Master Thread: Are measurements Everything or Nothing?

[antcollinet]

New video is out by the scientific audiophile:

Interesting stuff is the suggestion of uncorrelated noise from 125 Hz to 7 kHz
Nice compromise between the 1000 Hz test Signal and real music.

I wouldn't give that video too much credence. The uncorrelated noise is not a characteristic of the amp, it is one of the test signals he uses. He uses cheap as chips meters for his measurements (no sort of spectrum analyser, nor even an oscilloscope) which are not even true rms, and hence unable to correctly measure the test signals he is using. Further he doesn't even know at what voltage level the test signal is. He just sends it to the amp and says, (not even thinking about amp gain) - "oh look, no power"

The rest of the video just seems to be the usual sighted listening blah blah.

 

[burkm]

This really calls into question the validity of the originator's name "Scientific Audiophile"...

 

[Basic Channel]

[Edit: recommendations for products that ‘punch above their price point’ are all part of the same mental model: that there is a sound quality that you can get at each price point, and as the price goes up, the sound quality you can buy goes up, but you get ‘reach there’ for less by buying ‘bargains’.]

I agree with you but on this last point, it could also be motivated by the knowledge that there is a lot of diminishing returns. We all accept some correlation between price and what we get. An IEM for 20 EUR is not that shocking. A decent floor standing 3 way speaker cannot possibly be 20 EUR.

 

[peng]

I wouldn't give that video too much credence. The uncorrelated noise is not a characteristic of the amp, it is one of the test signals he uses. He uses cheap as chips meters for his measurements (no sort of spectrum analyser, nor even an oscilloscope) which are not even true rms, and hence unable to correctly measure the test signals he is using. Further he doesn't even know at what voltage level the test signal is. He just sends it to the amp and says, (not even thinking about amp gain) - "oh look, no power"

The rest of the video just seems to be the usual sighted listening blah blah.

No wonder there are so much hearsay, misconception etc., all over the internet. There are too many such YT stuff propagating them on daily basis, sad!! I guess all those Youtubers need to make a few $, or more, is to get enough people to click on such videos, whether they could recognize such contents are helpful or not.

 

[welwynnick]

I already run a test to cover what is happening here. From the review:

Look at the line in orange. it is the response at 20 Hz. See how it clips earlier. Almost every amplifier I have tested does the same thing. For a while I was noting the max power at 20 Hz.

Above is why I say you need more amplification power than you may think you do. This has nothing to do with Class D vs others. Simple fact that most music energy is at 40 Hz where speaker response is weak. So you need a lot of power to push that response to your ears.

Sorry I'm so late to this party, I never saw this until today, and a very strange thread it is.
I'm not going to say anything about the Scientific Audiophile beyond what's already been said.
With the Fosi V3 playing music into speakers, SA saw a power drop between 50 and 150 Hz in his SPL vs Freq measurement.
However, while most people accept Amir's explanation, I think it needs a closer look
Firstly, the power shortfall that Amir measured is at 20Hz, whereas SA measured no drop at 20Hz - the shortfall was above 50Hz.
Secondly, Amir's measurement shows a shortfall over a THD+N range of around -60 to -80dB, but virtually none at -40dB.
Thirdly, the worst case power shortfall is about 20 or 30W - just 1-2 dB down from maximum power. SA measured a shortfall of 10-20dB!
Maybe the Fosi does indeed lose a TON of power at 100 Hz (unlikely), or maybe its a speaker load problem (even though the impedance appears to RISE at around 80Hz)?
Suppose it's the latter, and the Fosi doesn't double down, it can't supply any more current and it's output voltage drops. The power might drop 3dB, but surely not 20dB!
So it pains me say it, but I think SA is actually onto something here, and conventional measurements don't seem to capture it.

 

[allmanfan]

I’m not sure a headphone requires the same money or has as many variables as a car. A planar headphone build requires some magnets and a membrane. It’s mostly expertise and testing.

