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BronsCon

join:2003-10-24
Walnut Creek, CA
reply to skeechan

Re: [iPhone] Bigger Fail Than Maps ...

Hmm... As much as it pains me to say it (not a Ford man), Ford might have the best OEM BT on the market. I wouldn't know, though; I don't usually keep an OEM stereo for long.



skeechan
Ai Otsukaholic
Premium
join:2012-01-26
AA169|170
kudos:2

I never have a car that a non-OEM head unit would look decent in.



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to BronsCon

while that's theoretically possible - it isn't actually utilized in any real world applications I've seen.

Light travel is theoretically possible -- no one uses it. See the similarity there?



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to skeechan

My wife's 2012 IS 350C can do it over BT from her iPhone - a first in our experience too!



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET
reply to Count Zero

said by Count Zero:

while that's theoretically possible - it isn't actually utilized in any real world applications I've seen.

Light travel is theoretically possible -- no one uses it. See the similarity there?

Yup, you've never seen either, so both must not exist.


Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to BronsCon

My car can do that over USB or BT from the steering wheel.

But on long drives I get annoyed at the lower quality of BT. I guess I consider myself something of an audiophile and if I'm going to pay for high end stereo equipment I don't see a point in feeding it lower quality audio to play.



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to BronsCon

Again, show me a consumer device that actually plays FULL QUALITY audio over bluetooth.



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

said by Count Zero:

Again, show me a consumer device that actually plays FULL QUALITY audio over bluetooth.

Let's go for a drive, then. I've already given you an example, but since you insist on seeing it with your own eyes, I suspect you'll be visiting the bay area this weekend?


Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

Seriously? I looked through the entire manual to see where it would validate your claim and could not find it (see several posts above). Again - your player uses A2DP and that typically re-compresses audio to 128kbps or less for compatibility. Since ALL of my files are 256kbps AAC or higher then I would expect your player to degrade the quality. Just because BT is theoretically capable of higher data rates DOES NOT mean that they are actually used for consumer applications. You seem to be unable or unwilling to accept that fact.



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

My ears tell me something different than your perusal of the manual. You can keep arguing but I don't see a point.

EDIT: In fact, the A2DP spec tells me something different than your interpretation of the manual.

See here: »en.wikipedia.org/wiki/Bluetooth_···8A2DP.29

Advanced Audio Distribution Profile (A2DP)

This profile defines how high quality audio (stereo or mono) can be streamed from one device to another over a Bluetooth connection. For example, music can be streamed from a mobile phone, to a wireless headset, hearing aid & cochlear implant streamer, car audio, or from a laptop/desktop to a wireless headset.

A2DP was initially used in conjunction with an intermediate Bluetooth transceiver that connects to a standard audio output jack, encodes the incoming audio to a Bluetooth-friendly format, and sends the signal wirelessly to Bluetooth headphones that decode and play the audio. Bluetooth headphones, especially the more advanced models, often come with a microphone and support for the Headset (HSP), Hands-Free (HFP) and Audio/Video Remote Control (AVRCP) profiles.

A2DP is designed to transfer a uni-directional 2-channel stereo audio stream, like music from an MP3 player, to a headset or car radio.[1] This profile relies on AVDTP and GAVDP. It includes mandatory support for the low-complexity SBC codec (not to be confused with Bluetooth's voice-signal codecs such as CVSDM), and supports optionally: MPEG-1, MPEG-2, MPEG-4, AAC, and ATRAC, and is extensible to support manufacturer-defined codecs, such as apt-X. Some Bluetooth stacks enforce the SCMS-T digital rights management (DRM) scheme. In these cases, it is impossible to connect certain A2DP headphones for high quality audio.

-- Peace.



Thinkdiff
Premium,MVM
join:2001-08-07
Bronx, NY
kudos:11
reply to Count Zero

I think the problem comes down to Apple not supporting MP3 in their A2DP implementation. I suspect that's more popular in bluetooth receivers/speakers than AAC, although they'd all be better off supporting AAC. If the receiving device does not support AAC (which iOS resamples to 132kbps no VBR), then it falls back to SBC - the base compression that all A2DP devices must support, which sounds like shit. All other codecs are optional.

So if your car supports the AAC codec over A2DP, you'll get pretty decent sound quality. 132kbps AAC is roughly equivalent to 256kbps MP3, imo. If it doesn't, you might as well use an FM transmitter hooked up to the audio out.

Source: »developer.apple.com/hardwaredriv···ines.pdf
--
University of Southern California - Fight On!



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to BronsCon

Nice wikipedia quote. That means IT CAN but does not enforce the support for all of those profiles except SBC (low quality profile).

