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What are trained listeners actually listening to/for during an ABX blind test?

Sombreuil

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We've all tried to see if we could tell the difference between a lossless file and a lossy one and I was wondering (since I personally can't), what are we supposed to listen to/for? What does being a trained listener actually mean?
For those who are able to tell the difference, where to do you put your attention on? High/medium/low frequencies, voices, acoustic music or certain instruments that tend to reveal the imperfections, a potential distortion? Does age matter?
 

Geert

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We pay attention to identifying what exactly makes the difference ;)

It means you need to be able to breakdown a sound or track into its different elements and zoom in on them. A novice listener might hear a difference but might not know what to attribute it to, which makes it more difficult to detect it repeatedly.

A novice might for example find a certain track more 'transparant' but not link it to more sibilance or less bottom on a vocal, or a more aggressive snare sound. Expressing differences in vaque audiophile terms immediately gives away the expertise level of a listener.
 

Zoomer

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Interesting questions.
Amirm delves into this the following video
 

Frank Dernie

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We've all tried to see if we could tell the difference between a lossless file and a lossy one and I was wondering (since I personally can't), what are we supposed to listen to/for? What does being a trained listener actually mean?
For those who are able to tell the difference, where to do you put your attention on? High/medium/low frequencies, voices, acoustic music or certain instruments that tend to reveal the imperfections, a potential distortion? Does age matter?
My view is that if you can't hear a difference think yourself lucky.
No need to waste time learning to and no need to waste money chasing differences which are so vanishingly small only trained listeners can detect them.
Usually once you have heard an artefact you can't un-hear it and you are doomed :)
 

Geert

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No need to waste time learning to and no need to waste money chasing differences which are so vanishingly small only trained listeners can detect them.
Unfortunately lots of people still waste money on differences even trained listereners can't detect ;). "Trained people are strongly biased" ;)
 

DVDdoug

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We've all tried to see if we could tell the difference between a lossless file and a lossy one
Personally, I haven't tried that hard! If it "sounds bad" I'll notice but I don't want to listen carefully for a defect/artifact. I'd prefer to be "dumb and happy" enjoying the music. I grew up with vinyl and I hated the clicks & pops. It was especially distracting when it was my record and knew when that bad click was coming... I'd be stressed-out waiting for the click instead of enjoying the music. I don't want to experience the same thing with MP3s. (I mostly listen to MP3s in my car with an older iPod connected to the car stereo.)

A couple of times when listening to a ("high quality") MP3 that I ripped myself I've thought I heard a compression artifact. But when I went-back and listened carefully to the CD, it had the same "defect". I have occasionally heard poor-quality lossy files but it's not the kind of thing I normally listen to (except with cell phone calls).

and I was wondering (since I personally can't), what are we supposed to listen to/for? What does being a trained listener actually mean?
For those who are able to tell the difference, where to do you put your attention on? High/medium/low frequencies, voices, acoustic music or certain instruments that tend to reveal the imperfections, a potential distortion?
Any difference that you can hear! At high-quality MP3 settings the "last remaining" artifact seems to be pre-echo so that's what trained listeners listen for.

I'm not sure if pre-echo is only an issue with MP3 or if it's also a characteristic of other lossy formats. Pre-echo isn't audible (or maybe not as-audible) in every recording. There are "killer samples" that "break" the format and reveal it's weaknesses.

(since I personally can't)
You can at lower bitrates.

Of course at lower bitrates (more compression = more loss = lower quality) artifacts will be more apparent, and there will be other distortions, not just pre-echo. Like I said, I don't listen to low-quality MP3s but you can try it yourself. I assume the way to train yourself is to start with low-bitrate files that will sound obviously bad, and work "up" from there.

Does age matter?
For lossy compression artifacts, I don't think it's that important. There is a loss of high frequencies, but that's not the biggest issue. Listeners sometimes hear high-frequency distortion but they rarely hear/report a loss of high frequencies. The idea is, even if you can hear very-high frequencies as pure-tones in a hearing test, in the context of music the highest frequencies are masked (drowned-out) by other sounds.

The loss of high frequencies is the easiest thing to measure so people often use a spectrogram to "prove" the file is lossy, or from a lossy source.
 
