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Topic: Bluetooth, transcoding and audio quality (Read 12488 times) previous topic - next topic
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Re: Bluetooth, transcoding and audio quality

Reply #25 –
I've been reading similar discussions in audiophile forums all my life, please let's not have them also in a post about audio codecs and bluetooth :-)

Has anyone compared codecs via bluetooth? Wavpack and especially Musepack (about 300kbps) are the ones I'm liking the most, but these are just impressions, I find it complex to find suitable samples and prepare an ABX test in those conditions, and I don't have a trained ear for that either.

Re: Bluetooth, transcoding and audio quality

Reply #26 –
Quote from: Chordeater on
I've been reading similar discussions in audiophile forums all my life, please let's not have them also in a post about audio codecs and bluetooth :-)

Has anyone compared codecs via bluetooth? Wavpack and especially Musepack (about 300kbps) are the ones I'm liking the most, but these are just impressions, I find it complex to find suitable samples and prepare an ABX test in those conditions, and I don't have a trained ear for that either.

I was tempted once but quickly gave up with the idea.
Firstly, Bluetooth doesn't mean much in terms of consistent quality. I mainly listened over LDAC, but I have no control over the bitrate, even if I try to force it. If you can control the environment, test is a bad idea. Other people also use SBC, APTX (which has many variants), AAC (which differs between iOS and Android), LHDC, and more. What scenario are you going to privilege? Would you test SBC because it's common to all Bluetooth transmitters, or would you avoid it because those who care about sound quality typically avoid this format?
Secondly, the purpose of the test wouldn't be clear. If a listener hears a difference between WV->SBC and MPC->SBC, is it due to the initial encoding (MPC or WV introducing audible distortion), or is the audible issue a result of the re-encoding process (inaudible transformation on first encoding triggering an audible issue on encoding in a secondary format)? How would you interpret the results?
Wavpack Hybrid -c4hx6

Re: Bluetooth, transcoding and audio quality

Reply #27 –
It certainly doesn't look like an easy task, different codecs/devices and little control over what happens internally. The whole bluetooth thing is crazy.

Quote from: guruboolez on

Secondly, the purpose of the test wouldn't be clear. If a listener hears a difference between WV->SBC and MPC->SBC, is it due to the initial encoding (MPC or WV introducing audible distortion), or is the audible issue a result of the re-encoding process (inaudible transformation on first encoding triggering an audible issue on encoding in a secondary format)? How would you interpret the results?

Yes, even if we consider the initial encoding (WV or MPC around 300kbps) to be transparent, there is an added problem, which is that the "reference" is a lossless file that also goes through the SBC/aptX codec, and is therefore also affected (perhaps in a different way) by the bluetooth chain.

Re: Bluetooth, transcoding and audio quality

Reply #28 –
AFAIK, there's isn't a ABX done for BT codecs on actual hardware. I am very interested to see one but I won't be holding my breath.

For all its worth, Minirigs (a UK based company that makes awesome full-range speakers that works either on BT TWS or wired analog) doesn't find any sonic advantages of AptX/LDAC over standard SBC in their own testing.

Re: Bluetooth, transcoding and audio quality

Reply #29 –
Quote from: Palladium on
For all its worth, Minirigs (a UK based company that makes awesome full-range speakers that works either on BT TWS or wired analog) doesn't find any sonic advantages of AptX/LDAC over standard SBC in their own testing.
Though such testing doesn't seem to be documented anywhere in their website and they merely state:
Quote
Contrary to the large Qualcomm marketing campaign, [LDAC] doesn’t offer much in terms of noticeable sound quality improvements over SBC. We could have licensed LDAC, but through lots of testing, we found it again unnecessary.
• Listen to the music, not the media it's on
• The older, the 'lossier'

Re: Bluetooth, transcoding and audio quality

Reply #30 –
Although the null hypothesis is "you cannot hear the difference", there is a difference between "doesn't offer much" and "doesn't find any" ... especially when there's royalty into the picture.

Re: Bluetooth, transcoding and audio quality

Reply #31 –
Quote from: guruboolez on
AAC (which differs between iOS and Android)
Oh, it's much worse. It differs even between different devices with the same Android version number, and between different flavours of Android on the same device. And in many (if not most) cases it is hot garbage, partly because it'll be limited to a very low bitrate for some reason. At least it's possible to confirm the "negotiated" bitrate by checking logs.

 
Quote
Contrary to the large Qualcomm marketing campaign, [LDAC] doesn’t offer much in terms of noticeable sound quality improvements over SBC. We could have licensed LDAC, but through lots of testing, we found it again unnecessary.
Unsurprising, if they're allowing SBC to use enough bitrate (which, I'd guess, is probably the case). it is actually really good when it's not intentionally handicapped, I basically find it transparent and I'm in general a rather picky listener.
A good reason to improve over SBC is reduce bandwidth and with it reliability (330+ kbps is a lot) but claims to improve sound quality over it are often hot air or worse (or paired with artificially destroying SBC quality, as in Samsung earbuds) and also in most environments there isn't really a problem sending 330 kbps over the air.
a fan of AutoEq + Meier Crossfeed

Re: Bluetooth, transcoding and audio quality

Reply #32 –
On a rooted Android phone, it's possible to modify the Bluetooth stack to change the negotiated bitrate to something higher. 

Re: Bluetooth, transcoding and audio quality

Reply #33 –
Quote from: Porcus on
Although the null hypothesis is "you cannot hear the difference", there is a difference between "doesn't offer much" and "doesn't find any" ... especially when there's royalty into the picture.
And FWIW, supposedly performed testing with no published results is effectively no testing at all.

Edit: After all, whether in or outside the academic world, I've yet to hear of any serious tester or empiricist who doesn't want to submit their hard labor's results for peer review - or at least showcase them to potential customers, as it's clearly their case.
• Listen to the music, not the media it's on
• The older, the 'lossier'