Having updated to SF 3.0.3.8, I though I would see if anything had changed with the Pulse Audio speaker/headphone situation:
Speakers continue to operate when headphones are plugged in, and headphone are mono.
Same thing happened in 2.x as well. A bit dissapointing really.
Note that headphones and headset both seem to route to only the headphone jack, resorting stereo operation. And I found a nice GUI program on open-repos simply called "audio output" which lets me change the audio output from the touch interface. So things are looking good.
Good call! I've installed it as well now. The 10 dB problem seems to be across the board. I wrote a little sensors daemon which watched the headphone port and toggled the speakers/headphones appropriately. I had the same issue, and ended up removing it because I had to manually set it anyway.
I'll temper this next bit with the admission that I have been using linux since day 1 - and I actually mean the day Linus posted to comp.os.minix asking if anyone wanted to give his project a try. The two things I hate, no loathe most about modern linux are pulseaudio and systemd. Leaving systemd for another day, my reasons for disliking pulseaudio is that it is so grossly overcomplicated, and has many "features" which lay undiscovered until you really need it. Now I am actually a pretty good programmer, however I still haven't got sailfish (pulseaudio) audio working even close to well. When talking on the phone, the microphone and earpiece are on the same side. Such a simple thing to change you might ask.....I had the same 10dB issue, which resisted all automatic fixes and relied on swapping back and forth. Ironically, bluetooth headsets work flawlessly. I was seriously thinking of removing it and going back to alsa, but it is engrained in sailfish, so I ended up leaving it be.
Anyway, I feel better now I've had a little rant. I totally agree with "audio wierdness". Unfortunately it is mostly by design.