Two Simple Questions About JBL S38

Discussion in 'Archived Threads 2001-2004' started by MikeDierbeck, Aug 12, 2002.

  1. MikeDierbeck

    MikeDierbeck Agent

    Apr 15, 2002
    Likes Received:

    I just got a pair of JBL S38ii about a couple months ago. When I watch some DVD's (whether loud or quiet movies), I seem to get a lot of distortion coming from my two JBL S38's. It's happening so frequently that I don't think it can be the source material on the DVD. I have the SVS X-over disabled and have the receiver crossover settings as follows:

    Front speakers Crossover: 80hz
    Center speaker crossover (S-Center): 80hz
    Surround speaker Crossover: 80hz
    LFE High Cut Filter: >80hz
    and the LFE at 0dB.

    Do these settings seem to be correct? I heard that setting the crossover on the center to 90hz and either lowering the fronts or keeping them the same can help clarity on the center this true?

    Also, I have a question about a function on my receiver called Screen depth: Here's what it says:
    Initial setting: MID
    In a movie theater, sound seems to come from inside the image reflected on the screen. This parameter allows you to create the same sensation in your listening room by shifting the sound of the fornt speakers into the screen. "DEEP" provides the greatest amount of screen depth.

    Now, I sit 18 feet away from the front speakers, so should I change my setting to DEEP or keep it at MID?


  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Feb 1, 2002
    Likes Received:
    The distortion is not normal, mine have been playing for almost a year powered by a 100 watts per channel Rotel amp. I do suspect the problem to be elsewhere though, like a loose connection or receiver/DVD player. I believe it is unlikely that both speakers are defective so you may have to try and isolate the problem.

    I think you should keep the depth at MID or turn it off if you can. The more tweaks and equalizers I turn on the worse the quality it seems.

    Are the allen screws on the enclosure tightened?
  3. ColinM

    ColinM Cinematographer

    Dec 9, 2001
    Likes Received:
    You sit 18 feet away? (!!) Maybe you are clipping your amp. Sony, I'm guessing by the features described. At 18 feet your approximate sensitivity rating would drop from 89db to about 77 - 80 or so, possibly 83.

    How loud do you listen? To get to 105db ref level you'd need ~128 clean watts per channel....not counting compression, etc.
  4. Dustin B

    Dustin B Producer

    Mar 10, 2001
    Likes Received:
    You say you've set the crossover for each channel, and 80hz is fine for all of them. But are you sure you have all the speaker set to use that crossover (ie set to small or what your processor uses as small). If you are feeding them a full range signal that too could be the problem.

    I'm running S38, S-Center with 70W per channel at 14ft and have no problems with distortion (at least at 10dB under reference with LOTR anyways).

Share This Page