If Bluetooth is a digital signal and the DAC is after the signal, how can BT degrade audio quality?

[zuboici]

Title says it all. I've read both opinions - Bluetooth does not degrade audio quality and the other POV: "music sounds like arse through bluetooth".

 

Although I've rarely used BT (from a computer user point of view) I'm well aware that wireless signals can be affected by range/obstacles etc... But if there's only 8 feet between receiver and source how bad can Bluetooth audio be? Conservatively, class 2 BT isn't likely to be anything but very good at that range with line of sight. It's a digital signal and conversion to analog is made within the receiving system, after BT is out of the picture - the signal is the same 0s and 1s after BT as it is before.

 

Some of the common general skepticisms regarding BT are not so relevant for an evening of music:

• There's no security issue when transmitting music to your stereo (edit: actually hard to say this unequivocally)
• After connection is established it'll stay connected and active (ie won't be idling / going into standby) for hours so establishing the connection is an issue once per evening
• It microwaves your head. It's nowhere near my head.

 

And what is apt-X Bluetooth? It's not mentioned on the Wikipedia page for BT.

 

 

The context of my question:- We're buying new sound systems for home and holiday. We've been playing music using an Android plugged in via 3.5mm jack but the wiredness of it's becoming annoying - I've tried remote desktop / screen sharing but no luck making that work so far. The current best idea, one that keeps both home and holiday systems almost identical to the user, is Dad's phone (Galaxy S5) on holiday connected to small BT speakers and a tablet (Galaxy tab 3 8") for home connected to... anything between much bigger/better bluetooth speakers (£350) and a Marantz network streamer (£250 +spkrs) with a BT receiver (£50-60?) added.

[Profquast]

We just have a chromecast plugged into our tv and a optical cable going from the tv to the receiver. Also, I believe most people say bluetooth sucks because mostly bluetooth speakers are tiny battery-powered speakers with no power at all.

[creatip123]

I don't know about speakers, but generally people hate BT in headphones. 1 theory is because of what you wrote above, the conversion to analog is done from the receiving end, meaning you're stuck with the DAC chip that came with the headphone. If the chip is good, then it's good. If it's bad, well....Say someday you wanna buy a better DAC unit, well you can't use them in tandem with the BT headphone.

 

Also, this is my theory, BT headphones contain battery unit, BT reciever unit, DAC unit, and (maybe) amp unit, inside the headphone itself. All that electronics potentially can introduce EMI (electromagnetic interference)

[Aphexx]

I've had 2 velodyne BT headphones fall into my lap. aside from a V shaped sound signature it is surprising how decent it performs. 

 

if your setup is a home type setup why not do it via wifi

 

I've been using air playit which is great for just music. I find it goes out of sync if you need it to be sync'd with video on another device

 

[SoItGoes]

Just to preface my response, I'm still doing research on this stuff myself -- I'll answer your questions based on my own limited knowledge on the matter.

 

On sound quality through BT:

 

It seems like a lot of the complaints levied against bluetooth SQ stem from the compression algorithms used when streaming music from source to receiver. Earlier bluetooth revs (think 1.1 and 2.0) didn't have the bandwidth or the compression algorithms to reproduce music in a way comparable to wired connections. Newer revs (3.0 and 4.0) have better algorithms for dealing with audio -- aptX (wiki) is an example of such an algorithm.

 

On Dacs:

 

I'd say the answer is twofold here: first you have compression algorithms feeding in a lossy signal through the dac, so naturally, no matter how good the dac is, the sound coming out would naturally be worse. Additionally (and this is me hypothesizing) the dac itself may be limited by form factor on some of these bluetooth devices. If you consider the fact that manufacturers have to fit the same object on headphones as what can take up its own separate box, it seems more likely that some delta would exist between the performance characteristics of such devices. It seems to follow that the Dacs onboard speakers (or standalone receivers) are probably of better quality on average in comparison to small, portable devices.

 

I personally think you'd be happy with that solution, just stick to newer bluetooth devices and, of course, read the reviews. 

[Sors]

Bandwith, bluetooth have a limit of bandwith that can transmit, so it compresses the music, and that takes a chunk of music's quality.

[MayflowerElectronics]

It's not that the technology CAN'T provide good audio, the physics are there, it's just that nearly all (in fact I can't think of anything good off the top of my head) that has bluetooth/wireless technologies sound good. It's a problem of going from analog to digital, sending those 1's and 0's through the air without picking up any noise/interference, ect ect, then the headphone has to decode those 1's and 0's without clipping, then send it to the headphones via analog without adding distortion/noise ect ect. It's not easy.

 

Speakers are more of the same, but they have it's advantages. Where as the headphones have to have the DAC and amp built in to a headphone, having it to be small and lightweight, speakers have more room and don't have to worry about weight, so in general the technologies are better with speakers, but far from perfect.

 

For your use case scenario, it should be fine. I doubt he will know the difference between wired/wireless play.

[zuboici]

!! Whole lot to think about now !!

 

Aphexx that vid has a lot of info and I'm gonna use it. It seems, whilst Bluetooth should be fine for bringing your music on holiday with no great expectations on quality, Wifi might be the obvious choice at home.

 

So the Marantz M-CR510 suggested to me in another thread might just be the ticket after all! I think I need to get one or two of our current Android devices to play music using our preferred player and stream that to my laptop or something to prove we can do it, then bring that to Richer Sounds (where we're likely going to actually buy the gear as it's same price as Amazon and Richer Sounds rock) to make sure it's as simple to use as it *should* be...

 

 

 

Crap... another project.

 

 

 

I've had 2 velodyne BT headphones fall into my lap. aside from a V shaped sound signature it is surprising how decent it performs. 

 

if your setup is a home type setup why not do it via wifi

 

I've been using air playit which is great for just music. I find it goes out of sync if you need it to be sync'd with video on another device

 

[creatip123]

For wireless audio, output to PC/laptop, using Wi-fi, I think you'd need a pair of application, meaning 2 applications working in tandem. 1 you install in the source device (phones, ipads, etc), the other on on the PC. Fire up the 2, let them communicate and establish audio connection. I think you can't, for example, turn on the Wi-fi chips (on mobile device, and on PC), and expect the PC to say, 'hey I found a wi-fi based mobile audio, you want to use that as media source?'

 

I used the airplay features on my ipad that's already built-in with the iOS package, so I only needed to install the PC end. I used to play the ipad's game, with the sound coming from my computer's speakers wirelessly

[xyza]

Wireless in general will always get interference no matter what kind of technology it is. Try listening to some music or just general use from a wireless device while the microwave is in use. Also I get distortion from my foobar settings when playing through upnp, probably not configured correctly though.

[ShearMe]

It's not that bluetooth makes headphones bad, just that bluetooth headphones are generally bad.