Smartphone & Pocket PC magazine - Comments for "The A2DP support & sound quality & power consumption of the Microsoft and Widcomm BT stack compared; a lot of new A2DP i"

I've just been told I'll get the new A2DP headphones next week, I'll publish some really extensive compatibility reports.

First, thanks!

I don't really know why the MS BT stack sounds OK with some stereo headsets, unlike with the rest. As soon as I receive some new A2DP headphones (I've been promised next Monday), I'll make some serious quality comparisons.

As far as I know, it was in WM5 AKU3 (delivered with, say, the Trinity) that MS has ever made an attempt to increase the sound quality. I don't know much about Crossbow; however, I've never seen any official, public MS announcements stating CB would have better A2DP sound quality than WM5 AKU3. That is, I don't think CB has better A2DP support than AKU3. (At least MS didn't officially state so.)

(BTW, I've also tested the AKU3 quality with the Trinity and the 590A. The same crap as with pre-AKU3 BT stacks...)

I, personally, am trying very hard to "push" the MS folks to increase A2DP quality in the MS BT stack (along with reimplementing BT DUN in AKU3 and, preferably, making Internet Sharing and BT PAN more general); hope they'll listen to my complains, advice and remarks.

Sure I have.

New info: the MS BT stack A2DP bug is apparent with some headphone models while, with the Jabra, isn't. See the above-linked PPCT frontpage link for the latest discussions.

Iâ€™ve played a bit with (drastic) low-pass filtering with Pocket Player to find out whether not letting high frequencies (which can cause aliasing) helps the situation.

Nope. It only worked when I set the (drastic) cut frequency to around 800 Hz (that is, I havenâ€™t let anything out of the PDA above 800 MHz). It seems the most affected frequency band is between 800 Hz and 3000 Hz â€“ that is, the frequency band mostly occupied by human sound. This is why Iâ€™s mostly with (clean) singing that the very bad distortion can be clearly heard.

In addition to the above-linked / mentioned VÃ¤rttinÃ¤ title, Iâ€™ve also collected some titles that sound (in cases, much) worse with the MS BT stack than with the Widcomm one (trust me: they DO sound much worse. Iâ€™m pretty much into Hi-Fi â€“ Iâ€™m not a noob in sound engineering and related areas). Sorry, theyâ€™re all Finnish; the case must be the same with English stuff (make sure you listen to some sound with pronounced singing, let it be either female or male). Dunno if they (or demos of them) are available on the Web; if you canâ€™t find them, give a try to the already-linked VÃ¤rttinÃ¤ title, it contains enough singing to show you the difference.

Clearly audible difference:
Pihikoppelo â€“ Kultamunat â€“ Kraatari (4th title on the CD), Talon perijÃ¤ (8th), Siantappojenkka (10th)

Awful with the MS stack:
Pihikoppelo â€“ Kultamunat â€“ Vangin kohtalo (6th) (male singing!)
Jyri Makkonen - Ja pokasaha soi â€“ Palapan Killi (19th)
Maailman Matkaajat - Mielen valtias (7th)

Note that the source format has no effect on the effect â€“ they can even be uncompressed WAV files, the distortion will be heard.

Iâ€™d like to point out again that Iâ€™m a Hi-Fi / audiophile guy. That is, I notice a lot of things (for example, excess distortion) ordinary people may not notice. My music preferences arenâ€™t in the instrumental-only world either (with them, the distortion will be much less conceivable for the frequency band reasons outlined above. That is, if you only listen to, say, jazz, you may never run into this problem at all). Also, as my BT A2DP headphones (Plantronics Pulsar 590A) are the best (according to most A2DP people), sound quality-wise, with much worse headphones, the quality difference between the two BT stacks may be less pronounced.

Jason, excellent idea! I'll thoroughly test pre-filtering and let you all know about the results.

I still don't have an (official) AKU3 ROM or AKU3-based model. Hope it'll be better than the sound quality in AKU2.

Dunno about AKU3-based new hacks; however, I don't think the XDA-Developers folks won't release an updated hack if it's really worth it.

Smartphone &amp; Pocket PC magazine - Comments for "The A2DP support &amp; sound quality &amp; power consumption of the Microsoft and Widcomm BT stack compared; a lot of new A2DP i"

Smartphone & Pocket PC magazine - Comments for "The A2DP support & sound quality & power consumption of the Microsoft and Widcomm BT stack compared; a lot of new A2DP i"