dig into the bass range where power demands start increasing drastically but solo piano can go a good half octave lower than an acoustic or electric bass and requires more power for realistic reproduction. An acoustic jazz trio doesn't produce the levels of a chamber orchestra which doesn't produce the level of a symphony orchestra and that doesn't approach the levels that some rock bands routinely produce in live performance. If your musical preference is stadium level rock performances then you're going to need a fair bit of power to get satisfying sound, even though you're not going to produce the same kind of level in your living room as you hear at a live performance and you also don't need enough amplifier power to put a strain on the electricity grid supplying your home.

"How much power do you need?" is a complicated question and I think there's a tendency to think that there's a simple answer based on speaker choice/sensitivity and the peak volume your speakers are capable of but it isn't as simple as that and in reality you can find 2 people with the same speakers, one of whom might be really happy and perfectly satisfied with a 140 Pro and another who needs a 1000 Pro and who can't wait for Devialet to produce a 2000 Pro.

As for Art Dudley, and I enjoy Art's reviews and share a few of his musical tastes, he likes a lot of small group acoustic music with the deepest bass content supplied by an acoustic bass or a piano which doesn't dig into its bottom octave all that often in the music. In his room he's getting good results with Harbeth's and modest amps because they deliver enough power for good reproduction of those instruments at listening levels he's happy with, and those are probably similar levels to what I like. He's also happy to accept symphony orchestra reproduction that doesn't deliver as well in the low bass as it does in the upper bass and mids, and that doesn't impact on the emotional impact of the music for him. He's willing to compromise with some music provided he doesn't have to compromise on getting what he wants from a lot of other music. That's a big factor also. His needs would be a hell of a lot greater if he "wanted it all" with all of the music he listens to, and he might not be able to satisfy his needs if that were the case. He's a happy man because he's willing to settle for a lot rather than demanding everything, he's willing to compromise. A lot of this discussion often gets conducted on the basis of compromise being unacceptable. Compromise is unavoidable, we can't have it all, and the only question is how much we're personally prepared to compromise. The decision we make on that determines whether we can be as happy as Art Dudley is or whether we're always going to be chasing more of something and being a lot less happy than Art. I like being as happy as Art is.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
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#66
@Confused

One important addition to my post above, probably more important in some ways than the post above.

You said you wanted peaks of 95 dB. That means you only need peaks of 92 dB. You've got 2 speakers and 2 speakers producing the same level result in a total level that is 3 dB louder than each speaker on its own. If you want 95 db peaks you want each speaker to produce 92 dB peaks and producing 92 dB from each speaker requires half the power that producing 95 dB from each speaker requires. Amp ratings tell you how much power you have for each speaker individually.

Sound falls off at 6 dB per doubling of distance in the acoustic near field and at around 3 dB per doubling of distance in the acoustic far field. Assume the boundary between near and far field is around 2 metres (it's a bit less than that).

Here's the type of calculation you were thinking of:

I listen at around 2.6 metres. At 2 metres I'd need an extra 6 dB for the doubling of distance, at 9 metres around an extra 9 dB. To be safe assume an extra 8 dB hat 2.6 metres.

My speakers are 91 dB sensitive according to Focal. I haven't seen a test report on the Sopra 2s but John Atkinson's review of the Sopra 3's measured them as around 2 dB less sensitive than rated so let's assume my speakers are 89 dB sensitive. To produce a 92 dB peak per speaker at my listening position, I need to raise 89 dB to 100 dB (92 dB for the peak at 1 metre plus the extra 8 dB for the listening distance) so I need enough amp power to deliver an extra 11 dB. According to an online calculator that requires 12.589254 watts. 

I think your figure of 95 dB peaks would suit me fine as well. You probably listen at a slightly larger distance. You still need 92 dB at 1 metre but you would need to produce 9 dB more to get 92 dB at 4 metres so you need to get 101 dB at 1 metre, an extra 8 dB over what the speaker produces for 1 Watt. The gain with your more sensitive speakers more than outweighs the loss with the increase of listening distance from 2.6 to 4 metres so you would need less power than I do in order to produce the same peak level.

Let's say you had 85 dB sensitive speakers and a 4 metre listening distance. We still need to get 101 dB at 1 metre for 92 dB at 4 metres so that's an extra 16 ddB. You still need less than 100 W. 100 W would deliver a 20 dB increase in level so a pair of 85 dB sensitive speakers would deliver a 95 dB level at 4 metres with 100 W.