Unless it’s housing is made out of something incredibly fancy or required extensive testing, there’s no reason it needs to cost more than 200 dollars.

this seems to be the aim of most every discussion I come across on this subject...nothing should cost more than 200 dollars and there is some imaginary measurement that declares a HP or component proper...price surely doesnt determine good or bad up to a point but as one who has and has owned many inexpensive HP's and expensive HP's I can say quite surely that the expensive HP's outperform the 200 dollar ones...just as more expensive amps do irregardless of measurements...an inexpensive amp cannot possibly have a similar power supply etc or internal components...do we believe 200 dollar speakers are the equal of 50k speakers?It is very true that a 10k speaker might outperform a 20k speaker but a 200 dollar speaker simply will not...

 

[Mart68]

s...an inexpensive amp cannot possibly have a similar power supply etc or internal components...do we believe 200 dollar speakers are the equal of 50k speakers?It is very true that a 10k speaker might outperform a 20k speaker but a 200 dollar speaker simply will not...

Agree with the general point you are making but there are some very bad $20K speakers out there and I could think of a few $200 speakers I'd take over them any day.

Also you can find expensive amps that couldn't drive the skin off a rice pudding. I'd never take higher price as a guarantee of better.

 

[BDWoody]

I can say quite surely that the expensive HP's outperform the 200 dollar ones...

do we believe 200 dollar speakers are the equal of 50k speakers?

With speakers and other transducers, you can't characterize them as fully through measurements, although that is getting better. What you can't just assume is that higher priced items are automatically better, as you seem to be saying here:

just as more expensive amps do irregardless of measurements...an inexpensive amp cannot possibly have a similar power supply etc or internal components...

More expensive than what, and why do you believe that there is this direct correlation? Do you have a technical background, or are you just repeating 'common knowledge?'

Ignoring measurements to buy based on price tag has to make you popular at your local hi-fi shop.

 

[NTK]

The problem with SA's test is that he should have recorded the amplifier output (the electrical output) to the speakers during his tests. It is so much easier and informative when you have the record of the actual electrical signal sent to the speakers, so that you can analyze it whichever way you want afterwards to see what had happened. Without the record of the signal, all anyone can do is speculation.

 

[voodooless]

an inexpensive amp cannot possibly have a similar power supply etc or internal components

That’s where engineering comes in. Actually thinking about design and using knowledge to make a well performing product, instead of throwing money at the problem.

If we can have a speaker amp with 150W for €200 including a power supply, then it should be no issue getting one for a headphone amp. The measurements show how well it works.

an inexpensive amp cannot possibly have a similar power supply etc or internal components

They don’t have to be similar, they just have to perform similar.

 

[allmanfan]

clearly there will be aberrations but in general for the same reason that a 75k car is likely to be better than a 20k car a 20k speaker will be better than a 200 dollar speaker all things being equal..obviously..but if a 200 dollar speaker is all you need or can afford thats perfectly fine and I am not trying in any way to denigrate it....certain things simply cannot be changed or overcome..I buy based upon what I hear not measurements or cost but lets be honest a 200 dollar speaker cannot possibly have the impact, soundstage,bass etc that a 50k speaker can...and again I do not say price is the only arbiter but components and parts do cost money...research and development does cost money etc...if somebody wants to argue with me that a 200 dollar bookshelf speaker or a computer speaker can equal a TOTL 50k speaker,well good luck

 

[Purité Audio]

I would judge components primarily on their performance rather than their price,
Keith

 

[allmanfan]

I would judge components primarily on their performance rather than their price,
Keith

sounds great but there are some things that simply cannot be replicated in a 200 dollar bookshelf speaker vs a 50k speaker...

 

[antcollinet]

So it pains me say it, but I think SA is actually onto something here, and conventional measurements don't seem to capture it.

