Ok, I'll answer my own bluetooth questions.
Background: just got the NWZ-A829 to use with my previously purchased DR-BT50 headphones (closed-back/over-ear BT phones). I also have the Samsung P2 and the Insignia Pilot players (both are bluetooth 2.0).
All of the audio effects and equalizers DO work over Bluetooth! (U have the ability to allow/disallow audio options to each paired BT device). The master volume control (side-mounted rocker) is reserved for the wired headphone jack only. U will have to use the BT headset's volume control. The A829 paired easily with the BT50 headphones and for some reason the bass bloat/bulge that was present in these phones when used with the other BT players was mostly-to-nearly corrected. I can't tell but there may be a preset "audio profile" in the A829 for these Sony phones when paired in the player...will know more when I try out a pair of DR-BT21's later this week.
As to audio quality over BT there are settings for the audio quality level verses RF connection in the setup menu. With the highest audio quality setting the fidelity is suprisingly good. Not quite the "air" or texture/depth compared to wired but definately much more than passible for those who need the wireless. I used a venerable pair of ol' Audio-Technica ATH-910 closed-back over-ear phone for a wired/wireless comparison to the BT50. Compared to the Samsung P2 the BT audio quality is definately a step or two up. To the poor Pilot, many steps up
To expand on the BT audio: I also had previously tried the Sony DR-BT22 headsets with both the P2 and Pilot and had to return them due to a irritating distorted/cracking sort of sound, hiss and odd background noises that would appear out of nowhere (not a RF connection problem as these sounds could be repeated perfectly, over & over). Research now leads me to believe this noise was some sort of modulation/re-coding error in the players (data file to PCM to SBC), really bad on the Pilot, not so bad on the P2 and AFAIK non-existent on the A829. I don't know if Sony has better BT implementation/integration, a better BT chipset (Broadcom?, CSR?) or what but it is the best sounding BT pairing I've heard so far. Although still saddled by the lossy SBC codec [and therefore shouldn't make much a difference] the BT sound is better. BTW, the BT chipset in the A829 is 2.0+EDR, the first that I know of in a player [even though the "EDR" part doesn't seem to be used here?].
YMMV but to me the wired connection with Sony also sounded a bit better than the P2; clearer/louder/stronger phone amps with a very slight nod to the Sony on depth/layering and clarity. It was no contest with the Pilot...it was left way back in the dust.
Also noted was what I first thought was an oddity in operation: When the BT is "connected" the wired jack is inoperative (and visa-versa). I thought this strange because the other makes of player's BT and wired outputs could operate in tandem (i.e. 2up listening). But thinking about it, the Sony probably cuts power to the headphone amps during BT operation to conserve battery power.
Otherwise, it seems like a well-built player. Nothing too fancy, good audio with decent build quality at less weight than the P2.
Woof