Assuming each speaker has to deliver the level you want at the listening position rather than 3 dB less because the sound of each speaker adds together to raise the overall level 3 dB makes a big difference when it comes to how many watts you need in order to deliver your desired SPL. For each 3 dB you raise your desired peak listening level you double your power requirements.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
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#67
@David A I roughly listen at the same peak level as you (97dB) in my case on classical programs having DR between 10 and 22 dB, meaning that my average SPL is around 80dB.

That means that the peak power I need (given two speakers at 88dB/W @ 1 meter and a listening position of 2.5m) is 25W. That is consistent with the fact that I’m listening with a volume setup to -8dB (I was using -6dB when i had the D120) [220W at 6 ohms is 165W at 8 ohms and -8 dB is 26W] [120W vs 220 is about -2dB so very consistant between the two]

So is the extra power I have providing any benefits?
I would say not much if SAM is turned off.
But SAM changes the equation and benefits from any extra power you can have, so this is where having 165W for SAM to play with instead of 90 in the case of the D120 made an appreciable difference.

So bottom line, I believe the statement that the ideal amplifier being one of infinite power is mostly true in the context of SAM, not necessarily in a “normal” use of an amplifier.

Jean-Marie
MacBook Air M2 -> RAAT/Air -> WiFi -> PLC -> Ethernet -> Devialet 220pro with Core Infinity (upgraded from 120) -> AperturA Armonia
France
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#68
@Stefan - Thanks for posting the measurements, good stuff.  As I mentioned in another thread, I often consider myself to be a frustrated objectivist.  That is, I rely on subjective observations simply because there is not enough objective data around that corelates with what I am hearing, in many areas there is no decent data at all.  

As a general point, it is always good to see some measurements.  It might be useful if between us we collect all the available Devialet test data relating to power.  It would be good to have it together in one thread, so if anyone knows of any power related measurements, please post!

@David A - Lots of detailed information as always.  With respect to your post #66, please note that I was not complaining about the "how much power does a Devialet produce" posts, quite the opposite, I fully agree that these are related topics.  There is some interesting reading there on many related topics.  My take from it is that what you have stated is more or less in line with my estimate that the SPL in the video was maybe 90 to 95dB(a), and certainly less than 100dB(a).  You make no view on this, I am guessing you position is that it is impossible to say with any certainty?  (you strike me as a cautious man who prefers not to speculate)  OK, there is some speculation here, but from about the 6:00 min mark in the video you can just about make out the voices, not what they are saying, when the camera and microphone are about three to four metres away from those talking.  After 7:00 min when the camera closes up on one attendees smart phone to show the track name, you can clearly hear his voice, it does not sound like he is shouting, and the camera is maybe half a metre away.  So based on your comments, would you be happy to estimate SPL's below 100dB(a)?  I would be interested in you view here.

Regarding your post #67, you make this statement:

Let's say you had 85 dB sensitive speakers and a 4 metre listening distance. We still need to get 101 dB at 1 metre for 92 dB at 4 metres so that's an extra 16 ddB. You still need less than 100 W. 100 W would deliver a 20 dB increase in level so a pair of 85 dB sensitive speakers would deliver a 95 dB level at 4 metres with 100 W.

I fully agree with this in terms of your calculations.  If my earlier assumptions re SPL are about right (if), then what you describe above is more or less in line with what we find in the video, in terms of the SPL's, the sensitivity of the speakers and the listening distance.  Yet, the amps are not showing 100 w, nothing close, they are showing 700 w.  OK, there are assumptions here and a fair margin or error, but the end result is a factor of 7 different.  I think there are some "real world" complexities here that the basic calculations do not fully address.

As am open question to all.  I have been thinking a bit about audio reproduction and the dB "A weighted" scale.  I have attached a dB weighting graph here for easy reference.  What I am thinking about is the fact that human hearing is far less sensitive to sound at lower frequencies, so with equal energy, a sound at 1000Hz will sound to a human a lot louder than a sound at 100Hz.  This is well known.  To me, the obvious consequence of this is that to produce a sound at very low frequency that sounds reasonably loud to a human will take considerably more power than to produce something equally loud at around mid range frequencies.

