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Comment by lz400 | Hacker News Reader

As far as I know, people consistently fail to tell the difference in blind A/B tests in listening between (any decent) FLAC and a well ripped mp3 from the same source. I know I can't. I can't link to proper double blind studies but that's the general consensus in the non-BS-audiophile community as far as I know.

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My anecdote is that I've done a number of these tests (Foobar has a plugin that allows you to do them on yourself), and I can reliably tell the difference between FLAC and 128 MP3, but can't tell the difference on 256 MP3 and up.

Yes, I've heard people putting the threshold in ~192kbps. Above that it's pretty much impossible these days. I can also tell the difference in 128kpbs, although sometimes it's a bit of nitpicking (can only hear differences in the sounds of hihats and things like that)

I think the type of music you are listening to assists with being able to differentiate. To me (much rock, blues, guitar music) 128kbps MP3 sounds like somebody chewed it first. Cymbals and bizarre snares that sound like the snare is now made of paper indicate the low bitrate.

But 256+ and I certainly cannot tell the difference reliably.

When I was considering Tidal vs. Spotify in the past, I ran across the ABX tests here:

http://abx.digitalfeed.net/list.html

Pretty much found the same thing for myself at 256+.

I had satellite radio for a while but had to cancel it because I couldn't stand the sound of cymbals at whatever bitrate they encode at. Weirdly, when the phone operator asked why I was cancelling and I told him "audio quality" he acted like he had never heard that before.

I'm not an audiophile at all but satellite radio sounds worse to me than anything other than AM/FM radio. Spotify over LTE and Bluetooth sounds night-and-day better.

The same in electronic music since there are many repeating sounds. 128kbps just sounds bad, especially on a proper sound system.

Any serious club system can produce peaks waaaaay hotter than 120db, cleanly. Especially horn loaded systems like most anything on the high end these days. Horn loaded PA speakers can give you perfectly clear peaks at absurdly high amplitudes, cleanly. We don't hear peaks, we hear RMS volumes which are invariably at least 6 db down from the peak if not much more (classic rock routinely has peaks 30 db over the 'body' of the sound as expressed in RMS loudness). This easily raises the grungy one-bit noise floor level of 16 bit CD audio up into the plainly audible, and as for any lossy-encoded format, forget it: an order of magnitude worse.

CD quality is the very least you could want for a serious big club or theater system (much less auditorium). Between peaks and the requirements for deep bass, the peak in a digital audio file is (a)much farther above the body of music than you'd think, and (b) should never be reached, because that's clipping.

People routinely behave as if the theoretical maximum dynamic range of a Red Book CD is relevant to anything. It's incredibly easy to play back music loud enough that the noise floor will get obnoxious and relevant to listening, it's only 96 db down. Any small system in an enclosed live space can push louder than that. Cranking music over headphones will blow way past that and you won't even hear the peaks, but you'll be able to hear how bad the subtleties (or lack of same) on 16 bit red book CD are.

Electronic music, especially live, is totally relevant to high resolution audio. I more than suspect some of the big name acts (for instance, Deadmau5) are using converters to the mains running at not less than 24/96. Certain synthesizer mixes are very revealing of faults in the playback. If the live performance over a modern PA sounds absolutely huge and awesome, but not strained or grainy, then they're not using CD quality. The SPLs are more than enough to make these distinctions obvious.

Anyone can get these SPLs over headphones, trivially, and headphones that'll handle it cleanly are only a few hundred dollars.

Doesn't this mean going past the 85 dBA limit in headphones? That's instant hearing loss.

I only ever recall finding one track where I could hear differences in bass soundstage / positioning on 256+ mp3, vs. uncompressed 44/16, back when I was using stereo subwoofers in a heavily acoustically damped room. Even then, I could only tell when abx'ing.

You can't tell the difference on the vast majority of music. But encoders occasionally mess up, producing an audible difference. In the case of MP3 this often takes the form of a pre-echo. For example encoding cymbals and hapsichords seems to be difficult, though much less of a problem than it used to be. My understanding is that such killer samples exist for good MP3 encoders, even at 320kbit/s, but it has been a couple of years since I last looked into the topic.

(Personally I downloaded some of those killer samples and couldn't tell the difference, but other people reliably tell them apart in an ABX test.)

c't magazine did a test all the way back in 2000 (see https://www.heise.de/ct/artikel/Kreuzverhoertest-287592.html) and even the best test listeners were unable to tell 256kbit mp3 and the original apart.

Was this the Arny Krueger stuff? I did that.

I ABXed 320kbit mp3 from an uncompressed original, I think 9/10 IIRC. It was a recording of castanets, and listening for frequency response differences was useless so I keyed off of 'personality' differences in the sounds and did it that way.

I was also just as horrible at detecting wow and flutter, as I was good at detecting lossy compression 'changes of sonic personality'. Comes from my experience being with analog audio, which is less true of people these days.

The idea that 'the best' listeners cannot tell 256k from even something as limited as 16/44.1 is ridiculous. Any mp3 format… any lossy format… is seriously compromised. Talk to techno/house DJs and producers about how useful it is to perform off mp3s, this is not a hypothetical argument.

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