--PEACE



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC
reply to Thinkdiff

That may well be part of my problem with A2DP but I find very limited information out there about what formats different devices support over BT/A2DP. Also if you have a significant amount of music in ALAC then no BT profile will support the playback of that and it will always be re-converted to something else of lower quality.



Thinkdiff
Premium,MVM
join:2001-08-07
Bronx, NY
kudos:11

said by Count Zero:

That may well be part of my problem with A2DP but I find very limited information out there about what formats different devices support over BT/A2DP. Also if you have a significant amount of music in ALAC then no BT profile will support the playback of that and it will always be re-converted to something else of lower quality.

I believe all audio is re-encoded when using A2DP, so the original codec is irrelevant.

If you're not happy with 132kbps AAC audio and you have an iOS device, then you'll never be happy with Bluetooth audio, regardless of the receiving device. That's all it supports (unless I'm reading that specifications document wrong).

Look for speakers/receivers that support Airplay for full quality (it uses ALAC). Who knows, maybe they'll start including it in cars.
--
University of Southern California - Fight On!


Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

I believe you are right about A2DP always re-encoding the audio - regardless of the source - and as well all know going from one lossy format to another will always result in some degradation of audio quality.

I think at the present time that would require the head unit to have a wifi link to your device - though maybe that will change in the future as the newer generations of BT do support higher data rates and there were rumors of future support for AirPlay over bluetooth on Macrumors some time ago as I recall..



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET
reply to Count Zero

said by Count Zero:

Nice wikipedia quote. That means IT CAN but does not enforce the support for all of those profiles except SBC (low quality profile).

--PEACE

Any device intended for music playback is going to support, at a minimum, MP3. Any device I've ever used as anything more than a glorified headset or speakerphone has supported codecs other than SBC; it's not hard to tell.


Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

Probably, and not at a rate higher than 320kbps - but not a lossless format so any music from your device will require that it be re-encoded for BT and overall disappointing quality/



Thinkdiff
Premium,MVM
join:2001-08-07
Bronx, NY
kudos:11
reply to BronsCon

said by BronsCon:

Any device intended for music playback is going to support, at a minimum, MP3. Any device I've ever used as anything more than a glorified headset or speakerphone has supported codecs other than SBC; it's not hard to tell.

The playback codec is different from the codecs used in A2DP. MP3 is an optional codec, and it's not enough for the receiver to support it. The sender must, too.

In the case of iOS, it appears only AAC and SBC are supported. I suspect it would be difficult to figure out the percentage of A2DP receivers that support AAC.
--
University of Southern California - Fight On!


Michail
Premium
join:2000-08-02
Boynton Beach, FL
kudos:1
reply to skeechan

said by skeechan:

Haven't messed with Airsync that much other than just try it out with airplay and a movie file I already had on my tablet. I haven't tried streaming another stream.

I contacted their support and they said that they are evaluating adding in Airplay as a system output for android devices.

That would be cool when/if they do. BT and DLNA suck horribly compared to Airplay.


BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

1 recommendation

reply to Thinkdiff

I understand the difference between playback and transfer codecs and how bluetooth in general works, but thanks for the explanation for anyone who may not.

The example I gave earlier (to which I was still referring) involved an Android phone marketed for its media support and an automotive head unit, so arbitrarily limiting the discussion to AAC at that point really does nothing.

The fact is, a good player will, assuming the playback and transfer codecs are the same, not even bother transcoding and will just send the raw data, which the receiver will decode and play. Since I know my head unit supports WMA, MP3, and PCM as playback and transfer codecs (WMA? really? okay, I'd be less than surprised to find out that nothing else supports that for transfer, because... WHY?!) and I built my music collection out of 320k VBR MP3s based on the fact that my previous head unit supported MP3 but not AAC (via USB or files burned to a CD), coupled with the fact that my phone supports MP3 (possibly PCM, as well, but in this scenario there's no way to tell if it's using it) as a transfer codec, it doesn't matter whether I put the files on a USB stick and plug them into my head unit or stream them over bluetooth, the decoding will be done by the head unit and there will be no loss of quality.

Would I have preferred to use AAC? No, not really, because it's not as widely supported for playback and I don't care how good a codec sounds if I can't hear it. Even my Pioneer head unit, one step down from the top of the line of the current generation, which has full iPhone support doesn't support AAC; it pulls an audio stream, transcoded into a different format (probably MP3) because, as discussed several threads ago, USB doesn't handle analog audio -- so if my head unit doesn't handle AAC, how's it play iPod audio?

Docking isn't always better. Just sayin'.


Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network

Our headend supports AAC/MP3/MP4/WMA. All I know is that I can't tell the difference between AAC and MP3 (haven't play WMA files) audio in our car. No one else can either. My guess is that the BT is carrying the data and the HE is decoding, just as you say.
--
“The future must not belong to those who slander the prophet of Islam." - Barack Obama, UN Speech 9/25/2012. Ever hear of the First Amendment, BO? Vote Romney/Ryan and take America back.



