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Thread: Testing 3,2,... (keywords: WinMLS, S2000, IB)

  1. #11
    Senior Member cvjoint's Avatar
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    No, I appreciate it. This is some cleaver peer review process. When I posted that I was doubtful people would buy my "hunch" which is all that it is, based on my 1 hour testing. I didn't get the mid completely out, I have the fan relay or whatnot puking a third of my samples, and the subwoofer LP is binding. I am also strapped for time. Got nearly 300 upper division econometrics exams to grade before I head out to Vegas in the morning or I would be out there running sweeps. Keep up the good work.

  2. #12
    Senior Member cvjoint's Avatar
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    Book 2: Making use of the soft top

    Abstract

    The S2000's soft top is vinyl. If the vinyl can create a 'cabin', then the difference between top down and top up should be cabin gain.

    Results


    First, here is a picture of how the subwoofer setup performs when all EQ, filters, and other speakers are defeated. Keep in mind that my Clarion amp. only has a frequency response up to 250hz, so judge from there down. At some point I'll test the subs on a full range amp to see how far it extends up, I know these subs can do woofer duty at the very least.

    Figure 2


    What you are looking at: 3 samples of a sweep in WinMLS. There is some odd behavior at 3khz and 15khz, but luckily it's way outside our window of interest. Testing was performed with me in the seat. I varied the output a bit over the three samples to get the cascade look. You can see that the FR is largely unchanged over the three measurements. Now let's see what happens when I put the top down.

    Figure 3


    Legend:
    Top up - red
    Top down - blue

    To verify the results are robust I ran 6 sweeps, three top down three top up:

    Figure 4


    The problem with the testing above is that the soft top folds over the region where the subs fire towards the cabin. We could have a condition where the wave gets absorbed/blocked by the top. For that reason I also ran a test where the soft top was half way opened (pics coming tomorrow).

    Figure 5


    Legend:
    Red-top up (cabin gain?)
    Blue-top half open (I'm thinking this means no cabin gain, no subwoofer restrictions either)
    Black-top down (top folded over the subs)

    Thoughts
    I take the Blue vs. Red in the last picture to be the best version of the test so far. If the difference between these two is cabin gain then it's something like up to 10db from 25hz to 45hz. This is somewhere between the theories we were forming based on the first teaser figure.
    Last edited by cvjoint; 03-23-2011 at 05:57 AM.

  3. #13
    Senior Member cvjoint's Avatar
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    Quote Originally Posted by cvjoint View Post
    Legend:
    Red-top up (cabin gain?)
    Blue-top half open (I'm thinking this means no cabin gain, no subwoofer restrictions either)
    Black-top down (top folded over the subs)





  4. #14
    Devil's Advocate Adam_MSS's Avatar
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    I think it would be interesting to try it with top up/windows up, then top up/windows down. Having an S2000 myself (for only another 60 days :cry, I'm rather confident the top isn't providing a substantial barrier to LF waves, but the windows certainly could be.

    Great experiment in general. It's awesome to see members testing concepts for themselves.
    You don't use science to show that you're right, you use science to become right. - R.Munroe

    The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them. - W.L.Bragg



  5. #15
    Tester Extraordinaire ErinH's Avatar
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    Take t a step further and do some impedance sweeps in the various situations. You should get some very interesting results...
    Your ears: The best tools you have... and they're free, too!

  6. #16
    Senior Member cvjoint's Avatar
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    Quote Originally Posted by Adam View Post
    I think it would be interesting to try it with top up/windows up, then top up/windows down. Having an S2000 myself (for only another 60 days :cry, I'm rather confident the top isn't providing a substantial barrier to LF waves, but the windows certainly could be.

    Great experiment in general. It's awesome to see members testing concepts for themselves.
    You bring up a good point. Coming up next!
    What's happening to the S2000? :stop:

    Quote Originally Posted by ErinH View Post
    Take t a step further and do some impedance sweeps in the various situations. You should get some very interesting results...
    I just looked this up. My level 1 software doesn't offer it. What would I do with that?
    $150 more would get me level 2 with the above, 2 channel operation, and phase response.
    $450 more would get me level 3 with sinusoid THD readings. :eek::wtf:

  7. #17
    Tester Extraordinaire ErinH's Avatar
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    the easy route would be this:
    Dayton Audio WT3 Woofer Tester
    Your ears: The best tools you have... and they're free, too!

  8. #18
    Senior Member cvjoint's Avatar
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    Oh I see what you mean. I am generally interested in post driver selection testing. I leave the raw driver testing to someone better fitted for the task...you haha. One day I'll be able to do this:

    THD measurement baby! But for now I'm going to cry. Thanks for ruining my utopia I had going on here with a level 1 license.

  9. #19
    Tester Extraordinaire ErinH's Avatar
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    I suggested the wt3 because it's very interesting to see how qts changes with each of the situations Adam mentioned. They do change and some are pretty large differences.
    Your ears: The best tools you have... and they're free, too!

  10. #20
    Senior Member cvjoint's Avatar
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    Clever! I'll see if anybody has one of these at the next local meet. I just have to basically disconnect the sub wire to the amp and clamp on the WT3 right?

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