Getting the horn - well 2 to be precise...

Discussion in 'DIY Discussion' started by speedy.steve, Oct 25, 2010.

  1. speedy.steve

    speedy.steve

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    Rough freq measure done on my laptop mic. Proper measuring gear will be used on Monday...

    [​IMG]

    This is the single Eminence kappa Pro 15" with JBL 2435 and JBL 2405 as Tweeters & low to mid X/O is for 8 Ohm drivers a 500Hz one but it behaves more like 1kHz here. The 2435's reportedly don't do much below 800Hz...

    This is from where I sit - Bass heads unite - sounds nice from here. Bass guitars really do sound like bass guitars - well so they should with Pro bass guitar drivers in GRF cabs but really it is not too much or out of hand IMO.
    The treble part would be higher with the mic 1m / level with the horn. Perhaps it would be flat - have to wait until Mr Coco come round kindly bringing his measuring gear.

    Keep in mind this was just my laptop with crappy lappy mic from where I sit cos' the lead ain't any longer and done out of curiosity more than anything.

    Looking forward to lots of session with it turned up loud - this rig does loud much easier tbh.
     
    speedy.steve, Nov 12, 2010
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  2. speedy.steve

    speedy.steve

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    Further updates...

    Mr Coco came round with the measuring gear.

    1st up the conical / JBL 2435 with just a big cap on for protection

    [​IMG]

    Here is the Eminence Kappa Pro without crossover

    [​IMG]

    Here is the lot with the 16ohm low pass and 8 ohm high pass

    [​IMG]

    Here's a 1/6th smoothing of it

    [​IMG]

    Then after some more measurements of the low and high pass the Eminence rising impedance was corrected with Zobel circuit impedance stabilization and the crossover designed for 8 ohm low and 8 ohm high pass.

    This is for the DC res and mH from the Emience spec. We actually tried with a slightly lower DC res and so bit bigger cap - all can be played with to test the water.
    [​IMG]

    [​IMG]

    This tightened things up nicely and improved on what I thought was an already good sound...
    Great work Mr Coco. Many thanks for all the help.

    Note some of the measurements did not have the tweeter connected hence the fall off. The JBL's in the conicals work between 1000 - 10000Hz. On that range they do sound wonderfully crisp, clear, pacey and detailed oh and of course that all important audiofool ingredient - musical:)

    So what have I got now? (well will have once I've built the crossover the same for the other side. That is still limping along a bit on the Tannoy crossover...

    A real kick ass pair of speakers that really do from deep effortless GRF bass through the rich mid and upper bass onto horn loveliness of midrange all for less than the price of a pair of carp small towers.
    Really happy and look forward to finishing the horns / building and boxing the crossover components.

    Hopefully the new crossover bits will arrive today or at latest tomorrow so the evening weekend can be filled with ever lovely horny music.
    If they don't arrive I will finish and varnish the birch ply of the horns and that perhaps would not be a bad thing...
     
    Last edited by a moderator: Nov 19, 2010
    speedy.steve, Nov 19, 2010
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  3. speedy.steve

    cooky1257

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    Great stuff.
     
    cooky1257, Nov 19, 2010
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  4. speedy.steve

    speedy.steve

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    Thanks Cooky, you got the raw driver measurements in the end;-)

    Well, the bits arrived today
    By evening I was staking the 2nd crossover out on a birch ply board that will become a box for the speakers conns in and 4 for the output to low pas and high pass.

    Made the Zobel corrections and connected up to replace the Tannoy crossover - yep all working but forgot to pad down a bit extra on the new side (the Tannoy crossover had that built in).
    Soon sorted.
    Amps warmed up..
    .
    .
    F me, that is good. Gone is the furriness of the previously un-Zobel corrected side. This has great bass weight but taughtness. Hearing subtle mid bass, snare and tom toms I've never heard before - that is always a pleasing thing isn't it.

    So pure and commanding, detailed and attention grabbing when it should be so but sweet and soft when the music is so.

    Many thanks to BigD for letting me come up and hear his Eminence's to ascertain their suitability and big thanks to Mr Coco for helping with circuit dia, calcs and measuring and all advice.

    So commercially available 15" drivers in thick birch plybackloaded horn bass cabs (GRF's) and readily available JBL2435 mids in birch ply 12 petal conical horns and a pair of sensible tweeters (thanks for the load Mr Coco).

    I could start making these for as a complete solution for folk... Cabs, drivers, crossovers all ready to roll and avoid the cost of Tannoy HPD's, Golds or worse still Reds / Silvers.

    What a fun project it's been. Plus thanks for the support and positive vibes from wammers along the way.

    Once finished I'll put some photos up of the horns and crossovers etc...
     
    speedy.steve, Nov 19, 2010
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  5. speedy.steve

    i_should_coco Monkey

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    You need to update your avatar! :p
     
    i_should_coco, Nov 19, 2010
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  6. speedy.steve

    cooky1257

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    Thanks Steve, that 2435HPL is an excellent Be compression driver-I could sent you a blob of aquaplas if you ever feel brave-the effect is subtle but worth it, as is recharging the ferrofluid.
    Cooky
     
    cooky1257, Nov 19, 2010
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  7. speedy.steve

    speedy.steve

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    Done - Just for you:) Need varnish though...
     
    speedy.steve, Nov 20, 2010
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  8. speedy.steve

    speedy.steve

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    Not brave enough for that yet...
     
    speedy.steve, Nov 20, 2010
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  9. speedy.steve

    Stuart

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    Wow. Looks like an excellent project. Congratulations.
     
    Stuart, Nov 24, 2010
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  10. speedy.steve

    speedy.steve

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    Thanks Stuart,

    Got around to whizzing up a couple of boxes for the crossover bits and built them in.

    [​IMG]

    Just a bit of varnish now (well prob not bother as they are going to be behind the cab)... oh and varnish still goes for the conicals too. All this GRF building is taking priority.

    Plenty of room for some nice low DCR inductors in there when BigD confirms they really do sound much better:)
     
    speedy.steve, Nov 25, 2010
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