Bluetooth DAC Questions...

[ScottFan355]

Hello all! I have a few questions and hypotheticals that I'm hoping some of the more computer/tech savvy members here can shed some light on. My main sources for some time has been vinyl and headphone to rca from my phone for convenience. I recently purchased a Pro-Ject Bluetooth Box E for an inexpensive wireless solution. It is being run through a vintage tube pre, tube amp, and passive speakers. To my ears it sounds very good, better in fact than using the headphone out on the phone. This is also without being able to take advantage of the aptx codec as my iphone5s doesn't support it. I have to assume it's because the dac in the bluetooth receiver is superior to my phone's internal dac. So much of the info I read about dacs is so much gobbledygook from people without technical knowledge of their workings, codecs, etc. So would a modern bluetooth dac beat out, say a mid-fi cd player from 1990? How about lossless format using a phone's internal dac vs lossy through the bluetooth? And in general is it better to use a lossy format through a better dac than a lossless format through a worse dac?

 

[E.Auer]

Bluetooth is still behind wireless.
So a wifi streamer like the affordable Chromecast Audio would sound better than BT.

Not sure how much lossless gets mangled by BT but for sure it does. Even Apt-X is lossy compressed.

A mid-fi CD player from the 90's with a decent DAC should sound better than non Apt-X BT.

A DAC cannot fix the issues that BT has. That's just how that format is.

Eric

 

[SoNic67]

So would a modern bluetooth dac beat out, say a mid-fi cd player from 1990? How about lossless format using a phone's internal dac vs lossy through the bluetooth?

Absolutely not, especially with iPhone's Bluetooth SBC codec (Low Complexity Subband Coding). A decent CD player (from the 90's top of the line) will be much better.
With AptX I would say it depends of how revealing the rest of the system is. ChromeCast Audio is a better wireless choice but again... iPhone garden might put up some fight:
http://www.businessinsider.com/chromecast-audio-ios-2016-3
Plus, if you are into Pink Floyd, forget about CCA. On Android there is just ONE app that can force CCA to play gapless (HiFi Cast). Not sure what's available under iOS.

 

[ScottFan355]

I learned about Apple Airport Express after purchasing the Bluetooth receiver. Being new to Apple I didn't know about it, and the salesman at the store pointed me to the Bluetooth device as the only affordable option. Seems the Airport is a much better option. Still, I do wonder if modern dacs and codecs have increased the fidelity of Bluetooth quite a bit, even without aptx.

 

[SoNic67]

Bluetooth SBC is limited by the available bandwidth and lossy encoding scheme.
AirPort Express (Air Play) and Chromecast use WiFi with 1000x more bandwidth and they can carry loseless digital audio.

 

[ScottFan355]

I guess what I'm really wondering is since processing power, and presumably dacs, has advanced by such magnitude in the last 25 years (1000x, 5000x?) is it possible that a modern dac can extrapolate the missing data as well or better than an older dac can process lossless input? From what I understand dacs are basically processing data into sound waves so it doesn't seem that much of a stretch. Of course a modern dac with lossless input is ideal.

 

[ScottFan355]

And as a side note, does anyone here really believe, given the nature of this hobby, that there will come a time that audio reviewers and people on this site will say 'well the dacs have finally surpassed the ability of the human ear to tell any difference, just spend $20 and you're good' even with lossless input? I can see the reviews of a $3000 dac in 2037 now 'lifelike imaging never before seen, bla blah blah...'

 

[SoNic67]

Nope, even if the digital processing advanced, the DAC's didn't advance that much. Marketing did though...
The "problem" is that the human ear is analog. Therefore the DAC's need to generate that analog signal. That's the part that, even today, cannot get better. The state of the art DAC's can claim they process 32 bits of "data" but the actual analog performance (THD+N) is at the 20-21 bit level.

As for the gimmicks that claim to "reconstruct" the audio signal from a lossy compressed file, sure they are many, but in my experience that's just marketing. There is nothing like preserving all the bits in the original mix/record (losseless compression).