Bluetooth Receiver: does quality matter if using digital out to DAC?

[mscholtz]

Hi, first post here! About to pull the trigger on buying some gear that will serve double duty. I want to be able to 1) listen to music on headphones (Sennheiser HD 598 Cs) via USB on my desktop computer and 2) stream music to my hifi system from google play/spotify/etc.

Originally I was looking at the topping DX3 but there seem to be a lot of problems with that unit. And having separate DAC/amp/BT seems prudent in case a unit goes bad or I want to upgrade one piece.

So now I'm thinking of getting topping D30 DAC, and pairing it with 1) a headphone amp to be determined , and 2) some random BT receiver that has digital out. I had been considering a Chromecast Audio but suddenly it seems they're not available anymore. The BT receiver I'm looking at right now is this https://www.amazon.com/Bluetooth-Receiver-Wireless-Streaming-Connections/dp/B07GTKH3ZK I would have to move the DAC back and forth from computer to hifi at times, but that's OK for now. And eventually I can buy a 2nd DAC.

My question is: should I spend any time at all deciding what BT receiver to get? Or does it not really matter as long as it has good reviews and has digital out? The sound quality will depend entirely on the DAC in that case, right? If it does matter, please recommend a better BT receiver.

Thanks!

 

[Webninja]

Bluetooth max bitrate can be a limiting factor depending on your source. I use it in the car and l can tell sometimes depending on if I'm using Tidal or Spotify.

Lots of info out there, but here is a thorough review of the different Bluetooth codecs.

http://www.sereneaudio.com/blog/how-good-is-bluetooth-audio-at-its-best

 

[infinitesymphony]

Historically speaking, the questions would be:

1.) Is the audio transmission lossless (ex. Bluetooth aptX)? If not, are you okay with regular Bluetooth even though it is lossy?
2.) Is the receiver's digital output bit-perfect, i.e. done without processing or resampling?
3.) Is there enough jitter present to affect performance? (Contemporary DACs and clocking systems seem to have this part mostly solved .)

Edit: I was wrong about #1 -- aptX is lossy.

 

[Dogen]

It’s my understanding that all Bluetooth, including aptX, is lossy. But, it does sound much better than the original Bluetooth - that didn’t sound so hot.

 

[Webninja]

I don't believe any current Bluetooth transport is lossless. Although the codecs are getting better, the limit that I have read is 350 kbps.

 

[infinitesymphony]

It’s my understanding that all Bluetooth, including aptX, is lossy. But, it does sound much better than the original Bluetooth - that didn’t sound so hot.

The "near-lossless" marketing blurb got me. Thank you for the clarification.

It seems strange to me that we've had lossless wifi streaming options for 13 years with Slim Devices Squeezebox + FLAC and AirPlay + ALAC, but Bluetooth still doesn't have a lossless solution.

 

[Dogen]

The "near-lossless" marketing blurb got me. Thank you for the clarification.

It seems strange to me that we've had lossless wifi streaming options for 13 years with Slim Devices Squeezebox + FLAC and AirPlay + ALAC, but Bluetooth still doesn't have a lossless solution.

As I understand it, Bluetooth is slower because it is designed to use less power and be inexpensive to implement. I guess it could be done, but then you may as well use wireless.

 

[Willem]

Bluetooth does not need wifi (it is point to point over short distances), so you can use it on the go, in the car to stream from your phone to the car radio, or to send music wirelessly to a headphone. Sound quality is a bit compromised (less and less so, however), but in the car or walking in the street that is not much of an issue. In the quiet home environment, and connected to a more revealing system, it is not a good idea. But at home you have wifi or even wired connections, so you have sonically better alternatives like Airplay or Chromecast Audio.

 

[Vincent Kars]

Bluetooth SBC = 328 kbs
AptX=384 kbs
AptX HD= 576 kbs
All of them requires lossy compression
Sony LDAP can go up to 990kbp, still “not” sufficient but this is in the realm of lossless compression FLAC style
At the present only Sony headphones support this protocol.

If you want lossless, WiFi is the way to go.
DLNA is a wide supported protocol for streaming audio.

Most streamers are rather expensive: http://www.thewelltemperedcomputer.com/HW/DAP.htm
However, a Raspberry PI can fit the bill.
An example: https://www.allo.com/index.html

 

[infinitesymphony]

Some interesting comparisons of Bluetooth SBC vs. aptX vs. MP3 compression:

http://www.sereneaudio.com/blog/how-good-is-bluetooth-audio-at-its-best

Bluetooth SBC appears to be the most accurate with test tones, broadband noise, and impulses. aptX appears to include more info when fed actual music.

I suppose these results are moot because the source files played back over NFC are predominantly already going to have MP3 or AAC compression (on services like Google Play, Spotify, and Apple Music), so you're getting double compression no matter what.

 

[mscholtz]

Thanks so much for all the info, everyone. Wading through the links now.

It seems that I may have been barking up the wrong tree. I want to listen to streaming music in decent quality, and I'm not wedded to Bluetooth, or to Spotify/Google Play as service. But I do have a very limited hardware budget at the moment, and would ideally like the DAC to play double duty as described in my original post.

