Is bluetooth actually worse for audio than coax/toslink?

[quadratique]

Hi All, I am new to to hifi, about to buy my first amp and speaker. I am currently considering Arcam A5/A15/A25 with JBL HDI-1600 or Revel M16 (but the later seems less available around here). My main issue is that I would mostly listen to music from laptop. Using an A5 with bluetooth seems like a convenient idea. Many audiophiles claim bluetooth is bad. (But they also claim quality to power cables and expensive speaker cables, which have been debunked here many times.) my assumption would be that bluetooth is digital, so it shouldn't really matter how the digital signal gets to the dac. Are there any facts/measurements/science about bluetooth audio quality over coax/toslink? Or is this yet another myth? (Most of my music is CD quality.)

In other words, does it make sense to buy a USB > coax/toslink bridge like Topping D10s even if I could connect directly via bluetooth?

thanks

 

[Steve Dallas]

Here is an objective analysis of BT CODECS. In short, the signal is degraded when using BT. If you are going to use BT, you want to use the LDAC CODEC if possible.

Topping BC3 Review (Bluetooth Receiver) & BT CODECs

This is a review and detailed measurements of the Topping BC3 Bluetooth receiver and headphone amplifier. It was sent to me by the online seller, Yaoyaotiger HIFI Audio Store and costs US $69. This is a follow up to our previous tests of Bluetooth receivers and investigating performance of...

www.audiosciencereview.com

 

[staticV3]

Bluetooth is lossy, which means it discards some of the audio data to shrink the file size to where it can be sent via the limited bandwidth of radio frequency.

It does this in the smartest way possible by only discarding what you're least likely to notice.

In practice, this means that even though Bluetooth doesn't transmit your audio 1:1, the effect of this compression is usually way smaller than other factors like room acoustics, loudspeaker performance, and of course mastering quality.

You can upload some music to this website and check if you can hear a difference between the lossy encoded versions and the original:

Bluetooth A2DP SBC/aptX Online Encoder

Bluetooth A2DP SBC audio online encoder

btcodecs.valdikss.org.ru

Toslink/Coax on the other hand, at least for stereo content, is capable of lossless audio transmission.

In a scenario where either transmission type would be equally convenient, I'd certainly choose the wire.

Though if being untethered via BT has value to you, then IMO, you can safely chose that without worrying about losing out on your music enjoyment.

 

[staticV3]

Here is an objective analysis of BT CODECS. In short, the signal is degraded when using BT. If you are going to use BT, you want to use the LDAC CODEC if possible.

Topping BC3 Review (Bluetooth Receiver) & BT CODECs

This is a review and detailed measurements of the Topping BC3 Bluetooth receiver and headphone amplifier. It was sent to me by the online seller, Yaoyaotiger HIFI Audio Store and costs US $69. This is a follow up to our previous tests of Bluetooth receivers and investigating performance of...

www.audiosciencereview.com

Although LDAC performs great when sending just single sine tones, use more complex signals and you'll see that Apple's AAC encoder achieves similar transparency at a fraction of the bit rate:


Source:
https://archimago.blogspot.com/2023/08/part-i-comparison-of-bluetooth-fidelity.html
https://archimago.blogspot.com/2023/08/part-ii-comparison-of-bluetooth.html

 

[Chrispy]

Funny how an integrated amp would have BT instead of wifi capabilities (you can do lossless easily enough over wifi).

 

[DonR]

Funny how an integrated amp would have BT instead of wifi capabilities (you can do lossless easily enough over wifi).

Yes, the whole point of BT is low-power portability.

 

[Chrispy]

Yes, the whole point of BT is low-power portability.

You're going to move the integrated around and use it in an area without wifi, tho? Or is wifi much different power-wise? I have low power portability over wifi as much as BT....

 

[Timcognito]

These have amps, wifi, BT and good review at ASR

KEF LSX Review (Wireless Speaker)

This is a review and detailed measurements of the KEF LSX "Wireless" speaker. It is on kind loan from a member and costs US $1,250 from Amazon including Prime shipping. In every way KEF could nail the look and feel of the speaker, it has done so: Not only is the iconic coaxial driver...

www.audiosciencereview.com

 

[pablolie]

the bandwidth tells the story - to a large degree. A2DP is pretty darn good, going up to about 500kbps with some wind from the rear. And I think compressed MP3 320k sounds pretty great. in any case it is beyond the SQ i'd be perfecty happy with when i listen to stuff in the gym, in a plane or on a walk. aptX goes beyond that, i think 1Mbps or so, which should support uncompressed FLAC nicely enough.
but of course toslink/coax/etc support any HD format you throw at it (24/192 all day long) if you think you can easily hear a difference.
the other aspect that tells the story is the fact that i don't think there are $4k bluetooth headphones around...

 

[Prana Ferox]

- Bluetooth is lossy
- How BT negotiates and maintains a certain codec and bandwidth is opaque and usually not easily controllable so even saying stuff like 'use LDAC' only has so much value
- How much this matters is debatable. Your source has to be higher fidelity in the first place. And whether you would hear a difference in a strict A/B comparison doesn't mean you'd notice in casual listening.

