Stereophile's snide editorial on ASR and Amir

[lc6]

Here is an example of one (self-admitted) non-technical guy not being able to show a statistically significant difference between USB cables in two different blind tests, then making up stories of why that happened, and finally declaring that blind tests are as fallible as sighted tests and even as measurements since "stuff happens that we do not know, like a brain region lighting up on MRI when the subject is exposed to ultrasonic content" (scroll to 9:45 or so into the video):
Blind Testing USB Cables - A discussion of what went wrong

In another video, which I currently cannot locate, the same dude was comparing 16- and 24-bit recordings played by a DAC, captured by an ADC (RME, as I recall), than lining them up manually in Audacity software by eyeballing zoomed-in samples, inverting one of the waveforms, summing them up and, voila, Sting was playing in the difference signal. Which is exactly what I believe @amirm was talking about when he discussed the need to sync the DAC and ADC clocks, normalize volume, and use software like DeltaWave to automatically time-align captured signals at the subsample level.

The moral of those stories: an "objie-wannabe subie" with tools but no in-depth knowledge is actually more misleading than a plain "poet subie" without tools. Unfortunately, tools are becoming more affordable, so if the current ASR-inspired trend to include "measurements" in "subie" reviews continues, we can expect "subies" to make even more damage.

 

[tmtomh]

Ayn Rand is bad.

Now there I agree with you 100%. Whenever I use the term “objectivism” here or on other audio forums, I cringe a little because I’d never want anyone to think I associate myself with that awful pathology.

 

[hvbias]

It was those kind (simple-minded objectivists) who put the new James Webb telescope up there in its stable position.

The funny thing about this is the number scientists I know (more physicians though) that are subjectivists, when it comes to audio

Sometimes you don't really want to live your work life outside of work.

 

[mhardy6647]

Sometimes you don't really want to live your work life outside of work.

QFT, as they say

 

[restorer-john]

Can we start a donation campaign here - pool our money and buy the squarewavereview.com

You'll have to make me an offer for that domain first!

 

[Mr. E. Guy]

The funny thing about this is the number scientists I know (more physicians though) that are subjectivists, when it comes to audio

Sometimes you don't really want to live your work life outside of work.

The proverbial plumber with the leaky pipes

 

[captainbeefheart]

This is because identical spectra can be produced by different types of IMD (amplitude and phase modulation), and those sure sound different.

What hifi amplifiers have you tested and found phase or amplitude modulation?

 

[hvbias]

The proverbial plumber with the leaky pipes

Is this a euphemism, because I think there would be more than a few plumbers with, erm "leaky pipes"

 

[theREALdotnet]

What hifi amplifiers have you tested and found phase or amplitude modulation?

Now there’s a good question. How would we even know? How would we investigate the nature of IMD? All we see is a % figure or some other quantitative measure that we arrive at by adding up the distortion spikes in a spectral plot of the multi-tone test. We can tell it’s there, and we can tell how much of it is there, but we can’t tell whether it’s the bad or the worse kind.

 

[Palladium]

Ah yes and of course, we should definitely heed and respect those with very clear conflicts of interest.

 

[JSmith]

I know that you believe

JSmith

 

[Deleted member 21219]

We can tell it’s there, and we can tell how much of it is there, but we can’t tell whether it’s the bad or the worse kind.

First we would need to define what is the "bad" kind and what is the "worse" kind. Then, and only then, could we progress to the next step. Jim

 

[MarkS]

It's only "bad" or "worse" if it's audible.

And it is very easy to test whether or not it is audible.

All that is needed is to listen to it, without knowing what it is, and then deciding if the sound is "bad", or not.

Easy-peasy.

They do this at Stereophile every day, except that they skip the part about not knowing which amp (or whatever) is in use.

 

[Blumlein 88]

View attachment 219845


JSmith

Not any more. Elon Musk's Roadster smashed it to bits. That is why you'll never be able to prove it now.