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Sombreuil

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Interesting questions.
Amirm delves into this the following video

I always forget that ASR has now a Youtube channel :facepalm:, thanks for the link.

At high-quality MP3 settings the "last remaining" artifact seems to be pre-echo so that's what trained listeners listen for.

I'm not sure if pre-echo is only an issue with MP3 or if it's also a characteristic of other lossy formats. Pre-echo isn't audible (or maybe not as-audible) in every recording. There are "killer samples" that "break" the format and reveal it's weaknesses.


I didn't know that, thanks for the link!

I assume the way to train yourself is to start with low-bitrate files that will sound obviously bad, and work "up" from there.

I've done that but once I "reach" the 320kb/s mark (even 256 for most songs) it becomes imperceptible to me, which is completely fine.

For lossy compression artifacts, I don't think it's that important. There is a loss of high frequencies, but that's not the biggest issue. Listeners sometimes hear high-frequency distortion but they rarely hear/report a loss of high frequencies. The idea is, even if you can hear very-high frequencies as pure-tones in a hearing test, in the context of music the highest frequencies are masked (drowned-out) by other sounds.

The loss of high frequencies is the easiest thing to measure so people often use a spectrogram to "prove" the file is lossy, or from a lossy source.

Probably a dumb question but do closed heapdhones help then? I believe they tend to have more straightforward highs in general?
 

amirm

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Probably a dumb question but do closed heapdhones help then?
They do although I prefer IEMs as they really block noise and aid in detection of small impairments.
 

amirm

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I've done that but once I "reach" the 320kb/s mark (even 256 for most songs) it becomes imperceptible to me, which is completely fine.
It is hard for me too despite my training.

I should also note that training is not limited to hearing impairments but optimal way to take the test. Ability to loop small segments for example is very important as compression artifacts vary from moment to moment. You can have all the training in the world but if all you do is play one clip, then play the other, you may very well miss the differences.
 
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Sombreuil

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I see. It's kind of reassuring to know that even trained listeners need to loop some parts to notice a difference.
 

raistlin65

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My view is that if you can't hear a difference think yourself lucky.
No need to waste time learning to and no need to waste money chasing differences which are so vanishingly small only trained listeners can detect them.
Usually once you have heard an artefact you can't un-hear it and you are doomed :)

I agree.

If the goal is to become immersed in the music, I would like to see data that shows that experience is enhanced by training oneself to hear those tiny differences in DBTs. As you point out, the ability to notice flaws tends to disrupt the immersion experience.

So I am unconvinced that it would help for listening to music through one's gear. But I can understand how people who like to listen to their gear through the music might want to learn to do this.
 

gsp1971

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I've done that but once I "reach" the 320kb/s mark (even 256 for most songs) it becomes imperceptible to me, which is completely fine.

I have also participated in a lossless vs. mp3 experiment.
At 128 / 192 / 256 kbps mp3 vs. wav file (from CD), I could tell which one was which. At 320 kbps it becomes more difficult, to the point that I could not tell the difference 60-70% of the time, especially when listening to well recorded albums.

However, I still rip to flac as storage is cheap but I use 320 kbps mp3 files when listening in the car.
 

DavidMcRoy

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This is a very interesting topic. Having grown up in the analog age and having worked in broadcast TV audio for decades, I have become conditioned to listening out for any kind of egregious distortion first, followed by digital artifacts. A little hiss doesn’t really bother me, nor does loss of detail, particularly. I mean, I hear them, but they’re secondary concerns. The worst audio experiences I have these days has nothing to do with digital. Rather it’s things like distorted sound from mics, analog mic preamps, consoles, etc. that are in the master itself. And listening with headphones or IEMs can be torture because too many sins are exposed.
 

Roland68

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I wonder what these comparison or ABX tests are about.
Should the testers simply compare the sound of the devices, i.e. describe differences that have been heard?
Do you want the testers to recognize a specific device?
Or should the testers evaluate the sound of the equipment after that sound if the recording / instruments "right"?

When it comes to the latter, I always ask myself whether the testers have ever been to a concert (regardless of the music genre) and / or have heard instruments live before.
If someone doesn't know how instruments sound, how should they classify the sound of devices?
 
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