This is relevant to the Pan Sonic track.  It has a lot of low bass content, right down to frequencies more felt that heard, so not just below 100Hz, but dipping below 20Hz.  (maybe someone has software that can analyse this aspect the track?)  Looking at the a weighted scale, these low frequencies sound -30dB down to human hearing at say 40Hz, even more as you drop to 30 or 20Hz.  -30dB is a lot!  So if you take the power needed to reproduce 1000Hz at 90dB(a), then you would need fully 1000 times the amplifier power for an equally loud sounding sound at 40Hz.  I am thinking aloud a little bit here, but could this be a factor in what we are seeing in the video?

   
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#69
Purely in the interest of science, you'll understand, I extracted the audio track from the YouTube video in the original MP3 format.  Here's Audacity's frequency analysis:

   

ETA: according to the relevant page in the Audacity manual, this is an amplitude spectrum.

Incidentally Audacity says that the track has full scale (0dBFS) samples and the RMS value is about -13 dB, which I believe means a crest factor of 13 dB.  The waveform diagram shows the samples in dark blue and the RMS value in light blue:

   

At the risk of stating the obvious, it's worth pointing out that this is not the exact same audio the guys in the video were actually playing (unless they've also invented time travel); presumably they were using an original, uncompressed version of the track.
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#70
@Jean-Marie

I don't think the extra power you have with a single 220 has any real benefits apart from the fact that if you really want to turn things up to 0 dB on the volume setting you'll get 2 dB louder peaks than you got with the 120 :-) Of course, since your current volume setting is -8 dB, those extra 2 dB mean that your peaks will be 10 dB louder than you're getting at a -8 dB volume setting and a 10 dB increase in volume, not only on the peaks but on all of the music regardless of level, means everything would actually sound a bit over twice as loud to you. Do you want to listen to music that's twice as loud as what you're currently listening to? Obviously not or you would be listening at higher levels right now.

If you were using SAM before with the 120 and had power in reserve and you're using it now with the 220 and have 2 dB more power in reserve, then it's a bit hard to say that upgrading from the 120 to the 220 has made an "appreciable difference" for you with SAM. You're not doing anything more with SAM now than you were before. If there is an "appreciable difference" then it's going to have to be in areas other than peak volume or SAM functionality for you because you're still listening at the same level and using SAM in the same way. Note that I'm not saying that there are no benefits from using a bigger amp. All I'm saying is that you're not getting any benefits in relation to peak volume or SAM functionality because you had enough power for both before given your needs and you're not using any more power now, the extra "headroom" you gained going from the 120 to the 220 has just been added to the headroom you had in reserve with the 120.

In terms of peak volume levels alone, ignoring whatever extra power SAM requires, I can easily see some people needing a 220 rather than a 140. Someone with a taste for louder music than you or I have, less sensitive speakers than you or I have, and a bigger room with a longer listening distance could easily need more power than a 220 provides and be looking at a 440. A 440 would give you 3 dB more power than you currently have, giving you 11 dB of headroom. You could run through that 11 dB easily and end up needing a 1000. A desire for 3 dB higher peaks, 5 dB less sensitive speakers than yours (there's more than a few 83 dB sensitive speaker options available) and larger room and a 5 metre listening distance would eat up all of your 8 dB peak volume reserve and the extra 3 dB that a second 220 would provide and have you running the 440 at a 0 dB volume setting to deliver the peak levels you wanted.. Go for an 82dB sensitive speaker rather than an 83 dB sensitive one and keep the same peak listening level and listening distance and you'd be looking at a 1000 because a 440 would deliver 1 dB less than what you needed.Every extra dB you need to meet your requirements chews up an increasing number of watts. Going from a 220 to a 440 only gets you an extra 3 dB to deal with higher peaks. lower sensitivity, or greater listening distances and going from a 440 to a 1000 probably only buys you another 4 dB. Infinite power may not be necessary but every time your power requirements increase they increase by bigger and bigger amounts. No one needs infinite power but with the right speaker choice (should that be the wrong speaker choice?), a taste for louder music, and a big enough room it's possible to create a need for more than a kilowatt of amplifier power and outgrow the 1000.

The fact that I'm happy with a 140 and you're happy with a 220 doesn't mean that there aren't people with a legitimate need for a 440 or 1000 or greater to meet their needs. 1000 W or more may not be infinite power but it's still something that easy for someone in our positions to shake our heads at in disbelief until we start looking at just how many more watts every extra dB we need over what we currently need is going to cost us in watts.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
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