PB2-ISD question

Discussion in 'Speakers' started by TonyWright, Oct 5, 2004.

  1. TonyWright

    TonyWright Second Unit

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    I currently have my PB2 sitting behind a chair and I am concerned that the chair may be hindering the subs' performance.

    I have read a few posts with people talking about having PB2-ISD's set to 1/4 gain and -5 level in the receiver settings. Mine is set to -5 in the receiver, but I have the gain up to almost 1/2.

    Some people talk about having so much output that they experience the "fluttering pants" syndrome. Is this just exaggeration, or should my sub be doing this? I really want to put the sub in a corner, but my wife is a royal pain about it. She likes the reduced visibility the chair provides.

    I have followed Edward J M's setup suggestions to the best of my ability. As far as I know I have it calibrated correctly.

    Any thoughts?
     
  2. Edward J M

    Edward J M Cinematographer

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    Hi Tony:

    The relative setting of the gain on the plate amp really doesn't tell you much, and I wouldn't be overly concerned about it. The signal strength running from the sub pre-out, the size of the room, the placement of the subwoofer in the room (corner loaded or not), and the location of the subwoofer in relation to the listening position, will all affect the relative amount of gain needed to achieve a given calibration level.

    Aside from basic calibration with Avia, it might be good to run a basic frequency response sweep with some test tones, the SPL meter, and the meter correction factors. Or if you want a really rough idea, run the reverse LFE sweep on Avia and look for any major drop-outs in the 30-60 Hz region that might be attributed to room acoustics.

    If the FR sweep shows no obvious anomalies, then try upping the sub calibration level a few dB, and keep it in the 25 Hz tune for maximum output in the most common bass regions.
     
  3. steve nn

    steve nn Cinematographer

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    I have read a few posts with people talking about having PB2-ISD's set to 1/4 gain and -5 level in the receiver settings. Mine is set to -5 in the receiver, but I have the gain up to almost 1/2.
    __________________________________________________ ___

    Just as Ed states Tony. Some to many also use a Y that will cause the gain on your sub to be set at a reduced level after calibration. So when you see their lower gains keep that in mind also. I'm not implying that you use a Y. Just that in corner loading and the use of a Y will lend to the lower gain setting.
     
  4. TonyWright

    TonyWright Second Unit

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    Is there a web page somewhere that contains a "how to" on doing a frequency sweep?

    I must have misunderstood what I was reading before as I thought that a frequency sweep required some software to plot a graph showing dips and peaks in your frequency range.

    Any pointers here would be greatly appreciated.


    Please understand that I am in no way dissatisfied with this sub. It is downright awesome. I had a bunch of people over to my house to watch football last Saturday and I played the Darla scene in Finding Nemo for them. Jaws hit the floor. THe funny thing is that I had all of my windows wide open so sound was escaping there. They couldn't believe the size of the sub for one thing, but when they heard it I just had a big grin on my face. Fun Fun!

    Tony
     
  5. steve nn

    steve nn Cinematographer

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    All you need is a $15 bass disk Tony that will play the individual bass tones from say 15Hz on up. I use Bass Alien which was purchased over at Parts Express. You would then use your meter to read the tones and then add correction and plot.

    Edit> This is not the one I was looking for but it would do the trick.

    http://www.partsexpress.com/pe/showd...number=510-310
     
  6. Kevin C Brown

    Kevin C Brown Producer

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    I use the Autosounds 101 disc:

    http://www.carsound.com/cds.shtml

    Only goes to 98 Hz, but then I switch to a disc Stryke used to have that has 1/6 to 1/3 octave tones up to 20 kHz.

    With a lot of sound editor software on the web, you can make up your own test discs. I use this:

    http://www.goldwave.com/

    An even better way is to use your PC (and its sound card), the Radio Shack meter, a couple of cables and connectors and this:

    http://www.etfacoustic.com/
     
  7. TonyWright

    TonyWright Second Unit

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    Sounds good all. Many thanks for the replies.


    I'll look more into your suggestions.


    Thanks again!

    Tony
     
  8. Eric Ha

    Eric Ha Stunt Coordinator

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    You can also download tones on the net. I cannot give the link being a new member, but others here can give you the snapbug site.
     
  9. TonyWright

    TonyWright Second Unit

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    I located the snapbug site last night and I have bookmarked it.

    I am going to do some more comprehensive testing tonight and this weekend.


    Thanks for everyone's help!

    Tony
     

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