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JBL Radio Distortion Problem

Discussion in 'Gen 3 Prius Audio and Electronics' started by tommyt, Feb 17, 2010.

  1. tommyt

    tommyt New Member

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    IV
    There's appreciable distortion on my 2010 Prius JBL audio system. I'm actually a recording engineer/producer plus my wife has a 2008 with JBL radio also, so I am speaking confidently that there's something not right with the sound that's coming out. I've been looking for a while to see if anyone has the same problem. The distortion I refer too is a high frequency distortion that happens with any source: radio, CD's, & bluetooth Ipod. It's harder to notice on radio since FM radio is so hyped on the high frequencies and AM radio is... distorted to begin with, but its there, for sure. On the Ipod (bluetooth input) and CD's it's very obvious because the original sounds are much more pure than FM radio.

    For those that are audio geeks out there (like me), it's the distortion that you hear when your preamp's output is a little too hot and is clipping before getting to the main amp. It drives me crazy and I'm not sure if there's some knob they can align this at Toyota. (I have a feeling they won't even know what I'm talking about.) :( I'll take it there, nonetheless and hope for the best but wanted to know if anyone feels they have the same problem. For those that are not audio geeks like me, you can easily notice it on a clean source (CD or Ipod), especially on vocals, you hear they have a weird raspiness on top, all the sibilance and breathyness gets "crunchy"...

    I hate to say it but right now my wife's 2008 JBL sounds a lot better than my 2010's. Although, I should add that I've always thought that JBL system sounds a lot more balanced than other expensive systems I've had from makers like Harman Kardon and Bose. Those have always been only highs and lows, but no mids. I like the mids of the Prius. I just hope I can get a clean sound on my 2010!
     
    #1 tommyt, Feb 17, 2010
  2. ScottG10

    ScottG10 Member

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    Probably the best thing to do is to compare it to another Prius on the lot ~ maybe it's common.
    Mine sure sounds great to me though.
     
    #2 ScottG10, Feb 17, 2010
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  3. KK6PD

    KK6PD _ . _ . / _ _ . _

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    As a fellow Audiophile, I can hear your pain!
    I would agree, find a second or third car with a JBL System in it , might as well stop by the Dealers, inform them of the problem, play a tune that helps ID the problem, and while your there, hit them up about sitting in another Pius and compare tonal and distortion quality of several other Prii on the lot with JBL. If you find better results with one of their cars, pull your Service Advisor over to the car that you think works just perfect, and play the same tune for him! He needs a good example of audio, so he has a point of reference to compare to your car to.
    Second note, since the Power Amp is located separately, and it only has a L & R feed you could put a couple of attenuators in line and turn down the input to the amp and really hear if it is overdriven. It is a Hi-Z impedence unbalanced line, so plan your attunation scheme with that in mind! You should be able to hear that distortion go away if that is indeed the problem.

    Let us know what develops!!
     
    #3 KK6PD, Feb 18, 2010
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  4. tommyt

    tommyt New Member

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    2010 Prius
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    IV
    Thanks for your replies. I'm taking your suggestion of taking a CD to compare with other new Prii (I liked that term... :))

    A question for KK6PD, where is the feed for the Power Amp located?

    The attenuator sounds like a great idea, if indeed that is the problem. That should be easy to prove by connecting an I-pod to the Aux Input and lowering it's output to see if it still distorts. If that doesn't work, I would think I might have damaged tweeters, right?
     
    #4 tommyt, Feb 18, 2010
  5. KK6PD

    KK6PD _ . _ . / _ _ . _

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    I have a 2008, but I believe the JBL amp is still located under the passenger seat. Look for a small square box with 3 plugs going into it! There are a couple of posts with the pinout of L & R in them out here that you could seach for to get pin out sequence!
    Anybody else who has the pinout, step to the plate and help this gent out!!!
    As far as lowering the Ipod level into the AUX jack, if the preamp output is hot, that will indeed diminish the distotion , but signal to noise may suffer a bit. It will prove the point, unless the HU preamp itself is causing the distortion! Which then calls for a new HU.

    Here is a little device that may interest you...
    STP-1 Universal Audio Attenuator - 2 channel

    It runs about 55 bucks from MCM. It's exactly what you will need to knock the input to the power amp down to a proper level. Hi-Z unbalanced, or 600 ohm balanced...passive, simple, works!
    It don't get better than that!
     
    #5 KK6PD, Feb 18, 2010
    1 person likes this.
  6. Econ

    Econ Member

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    Five
    Make sure that you have a good reference source. The old story , junk in ..junk out. Not all Cd are created equal.
    Perhaps the sample rate is too low. generally this causes nose to my ears.
    I am under the impression that the JBL is very good and interpets what is imput. I have a CD that was created to test systems out. This is what I use as a reference.
    I also think the FM is too sensitive and you pick up stations that one would not normally receive. I find that true in my area. I listen to a couple of station that I know that I am on the fringe and they are quite acceptable. I do miss the feature of ASL as found in the Honda I frequent that feature when I drive on of the Hondas.

    I do have some reservations on this Prius radio. It is not like the radio in my GS or IS for sure.
     
    #6 Econ, Feb 18, 2010
  7. tommyt

    tommyt New Member

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    Vehicle:
    2010 Prius
    Model:
    IV
    I went to the dealer and, as expected, it was pretty hard to have the guy notice the distortion. We did sit down on another 2010 and listened. To my surprise, that one sounded a bit crunchy in the highs, too. However, the sound was more focused and fuller sounding. I'm starting to believe that aside from the distortion issue, I might have a speaker wired out of phase. That would make some of the sound get cancelled and would explain why some songs sound in mono to me.

    I will try doing the I-pod bya the Aux input today and see if I can drop the volume enough to not hear distortion.
     
    #7 tommyt, Feb 20, 2010
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