I don't want to beat a dead horse but I'm bugged.
I just can't clear my head of this. I don't want to start a measurements vs listening war and I'd appreciate it if you guys don't, but I bought a Rogue Sphinx V3 as some of you may remember and have been enjoying it quite a bit. So, I head over to AVS and read Amir's review and he just rips it apart. But that's OK, measurements are measurements, that is not what bugs me. I learned in the early 70s that distortion numbers, etc, may not be that important to me. Then I read that he didn't even bother listening to the darn thing. That is what really bugs me. If something measures so poorly, wouldn't you want to correlate the measurements with what you hear? Do people still buy gear on measurements alone? I learned that can be a big mistake. I just don't get it, never have. Can anybody provide some insight to why some people are stuck on audio measurements? Help me package that so I can at least understand what they are thinking without dismissing them completely as a bunch of mislead sheep.
This article is about this discovery i spoke about above about Oppenheim and Magnasco and our model of hearing and dac design ... i think that this clarify andjustify atmasphere opinion but from another perspective which is not amplifier design, but more hearing abilities in itself, but i am not a specialist... 😊
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This statement is misleading IMO. Most fail requirement 1) of my prior post. If you look at the distortion amount and its spectra, you’ll find that most amps have distortion rising with frequency and the spectra changing along with it. This is because (as I’ve mentioned before) that they lack sufficient feedback, because they also lack sufficient Gain Bandwidth Product. There are exactly two ways around the problem of rising distortion and changing spectra: 1) build the circuit with zero feedback and wide bandwidth or 2) build the circuit with really enough Gain Bandwidth Product to support over 30dB of feedback (such that feedback is actually the same at 15KHz as it is at 100Hz). Most amps spec’ed to have ’30dB of feedback’ might have that at 1KHz but they will be less than that at 10KHz since the feedback is falling off due to insufficient GBP. This causes distortion to rise with frequency and it also means that the distortion caused by the application of feedback can’t be corrected by the circuit. That translates to ’harsh and bright’ and we’ve all heard amps with this problem; we’ve been hearing them for the last 60-70 years! There are plenty of amps made like that today and only a very few that actually meet the requirements stated in 2) of this post above if they have feedback.
Its not that we as an industry can’t do it, its that we lack the will, plain and simple. You do also need to know enough to understand how something will sound by looking at the distortion spectra... I’ve no doubt that some of these measurements don’t occur because there isn’t the education out there to really understand the data! Plus- heaven forbid- you know how something sounds by looking at the measurements!
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The problem if i may give my grain of salt, is that we dont exactly know what are human hearing abilities... Human hearing limit in decibel scale and in the frequency scale yes we know but what about the way the brain/ears used the information and decipher it with the non linear tool kit of the cochlea/brain ?
In the words of these mathematical physicists turned acoustician: Jacob N. Oppenheim and Marcelo Magnasco of the Laboratory of Mathematical Physics at Rockefeller University have conducted experiments indicating that the human brain does not use the Fourier transform when resolving a cacophony of noise into individual sounds and voices. While the Gabor limit associated with the Fourier transform stipulates that you can't simultaneously determine a sound's frequency and duration, the 12 musicians subjected to Oppenheim and Magnasco's battery of tests beat the limit by as much as a factor of 13. The Fourier transform cannot, therefore, fully explain the machinations of the human brain. "The actual algorithm employed by our brains is still shrouded in mystery," says Magnasco.
«You see, physicists tend to think hearing is spectrum. But spectrum is time-independent, and hearing is about rapid transients. We were just told, by the data, that our brains care a great deal about timing.» «For the first time, physicists have found that humans can discriminate a sound’s frequency (related to a note’s pitch) and timing (whether a note comes before or after another note) more than 10 times better than the limit imposed by the Fourier uncertainty principle.» « The results have implications for how we understand the way that the brain processes sound, a question that has interested scientists for a long time. In the early 1970s, scientists found hints that human hearing could violate the uncertainty principle, but the scientific understanding and technical capabilities were not advanced enough to enable a thorough investigation. As a result, most of today’s sound analysis models are based on old theories that may now be revisited in order to capture the precision of human hearing.» This article is particularly illuminating if someone take the time to read it and his imnplication to understand hearing and why our measurements are not the good one...
