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mmry404 OP t1_jd0222i wrote

Recently I became concerned with bit-perfect playback: does it make an audible difference?

TL;DR: it does, seems like, but difference is not huge and depends on the genre. Also, statistics are not very reliable and require further tests

For those not in the know: bit perfect playback bypasses OS's system mixer and delivers music to the DAC "as is", without resampling it to a system wide bit depth and sample rate. This should, in theory, sound better(?). Dedicated digital players (DAPs) usually have their system mixers disabled, but on computers and phones this presents a problem, even when using an external DAC: bit perfect playback requires the player software to connect to DAC directly, and not all players can do that. I was very skeptical that upgrading from lossless CD quality playback, albeit not bit perfect, would make a difference.

So, i conducted a blind test. I was comparing a Hi-Res bit perfect streaming service Qobuz and a CD quality non bit perfect service Deezer. Both services were running using their apps on a Xiaomi laptop (RedMi book pro 15 2022), which runs Windows 11. I used dongle iBasso DC05 DAC and Moondrop S8 IEMs. Qobuz was connected to the DAC using WasApi Exclusive mode, which should provide bit perfect playback. Deezer doesn't have that feature and was using system mixer. Windows was using iBasso in default mode, 32bit 48kHz. I matched volumes by ear. I hear frequncies up to 16.5kHz and have mild tinnitus when in a quiet room. I'm 26.

I created two similar playlists of 14 tracks and my GF played me each track on both services. Random number generator was used to determine which service is used to play the track first and which second. My goal was to guess, which service was used for each playback. I could ask to go back and forth between the services and to go to the next track. Most of the tracks on Qobuz were marked Hi-Res (24bit, from 44.1kHz to 196kHz), CD quality on the others (16bit 44.1kHz); and Deezer offers them all in CD quality. I mostly used tracks from my library, as well as some test signals and some jazz I haven't heard (cuz audiophiles love jazz for some reason?).

On busy math rock stuff (Delta Sleep, The Yacht Club) I couldn't grasp the difference and was frantically going back and forth, just to make a guess in the dark. On modern electronic tracks (i.e. Chivalry Is Not Dead by Hiatus Kayote) one playback sounded a bit sharper then the other, sometimes it had more bass. Every time I liked a playback a little more, I attributed that playback to Qobuz (well, it should sound better, right?). The difference was never obvious. Radiohead tracks sounded virtually the same. The American Beauty soundtrack, Arose, has these heavenly little bell plucks, which sounded more clouded during one of the playbacks. The test sounds seemed to be more revealing, as it seemed to me that one playback had somewhat more aliasing, especially on 14kHz tone. The test lasted about 40 minutes.

So, the results? I guessed the service correctly 10 times out of 14. I missed on both of my favorite math rock bands, but was correct on all the others, except for two jazz tracks that I haven't heard before. I guessed both test tones correcly. I think, I proved to myself that it is worth it to pursue bit perfect playback and maximum file resolution, although not for all genres. It seems like rock music doesn't benefit from it as much as, say, acoustic or electronic music.

I will conduct further blind tests to investigate more granular use cases (i.e. test tones only, and different tests for different genres) and to make the results more reliable.

Yup, I used the word "albeit" haha

UPD: Also, next time I will use an EV meter to set the volumes instead of by ear and make more test cases to rule out the probability of a random guess (as proposed by u/ultra_prescriptivist)

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ku1185 t1_jd08l4l wrote

After trying Tidal and seeing there are sometimes multiple copies of the same album (apparently, different masters, according to internet strangers), I no longer know if it's something with the service or if some of them are simply using different masters. Sometimes the different versions on Tidal sound different, sometimes they don't (at least, nothing that I could discern).

FWIW, I think Qobuz generally tended to sound better than Amazon or Tidal (though that album version thing throws a wrench into the whole thing).

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mmry404 OP t1_jd099lq wrote

Pretty much all the tracks I used come from modern albums that likely don't have many different masters. There was a track from Depeche Mode's Black Celebration in my playlist that had a different intro and was louder on one of the services, so I didn't use it. The usage of different masters cannot be accounted for, so it the tracks don't obviously sound different, I would assume same masters and just roll with it

And I also didn't want to try Tidal because of its crazy pricing and the MQA controversy

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ku1185 t1_jd0d5yi wrote

I don't think modern albums are exempt from this. Taylor Swift's Lover album was one I distinctly remember there being 3 different versions, with one of them sounding quite different. FWIW, I tested this on a non-MQA DAC.

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mmry404 OP t1_jd0dwnw wrote

That's kinda odd. I mean, being an artist, why would you put out several masters of your new album? Why is Tidal the only one to carry several masters? Is there a way to check that there are several different masters of a particular recording if I don't have Tidal?

Yeah, it never crossed my mind that having a non-MQA DAC eliminates the MQA issue, lol :)

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ku1185 t1_jd0fjem wrote

>That's kinda odd. I mean, being an artist, why would you put out several masters of your new album? Why is Tidal the only one to carry several masters? Is there a way to check that there are several different masters of a particular recording if I don't have Tidal?

No idea. Kind of just gave up on trying to figure out what was going on lol.

As for MQA, don't know if an MQA DAC would've made any difference. I never got around to testing it when I had MQA DACs.

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mmry404 OP t1_jd0ijvv wrote

There's a video by Golden Sound, proving that MQA is actually lossy, so an MQA dac sould probably just sound worse. Although it seems like more and more dacs are supporting it now... which in itself is a worrying observation that hardware manufacturers may be prioritizing marketing claims and fancy labels over performance. Ideally everything should be checked in a blind test, but these are cumbersome to carry out correctly. I'm just dipping toes into it..

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ku1185 t1_jd0lsk1 wrote

Yeah I'm aware of the video. My understanding of the tech (or at least, what is claimed) is that it stores information under the noise floor or something, and MQA hardware can "unfold" that information to generate a more complete reconstruction. Whether there's any audible benefit, I have no clue. Given all of the different masters on Tidal, it makes it difficult to determine whether the codec is actually making any difference or if its the master itself. So I just gave up trying to see if there's any real sound quality differences for MQA itself.

I think the biggest issue with MQA is false marketing claims and the proprietary nature of the tech. If they made more accurate claims that were verifiable and improved the listening experience, I wouldn't mind it.

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mmry404 OP t1_jd0mynl wrote

Indeed. The thing with marketing claims is that people need a deep technical understanding of the subject to be able to discern false marketing from real marketing, and it is just not feasible, since said marketing is addressed to the masses. And even with that level of understanding there is still a chance that something could be dodgy under the hood where we can't see. With enough critical thinking/paranoia it gets impossible to consume and be happy about it, so maybe it's the case that "the less I know, the better". Simulacra and simulation, all that..

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