Why Audio Science Review's measurements are so different compared to other sources?

[Racheski]

The most common criticism of ASR, and one I agree with, is that Amir handed out a *lot* of negative reviews to amps/DACs that "measured badly" ...in ways that were just literally inaudible, even by Amir's own admission.

This is criticism that seems to be mostly unfounded to me. Can you provide an example(s) where Amir did not recommend the Amp/DAC, but all of the issues were below the audible threshold?

 

[pozz]

This is criticism that seems to be mostly unfounded to me. Can you provide an example(s) where Amir did not recommend the Amp/DAC, but all of the issues were below the audible threshold?

There are many. Just go into the reviews table and filter for all no recommendations. They all had other problems though, one of which could be an uncompetitive price.

Remember too that "audible threshold" isn't a single number given room noise, masking, the spectrum of distortion and playback level.

 

[Koeitje]

A lot of those guys make purchases based on advice and listening only. I remember trying that approach early on and then realizing the futility when confronted with 30+ possibilities at the store.

Many others will "half read" reviews and comments and so on. Pretty common thing. Anyone who really understands how to read graphs wouldn't say stuff like that.

Its so much more efficient to get a shortlist of speakers based on measurements and then start listening. Why bother wasting time on stuff you wont like anyway...

 

[Thomas savage]

A lot of the criticism ASR gets is unfair , plenty of misconceptions about amirm's motives too but I can understand why people react like that and tbh we deserve some of the flack we get .

We are not perfect, we don't always get it right but ASR represents a genuine attempt to shine a light in a industry that till now has largely got a free pass . Genuine and without commercial conflict.

Not too many can say that, so maybe folks can forgive our ills and be thankful we are here helping bring some accountability to the Industry and celebrating well engineered audio products . .. all for free and thanks to a great deal of time , effort and money from many of you.

We should just focus on us , making sure we are being as self critical and aware as possible while striving forward with confidence.

 

[Victor Martell]

I have always believe the issue is way simpler - I may be wrong, of course, but...

1) First of all, indeed measurements will show you that a device does and how well. Simple. When I used to test devices, we measured and if the measurements were within a tolerance spec, the device worked. Period. We were not looking for "musicality" or "empathy" or anything not measurable. The measurements show the device works and does what is supposed to do. Period.

I think I am preaching to the converted here, but because of my next statement, wanted to establish that indisputable fact, in case I am misunderstood.

2) That said, when it comes to audio I am a full on skeptic - specially of HUMAN HEARING, mine specially. That's why I did not care that much about the Yggy's glitch (and about Schiit measurements in general). I am skeptical that I could hear it. In fact I don't, because I am human, with fallible hearing and I admit it - have spent all my life trying to avoid Dunning-Krueger (and I believe I have fallen to impostor syndrome - but you know? that is better than having Dunning-Krueger).

So it all comes down to @amirm 's idea - there is always a technical narrative from magical thinking audiophile companies that can be extremely sophisticated and even technically accurate, including possible issues BUT they have never proved that those issues are actually issues. Let alone that they are... AUDIBLE.

v

 

[KeithPhantom]

I would like to ask ASR what they consider as inaudible. For example, defining 0 dBFS as the maximum level a signal can be reproduced in a system without clipping that device, if harmonics and IMD are -80, -90, or -100 dBFS down, which of these levels are audible and inaudible. Also, if possible, could you provide some kind of study which I can read and learn more about this topic.

I have some knowledge of the Fletcher-Munson curves and ear resonance gains (extremely important for headphones though), bit I would like to dive deeper in this aspect of audio and physiology. Thanks.

 

[SimpleTheater]

I would like to ask ASR what they consider as inaudible. For example, defining 0 dBFS as the maximum level a signal can be reproduced in a system without clipping that device, if harmonics and IMD are -80, -90, or -100 dBFS down, which of these levels are audible and inaudible. Also, if possible, could you provide some kind of study which I can read and learn more about this topic.