BT is more common than WiFi because BT is specifically designed to pair usually one-button, easy and transparent between audio source and receiver. WiFi is considerably more complicated depending on whether you're sharing some file structure to a smart player, just pushing a stream to DLNA etc. not to mention both devices need to be able to get on a wifi device (which, among other things, means you have to have some way of entering a network password)

 

[DonR]

You're going to move the integrated around and use it in an area without wifi, tho? Or is wifi much different power-wise? I have low power portability over wifi as much as BT....

I meant, yes it is funny. Generally, WiFi is about an order of magnitude more power-hungry than BT although this varies between the different standards. Obviously this is a non-issue for a stationary, mains-powered product.

 

[pablolie]

- Bluetooth is lossy
- How BT negotiates and maintains a certain codec and bandwidth is opaque and usually not easily controllable so even saying stuff like 'use LDAC' only has so much value

But that's not different from any other technology if you look at the principle. If you get loss, the protocol stack adjusts to working at a lower bandwidth. At least you keep connectivity, even though the connection quality itself goes down some. With any wireless stuff, staying close to the connection peer is the best way to ensure connection quality.

- How much this matters is debatable. Your source has to be higher fidelity in the first place. And whether you would hear a difference in a strict A/B comparison doesn't mean you'd notice in casual listening.

BT is more common than WiFi because BT is specifically designed to pair usually one-button, easy and transparent between audio source and receiver. WiFi is considerably more complicated depending on whether you're sharing some file structure to a smart player, just pushing a stream to DLNA etc. not to mention both devices need to be able to get on a wifi device (which, among other things, means you have to have some way of entering a network password)

Bluetooth is awesome because it provides good connectivity with low power consumption - they have tried it with some WiFi add ons at times, but WiFi will always be higher power, and none of us would like 3lbs headphones on our heads.

 

[Zapper]

In other words, does it make sense to buy a USB > coax/toslink bridge like Topping D10s even if I could connect directly via bluetooth?

Since no-one has answered this question directly, the answer is yes (with caveats). Yes because the USB > coax/toslink bridge should transfer bit-perfect data to the amp, so no degradation. Technically, Bluetooth degrades the signal to some extent and this can be measured, as described above.

The caveat is that BT degrades the signal so subtlety that most people can't tell it apart from the original signal. Comment #3 gives a link to a comparison test that you can try yourself. I can't tell rhe difference, so I use Bluetooth without worrying about it. But many audiophiles have OCD, and can't stand the thought of lossy compression, even if they can't hear it. And some audiophiles have very good hearing and can hear the difference.

 

[staticV3]

@quadratique if you'd like to give Toslink a go, then there's a much less expensive USB -> Toslink bridge than the D10s, that's just as good: the Hifime UT23.

 

[Prana Ferox]

But that's not different from any other technology if you look at the principle. If you get loss, the protocol stack adjusts to working at a lower bandwidth. At least you keep connectivity, even though the connection quality itself goes down some. With any wireless stuff, staying close to the connection peer is the best way to ensure connection quality.

If I am transferring music as FLAC over wifi, the wifi devices will constantly negotiate the link up and down in the background, but if the connection gets bad enough, it's not going to suddenly start lossy compressing the FLAC file. My transfer will either work or not work, and in the worst case the music will stutter or pause. The other transit protocols here (Toslink and coax) are the same way.

 

[voodooless]

I have major doubts on all the stories about the inferiority of Bluetooth audio codecs. Strangely when it comes to Bluetooth, these are readily accepted where in other subjects we ask for actual proof. It’s really puzzling

So what actual proof is there? Not that much it seems. I found this blind study: https://hydrogenaud.io/index.php/topic,120182.0.html which seems to indicate that at bitrates above 300 Kbps, all (tested) codecs are basically transparent. AAC does a lot better with less bits as well.

Given this, I think the biggest issue is not the codec, but the available bandwidth at any given time. Seems like Apple was onto something with AAC after all.

An no, looking at single or multitone graphs does not tell you anything about the perceived transparency of the codec. These things are meant to encode music, and these graphs tell you little about how audibly transparent the codec will be. You cannot judge these things like a DAC or lossless digital audio interface.

 

[quadratique]

Thanks for all the useful hints. I will dig myself into the materials.

 

[quadratique]

The caveat is that BT degrades the signal so subtlety that most people can't tell it apart from the original signal. Comment #3 gives a link to a comparison test that you can try yourself. I can't tell rhe difference, so I use Bluetooth without worrying about it. But many audiophiles have OCD, and can't stand the thought of lossy compression, even if they can't hear it. And some audiophiles have very good hearing and can hear the difference.

Thanks for the great summary. If I listened hard, on certain very instrumental jazz tracks with very separated instruments I could hear some very minor difference. Very little, and only in edge cases. A bit more white noise on SBC and a bit of higher freq on aptX. But maybe this is only due to the sighted test. I don't think I would realize the difference if somebody switched it on my setup overnight. Very interesting. I think I will still have a cheap cable solution, but will also be proudly switching over to BT when required. I love this forum! So many myths busted.

 

[quadratique]

You can upload some music to this website and check if you can hear a difference between the lossy encoded versions and the original:

Bluetooth A2DP SBC/aptX Online Encoder

Bluetooth A2DP SBC audio online encoder

btcodecs.valdikss.org.ru

Thanks, this is gold! I will save this for busting my audiophile friends with a blind test.

 

[Vacceo]

I guess the issue with bluetooth is ultimately a problem of bandwidth. Perhaps in the coming years, transmission will be large enough to make codecs moot.