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  1.    #1  
    I'd love to use slacker and shoutcast in my car, but the horrible distortion at the high end when using bluetooth really sucks. Does anybody else have this problem? I have had it with 2 different head units, and normal audio (radio, cd, pre connected via Aux, etc) sounds fine. It's only when using bluetooth.

    The convenience of bluetooth is great, but the sound quality as the pre is doing it is really unacceptable.
  2. edlex's Avatar
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    #2  
    Yea me too, although the real problem may be with the speaker in the headset. Just may not be made for high fidelity playback. I have been having issues lately with distortion from my Jabra Stone. Almost sounds like a blown speaker kind of at the higher ranges. Even with phone calls. I'm going to warranty exchange it to see if it's the speaker or the phone.
    FYI: My Pre is as plain vanilla as the day it came out of the box...
  3. #3  
    sound quality over bluetooth isn't that great in general. It wasn't designed for that initially. It was initially designed for voice calls, so frequency range wasn't a priority. The bluetooth 3.0 spec is supposed to fix that, but it'll also require new hardware, so it won't be backwards compatible.
  4.    #4  
    Quote Originally Posted by edlex View Post
    Yea me too, although the real problem may be with the speaker in the headset. Just may not be made for high fidelity playback. I have been having issues lately with distortion from my Jabra Stone. Almost sounds like a blown speaker kind of at the higher ranges. Even with phone calls. I'm going to warranty exchange it to see if it's the speaker or the phone.
    Not a headset. Headunit in the car. As in, audio goes through the car stereo.

    Oh well. Guess I'll take the time to run an AUX cable instead. So much for the convenience.
  5. #5  
    I connect mine to my Alpine using their KCE-350BT module and have noticed the same thing, but I've found it also depends a lot on the source material.

    While A2DP optionally supports direct passthrough of mp3, aac and other stream types to preserve quality, most devices (and probably the Pre) only implement the required low-complexity SBC codec. Even that can be run (as I learned from SAG on my Treo) at different quality levels and bit rates depending how much CPU you're prepared to throw at it. (Makes you wonder what settings the Pre is using?) What it adds up to is that your audio is being transcoded on the fly before being sent across Bluetooth, and depending on the source material and how it's compressed the artifacts of the original compression can constructively interfere with those of the SBC codec to really trash the end result...

    I haven't done any experiments to figure out what source compression works best with the Pre's A2DP, but I keep (wishfully) thinking that someday I will and re-rip my most listened to material accordingly. Yeah right.
    Yeah, uhh... it's Kevin. (KevinT was already taken.)

    PalmPilot Professional, Palm V, Kyocera 7135, Treo 600, Treo 650, Treo 700p, Palm Prē & Prē 2, HP TouchPad & Veer
  6. #6  
    I will say that my iPhone 3G did stream music over BT with better quality than my Pre. However, the lack of decent AVRCP on the iPhone killed that benefit.

    Do what I do, just turn the volume up on the car stereo. Below 20 and I get the BT distortion. 20 and above, its too loud to notice.
  7. #7  
    I suspect that the BT receivers may vary in quality using the A2DP profile. I bought the BlackBerry Bluetooth Stereo Music Gateway which plugs into my Aux port (and is powered off the USB port in my stereo), and I think it sounds pretty good. I use my Pre all the time in my car, and love just being able to drop it in the vent-mounted holder and not fool with any cables.
  8. #8  
    have you tried messing with the volume on the pre? Also what headunit(s) is this happening on?

    I have not tried slacker, but will test it out tonight on the way home and report back if i get a chance.

    Also have you tried any other apps (music, dr poddder etc) to see if the issue is not compression related due to limited bandwith over EVDO? When the bitrate drops its usually the high end that start to suffer.

    On another note, i had a similar issue with a T505. So i turned the volume down some on the pre and turned it up on the HU. Since then i have replaced that set up with a new Eclipse CD5030.