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The absolute truth in my opinion. Current test bench measurements are inadequate. It makes no sense to measure good and yet sound poorly. What good are measurements such as these? There are numerous audio components that don’t measure particularly well yet sound fabulous. Ralph is correct in that what really matters in determining good sound quality is not being done currently with measuring instruments. I do believe at some future point this dilemma will be properly solved. It sure is not the case now. I guess for some there’s a degree of reassurance or peace of mind with current methods of audio component bench testing. As it stands presently the ears are far more reliable and trustworthy in judging audio product sound quality. Charles |
Many amplifiers on tested on Stereophile and ASR meet those criteria @atmasphere . By low, I don't mean only low at 20KHz, but low at all frequencies, <<0.01% at all frequencies. I don't think distortion has any particular meaning at >10KHz as the distortion is >20KHz. I assume the measurements are using an extended bandwidth beyond human hearing. ASR shows distortion from low to high power at a range of frequencies in their reviews. |
It needs to be more than just low distortion at 20KHz although that certainly does not hurt. What is important is four things; if these four things are met, the amp will be easy to listen to, regardless of its technology: 1) the distortion will be consistent at all frequencies- the same at 100Hz, 1KHz and 10KHz. 2) the distortion spectra at 1 Watt will be such that the higher ordered harmonics will not be audible- for whatever reason. 3) The distortion spectra at 6dB below full power will also prevent higher ordered harmonics being audible. 4) IMD is well controlled. These things sound simple and easy but they can be quite tricky! Most amps fail them outright- and sound bright and harsh as a result, even though they 'measure well' otherwise. The real problem isn't that they measure well, its that the proper measurements aren't made at all! |
The problem was not Amir himself but few of his zealots disciples... Because the notion of a measured distortion in engineering design is not the same than in acoustic... Why ? Because acoustician test a subjective response from a musician for example in a timbre experiment perception test...harmonics here means something very different than " harmonics" in engineering standard measures... And the engineer read a dial and his "distortion" THD is a way more simplistic concept of what a distortion do to the subjective impressions and why....It is an engineering % about a relation between input and ouput...Not the way sound affect humans ears... Electronic Engineering is SUBORDINATED to psycho-acoustic research or a tool for it not the reverse ... Save when the psycho-acoustic research is done and applied.... Timbre perception is not reducible to a simplistic concept of the spectrum for example....but the engineer most of the times work with this simplistic concept which is well enough for his design trade-off practice anway ... There is exception but they are exceptional designer not a crowd of them ...All audio products are not ultra high end... 😁😊
Exactly....Some designer like atmasphere know....
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@russ69 I didn't say the measurements have to be great, they can just be good. Good is more than acceptable. |
Why would he bother with listening to this amplifier?
Not particularly, this amp was given a not recommended not so much because it could be differentiated from other amps if kept within it's limitations but because it wasn't considered a good buy and the engineering of the thing is a bit weird.
Yes, I do. They can tell me enough to know what I want to consider. I've yet to listen to a component that measured well and sounded bad, but I only consider this with speakers as amps, Dacs, etc.. are commodities I can look at the numbers and know if I want it and they don't have to be that great since the speaker and room will swamp the electronics in terms of audible distortion.
I don't understand the gripe with ASR, if you don't like their approach then don't pay attention to it. From my reading on their site they pretty much ignore this place try to do the same. |
We also used to think the sun was the center of the universe. Why is it so hard to accept people like different things and even what they like changes? If you have become accustomed to a certain sound, that is what you may prefer even if it does not measure well. Someone else may have become accustomed to and like a different sound that measures well.
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i remember replying to a similar thread a while back asking this question... my answer was 3 fold 1. some folks do not trust their ears to tell them which is 'better' 2. some folks with scientific training believe (mistakenly in my view) that measurements tell all that one needs to know 3. some combo of 1 and 2 |
Amir is a good resource as an alternative viewpoint. His ‘truth’ is a series of measurements, that can tell a lot about how some components will perform. But he does miss some of the picture no doubt. A couple of his component reviews are way off the mark. Maybe a faulty product? Or his measuring system at fault? Who knows? Take Audio Science Review for entertainment value, and some worthwhile information. |
Atmasphere has numerous posts about amplifier harmonic distortion and listener perception. Simply stated, vanishingly low harmonic distortion is not necessary. The harmonic spectrum and linearity of the distortion are more important. So whether THD is .001% or a hundred times greater is pretty irrelevant. Clearly measurements matter, it's just that the most commonly cited amplifier measurements aren't the most important regarding sound quality. IMO a well designed amplifier should both measure well and sound good. |
Thanks for posting. This thread was designed to help me understand people that rely on measurements above what they hear. You make a good point but if an amp or whatever sounds good even though it has measurements different than some other amps is that amp no good? Should it be dismissed without listening? Are we measuring the right things? Is looking at .01% difference important? Is distortion that is not audible important? We don't prefer distortion, we just don't think inaudible distortion is important. Are we wrong? |
Oy vey! I guess I’m just not picking up the logic here. Oh well, nonetheless I do appreciate and respect everyone’s point of view on this topic. Charles |
The fact that one component can measure better than another isn't the point of my earlier comment. I believe audiophiles should not have to accept poorly measuring equipment. The tube equipment that I see measured in Stereophile actually measure fairly well. As a group they don't measure as well as the majority of solid state amps, but it's not as if they don't have good measurements. |
Agreed and exactly my point. You have to hear and listen to make a final choice determination. If some folks prefer to downplay actual listening, more power to you and enjoy your scrutiny of numbers. Listening has served me well so I'll stick with that. Charles |
You are right if you speak about the differences in gear.... But sound subjective evaluation is not only pure relative taste, it is also a LEARNED HEARING experimental journey with acoustic and psycho-acoustic experience and principles... Difference in gear design and specs are also SUBJECTIVE and are judged by our own needs and expectations... Difference in room acoustic are no more only subjective, you can objectively CONTROL a system/room at will and you can learn from this OBJECTIVE experiments installation the more you explore it... That is my point... Differences between relatively basic good gear at any price will not replace the HUGE impact of small room acoustic and psycho-acoustic control done right... We learn to listen... Our tastes are secondary like our gear pieces are secondary if they are well chosen gear to begin with and in accordance with our wallet...acoustic is primary for our understanding of sound... Saying the opposite is pushing people in the marketing trap of obsessive upgrading and entertain a universal ignorance about how good sound experience emerge in a specific room for our particular ears...
