[Sony Xperia T, TL, TX, V] mdc1983uk:
Heating issue - Phone gets as hot as the 3G transmitter inside when in use no matter what ROM or network you use. BUT the less signal bars you have the more the phone raises the transmit power to keep the connection to network and thus uses more power and generates more heat. Someone living near a phone mast may not get heat after 30 mins of data use but someone else with 1 bar struggling to keep signal will heat up in 3. It's a vicious circle because the lower your signal the longer the data takes to transfer and so phone is not only transmitting a higher power to compensate its also doing it for longer.

Example - A 5 meg file could take 60 seconds to download over 3G in a good signal area and 60 seconds transmitting to a nearby mast won't use much power or make much heat. But that same file on the same phone in a bad signal area could take 180 seconds at high power and would generate a lot more heat than doing the same file 10 times in the good signal area. Multiply that by a few files and you get the idea of how the heat can build up/battery go down quick with anything but good signal... The best advice is simply try and use the 3G when you have a good signal and if you don't and its running at a snails pace switch to 2G. You'd be surprised how often a good stable 2G signal can be just as fast as a weak 3G one, but without all the extra heat and drain the goes with it.

3G is also very line of sight in its transmission due to high frequency band (2.1GHz). This means you can have a good signal from 2 or 3 different masts depending which side of a house you are in. Just moving around while using 3G can cause packets to be resent to different masts in an attempt to pick the best at the time. Nice and cellular like its supposed to be but very power intensive if its changing masts every few seconds. Also bear in mind network side 3G load balancing/cell breathing - the network will kick you off a perfectly good mast, just because you have alternatives available and other subscribers may not. If a few people start downloading through the local mast and it's the only one they can reach, the network says hey lets kick him with a choice onto another mast to balance the load on that one. It may put you on a weaker mast with more free capacity for a better experience but at the expense of reduced battery life.

Another option if you are in the same area most of the time is change to/stick with a network that has 1 local mast not 3 semi-local ones. In the UK I tested a few networks at home and found I could get extra 36 hours battery life on standby if my phone stayed on the one mast the whole time. Another network with 'better' theoretical coverage couldn't match because it was swapping me to another mast in the back garden and yet another upstairs. Over a day that's a lot of battery used just maintaining connection to network without actual usage - 36 hours worth in fact. Sorry this isn't directly related to Omni on the thread, but it serves to show how we can't compare some ROM 'issues' unless we are all running the same kind of tests on the same mast of the same network from the same place. Otherwise there are just too many variables as to why one battery will last longer or one phone will heat more for it to be a fair comparison.

---------- Post added at 02:16 PM ---------- Previous post was at 01:19 PM ----------

Speaker whistle - I really can't agree that our speaker is set too loud. It's not set as loud as stock ROM and Sony managed that volume without breaking the speakerphone so clearly we have some problem. It's only too loud if the sound distorts on max which it doesn't even come close on Omni. Stock maybe on max its bordering on distorting with some heavy bass songs but for ringtones and such it needs to be that loud to be heard in a pocket while in a noisy environment. At least we have the choice of a nice loud ringtone but turning it down to play music if it gets too much. Custom ROM's just aren't as loud in the first place and never will be because of this speakerphone issue.

This speakerphone whistle is just feedback of the same kind you get with a PA system or karaoke machine. If you walk near the speakers making the sound with the mic in your hand you get a whistle no? That's the echo of the sound going round and round from the speakers back into the mic and back out the speakers in a circle - feedback. There are 3 ways to solve this issue in say a PA system :

1: Turn the speakers down (but run the risk of people not hearing them) - works but not ideal

2: Turn down the mic gain (but then shout into the mic) - works but not ideal

3: Which would be used by any decent sound engineer - make sure there is enough distance between the speakers and mic that there isn't a chance of feedback in the first place!!

Sony in their wisdom knew that the bottom mic was too near the speaker to be effective, and since its a phone there is no chance to separate them further so they come up with the sound engineer solution - use another mic that is far enough away from the speaker in use when its in use. That's why on a earpiece call the bottom mic is used (earpiece to ear, bottom mic to mouth, no chance of feedback between the two). On a speakerphone call the reverse should apply (top mic active, bottom speaker is active, no chance of feedback and the phone isn't to your ear so you CAN talk into the top of it without looking like a complete idiot.

I know i'm wasting my time typing this all out again - I did it hear http://xdaforums.com/showthread.php?p=44779673#post44779673 over a year ago and we're still not using the correct solution but I can only repeat and hope someone understands me this time.

Elbowface fix as with many other snd_soc_msm files just reduces volume and or mic gain to keep within tolerances where the speakerphone won't whistle but we are still using the bottom mic for both speaker and handset calls which is far from ideal. If that bottom mic got deactivated on a speaker call (as it is on stock) i'm 99.9% sure we could have the volume considerably louder and the speakerphone won't whistle because the top mic is at least 6 times further away from the speaker than the other mic.

---------- Post added at 02:54 PM ---------- Previous post was at 02:16 PM ----------

Another quick test shows Omni's snd_soc_msn file also fixes CM.

CM clean install default volume is 71 there and it whistles. Omni clean install volume is 72 and it doesn't whistle. Seems good until you realise Omni gets away with that because the mic sensitivity is turned down instead of the speaker. It's reasonable but calling my brother a few times he says i'm quieter on Omni and although the speaker doesn't whistle he can't hear me when i'm away from the phone using it. On stock he can hear my music playing in the next room in the background as you'd expect on a speakerphone and I can hear him through the speaker still in the next room - perfect.

The Sony default snd_soc_msm doesn't work because things that file calls on don't appear to be suported on CM or Omni at the board level. It seems to me with all the people that have looked at snd_soc_msn and failed to get it to work as it should we need to be looking elsewhere. Like when rimmer actually got the top mic working but it took off the bottom mic all the time. Was that because he made a mistake with the file or because the board won't support dual mics or digital mics without the correct options? I'm not seeing much in the way of explanations from devs as to whats going on.