Beolab 7-2 distortion only on some soundtracks

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Home Forums Product Discussion & Questions BeoLab Beolab 7-2 distortion only on some soundtracks

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  • #56427
    DT79
    BRONZE Member
      • Topics Started 6
      • Total Posts 61

      Hi folks,

      Hoping for advice on a strange issue.  I have a Beolab 7-2 speaker used as a centre channel in a 5.1 set-up, alongside BL8000 fronts, BL6000 rears and a BL19.

      These are all being driven from the preouts of an Anthem MRX520. The 7-2 is connected via an RCA-to-powerlink cable which also incorporates a 5v trigger which is connected to a USB socket on the TV

      A couple of months back I first noticed a distortion on loud voices when playing one particular film.  I thought it was a one off and as it was a rip, I thought maybe I’d done something wrong. Since then I’ve noticed it on a few other things from various sources: other rips and also some streaming services. However it definitely doesn’t happen on everything.

      I did wonder whether it was an input sensitivity mismatch and tried lowering the output level of the anthem, but then of course I was turning up the volume commensurately more, so I guess it’s all the same in the end and indeed I don’t think that made a difference.

      It’s a weird one because it never happened before a couple of months ago, and it doesn’t occur on everything.

      Any ideas? Does anyone have the input sensitivity spec for the 7-2, then I can check if that might be the issue?

      I could pick up another 7-2 for a relatively modest cost, but want to be sure that this one is actually faulty before doing that, and at the moment, that seems unclear.

      Thanks for your help.

      Dan

      #56446
      DT79
      BRONZE Member
        • Topics Started 6
        • Total Posts 61

        FYI, in case anyone finds this with a similar issue…

        I’ve confirmed that it really is just certain soundtracks. I dug out the disc of the rip mentioned above where I first noticed the issue and it played fine, even when turned up very loud: no distortion. The rip was not 1:1 I had converted the soundtrack to save space.

        I think the issue might also be with the Anthem Room Correction EQ curve as I tried toggling it off when experiencing the distortion and it reduced significantly.

        I think it might be a combination of the characteristics of the soundtrack and the ARC EQ.

         

         

        #56450
        Die_Bogener
        BRONZE Member
          • Topics Started 2
          • Total Posts 245

          I have something like that with HDMI and DVD Player Software.

          The sound is playing with 16-bit resolution. A loud section of the music/movie can use these 16-bit 100%.

          If you use a software, that is increasing this 16-bit range to make it louder again, then there is a software bug… it’s an overrun of the system, you would need 17 or 18 bit or even more… and these bits are not available.

          It’s a cheap and mean software bug of calculating the value.  It would be better, to limit the sound to the maximum instead making a overrun…

          #56451
          DT79
          BRONZE Member
            • Topics Started 6
            • Total Posts 61
            Thanks for your reply. If I understand correctly, and to put this in terms I understand, what you’re basically saying is that the loud parts of the signal are exceeding 0dBfs which is causing distortion when decoded by the DAC in the AV processor?

            Thats a reasonable theory and would explain why it happens from some sources/soundtrack and not others and why the room correction EQ also appears to have an effect.

            now I come to think about it, I have only heard the problem from different apps on the TV (Plex playing back files or streaming services), not external sources like sky box or blu-ray. Is there some kind of audio setting on the TV that I should be looking for?

            I will continue to experiment with the amp’s eq as well.

            I have something like that with HDMI and DVD Player Software. The sound is playing with 16-bit resolution. A loud section of the music/movie can use these 16-bit 100%. If you use a software, that is increasing this 16-bit range to make it louder again, then there is a software bug… it’s an overrun of the system, you would need 17 or 18 bit or even more… and these bits are not available. It’s a cheap and mean software bug of calculating the value. It would be better, to limit the sound to the maximum instead making a overrun…

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