Mobility Site - View Single Post - A full compliance & test report of stereo Bluetooth sound (A2DP) in iPhone OS 3

Menneisyys · 06-25-09, 07:49 AM

UPDATE (06/25/2009 13:47CET): I’ve continued playing with the A2DP in OS3, all this on a non-jailbroken iPhone 3G.

1.) I’ve thoroughly tested the Plantronics Voyager 855 to check whether it has annoying pauses / stuttering while playing back Wi-Fi content. While there are very short (0.1…0.3s), occassional pauses, only 1-2 happens at most every 2-3 minutes; that is, they’re completely acceptable.

2.) The audio quality of the Altec Lansing BackBeat 903 / 906 is in no way worse than that of the other A2DP headphones. I’ve done some serious tests with THIS (stereo; if you play it back it on Symbian / Windows Mobile under CorePlayer, make sure you choose H264 – High quality for it to be played back in stereo).

Pay special attention to the highs. On headphones with bandwidth-limited highs (e.g., the Pulsar 590), use the equalizer (I’ve used this in CorePlayer) to boost them so that the headphones become fully comparable to the headphones having good highs without any boosting (e.g., the Voyager 855 or the Altec Lansing BackBeat 903/906). Yes, they are indeed more distorted on all headphones (particularly the in no way recommended Cellink one) and on all A2DP-capable phones (I’ve tested this, in addition to the iPhone 3G, on the Windows Mobile 6-based HP iPAQ 210 PDA) – unfortunately, you have to live with this. Being without wires that have certain disadvantages you just can’t fight – in addition to the somewhat less battery life (which I’ll try to test on the 3G some day), the somewhat distorted highs. They, however, aren’t THAT bad – I certainly prefer the somewhat worse sound quality to wires.

To check for the well-known aliasing distortion common to the Microsoft Bluetooth stack prior to Windows Mobile 6, use THIS clip, and, in addition to the highs during playback, pay special attention to the doublebass in the first 5-10 seconds of the song. It’s mostly there that aliasing could easily be heard. (If you can’t imagine what it sounds like, I recommend giving a try to a pre-WM6 Windows Mobile PDA or phone with the MS BT stack supporting A2DP.) No such effect on the iPhone – and, of course, not with the Altec Lansing BackBeat 903 / 906.

3.) I’ve re-run the Wi-Fi streaming + BT A2DP playback tests on my HP iPAQ 210 with all my A2DP headphones, just to be on the safe side. No pauses in the sound at all, unlike with the iPhone 3G (with the latter, except for the Voyager 855 and the Altec Lansing BackBeat 903/906, of course).

Bottom line: it seems the iPhone 3G, unlike most other contemporary, A2DP-enabled mobile phones, has major Bluetooth A2DP and Wi-Fi streaming compatibility problems. If you do plan to watch / listen to YouTube / radio or TV stations, double check the A2DP headphones you want to buy for your iPhone 3G by playing back some YouTube clips and watching some TV stations (for example, in the free netTV Lite) to see whether there are sometimes some second-long drops and pauses in the sound. If there are, never ever get the particular model. These, after my tests, include the Motorola HT820 (at least model D), the Gear4 BluPhones, the With the Cellink BTST-9000-D and the Plantronics Pulsar 590 (as opposed to what THIS JKOnTheRun article states – they’ve only tested playing back local and not streamed contents; this is why they haven’t noticed the Wi-Fi streaming problem). Currently, I can only say the Plantronics Voyager 855 and the Altec Lansing BackBeat 903/906 are the only models I’m absolutely sure will flawlessly work with the iPhone 3G. I think this all is related to some newer technology used by these two new models (BT 2.0 EDR maybe?), which the older / other headphones aren't capable of.

Again, this only applies to playing back streamed contents (YouTube, online radio, TV etc.) over Wi-Fi (but NOT the cellular!) and not local files in iPod or listening to in-game music. Listening to local content and streaming over cellular (GPRS / EDGE / UMTS / HSDPA) is 100% OK on headphones pretty much useless when streaming over Wi-Fi.

(BTW, as far as the Altec Lansing BackBeat headphones are concerned, after repairing it with the iPhone, the initial problem I’ve explained in my first article was gone.)

And now, for something entirely different: the play/pause headphones button starts / stops the playback of the last song in the iPod app, unless you use an app (e.g., the built-in YouTube client) which overrides this functionality. That is, if you use YouTube, the button will start/stop the YouTube playback and not that of the iPod. In a game or a Tv streaming client like netTV Lite, it’s the iPod playback that will be (re)started. Unfortunately, with netTV Lite, the sound of the currently streaming channel won’t return after you stop iPod playback – you’ll need to exit the channel and restart it.