I very much doubt it. My experience with SA is he doesn't have the best understanding of how to properly carry out good quality measurements.

in this case he seems to be measuring in the audio domain with a microphone. As pointed out by @NTK, a fundamental mistake compared with measuring electrically at the speaker terminals.

Lets give him the benefit of the doubt and assume he didn't move the speakers between tests. Are we confident there was no other movement of objects (including the person carrying out the measurements) in the room which might disturb the sound field and result in exactly this sort of change?

I, for one, am not.

EDIT : Further - he is comparing with an amp with significantly more power. He may well have driven the FOSI into current or voltage limit where the Yamaha was not.

Simply put there is nothing in the video to justify the extremely unlikely conclusion that they have discovered a test that shows something unknown by the very many competent engineers present here on this forum.

 

[Purité Audio]

Really I would use measurements and specifications to compare rather than price.
Keith

 

[BDWoody]

sounds great but there are some things that simply cannot be replicated in a 200 dollar bookshelf speaker vs a 50k speaker...

Which no one is claiming.

Are you interested in participating in good faith, or are you just here to tell us how dumb we are?

 

[voodooless]

I’m pretty sure some 200 dollar bookshelves will sounds loads better than some 50k dollar ones…

 

[welwynnick]

Simply put there is nothing in the video to justify the extremely unlikely conclusion that they have discovered a test that shows something unknown by the very many competent engineers present here on this forum.

I think you over estimate the engineers on this forum.

No-one questioned Amir's explanation.

 

[voodooless]

I think you over estimate the engineers on this forum.

Well, why not start by debunking the arguments made instead of handwaving..

No-one questioned Amir's explanation.

So go for it…

 

[Newman]

clearly there will be aberrations but in general for the same reason that a 75k car is likely to be better than a 20k car a 20k speaker will be better than a 200 dollar speaker all things being equal..

“…all things being equal”…??

Look, no-one would deny the potential for a higher price point to permit better engineering and performance. But the proof is in the pudding, and carefully conducted listening experiments have shown that the link between speaker price and listener preference for the sound waves is effectively broken.

For electronic components, the correlation is truly terrible, and the biggest single reason for that is how easily and cheaply electronics can exceed the limits of human hearing and become effectively audibly transparent. Further money spent purely for sound quality is largely waste.

For speakers, there are two big issues that tend to break the correlation.

1. It isn’t very expensive to make speakers that closely conform to the frequency and dispersion characteristics that carefully conducted experiments have shown to be preferable to the vast majority of listeners.
2. In general the money put into engineering big dollar speakers is put into delivering big SPL. That doesn’t make them sound better, once you have spent enough to get the SPL that you realistically need.

All too often, we see expensive speakers with worse correlation to Issue 1 above than many much cheaper speakers. They won’t sound better. As for SPL, a pair of $500 satellites with a good $800-$1000 subwoofer can usually deliver all the SPL needed in a domestic room without objectionable distortion. More money spent on even more SPL, to what end?

obviously..but if a 200 dollar speaker is all you need or can afford thats perfectly fine and I am not trying in any way to denigrate it....certain things simply cannot be changed or overcome..I buy based upon what I hear not measurements or cost

If you are unfamiliar with the science of human perception, then it may come as a surprise that “what you hear” in uncontrolled listening scenarios is often not in the sound waves at all, and actually dominated by your perceptual biases (which are complex and another topic). Therefore, if you actually want to know “what you hear”, then you need to conduct controlled listening tests that are controlled for non-sonic variables.

but lets be honest a 200 dollar speaker cannot possibly have the impact, soundstage, bass etc that a 50k speaker can...and again I do not say price is the only arbiter but components and parts do cost money...research and development does cost money etc...if somebody wants to argue with me that a 200 dollar bookshelf speaker or a computer speaker can equal a TOTL 50k speaker, well good luck

You have picked such an extreme example. But if you lift the low price to about $1.5k and look at Issue 1 and Issue 2 above, it all starts to fall apart.

cheers