I have some knowledge of the Fletcher-Munson curves and ear resonance gains (extremely important for headphones though), bit I would like to dive deeper in this aspect of audio and physiology. Thanks.

Amir has said in many, many posts/reviews that -115 dB is the audibility threshold for trained, golden eared humans. Personally I've trained myself and can't hear anything below -85. That's total SINAD, meaning that multiple products in the chain will continue to add their distortion, so personally I want products that can get over -95, because between the source, pre-amp, amp will just add to the distortion chain.

 

[KeithPhantom]

Amir has said in many, many posts/reviews that -115 dB is the audibility threshold for trained, golden eared humans. Personally I've trained myself and can't hear anything below -85. That's total SINAD, meaning that multiple products in the chain will continue to add their distortion, so personally I want products that can get over -95, because between the source, pre-amp, amp will just add to the distortion chain.

Doesn't this threshold change with frequency, since the frequencies between 1 to 4 kHz are amplified by the ear by an average of 6 dB and a maximum of 10 dB (excluding outliers).

Also, as I asked, could you provide me with the evidence or the document supporting this? I would love to have a read on it.

 

[SimpleTheater]

Doesn't this threshold change with frequency, since the frequencies between 1 to 4 kHz are amplified by the ear by an average of 6 dB and a maximum of 10 dB (excluding outliers).

Also, as I asked, could you provide me with the evidence or the document supporting this? I would love to have a read on it.

My emphasis added.

"If our goal is to build transparent audio systems, there should be no audible distortion. If we keep the total distortion at or below the threshold of hearing (0 dB SPL), we can guarantee that it will be inaudible. When this level of performance is achieved, we are not relying on masking to hide the distortion. Instead, the distortion is inaudible because it is reproduced at levels that are below the threshold of hearing.

If we want to listen at 80 dB, peaks will reach about 100 dB. At this playback level, the distortion must be lower than -100 dB (0.001%) to absolutely guarantee that it is inaudible.

If we want to listen at 90 dB, peaks will reach about 110 dB. At this playback level, the distortion must be lower than -110 dB (0.0003%) to absolutely guarantee that it is inaudible."

SOURCE: https://benchmarkmedia.com/blogs/ap...preting-thd-measurements-think-db-not-percent

 

[Racheski]

There are many. Just go into the reviews table and filter for all no recommendations. They all had other problems though, one of which could be an uncompetitive.

Right, which is why I specified "all of the issues." Because the stereotypical criticism of this nature on other forums usually do not mention anything other than the measurements are inaudible. Price to performance/features, design defects, etc...these other more subtle aspects of the reviews are ignored.

 

[Thomas savage]

I would like to ask ASR what they consider as inaudible. For example, defining 0 dBFS as the maximum level a signal can be reproduced in a system without clipping that device, if harmonics and IMD are -80, -90, or -100 dBFS down, which of these levels are audible and inaudible. Also, if possible, could you provide some kind of study which I can read and learn more about this topic.

I have some knowledge of the Fletcher-Munson curves and ear resonance gains (extremely important for headphones though), bit I would like to dive deeper in this aspect of audio and physiology. Thanks.

https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

 

[Koeitje]

I would like to ask ASR what they consider as inaudible. For example, defining 0 dBFS as the maximum level a signal can be reproduced in a system without clipping that device, if harmonics and IMD are -80, -90, or -100 dBFS down, which of these levels are audible and inaudible. Also, if possible, could you provide some kind of study which I can read and learn more about this topic.

I have some knowledge of the Fletcher-Munson curves and ear resonance gains (extremely important for headphones though), bit I would like to dive deeper in this aspect of audio and physiology. Thanks.

https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

 

[KeithPhantom]

Where does the -120 dB number come from? I know it is a strict threshold, but I do not see how it relates to actual psychoacoustic results.

 

[Robin L]

Where does the -120 dB number come from? I know it is a strict threshold, but I do not see how it relates to actual psychoacoustic results.