06-25-09, 07:49 AM	#4 (permalink)
Menneisyys Contributing Reviewer Join Date: Jan 2005 Posts: 4,575 Thanked 1 Time in 1 Post	UPDATE (06/25/2009 13:47CET): I’ve continued playing with the A2DP in OS3, all this on a non-jailbroken iPhone 3G. 1.) I’ve thoroughly tested the Plantronics Voyager 855 to check whether it has annoying pauses / stuttering while playing back Wi-Fi content. While there are very short (0.1…0.3s), occassional pauses, only 1-2 happens at most every 2-3 minutes; that is, they’re completely acceptable. 2.) The audio quality of the Altec Lansing BackBeat 903 / 906 is in no way worse than that of the other A2DP headphones. I’ve done some serious tests with THIS (stereo; if you play it back it on Symbian / Windows Mobile under CorePlayer, make sure you choose H264 – High quality for it to be played back in stereo). Pay special attention to the highs. On headphones with bandwidth-limited highs (e.g., the Pulsar 590), use the equalizer (I’ve used this in CorePlayer) to boost them so that the headphones become fully comparable to the headphones having good highs without any boosting (e.g., the Voyager 855 or the Altec Lansing BackBeat 903/906). Yes, they are indeed more distorted on all headphones (particularly the in no way recommended Cellink one) and on all A2DP-capable phones (I’ve tested this, in addition to the iPhone 3G, on the Windows Mobile 6-based HP iPAQ 210 PDA) – unfortunately, you have to live with this. Being without wires that have certain disadvantages you just can’t fight – in addition to the somewhat less battery life (which I’ll try to test on the 3G some day), the somewhat distorted highs. They, however, aren’t THAT bad – I certainly prefer the somewhat worse sound quality to wires. To check for the well-known aliasing distortion common to the Microsoft Bluetooth stack prior to Windows Mobile 6, use THIS clip, and, in addition to the highs during playback, pay special attention to the doublebass in the first 5-10 seconds of the song. It’s mostly there that aliasing could easily be heard. (If you can’t imagine what it sounds like, I recommend giving a try to a pre-WM6 Windows Mobile PDA or phone with the MS BT stack supporting A2DP.) No such effect on the iPhone – and, of course, not with the Altec Lansing BackBeat 903 / 906. 3.) I’ve re-run the Wi-Fi streaming + BT A2DP playback tests on my HP iPAQ 210 with all my A2DP headphones, just to be on the safe side. No pauses in the sound at all, unlike with the iPhone 3G (with the latter, except for the Voyager 855 and the Altec Lansing BackBeat 903/906, of course). Bottom line: it seems the iPhone 3G, unlike most other contemporary, A2DP-enabled mobile phones, has major Bluetooth A2DP and Wi-Fi streaming compatibility problems. If you do plan to watch / listen to YouTube / radio or TV stations, double check the A2DP headphones you want to buy for your iPhone 3G by playing back some YouTube clips and watching some TV stations (for example, in the free netTV Lite) to see whether there are sometimes some second-long drops and pauses in the sound. If there are, never ever get the particular model. These, after my tests, include the Motorola HT820 (at least model D), the Gear4 BluPhones, the With the Cellink BTST-9000-D and the Plantronics Pulsar 590 (as opposed to what THIS JKOnTheRun article states – they’ve only tested playing back local and not streamed contents; this is why they haven’t noticed the Wi-Fi streaming problem). Currently, I can only say the Plantronics Voyager 855 and the Altec Lansing BackBeat 903/906 are the only models I’m absolutely sure will flawlessly work with the iPhone 3G. I think this all is related to some newer technology used by these two new models (BT 2.0 EDR maybe?), which the older / other headphones aren't capable of. Again, this only applies to playing back streamed contents (YouTube, online radio, TV etc.) over Wi-Fi (but NOT the cellular!) and not local files in iPod or listening to in-game music. Listening to local content and streaming over cellular (GPRS / EDGE / UMTS / HSDPA) is 100% OK on headphones pretty much useless when streaming over Wi-Fi. (BTW, as far as the Altec Lansing BackBeat headphones are concerned, after repairing it with the iPhone, the initial problem I’ve explained in my first article was gone.) And now, for something entirely different: the play/pause headphones button starts / stops the playback of the last song in the iPod app, unless you use an app (e.g., the built-in YouTube client) which overrides this functionality. That is, if you use YouTube, the button will start/stop the YouTube playback and not that of the iPod. In a game or a Tv streaming client like netTV Lite, it’s the iPod playback that will be (re)started. Unfortunately, with netTV Lite, the sound of the currently streaming channel won’t return after you stop iPod playback – you’ll need to exit the channel and restart it. __________________ MS MVP- Mobile Devices.