I agree about battery life. Do you listen through the amped headphone jack or the line out?
While I sometimes listen over my Grado headphones, I most often have my X3 running from the line jack out into my car stereo or my DIY "Sprite" boombox I built. Although I've never actually measured the hours of playtime, I have noticed that when running Rockbox, the X3's battery life seems shorter than XDuoo's published specs, even when running from the line out, which surprises me.
Here's my suspicion as to what my be using up the juice... Will some folks please try this little test and confirm that you get the same results? If my hunch is right, maybe we could convince Roman to look into the possibility of solving the issue for us with an update. Here goes:
Boot your X3 to the original firmware with your headphones off and put your ear right next to the X3's aluminum body. You should hear a little click inside as the device powers up. Now, plug your headphones into the headphone jack. You will hear nothing change. Then plug your phones into the line out. You will hear another click. Unplug the phones. This time you will hear a pretty loud click. What the heck is the click? I believe the X3 firmware activates a hardware switch that disables the amplifier circuit entirely when the line out jack is engaged.
Now boot Rockbox and do the test again. There's a click at power on. No clicks at all when engaging or disengaging the line out jack. Hmmm... I think that Rockbox is powering the amp at all times, even when only using the line out. Seems to me that this would definitely shorten battery life.
Can anybody else weigh in on this notion? I guess the real test would be measuring battery life while using the headphone jack vs. line out jack in BOTH firmwares, and then comparing the results. I've just never even used the stock OS except for about 5 minutes when I bought the X3. Has anybody else noticed a difference?