The audibility of Psychoacoustic artifacts happens to be one of Amrir's specialities:

. . . During my time at Microsoft, as VP of Digital Media Division, I grew to manage a division of nearly 1000 engineers, testers, marketing and business development people. One of the groups I managed though was the signal processing team which produced audio and video compression technologies. Both of those relied on refreshing my knowledge of the core signal processing science back in college and learning a ton more about new domains like psychoacoustics. Formal and controlled testing was a part of that just the same. Through training, I became an “expert” in finding difficult audio distortions that many could not. This training is serving me well to this day in being able to pass audio objectivist challenges of blind tests of small distortions. . .

 

[KeithPhantom]

The audibility of Psychoacoustic artifacts happens to be one of Amrir's specialities:

. . . During my time at Microsoft, as VP of Digital Media Division, I grew to manage a division of nearly 1000 engineers, testers, marketing and business development people. One of the groups I managed though was the signal processing team which produced audio and video compression technologies. Both of those relied on refreshing my knowledge of the core signal processing science back in college and learning a ton more about new domains like psychoacoustics. Formal and controlled testing was a part of that just the same. Through training, I became an “expert” in finding difficult audio distortions that many could not. This training is serving me well to this day in being able to pass audio objectivist challenges of blind tests of small distortions. . .

Not enough, I am trying to find something with professional peer review. Remember, you don't trust the first good result, others have to be able to replicate it, but thanks for sharing this information.

 

[SimpleTheater]

Not enough, I am trying to find something with professional peer review. Remember, you don't trust the first good result, others have to be able to replicate it, but thanks for sharing this information.

The good news is you have answered your question from the original post. ASR is the real deal. You are now trying to figure out where the -120 dB is coming from, so I'm assuming you've accepted the -110 dB is audible to some people (as I posted and linked the source).

I'm glad you've moved on.

 

[Thomas savage]

Asking the right questions in the right threads a good start lol

 

[pozz]

Where does the -120 dB number come from? I know it is a strict threshold, but I do not see how it relates to actual psychoacoustic results.

120dB SPL is the threshold of pain. -120dB below that or 0dB SPL is the average for the absolute threshold of hearing in the most sensitive range around 3kHz to 4kHz. It translates to 20 micropascals of atmospheric fluctuation.

Edit: If you want to get really technical you can find sources that quote from 130dB to 140dB dynamic range for human hearing. This is because they raise the threshold of pain to guaranteed pain, which is 130dB SPL, and take the absolute threshold of hearing as -9dB in the most sensitive range. This is of course accurate, but that 120dB figure is an average which assumes 10dB swing in either direction from person to person, more going in the direction of insensitivity, especially with age. The bottom figure is also only possible in laboratory settings. In a real room you'd have a lot of noise across the spectrum (air conditioning, traffic and so on), but it's not unusual to have close to 0dB SPL in that same 3kHz/4kHz area.

Right, which is why I specified "all of the issues." Because the stereotypical criticism of this nature on other forums usually do not mention anything other than the measurements are inaudible. Price to performance/features, design defects, etc...these other more subtle aspects of the reviews are ignored.

Oh, you meant a completely unfair "no". I've never seen one of those.

 

[scott wurcer]

If we want to listen at 80 dB, peaks will reach about 100 dB. At this playback level, the distortion must be lower than -100 dB (0.001%) to absolutely guarantee that it is inaudible.

If we want to listen at 90 dB, peaks will reach about 110 dB. At this playback level, the distortion must be lower than -110 dB (0.0003%) to absolutely guarantee that it is inaudible."

There is no speaker on earth that will even remotely meet these numbers. At 90dB average SPL in an average listening situation you have the lot, THD, IMD, and FM.

EDIT - See Klippel for a lot of hard science on this.

 

[pozz]

https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

https://www.audiosciencereview.com/...-thresholds-of-amp-and-dac-measurements.5734/

The ASR hive mind in action.