Velodyne CHT-10 given up the ghost? HELP!

Discussion in 'Subwoofers' started by Simon Young, Jan 22, 2008.

  1. Simon Young

    Simon Young
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    I've been very happy with my Velodyne CHT-10 subwoofer until recently, when it began to sound awfully quiet. I've got it connected to the subwoofer pre-out on my Harman Kardon 4550 receiver, and am using direct mode (i.e. bypassing the subwoofer's internal crossover) which I've always found satisfactory. I've got my receiver configured to output just LFE to the sub, with full range frequencies output to all the other speakers. However, even in parts of movies that I know are incredibly bassy, even with the subwoofer's volume turned right up to maximum and the subwoofer volume on the receiver raised up to +10dB, all the Velodyne can manage now is a pitiful little rumble. I've just switched over from a Denon 2900 to a PS3 as my main source, which I feel has exacerbated things somewhat. You see, the Denon enabled me to boost the bass output to compensate for low bass on SACD recordings. Boosting the bass in this way gave me somewhat satisfying results from the subwoofer, even after it started to get quieter. But now, with the optical output from the PS3, the subwoofer is next to useless.

    I've tried disconnecting, reconnecting, resetting the receiver, checking the PS3 audio output settings, adjusting all the settings on the subwoofer, and still nothing. Can anyone suggest anything else I might try, or has my sub really given up the ghost? I hope not, as it was fairly expensive and I've only had it about 3-4 years. :confused:
     
  2. chrisgeary

    chrisgeary
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    first of all, change the cable between the amp and sub!
    secondly, connect an mp3 player directly to the sub input, starting with the sub gain right down low of course. this will isolate your sub from the rest of the system and verify that with a known good output, it generates bass. if this turns out to have the same weak output, again with the gain down low, continue playing music into the sub and gently wiggle the connections and controls of the sub to check for a loose connection.

    if all of this fails, then its probably time for a service at a dealer. unless you are handy with a soldering iron (and electrically aware) that is. you could check for dry joints.
     
  3. Gerbil

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    Hmmm, my CHT-10 failed a couple of months ago, not quite the same problem as yours though. Mine would work if I left it switched on all the time, but if I ever turned it off then it then it seemed to need to warm up overnight before it would spring into life again.

    You could try Red-Line who are the UK importers, but they weren't particularly helpful in my case. They confirmed that a new amp board would be approx £100 with shipping on top, but refused to sell me one directly despite it being easy to swap out. They were insistent that I took it to a dealer which as far as I was concerned just made the repair even more uneconomical.

    In the end I put the £100 towards a Monolith which at least looks more like a piece of furniture than the cheap black finish on the Velodyne.

    Good luck if you go down the repair route hopefully you'll have better luck than me.
     
  4. Simon Young

    Simon Young
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    Thanks for the comments guys, very helpful!

    OK, I have made some progress. I tried swapping out the cable for another phono-to-phono I had lying around. Made no difference. I guess this doesn't necessarily prove that the cable was at fault, as the replacement cable may also have been unsuitable or faulty. Anyway, next I tried plugging in my iPod nano directly using a 3.5mm to twin-phono cable I had lying around. To my surprise, I got stonking bass even at low volumes on the subwoofer! I guess this proves that my subwoofer isn't screwed.

    Next I tried resetting my receiver to see if the settings had been scrambled. Re-input all my settings and tried again, but still no joy. I wondered if it was simply the receiver's subwoofer pre-out that was causing the problem, so I hooked up my old Denon DVD player to my receiver's 6-ch analogue inputs and played a bit of Terminator 2. To my surprise, I was getting bass (albeit slightly weak bass) from the subwoofer. No bass boost on the Denon, same settings on the receiver. So basically, that leaves three possibilities as I see it: either my optical cable is dodgy and isn't carrying .1 from the PS3, or my receiver is losing the bass somewhere in the digital-to-analogue conversion, or there's a setting somewhere on the PS3 to control LFE. The last option seems unlikely, however.

    Hmmm, what do you guys think? It's a bit of a mystery. I don't really want to go spending money on a new optical cable and new subwoofer cable just now. However, I was contemplating buying a new receiver anyway. Maybe I should just assume it's the receiver's fault and hope a new one will fix the problem? :confused:
     
  5. Gerbil

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    I don't have a PS3 so I've no idea if the following helps, but it appears that the PS3 output options have to be set to bitstream for Dolby Digital to pass through to the amp via optical cable. The default appears to be LPCM.

    A quick google for

    ps3 dolby digital settings lfe

    suggests your not the only one who's got the problem.
     
  6. Simon Young

    Simon Young
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    Cheers, but I've always had the PS3 set to output bitstream via optical. It does indeed seem that the PS3 has a problem outputting LFE over optical. Perhaps the simplest option would simply be to upgrade my receiver and connect the PS3 to it via HDMI. That might cure the LFE problem. :rolleyes:
     

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