A2DP and sound quality?

I don't know exactly where to ask this question. Please move it if necessary.

Here's the question: I want to play my favorite music on a stereo speaker system over bluetooth (A2DP).

I worry if whether the output quality I'll hear is based on the quality of the speaker system themselves or the source of the device that is sending the music via bluetooth.

Can anyone help me?

I also have a DoCoMo SH-01B cellphone that outputs DOLBY 5.1 Surround. It sounds amazing when I listen to music with a headphone. If I link this cellphone to a bluetooth stereo system, will I loose music quality?

 

An ages old question with a very simple answer: Your maximum quantity will be no better that the weakest link in the audio chain. That said, it typically isn't the speaker--or the system.

Generally, ANY wireless signal is sub par to a wired system since once it goes wireless the signal can be effected by so many things. In music, that's definitely what you don't want. If its maximum audio quality you're after, you need to have a wired connection.

Again, generally yes. Any time you add a connection (link) you loose something in the translation (the electronic processing of each connected device.

 

people aim for wireless doesnt really care about quality...but more for the portability and hassle free...

i compare using my aino , using the wireless headset that comes with it ... loss of fidelity , weak / no bass at all

while using wired , the SQ can be maintained ...

 

I have 2 pairs of bluetooth headphones.

Quality is fine in my opinion.

devil kinda hit the nail on the head, if quality was your main concern wireless is not what you would be looking into, its convenience and mobility. And while needing those things the quality is still more than good enough to enjoy your music.

I actually have a well rounded assortment of devices to do a fair comparison

On the A2DP side for headphones I have Plantronics 590A a wireless headphone with great comfort and bass and great sound quality.

For earbuds I have the Motorola S9-HD a headphone style worn earbuds designed for active use.

On wired/quality side

I have Audio Technica A700 for my headphones and I just got some Logitech Ultimate Ears Triple Fi 10's

While I can say yes there is more quality to be had with the wire on there, its not of any concern to me when I use the bluetooth stuff instead, the music still sound great and when I use them I am doing something that the wires would be in the way so I gladly trade the wires and a subtle amount of quality for the mobility and convenience.

 

Yeah, quality over wireless is rarely a problem. Keep in mind Bluetooth isn't a lossy protocol.

Data is delivered in packets that are encrypted and verified. The sound will be the same whether over wire or wireless.

 

Fixed! I just wanted to make sure there's no misunderstanding.

 

Again I would not call the sound sub quality, nor would I attempt to substitute wireless or audiophile quality listening.

Each person is entitled to there own opinion on the mater and some have a stronger opinion about it one way or another, so its best to stick to the facts.

> Wireless is meant for convenience and in that it excels,
> Audio quality is going to be determined by the quality of the device be it wired or wireless
> Unless you have used both you have no basis to have an opinion, reading other peoples opinions online and drawing a conclusion based on that doesn't work (especially the holier than thou audiophiles)

It always ends up like this when its something you cant solidify into numbers, if we were asking what cpu or gpu was better, its simple enough to backup a claim with a benchmark. But the only benchmark for sound is realistically your listening experience and that can be different for each and every person.

So you cant even for a moment believe that your "benchmark" on sound quality is valid or can be imposed on another person as they could have a totally different listening experience.

 

I missed the part about the Cellphone outputting the signal. LOL.

 

i have a pair of Sony Bluetooth stereo headphones. The sound quality is good -- when there's sound coming out of them. The problem is, the sound cuts out a lot, and I get a second or two of silence here and there. I don't know if the problem is radio interference or my bluetooth card in my computer or the headphones or what. But... I don't get a consistent connection.

 

Bluetooth itself may not be lossy, but the A2DP protocol which runs on top of it to transmit audio is lossy I believe. From Wikipedia:

http://en.wikipedia.org/wiki/Bluetooth_profile#Advanced_Audio_Distribution_Profile_.28A2DP.29

MPEG-2, MPEG-4, AAC... sounds lossy to me.

There's been some talk about lossless audio over Bluetooth... but I'm not sure if that's actually commonly available yet.

Once that happens, Bluetooth audio quality should be able to be equivalent to a digital wired connection -- but a lot also depends on the quality of the DAC and amplifier built into the particular receiving device.

 

Well - not always true.

A2DP uses a means of audio compression for transmission which can encapsulate AAC, etc - but since most BT clients don't have the intelligence for such encapsulation, it usually relies on recompressing the source signal to send over Bluetooth using a simpler codec, as swarmer points out.

There is some quality loss. I've always felt however that the relative crappiness of the headphone / decoding / amping parts of most Bluetooth headphones is more what holds them back - the need to pack in a battery, circuitry and a headphone in a lightweight and affordable package obviously results in many compromises. I've no experience with speakers, but I'm sure they'll do a reasonable job and that whether the compression is getting in the way or not will be the least important part impacting the quality of the setup.

 

You are misreading the Wikipedia article. A2DP also supports direct decoding of said formats. The Toshiba stack itself that comes with Windows allows direct streaming of 328kbps MP3.

This is not referring to a lossless transmission of the audio datastream, but a direct decoding of a lossless codec. Two different concepts.

Yeah, if it decodes the MP3s down to SBC, then ya there is going to be audio quality loss. I left that part out because I thought the streaming device was going to be a Windows laptop and not a cellphone.

Again, this has been the biggest criticism of Bluetooth/A2DP. The crappy hardware that comes with it, not the technology itself.

 

That what I've been trying to tell you all along. Wireless signal are prone to all types of interference. That alone makes them second rate.

I suggest you go to your local boutique audio store with your favorite cd (preferably something musical) and listen to it on a high quality sound system for a while. If hearing is believing, you will never make a comment like this one again.

 

Another double post.

 

Yeah I guess my new Logitech Ultimate Ears Triple.Fi 10's are wallmart stuff and my Audio Technicas and lossless .FLAC rips.

I guess his is where your going to say I dont have a proper DAC or something along those lines right? So go ahead and say it.

Goes to show you totally missed what I said, I have listened and I have spoken. If you want to input your own opinion fine but done try to invalidate somebody elses.

Since when was the comparison super high end audiophile equipment vs bluetooth anyways?

 

I've given it some thought and looked up the Bluetooth spec sheets.



Looks like I was the one who misread the article.

Apparently, most programs actually send an uncompressed audio stream to the Bluetooth network stack, which encodes it, then sends it to the Bluetooth devices, which then decodes it and plays it.


Now some programs however, rather than decoding the MP3, send an undecoded mp3 stream through the Bluetooth network stack. More on this later....

 

No, your original assumption was right if I get what you posted properly.

Assuming you're going from e.g. AAC to A2DP, most implementations decode the lossy AAC to uncompressed, encode the uncompressed to SBC, sling it out over Bluetooth where it is decoded back to uncompressed.

So you are in effect introducing another lossy compression into the audio chain, one that is more CPU/wireless transmission optimised than for positive psychoacoustic characteristics.

Almost no devices encapsulate existing encodings and sling it directly over BT, because usually the receiving end doesn't have the intelligence to decode it.

 

Lets try and remain objective shall we? Providing additional information or an alternate point of view is not invalidation.

Since someone opened the debate about sound quality

 

Could you please provide some info about these programs, that can send an undecoded mp3 stream through BT stack?