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

  1. #51
    Senior Member cvjoint's Avatar
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    Got my omnimic in at 4:13PM.
    Installed software 4:15PM.
    Calibrated mic 4:18PM.
    Tested my HT setup in whole 4:38PM.

    going out to the car!

    Tested my car's FR, HD and lots of other stuff 5:33PM.

    That's how easy this thing is. Whoo hooo.

    Frequency response, summed L, R



    Harmonic Distortion ~95db



    Harmonic Distortion ~100db



    Highest distortion areas seem to be 65hz and 20hz @ 3% THD. Almost everything else is bellow 1% THD. The majority of the midrange is at .5% THD.
    Last edited by cvjoint; 04-29-2011 at 08:54 PM.

  2. #52
    Senior Member cvjoint's Avatar
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    More tests, more output after I put my headphones on :
    105 db



    110db


    115db


    From about 105db on it's obvious the B&C midbass is putting the brakes on, it's highpassed at 100db, 125hz distortion is representative of that. Higher up the planar is highpassed at 1,600hz. At 2000hz the distortion starts increasing as I increase output. The Neo8 diaphragm is starting to lose composure. At this point I'm close to maxing out the headunit and amplifiers so that's as high as I would go, not to mention the speakers are starting to show stress. Still, the midbass distortion is highest and even that one is less than 9% at 115db.
    Last edited by cvjoint; 04-30-2011 at 04:37 PM.

  3. #53
    Senior Member cvjoint's Avatar
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    After EQ., xovers, and gain adjustment:



    Legend:
    Blue = Left speakers
    Red = Right speakers

    Each side of the car got over 40 averages with the mic orbiting around my head. I used a short sine sweep signal for accurate results. The difference between EQ. and no EQ. is enormous. The FR goes from +-10db without EQ. to +-3 with EQ.

    EDIT: right click image to see the full size picture. Then zoom to full size.
    Last edited by cvjoint; 05-04-2011 at 04:56 AM.

  4. #54
    Senior Member cvjoint's Avatar
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    I started a thread for car testing here:

    Southern California Test Bin - DIYMA.com

    Many things still to do on my car, but I'm eager to see other people's cars as well on this Omnimic setup.

  5. #55
    Senior Member cvjoint's Avatar
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    Got one test of cabin gain that is fairly useful.



    Compared to the Accord, the s2000 has very little gain under 27hz. The smaller interior probably has a lot to do with that. Above 27hz there is a decent amount but the sub box was in the passenger seat in my car whereas the sub box was in the guy's trunk for the Accord test. Quite a bit of output is lost with distance yet they tie more or less around 30hz.

    The trouble with this method is that the distance from the mic to the sub box is almost always different. When I test the sub outside I have the mic 10 inches from the cone. In my car the sub box was on the seat so half a foot away. In the Accord it was over 6 feet away. Relative output levels can be thrown off like that but I suspect the transfer function remains the same shape wise. That is why I chose to match the frequency response curves at 60hz by shifting the plot. This way it's easy to see the changes in cabin gain. The rest is copied form the other site:

    Big thanks to Circa40 for donating the box and JT Audio for tools and hosting. In this series of tests I will be mapping the transfer function of So. Cal. vehicles. Some may find this even more useful than simulating subwoofer boxes in WinISD. More importantly if you combine the transfer functions from these tests with the simulation you can get a very good idea of the final frequency response of your subwoofer.

    Gear:
    Seas CA26RFX
    Sealed box
    180w @ 8ohm from my car

    Design
    Sine sweeps are ran though the woofer from my car. I keep the output fixed across all vehicles this way and the power supply is external. I have a long wire which enables me to drop the sub in any car, anywhere.

    First the sub was tested outside of a car, on the concrete floor facing up. The mic position is about 10 inches from the woofer. I average about 15 sweeps. This frequency response graph is the BLACK line in ALL graphs that I will post for this test.

    All the in car tests are from the driver position. The sub placement varies by car, we can test one location or more.

    Finally, all output levels are matched at 60hz. I do this so that enthusiasts can get a good idea of the shape of the FR graph compared to reference and other cars. I will also state the output shifts I do that are needed to match at 60hz. All graphs will therefore overlap at 60hz by construction.

    First test

    Reference output, Seas woofer outside in BLACK. See how well it matches the manufacturer's white sheet here:

    http://www.seas.no/images/stories/pr..._datasheet.pdf

    Test Car 1: My 2001 Honda S2000, sub on the passenger seat, FR shifted up 6db, BLUE
    Test Car 2: Duckymcse 2002 Honda Accord 4dr, sub in the trunk facing up, FR shifted up 6db RED

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