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Comment by TheHideout | Hacker News Reader

When I was at Berklee [0] we had considerable ear frequency response training that would involve weekly hearing quizzes where they would boost/buck certain frequency bands of either pink noise or music and you had to pick out which band was made louder or softer. Additionally, we had a quiz where you had to listen to lossless vs mp3 at different bit rates and determine which was which. We also did neat things like trying to pick out what type of guitar and pickups someone was using in a recording simply by ear.

320 kbps mp3 vs lossless 16bit WAV (cd quality) is extremely difficult to hear the delta without training, but if you know what the source instruments are supposed to sound like, such as hats and you can focus on their frequency band, you can hear compression artifacts and comb filtering.

This course really changed how I take in music and sounds in general.

[0] https://online.berklee.edu/courses/critical-listening-1

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I was hoping the course you recommend would be available for the general public, but at >$1000, this is a no go. I would happily pay for something like this, but not this much. Can anyone recommend an affordable equivalent?

https://pae.izotope.com/ is a good resource

Harman Audio created a free "How to Listen" application years ago for both Mac and Windows, which "consists of a number of training exercises where different kinds of timbral, spatial and dynamic distortions commonly found within the recording and audio chains are simulated and added to music." It isn't about MP3 compression specifically, IIRC, but it's a good critical listening course.

But: while it's still available, it's about ten years old, and I have no idea if it still runs on modern hardware.

http://harmanhowtolisten.blogspot.com

There's a $8 or so app called hearEQ that trains you on the pink noise or music part of this I think.

So what are the characteristics of has that make them noticable? Would it high-freqency almost random noise?

I think of how mpeg video cannot accurately portray looking at a rippling lake.. the sinusoidal motion does not have much in common with blocky mpeg.

Audio has its own equivalent. It's not noise, it's more of a gargly quality. You can hear it very clearly at more extreme compression settings.

The overtone movements become disassociated and start splitting up into disconnected sine wave blocks. Transients also become softened.

With MP3s this is obvious at the high end, while lows/mids sound passable. The compression algorithm has more frequency bins at the high end, so the damage is more obvious there.

There's also a loss of low-level detail. Reverb tails lose definition, and the music loses front-to-back depth.

Which headphones/speakers would you recommend/do you use?

In my experience I will hear a shimmering effect that sounds like a tremolo where the volume of the hi-hats and other cymbals are fluctuating. It also causes the overall sound of cymbal crashes to be mushier and less distinct. In addition I've noticed an effect where certain sounds such as the attack of high-gain guitar is stretched and doesn't sound consistent throughout a song. It seems like these artifacts are most noticeable in higher frequency ranges or perhaps transients.

There's something about the really low tones that simply... changes at lower bit-rates. High-frequency tones are somehow clearer when uncompressed. It feels like the tones are right, but the waveforms distorted. Your rippling lake MPEG analogy is pretty much spot on.

That being said, age, tinnitus and amazing progress within the audio compression sciences have made it more difficult for me to separate uncompressed WAV and 320 kbps MP3, though the 320 kbps files in the article had noticable artifacts in most cases.

does it ruin your appreciation for great music in lower quality formats?

Not OP, but just a random ex-audio guy who did his fair share of listening experiments with different formats and bitrates.

FWIW, it had the complete opposite effect on me. I stopped caring about things like flac or other lossless formats for general music listening.

If the only way to maybe sometimes pick out a 320kbps mp3 from a flac one was to be on my best headphones, in my quietest room, focusing all my attention... the difference doesn't matter for practical listening. My ears may just be garbage, but it made me skeptical of people who make bold claims about what minutia they can discern -- although magical claims are more prevalent in the audiophile world ("these cables sounds great!") than the actual audio production world.

Not an audio professional but I'm the sound guy for a nonprofit.

Along similar lines, I can't tell the difference between a $250 microphone and a crazy expensive mic in anything but ideal conditions -- and even then, I need to hear them side by side.

+1; there are so many more important factors before the smaller things start making a very noticeable difference. A Neumann U 87 into a 1084 or VoxBox will sound marvelous with good talent giving a great performance, but that performance would still sound damn good with a $100 Shure SM57/58 into a Focusrite interface costing about the same. It’s never been easier or cheaper to be able to make music that’s good enough to get plays on Spotify.

Buying a Ferrari won’t make you Michael Schumacher, but he could probably lap your car round a track faster than you ever thought possible.

+1, I think for those with even a little musical background, the brain fills in the details to a much greater extent, especially if it’s something you’ve heard before on a good signal chain / live. You know what’s there, so you know what to listen for, and your brain kinda just interpolates the rest.

This is not my idea btw, I read it somewhere, just forgot where I read it. Googling a bit around “musician audio quality ‘fill in the gaps’” didn’t ring any bells. I’ve been reading up on acoustics and audio engineering over the past year trying to get my personal music project together, so it may have just been from a book as well.

Psychoacoustics and "perceptual audio coding" are the search terms you were looking for, here's a couple of links:

https://www.izotope.com/en/learn/psychoacoustics-how-percept...

https://www.i-programmer.info/babbages-bag/1222-mp3.html

http://www0.cs.ucl.ac.uk/teaching/GZ05/05-music-coding.pdf

>does it ruin your appreciation for great music in lower quality formats?

As someone that has high-end gear, I can absolutely tell the difference in most cases between 320kbps MP3 and lossless when switching between the two versions of the same song. It's hard to put a finger on, but it just "feels" different to my ears/perception. However, after listening to exclusively one or the other for a few minutes or not A/B switching the same song, I have a much harder time detecting the difference.

Quality of the master and quality of the equipment matter much more, IMHO.

Not at all, but I do have much greater appreciation for the time that sound engineers took to cram as much frequency information into the fixed size spectrum box using level variation, panning, parametric equalizing, and compression. All of those things we had to listen for and critically evaluate in that class.

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