We currently have a Sonos speaker. The quality is OK but not great, but we do mostly like the UI for playing music from a phone. So whatever we come up with for the hifi, I don't want to have to queue up music from my laptop or anything like that.

I've just been reading that Tidal offers higher-quality streaming. And I'm happy to use wifi to stream instead of BT. If I make both of those switches, what are my best bets for inexpensive hardware? Is it the Raspberry Pi options that Vincent Kars suggested? Or something like an Airplay receiver? Would love recommendations for specific hardware.

Happy to go with a different DAC too, as long as it's not very expensive and can be used for the desktop headphone listening as well.

Thanks!!

 

[Webninja]

Take a look at BlueSound Node 2i. I have read it has a decent DAC, still waiting on Amir to test it, but for the price it checks off a lot on your list. It's on my short list, just don't need it at the moment.

Streaming WiFi and AirPlay 2, and Roon end point
DAC
Headphone amp? Has a jack, not sure how good of a headphone amp it has

 

[mscholtz]

Hmm, interesting. Is Bluesound mainly a Sonos competitor? Looks like a similar approach. For that price, I guess why not get a Sonos Connect instead? https://www.sonos.com/en-us/shop/connect.html I've heard it has a lousy DAC but it would be compatible w/ the speaker we already have, and for the $150 I save I could get the Topping DAC. You can't airplay to it, but I don't think I'd need it as Sonos supports all the streaming services natively. Would rather the box do the streaming than have to stream via my phone.

...and I'm definitely not the first to ask that question: https://www.avforums.com/threads/sonos-connect-vs-bluesound-node-2-or-other-streamer.2151849/
Looks like one advantage of the BS is it supports the Tidal MQA format. Not sure I care that much about that.

I guess if the BS could also serve as a headphone amp then it starts to save a little money over the Sonos. But not much. And it gets me into the all-in-one box arrangement that I was sorta hoping to avoid.

 

[mscholtz]

It also isn't clear that you could use the Bluesound to listen to music out of a desktop computer. It has a USB port but doesn't list it as an input. Instead it says "for connection to USB memory sticks (Fat32 or NTFS formatted) and supported peripherals". I may be interpreting that wrong. But if not, then seems like getting the Sonos (or an Allo or etc.) plus a separate DAC would be better for me.

 

[Vincent Kars]

I may be interpreting that wrong.

No, correct interpretation.
Reading data from a stick is something completely different from being a USB DAC

 

[Webninja]

@mscholtz

From what I read, and it was all subjective, BlueSound came out ahead of Sonos. I don't have either, but if you already do have Sonos that might be better.

What I ended up with for my desktop, thanks to this forum, was a Topping DX7s connected to a Mac mini, using Roon to stream Tidal. I'm currently listening via JBL 305s. I wanted to be a headphone guy, but I seem to default to speakers, even though I have 3 headphones.

Thrilled with the setup, and maybe it might be something you consider since we have similar goals.

 

[MediumRare]

Could I ask you folks to clarify one thing: If I use BT aptX to transport a digital stream from my laptop to a DAC (as opposed to a USB connection, is the DAC receiving anything different from the original stream than would have been sent via USB instead? No upsampling, just a data stream from a redbook FLAC file. Why would it not be bit-perfect? It seems to me the codecs would only matter if you're sending an analogue stream, for example, to ear buds.

@amirm, have you ever tested a signal sent via BT and looped back to your APx?

 

[RickSanchez]

Could I ask you folks to clarify one thing: If I use BT aptX to transport a digital stream from my laptop to a DAC (as opposed to a USB connection, is the DAC receiving anything different from the original stream than would have been sent via USB instead? No upsampling, just a data stream from a redbook FLAC file. Why would it not be bit-perfect? It seems to me the codecs would only matter if you're sending an analogue stream, for example, to ear buds.

Assuming your source music is a high quality (e.g., CD 16/44.1) file there would be a difference in what the DAC received between USB and any bluetooth codec. USB has a much higher data transfer rate and therefore has no need to compress high quality audio files. Bluetooth codecs are built to handle some of the core requirements of Bluetooth (such as low power and trying to maintain a stable connection), and therefore will use lossy compression to handle larger data streams like music.

To get a sense of this look at the data rates for Bluetooth codecs vs. USB. And keep in mind that for Bluetooth those are the max data rates. Often times manufacturers use implementations of a particular codec that don't reach those maximums.

[source: https://www.soundguys.com/understanding-bluetooth-codecs-15352/]

[source: https://www.sony.com/electronics/support/articles/00024571]

 

[Jimbob54]

As I understand it, Bluetooth is slower because it is designed to use less power and be inexpensive to implement. I guess it could be done, but then you may as well use wireless.

Thats my limited understanding too. Think that is why Google pursued a none peer to peer solution with chromecast (the tech, not the devices). Let the powered devices do the legwork (TV/hifi and router), not the phone, twice (receive the stream, cast the stream)