Also keep in mind that there exist a minimal threshold for what may be experienced as a good sound experience related to the S.Q./price ratio for the gear you own...One this treshold is reached and master upgrade are way less attractive...An improvement is ALWAYSpossible for sure but here the ratio S.Q./ price plays for most of us... Acoustic cues and factors that may be and must be controlled : timbre, bass, dynamics, imaging, soundstage, LEV/ASW ratio, etc all these acoustical cues and factors will give us an OBJECTIVE number of "tags" and indexes all along the subjective road... Controlled Correlation between our subjectivity and objective installation is the heart of acoustic and psycho-acoustic learning experience and experiments...
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Tube parameters change significantly over their life. Put in a new tube it sounds like a different amplifier. It’s not the reliability that I had issue with, it was that I never knew whether my amp was operating at its best. I enjoyed it at the time. Pick what works for you. Superior sound is subjective. What you like someone else may hate. Many roads to the same place. |
Of course if you substitute the term reliability in place of measurement, that’s a fundamentally different argument. Without question I would choose high reliability compared to low reliability. But that wasn’t the point of this topic thread. Tube audio components are notorious for yielding poorer measurements as opposed to transistor audio components. Yet well made tube components are wildly recognized for their Very long lifespan/years of service with reliability. This is accomplished with their relatively comparative poorer measurements. So even here there is no correlation with test bench measurement and reliability/longevity as it regards tube equipment.
In the example above you would choose product A over product B. That’s fine. My point is those measurement do not ensure superior sound quality nor reliability. So I’m trying to determine where/what is the intrinsic advantage of bestowed by the better measurement numbers. Charles
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Rather than measures well, let's substitute reliability. Just for this example high reliability equipment works as designed every time and low reliability equipment only works 50% of the time. So wouldn't you want to move on from the equipment that has low reliability yet sounds superb? Why can't you have your cake and eat it too? @charles1dad I would take product A all other things being equal. |
I have lots of gear, no emotional attachment at all. It either does the job or it doesn't. I currently run 7 complete systems, the gear that doesn't cut it goes out to the garage system. I have a pair of Stereophile magazine class A rated speakers in the garage, they weren't cutting it so they were banished. Although I don't necessarily disagree with you. |
Interesting conclusion. Why would one want to move away "regardless of how it sounds " . For example if an audio product sounds truly superb yet measured poorly why on earth would one be motivated to move on to something else? The mere fact that it sounds superb renders the "poor measurements " irrelevant. It would seem logical that the poor measurements have zero bearing on the superb sound quality outcome. So I don't see why subpar measurements have any meaningful consideration if the audio product sounds fantastic. Perhaps it's just me but I don't follow the "move on" rationale. product A measures well and sounds well. Product B measures poorly and sounds well. Same listening outcome. What is the inherent advantage of the better measurements if they don't yield superior sound? Charles |
@atmasphere was kind enough to talk about this in detail in another topic. Paraphrasing, if the distortion is low at high frequency, then the issue you have described is not an issue. It seems many amplifiers have lots of negative feedback and they have low distortion at 20Khz. I don't think it is back in the day any more. There are lots of amplifiers on Stereophile and ASR that have very low distortion at 20Khz. Lower than this Rogue at almost any frequency. @onhwy61 people are emotionally attached to their purchases. I work in batteries. Look at how emotional people get in defense of internal combustion. I had tube amps in the past. They are neither good nor bad. They just are. I have no doubt it was less accurate but I still enjoyed it at the time.
