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Tips Optimized Voice Quality

Discussion in 'Android Devices' started by Gene-O, May 30, 2011.

  1. Gene-O

    Gene-O Lurker
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    Hello, I've been an audio engineer for some years and I decided to bite the bullet and see what I could do to get mine and my family's Dincs to sound better, without the clipping of initial and ending syllables. So i spent a ridiculous amount of time over the weekend doing research and trying every trick i could find. Below are the best settings I have found. Now of course, it's a little late in the game what with Dinc 2 out and no more updates for Dinc 1, and in fact, the second noise cancellation mic on the Dinc 2 may have solved the sound issues I objected to (which I believe were caused by poor background noise clipping routines). But for anyone who likes their phone (with extended batteries and battery managers) like I do and wants to get some more life out of it, here's my tips:

    NOTE: In all cases, you'll have to search the forum for each issue that I don't spell out the procedure for. In one case (ironically, the one that made the most audible difference), you'll have to root your phone, which you need to do your research on (Revoked is a good place to start).

    In testing, I used two Dincs, and reset only one parameter at a time and had the same two people, plus myself listen after each test reading the same phrases with the same spacing between words at several levels of loudness, often resetting the phone back to original to compare and make sure we were not fooling ourselves. I'll state up front that in my humble opinion, a lot of the claims of wildly better quality didn't pan out.

    Here's what I've tried that did NOT work, in my professional opinion:

    1) Changing EVRC to EVRC-B using the ##778 routine. This changes the digital protocol used between your phone and the radio on the tower. The net result, is to make the vocal quality less smooth, more gritty and does NOT do anything about the clipped syllables and words.

    2) There have also been some discussions about changing the actual physical structure of the phone in certain places. I have very strong feelings against this as the process I am hearing is quite easy to duplicate in am audio studio and it is very implausible that the answer is not in the software that translates your analog voice into digital bits.

    The following change made a "small" change that i could hear but you may not.

    3) Menu/Settings/Call/Voice Privacy. The default is "checked". This encrypts the data before transmitting it to the tower. I have found this to be a very small improvement if left "unchecked", as if the encrypting/decrypting is not a lossless process. But again, not the largest improvement I've found, and definitely not a solution for syllable clipping. I've left mine off to benefit from the small improvement anyway.

    Here's the one thing I've found that makes a difference that all of us could hear:

    4) FOR ROOTED PHONES ONLY: Changing two lines in the Build.Prop systems document under the category "ADDITIONAL_BUILD_PROPERTIES" near the bottom of the document:
    htc.audio.alt.enable=0
    htc.audio.hac.enable=0
    Once your phone is rooted, you'll need to load a program called "Absolute System" that lets you edit the Build.Prop file. NOTE: It's a bit finicky, but be patient with it.
    In both cases, the default values =1. You're going to change both = 0. And unlike another post i found, only changing audio.alt was not enough. You need to change both audio.alt and audio.hac to =0 to make the most improvement to the voice quality. Now the clipping is reduced to a reasonable level. I think you'll like the improved sound.

    I have not seen any large battery burns or other problems since my changes, but my suspicion is that these functions were added to stretch battery use using the original measly battery in the Dinc's.

    So good hunting, but DO YOUR HOMEWORK. I take no responsibility if you brick your phone. It's a big risk and don't let anyone tell you otherwise.
     

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  2. gwlaw99

    gwlaw99 Android Expert
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    I was able to edit the file with Root Explorer. Select r/w at the top and then press and hold on the file untile the menu comes up. Then select open in text editor. After you make the change, hit menu and then save and exit.
     
  3. bowerman

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    I am unable to find the options listed. I am on CM7. Anyone have an idea?
     
  4. sdrawkcab25

    sdrawkcab25 Android Expert
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    are you using root explorer to locate the build.prop file?
     
  5. bowerman

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    tried root explorer as well as absolute system
     
  6. sdrawkcab25

    sdrawkcab25 Android Expert
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    I haven't tried it. Are you running a custom rom? Maybe the dev modified the build.prop and those lines no longer exist.
     
  7. Andoug

    Andoug Member
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    I'm running CM7 as well and don't see the two lines in my build.prop either. I did see some lines that had the text cyanogenmod in there so I suspect CM7 mods the file.
     
  8. sdrawkcab25

    sdrawkcab25 Android Expert
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    It looks like the suggested tip only applies to sense/htc roms.
     
  9. bowerman

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    Looks like it! Thanks for the help guys. I am thinking about loading up a sense rom and trying it. If i change it in a sense rom, then decide to load CM7 back up, it will not keep the changes right?
     
  10. kenn

    kenn Android Enthusiast
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    What, exactly, do these two settings do if you don't mind me asking? Are they part of a DAC process? If so the question to the CM7 team would be where those settings went and, if gone, what does that mean in terms of phone operation.
     
  11. sdrawkcab25

    sdrawkcab25 Android Expert
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    They seem to be some type of compression, and there may or may not truly be a difference in quality if you change the setting. AOSP roms simply don't use it since the build.prop is not based off of HTC source code. For all we know the setting has nothing to do with audio when in a call.

    I hate to base opinions off post count but that is the user's first and only post and has not come back to clarify.
     
  12. kenn

    kenn Android Enthusiast
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    Ok, here's an interesting observation:

    htc.audio.alt.enable=0
    htc.audio.hac.enable=0

    Those are the current settings in Nils Business Gingersense. I don't know if he changed them or they were set that way in the leaked build... Either way, clipping was really bad when talking to my wife. Way worse than with my CM7 N90 install. I may nandroid this and go back and forth just to see if it is something in the Sense Rom that induces clipping that isn't in CM7 as I don't have near the clipping issues with CM7 that I have discovered with Sense today...
     
  13. sdrawkcab25

    sdrawkcab25 Android Expert
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    I have never tried that rom, but comparing the two sense roms I've used to CM7 and MIUI, I've never noticed any call quality issues.

    And 0 is what the OP suggests you turn the setting to, to avoid the clipping, so it's interesting you experienced it.
     
  14. Gene-O

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    Yeah, well, I don't know you either but I still give credit to what you say. Sorry for the delay. I'm 58 and I don't do a lot of Forum sitting, but I thought after all this work it would be worth posting. I would love to know what those settings control for sure. I know that it makes the most difference if both user's phones have the same settings, which is my case as my family all has Dinc's.
     

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