 

[Deleted member 21219]

It's only "bad" or "worse" if it's audible.

And it is very easy to test whether or not it is audible.

All that is needed is to listen to it, without knowing what it is, and then deciding if the sound is "bad", or not.

Easy-peasy.

They do this at Stereophile every day, except that they skip the part about not knowing which amp (or whatever) is in use.

Jim

 

[bkatbamna]

The funny thing about this is the number scientists I know (more physicians though) that are subjectivists, when it comes to audio

Sometimes you don't really want to live your work life outside of work.

Physicians and scientists are human and have character flaws. There have been so many articles that have been withdrawn due to shenanigans by the researcher.
The fact that stereophile took a swipe at ASR tells me that they are afraid. Elephants don't care about dogs barking.

 

[theREALdotnet]

First we would need to define what is the "bad" kind and what is the "worse" kind. Then, and only then, could we progress to the next step. Jim

Well, we know they can sound very different. Which is worse might be in the ear of the beholder. I suppose of the two sample I linked earlier most people would agree on which is the less bad.

The point is, spectral plots or other conventional methods of measuring THD don’t give us the required information. They treat all distortions as equal.

 

[Bruce Morgen]

Engineering is applied physics.

It can also be applied chemistry, e.g. chemists working in some industries have the title "chemical engineer." Computer programmers are called "software engineers," yet they don't need to know anything about the physics behind the hardware for which they code -- and only at the very deepest level, e.g. operating system kernels and device drivers, do they even have to know about the architectural details of the hardware platform for which they code, let alone the physics of the components that allow that platform to function.

 

[Audiofire]

The point is, spectral plots or other conventional methods of measuring THD don’t give us the required information. They treat all distortions as equal.

My impression is that waveforms, spectrograms and REW comparison through a transparent audio interface will give all the required information about how transparent a power amplifier or preamplifier is to music. A voltage divider is used for a power amplifier in order to bring the voltage down to line level.

If there is something else to measure for sound quality, except for loudspeakers, headphones, microphones and acoustics, then I know nothing about it. Stereophile should be interested in knowing about this too and making measurements with an audio interface, it's a trivial magazine until they do that.

 

[captainbeefheart]

Now there’s a good question. How would we even know? How would we investigate the nature of IMD? All we see is a % figure or some other quantitative measure that we arrive at by adding up the distortion spikes in a spectral plot of the multi-tone test. We can tell it’s there, and we can tell how much of it is there, but we can’t tell whether it’s the bad or the worse kind.

I would think if it's there and effecting the sound it would be quite obvious no?

Same goes for testing, say amplitude modulation, input sine wave and look at output on a scope. If it were audible you should see the amplitude not constant, when the signal gets larger the modulation frequency is in the positive cycle and when smaller the negative cycle. Possibly set up a simple diode detector with cap and resistor and view output of detector for the modulation signal?

Frequency and phase modulation would be trickier to test but if really bad when viewing the output on a a scope the sine wave would increase/decrease horizontally just as if you were adjusting the horizontal time vernier when viewing a constant sine wave. As the modulation frequency is going positive you would see more cycles of the waveform and as the modulation frequency is going negative you would see less cycles.

Phase modulation would be easy since when finding the amplifier breakpoints to calculate the feedback compensation networks it would be nightmare, the results would be all over the place as phase is constantly being modulated tipping you off something is wrong with the circuit. Or a phase comparator maybe? Two inputs and one output: a reference signal is applied to one input and the phase or frequency modulated signal is applied to the other. The output is a signal that is proportional to the phase difference between the two inputs.

Personally I would think it would quite difficult for there to be these anomalies in a regular audio playback amplifier circuit that is functioning correctly with no oscillations. If there were one of these issues present it would be quite audible which would tip you off something is wrong.

This goes back to why I don't think it's relevant for music playback amplifiers and FFT's will show us what we need to know with no hidden extra anomalies lurking about.