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Thread: My 4520 project

  1. #76
    Senior Member Lee in Montreal's Avatar
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    One of my cats is a real basshead. Picture taken while a movie was playing .

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  2. #77
    Senior Member Eaulive's Avatar
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    Okay, today was the big day.
    Me an a friend gathered some 4520s, 4530s, 2225H, 2225H on E140 frames, E145, Pyramid woofers and really cheapo speakers, also Cerwin-Vega P36 and two kinds of 18 inchers (not JBL).

    I'm gonna post the results of those tests here because it answers some questions I had about bass scoops.

    All the readings were made with 3.75VRMS at the driver, taken at a distance of 13'.
    This was the setup that gave us the most consistent readings dealing with reflections, wind noise and other stuff.
    I didn't want to get too close to the speakers and also I didn't want to drive the whole neighbourhood crazy with sweeps (I didn't succeed with this part however )

    My goal today was to make sweeps of the 4520 and the 4530, to check the difference between Stéphane's original 2225H and my 2225 mexican cones on E140 frames (1.35T motor)
    Also I wanted to properly time align my midbass and midhigh units.

    Test # 1: 4520 with E140 as 2225, 3.75VRMS at each driver taken at 13'

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    I took a reading of 102.4dB @ 4m with 3.75 V in each driver, it gave me -32dB on the graph which means that the -30dB line represents approximately 111dB SPL @ 1W/1m

  3. #78
    Senior Member Eaulive's Avatar
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    Now we took a 4530 with the same driver, again 3.75VRMS at 13'

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    Major difference in bottom end, falls more rapidly below 60Hz, also a good 5dB lower ioverall, even if there's only 3dB less in power... mutual coupling works

  4. #79
    Senior Member Eaulive's Avatar
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    This is the same 4530 but with an original 2225H

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    More or less the same, the difference is _maybe_ a little less low end and a little more top end for the E140 frame, that would be consistent with the predictions of a stronger motor.

  5. #80
    Senior Member Eaulive's Avatar
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    Finally, I wanted to check 2 4530 side to side versus one 4530 with the same drivers.

    Blue: 4520, orange: 2x 4530

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    Draw your own conclusions

  6. #81
    Senior Member Eaulive's Avatar
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    Last task was to try to set the delays and EQ on my stack of 4520/midbass horn/2426/2370.

    I arrived to this final result. I could do better maybe, but I had no time.
    Impossible to do better below 200Hz though, the design of the 4520 has a phase reversal inherent to the design.

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  7. #82
    Senior Member Eaulive's Avatar
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  8. #83
    Senior Member pos's Avatar
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    Nice experiment! Thank you for sharing!!
    The 4530 has a dip around 130Hz (more like 150Hz for the 4520) that seems typical of the scoops.

    Quote Originally Posted by Eaulive View Post
    More or less the same, the difference is _maybe_ a little less low end and a little more top end for the E140 frame, that would be consistent with the predictions of a stronger motor.
    A stronger moto should give you for midbass efficiency (higher mass break point) but should leave the lower part unchanged, which seems pretty much consistant with what you measured.
    (to compare you can open each graph in a different tab in your broswer: 2225H, E140/2225H)


    Now why don't you start buying (or building) W-bins?
    (I know they are quite rare on your side of the ocean, whereas they are plenty in europe)

  9. #84
    Senior Member stephane RAME's Avatar
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    Hi Eaulive,
    The measurements are done with the cat?
    It takes two cats for the stereo.

    Stéphane
    Club double 16"
    "Laissez les Bons Temps Rouler"

  10. #85
    Senior Member Eaulive's Avatar
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    Quote Originally Posted by Eaulive View Post
    Hey, I can do the same
    I wanted to take this picture but never got around to it
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    http://www.flickr.com/photos/eaulive...th/6310979828/
    My avatar: 4520 loaded with 2225H on E140 frames,
    1x B&C 12PE32 on custom front loaded horn, 2x 2426 on 2370.

  11. #86
    Senior Member Eaulive's Avatar
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    My avatar: 4520 loaded with 2225H on E140 frames,
    1x B&C 12PE32 on custom front loaded horn, 2x 2426 on 2370.

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