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

1 recommendation

said by Badonkadonk:

Our headend supports AAC/MP3/MP4/WMA. All I know is that I can't tell the difference between AAC and MP3 (haven't play WMA files) audio in our car. No one else can either. My guess is that the BT is carrying the data and the HE is decoding, just as you say.

Being an early-adopter (I've been ripping my own CDs since before MP3 was even a thing) I've become quite familiar with transcoding artifacts, even when re-encoding to the same format and bitrate with an encoder that's tweaked slightly differently, and I've become quite good at recognizing them. It's funny that people on these boards assume that anyone who disagrees with them is simply uneducated or inexperienced, but given my own experience, I'm going to assume you are similarly experienced when you make these statements.

Just another case of projection -- "It's what I'd do, so it must be what everyone does."

But, then, you've been around here long enough to know how dangerous it is to make contradictory statements on these boards.

Back on topic, I think the argument being posed was "just because it's possible doesn't mean it's happening; and because I've never seen it and you can't prove it, it's not happening", which we both know is a BS argument. Thanks for the backup and good luck standing against the onslaught of argument you'll see for it.

Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network

I have to admit I like the technical discussion going on. But at the end of the day, if the music sounds good for us, that's all we care about. And typically whether we're in the car or at home, we rip at a high enough bitrate that the sound quality is pretty good throughout. I went and did a huge purge of everything that was lower than 256 kbps. Most everything we have now is at 320 kbps. Good enough for us. Again, we're not audiophiles.
--
“The future must not belong to those who slander the prophet of Islam." - Barack Obama, UN Speech 9/25/2012. Ever hear of the First Amendment, BO? Vote Romney/Ryan and take America back.



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

Now that's what I'm talkin' about!

If I wanted concert quality sound, I'd be recording from virgin vinyl at 24-bit 96khz, to be played back from an SSD installed in a vehicle-mounted PC connected directly to a pair of $5k 2Kw digital amps powering an array of speakers costing no less than $20k.

But, since I just want to enjoy my music without having to fiddle with cables or spend 3mo salary, Bluetooth works great.



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

whatever, if you're saying that your audio equipment, your sound files or your ears cannot discriminate between BT and wired audio then fine.



BronsCon

join:2003-10-24
Walnut Creek, CA
Reviews:
·SONIC.NET

1 recommendation

Yes, that's right, I can tell when a file has been transcoded, usually including the from and to which codec, often down to which encoder was used, but my ears are the reason I can't tell the difference between bluetooth and analog. It has nothing to do with the *fact* that the audio is being sent without transcoding; nope, that can't have anything to do with it.



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

Except it isn't being sent that way. You're making false assumptions. »soundexpert.org/news/-/blogs/blu···ity-a2dp

Notice that even though many devices support MP3 and other codecs, in practical use nothing uses it. Your device maybe transcoding to a 320 kb stream, but it's still re-encoding the file.



Thinkdiff
Premium,MVM
join:2001-08-07
Bronx, NY
kudos:11

That's assuming SBC is the only available codec. Why do you claim nothing uses MP3 w/ A2DP?

BronsCon is correct that if the sender and receiver both support MP3 in their bluetooth stack, then it's possible no transcoding takes place (I have no idea if this is how Android does it.. I couldn't find very clear guidelines like that Apple tech document. Android does support SBC/MP3/AAC for A2DP though). You could check by comparing CPU usage while playing an MP3 locally and then playing the same MP3 via BT (more usage may indicate the MP3 is being re-encoded).

If you're using an iOS device, your chances of getting good quality audio over BT is likely much lower as only AAC at a specific bitrate is supported. So your only options are re-encoded AAC or SBC, depending on the receiver. I bought a $10 bluetooth receiver off eBay awhile ago for use with my iPhone. Unsurprisingly, it sounded like shit (most likely only supported SBC).
--
University of Southern California - Fight On!



Count Zero
Obama-Biden 2012
Premium
join:2007-01-18
Winston Salem, NC

In the article I referenced he pointed out that although the Bluetooth headphones he was discussing supported MP3 over Bluetooth, in practical terms the devices used SBC regardless.



Thinkdiff
Premium,MVM
join:2001-08-07
Bronx, NY
kudos:11

That was 2008. I'd be surprised if that's still the case, but maybe.

Edit:
According to this, the issue with those headphone, specifically, is that the included transmitter only supports SBC. It seems if you use them with a MP3-capable transmitter, it'll work properly. So the author's premise may be incorrect due to the crappy transmitter Sony included:
»www.avforums.com/forums/headphon···ity.html
--
University of Southern California - Fight On!