I've done ABX tests multiple times, and the vast majority of the time AAC at 200+kbps was indistinguishable from the source (CD WAV), and even 128kbps was fine for a lot of tracks. That said, one or two tracks tripped up the encoder and could reliably be distinguished even at 320kbps (IIRC 20 trials with 100% success rate). Not enough that I'd notice in casual listening, but the difference was audible.

You also need to use a decent encoder - I compressed a video using Handbrake with a 256kbps AAC audio track a few months ago (faac/Windows), and noticed immediately that the audio was bad (I initially assumed the source was bad, but the FLAC track in the source sounded fine). Replaced it with a 192kbps AAC track using Quicktime/OSX and the quality was significantly better.

Yes, ALL lossy codecs have some "killer samples" -- the source material always matters.

It's a sad fact that there are so many sub-par AAC encoders around. Best to use either Apples implementation, or either of those from Fraunhofer -- FhgAAC (free version distributed with Winamp), or the Open Source FDK-AAC that was developed for Android.

opusenc is quite decent, and not patent encumbered unlike AAC encoders.

Yes, Opus is fantastic -- been following it's development since the start due to Telecoms background.

For those of us that care and have software that plays it, it's great but AAC is still the next best thing for compatibility on a wide range of devices (whilst still beating MP3 for sound quality and file size) which makes ad-hoc sharing with non-techies possible.

Hopefully that will continue to improve as it grows in popularity.

For sharing, it's better to use FLAC originals anyway. For playback - Opus is supported by Rockobx, which is useful on Sansa players if you need something very portable (that's what I use sometimes), and is supported on Android too. On desktop systems it's not an issue. Any decent cross platform player can play Opus.

If you had done such blind tests, you would have reached a different conclusion. Or, in the alternative, your hearing is orders of magnitude "better" than anyone else ever tested.

I think you're confusing lossless vs lossy with 192khz vs 44.1khz - in that case I agree with you, no percievable difference.

I can also hear differences between lossless/lossy encodings. If I tweak encoding parameters until I don't notice a difference, there is usually no real space saving afterwards - so why not go with lossess instead?

I'm not confusing these matters. I'm specifically talking about lossless vs lossy. The key point is I'm taking about nominally transparent lossy which for codecs like AAC and Opus is around 160-256 kbps depending on the listener. Even at 256 kbps, that's anywhere between half and quarter the bitrate of FLAC. (Which has an average bitrate around 700 kbps but can swing wildly up or down depending on the specific material.)

Blind tests comparing lossless against what codec at what bitrate? How many runs and how often were you able to correctly identify lossless?

Audiophiles believe a lot of things with no evidence. How else could you sell them cables costing thousands of dollars? Reminds me of homeopathic medicine. The only reasonable use case for FLAC is archiving music you expect may need to be reencoded later.

Firstly, on a personal note, I must say getting heavily downvoted on a factual statement and not an opinion is a new and confusing experience for me.

My comparisons were made several years ago using LAME 320 CBR, LAME VBR, OGG, lossless (WAV) 16bit 44.1kHz and lossless (WAV) 16bit 48kHz. I believe at least most professional musicians and sound engineers would be able to identify the difference between all of these; while they might not always be "worse", their sonic character is certainly different.

FWIW I didn't downvote you and I don't think you should be downvoted, but as sjwright points out, if you did indeed make all of these blind comparisons and were able to reliably spot the difference between LAME 320 CBR and lossless and between 44k and 48k, and were able to hear the difference so clearly that you would find the lossy formats jarring or painful to listen to, then given all published research on this topic you would have to have superhuman hearing as most professional musicians and sound engineers in fact can not... so to put it very bluntly there's a concern that you might be selling bullshit.

Exactly. Given how much we know about psychoacoustics, and considering how often people who claim to hear dramatic differences end up failing the most basic ABX tests, it's just not a credible assertion without robust supporting evidence.

ABX tests are putting sensors and short-term memory under stress, while users are reporting about their long-term feelings about music. It's like trying to spot difference between fruits of same kind while consumers have problem with lack of a nutrient.

Why to bother with various tradeoffs if you can get the best?(i.e lossless). You can make the same argument on video technologies(i.e HDR). The truth is that people usually adapt so "painful" audio or video quality stops being painful after a while.

If it was even remotely painful, it would sail through an ABX test.

It may sail through months long ABX test.

Artefacts that can only be discerned after months of sustained listening? Sounds like you're clutching at straws.

Not an artifact, but loss of variance in music. Same patterns are activating same neurons, so they are tired.

I confirm that I feel myself tired when listening low-quality audio even when I cannot spot any audible problems with audio. It's bland.

I.e. I will definitely fail ABX test, but I still feel difference. IMHO, ABX tests are wrong tests for that problem.

If you will fail an ABX test then you don't feel a difference due to an actual difference in quality almost by definition. Maybe you feel a difference because outside an ABX test you know when you are playing lossless files? That's fine but it's not the same thing.

IMHO, lossy codec just removes some variation from music, so some nerves in ear are activated more often than other, so they are tired.