Feedback problem with shaker amp

Discussion in 'Archived Threads 2001-2004' started by DonnyD, Aug 11, 2001.

  1. DonnyD

    DonnyD Screenwriter

    Joined:
    Jun 12, 1999
    Messages:
    1,145
    Likes Received:
    0
    Trophy Points:
    0
    Need some input from you guys on this problem....
    I just added two Aura Pro shakers to my system and hooked them to an old Technics amp. I ran the signal to it by splitting the mono sub out signal from a RXV1 (one to my SVS and one to the Technics). I ran the signal to the CD input of the Technics. All this sounds and feels great but when I turn the Technics on, I get a loud pop out of the SVS sub. Seems like the Technics is sending some sort of feedback up the line which in turn is getting back down to the SVS. The Pros replaced a set of the smaller shakers which had their own amp also but I never had this problem.
    Any suggestions on how to eliminate this?
    ------------------
     
  2. John H

    John H Second Unit

    Joined:
    Nov 27, 1998
    Messages:
    472
    Likes Received:
    0
    Trophy Points:
    0
    Are you using the PC or CS version SVS?
    I'm sure you have thought of this. If you are using the CS with an outboard amp you need to turn on the technics first and SVS last. If you are experiencing noise during technics shutdown reverse the sequence during powering off.
    If that is not an option and you are using the auto on feature wth a PC version you may want to reduce the SVS amplifiers level slightly and compenate by raising the LFE/SUB line level signal in your receiver. This should attenuate the pop.
    Also does your RXV1 have split LFE preouts like the DSP-A1? You may try combining the L/R and feeding the technics spearatley. I beleive they are isolated.
    I could be wrong on this one. Could this be an AC problem? Are your technics and SVS on the same AC circuit? You could try using different circuits for the two.
    And then again I could be wrong on all of the above advise! [​IMG]
    John
    ------------------
    Bedroom Based Theater
    [Edited last by John H on August 11, 2001 at 08:54 AM]
     
  3. DonnyD

    DonnyD Screenwriter

    Joined:
    Jun 12, 1999
    Messages:
    1,145
    Likes Received:
    0
    Trophy Points:
    0
    Got it figured out....I think.
    I'm using the 20-39 PC SVS auto on mode but changing that around did not help. I changed the feed to the Technics from using the splitter from the RXV1 to using the output on the SVS itself. This apparently has cured the pop. In doing all this, I apparently have also kinda figured out the SVS settings too. Everything is pounding and shaking much to my delight.
    ------------------
     
  4. John H

    John H Second Unit

    Joined:
    Nov 27, 1998
    Messages:
    472
    Likes Received:
    0
    Trophy Points:
    0
    Does the SVS implement any high pass filtering on it's output or is it a straight pass through?
    John
     
  5. DonnyD

    DonnyD Screenwriter

    Joined:
    Jun 12, 1999
    Messages:
    1,145
    Likes Received:
    0
    Trophy Points:
    0
    Actually haven't even checked the SVS output config but shakers appear to be only responding to bass signals. Changing the turn-on sequence also appears to reduce the pop.
    Another strange thing I found was that I needed to reverse polarity on ONE of the shakers to get them to really fire up. This was also the case for the first set that I had. They really make a difference in an HT setting.
    ------------------
     
  6. John H

    John H Second Unit

    Joined:
    Nov 27, 1998
    Messages:
    472
    Likes Received:
    0
    Trophy Points:
    0
     

Share This Page