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Back in the day amps strived for THD of .001. You can achieve that number by adding negative feedback, sometimes lots of negative feedback. But it turns out that amps sound better if negative feedback is reduced or eliminated. Just one example of a measurement that hurts sonic performance. |
Many great thoughtful comments above most of which I completely agree with. I will say that I have enjoyed several of the ASR vids. No, not a fanboy and his overall opinions on sound quality are to be taken with a grain of salt. I don't care what he is measuring I just find it interesting in the sense of a procedural exercise. Regards, barts |
@realworldaudio , I feel most of what you wrote is made up. I don't think you will be able to clearly articulate what is missing from the measurements and certainly not 95% of the things that are missing. Perhaps this is the issue. This sounds more like outrage mob mentality that reasonsed criticism. I am welcome to be proven wrong.
@realworldaudio I am still waiting for you to answer the above. You have not provided one missing measurement let alone the 95% missing you claim. You can do your own Google, I did. When you can list some of that missing 95% of measurements I will indulge your request.
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You are buying audio to listen to it, not to put a meter on it and measure it. Obviously how it sounds is the most important thing. In my own case I recently bought a Lindeman Limetree Bridge, even after it was lambasted by ASR, why, it sounded wonderful, it still sounds wonderful. It was lambasted for high distortion, well I doubt anybody could hear 10x the distortion or even a 100x the distortion it was criticised for. We are in the zone of analysis paralysis. ASR criticised the Bluesound Node similarly, there of hundreds of thousands sold and 99% of people are probably completely satisfied. There is a great story about washing machines (sort of) a well known speaker on product quality in the 1980's showed a slide to the audience with data from experts on washing machines. They concluded which was the best washing machine. He then asked the audience who owned a washing machine, he then asked them what they thought the best brand was, the outstanding vote was Maytag. Maytag was not the best according to the experts. At the end of the presentation he asked people who didn't have a current machine or were unhappy with their present machine what brand they would buy? Overwhelmingly they said Maytag. Because they trust the people that have got them, more than the people who measure them. Trust yourself and how it sounds to you, there is no one else who can predict that, no matter how many reviews or how many measurements. |
Not sure you are interested but the spuriae (peaks at certain frequencies) make the average number look worse than it is. You are just looking at the raw number and that isn't telling the whole story.
Links please. |
In other words, peaks or spikes that make the measurement seem worse than it is. In this case low frequency spuriae due to class D design. No reviewer, and I must have read a dozen reviews heard any issues in the lower frequencies, nor do I. We can go all night on this. Do you own or have you heard the Sphinx V3? No mater, either has Amir. |
It appears it does not get better from there. But if you happy with it it does not matter. I would be surprised if this was not audible in some manor.
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You would be totally wrong. If I heard any noise I would freak out. All my gear is dead quiet, I work hard to make sure it is. If it’s not dead quiet it gets repaired or returned. I hear zero noise from my Sphinx V3. 80 db were the peaks at certain low frequencies (Class D issues), but most of the noise was minus 100 db.
Yes, that is db down, it gets better from there. |
How do you measure in DB the addition of a piece of shungite+copper+graphene on my main comnputer router? It is my homemade "golden plate"...Or on the wall socket? 😁😊 These debates are ridiculous not because "measuring tools fetichists" are wrong, they are not even wrong... Like the "gear tasting fetichists" who at least use their ears...
The only meaningful measures in audio are CORRELATED with a listening impressions, it is called psycho-acoutic science... The rest is only a debate beween Amir and the designer of a Dac for example about a RESTRICTED set of measures and ABOUT THE DESIGN CONCEPTION not about his quality sound ... Because a Dac could have a sound PERFORMANCE only in a specific room with specific ears and specific system... And only acoustic and psycho-acoustic can USE the dac design in real time listening...
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Those are peaks. The total noise level from the power supply would be much higher. In 2022 that does not seem acceptable. Is it audible? I expect at high volume in quiet passages it may be. Now let's play devil's advocate. When it suits you you will claim -80db is not audible but if a cable was tested and it showed nothing at greater than -90db and Amir said that's totally inaudible then a 100 audiophiles on this site would be losing their minds. You can selectively accept the measurements you want especially when they are measuring the same thing.
I noted that ASR seems to measure THD from very low power to high power at several frequencies but it does not seem to be consistent for all products |
As a measurement standard most amps are measured at full power. That is where they perform the best in most cases. Although we don't listen at full volume, the measurements would make more sense if they were at a realistic level but you can't compare amps if you are setting output to some arbitrary level. |