    Again i will report back hopefully tonight.....
  9. #9  
    I A2DP bluetooth stream to my car headunit all the time with Slacker, Pandora and RadioTime. I get small hickups in playback every once in a while and in-between songs/tracks I can hear a high pitched feedback that is masked as soon as something starts to play. I'll try the lower volume bit and see if that improves the "humming".. I'm fine with it regardless..
  10. #10  
    I turned the volume on the Pre all the way up and this seemed to clear up all my problems. It seemed to me that a certain amount of distortion was introduced over BT regardless of the phone's volume. Try changing the volume on the phone up & down and see if the hum changes at all. If it stays constant, then you see what I saw and I just compensated by increasing the volume from the phone.
  11. #11  
    I've been using the Soundfly bluetooth FM retransmitter with my Pre in my car which adds yet another place for distortion to occur. On the streaming services that I tried (Pandora and Slacker) I get definite distortion, but when I play high bitrate MP3's from the Pre, they sound much better. I also found adjusting the volume of the Pre to about 80% helps with distortion.
    - Dan Butterfield (dan@butterfields.net)
  12.    #12  
    Quote Originally Posted by ktessner View Post
    I connect mine to my Alpine using their KCE-350BT module and have noticed the same thing, but I've found it also depends a lot on the source material.

    While A2DP optionally supports direct passthrough of mp3, aac and other stream types to preserve quality, most devices (and probably the Pre) only implement the required low-complexity SBC codec. Even that can be run (as I learned from SAG on my Treo) at different quality levels and bit rates depending how much CPU you're prepared to throw at it. (Makes you wonder what settings the Pre is using?) What it adds up to is that your audio is being transcoded on the fly before being sent across Bluetooth, and depending on the source material and how it's compressed the artifacts of the original compression can constructively interfere with those of the SBC codec to really trash the end result...

    I haven't done any experiments to figure out what source compression works best with the Pre's A2DP, but I keep (wishfully) thinking that someday I will and re-rip my most listened to material accordingly. Yeah right.
    Thanks for the post.

    I had originally started looking into the pulseaudio quality settings on the phone, but I guess that is the wrong place to go. I don't know where (or if it's even possible) to change how stuff encoded/compressed over bluetooth, or if it's just the hardware doing it.

    So,
    I ended up putting the old head unit (which I like better) back into the car, and will just plug the pre in via aux jack. Oh well.

    DrPodder stuff, BTW, would always sound fine. It was only streaming via shoutcast or slacker that I had the problem. I never experimented with MP3s on the device itself, since I don't use it that way.
  13.    #13  
    Quote Originally Posted by davis.rob View Post
    I suspect that the BT receivers may vary in quality using the A2DP profile. I bought the BlackBerry Bluetooth Stereo Music Gateway which plugs into my Aux port (and is powered off the USB port in my stereo), and I think it sounds pretty good. I use my Pre all the time in my car, and love just being able to drop it in the vent-mounted holder and not fool with any cables.
    Hrm. Maybe I'll try something like that if plugging into the aux port becomes too much a PITA. Kinda defeats the purpose of having bought the Pioneer with the capability built in though. Hello, Ebay :-)

    Now, if only I could put a rockbox firmware on my Kenwood DPX701. That would be SO NICE.
  14. #14  
    Is just BT and car stereos? I use BT with my Backbeat 903s stereo headset and the music sounds awesome. I know that the internet radio stations have to deal with bandwidth so the music does not sound as good as regular music on car stereos. When I play Pandora thru my car's stereo via a cable, I have the bass set on +5 and the treble set on -5.
  15. #15  
    I have a Motorola S305 stereo headset and a Blackbery Stereo Gateway. The Blackberry Stereo Gateway work perfecly with my Toshiba netbook (NB200 - same as NB205 in the US) but distortion is present, and annoying, when driving it with my Pre.

    I think it's really an encoding issue as the audio level on the Pre does not change anything. The distorition is also present only at some frequencies (mid-high) as some tunes play fine and others are really bad.

    I was planning on using the Stereo Gateway in my car (thru an wired FM aux input), but reverted to using an audio cable instead as the distortion was really annoying. With the audio cable... no distortion at all.

    When out of my car, I use the Motorola S305. With this headset, I get the same result from my Netbook and my Pre. A bit of distortion, but it is generally bearable. I don't know about these devices capabilities in term of codecs and direct stream support (or how I can find out). But it would be really nice to get a fix.

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