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Thread: WhIch JBL Drivers Horns Xovers and Woofers Would give you most musical DIY system?

  1. #16
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    Quote Originally Posted by edgewound View Post
    You can use a 175, which this system did, as long as it's not an early narrow gap model. 2410/2421/2460/2470 will work as well with a new diaphragm. I didn't do anything to this pair of 175s in order to preserve the wax seals per the customer and they swept great. The LE85/2420/2421 is a stronger motor which will yield increased upper end reach.

    Here's the basic circuit. I ended up tuning it by ear by adding an additional 10uf cap in series with C2 which yields 8uf...and added a mechanical 50 watt L-Pad. Seems it brought the hi pass up to ~1800 or so. I can't really explain what happened electrically in detail, it just sounded right.
    Thank you!
    Not following what you're telling about the caps in series netting you 8uF though?
    In series means subtractive, correct?
    If 8uF was what you settled on and liked, could I just use an 8uF to start with?
    I like your approach, less is more!
    Thank you for taking the time to put this up

  2. #17
    Senior Member edgewound's Avatar
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    Quote Originally Posted by Tony Sullivan View Post
    Thank you!
    Not following what you're telling about the caps in series netting you 8uF though?
    In series means subtractive, correct?
    If 8uF was what you settled on and liked, could I just use an 8uF to start with?
    I like your approach, less is more!
    Thank you for taking the time to put this up
    Sure....start with the 8uF. You won't hurt anything...although my circuit is probably violating all sorts of audiophile CC&Rs...but frankly I don't care. It's what sounded best to my musician ears on many familiar great recordings on CD. I added the extra cap so I didn't need to desolder and muck up the other components, and Solen 400V caps aren't particularly cheap. The 30uF had too much mid through the 175 which made it sound harsh so I had to tame it. The 6dB/oct roll-off on the 130A(reconed to 2220) blended very nicely with the 18dB/oct roll-in with the 175.

    And....You're most welcome.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  3. #18
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    Quote Originally Posted by edgewound View Post
    Sure....start with the 8uF. You won't hurt anything...although my circuit is probably violating all sorts of audiophile CC&Rs...but frankly I don't care. It's what sounded best to my musician ears on many familiar great recordings on CD. I added the extra cap so I didn't need to desolder and muck up the other components, and Solen 400V caps aren't particularly cheap. The 30uF had too much mid through the 175 which made it sound harsh so I had to tame it. The 6dB/oct roll-off on the 130A(reconed to 2220) blended very nicely with the 18dB/oct roll-in with the 175.

    And....You're most welcome.
    Thank you again for being so gracious
    Makes sense now but what I still do not understand is how 30.61uF less 10.2uF gave you 8uF?
    I'm thinking it would be 20.41uF unless I just don't get how caps in series work

  4. #19
    Senior Member edgewound's Avatar
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    Quote Originally Posted by Tony Sullivan View Post
    Thank you again for being so gracious
    Makes sense now but what I still do not understand is how 30.61uF less 10.2uF gave you 8uF?
    I'm thinking it would be 20.41uF unless I just don't get how caps in series work
    It helps to use a capacitance meter to measure the capacitance of the capacitors in series or parallel for that matter. But you can also Google a capacitor calculator and it will tell you. Putting capacitors in parallel doubles of the value but in series it's some other formula such as a reciprocal of certain numbers. I don't remember the formula off the top of my head.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  5. #20
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    Quote Originally Posted by edgewound View Post
    It helps to use a capacitance meter to measure the capacitance of the capacitors in series or parallel for that matter. But you can also Google a capacitor calculator and it will tell you. Putting capacitors in parallel doubles of the value but in series it's some other formula such as a reciprocal of certain numbers. I don't remember the formula off the top of my head.
    Thank you - I figured there was more to it with which I was not familiar
    I always check new caps before installing in a circuit but have never had occasion to verify cumulative values due to in series wiring
    I have only ever wired caps in parallel to achieve a larger target value
    Thank you again for a good idea - you have planted a seed

  6. #21
    Senior Member Jan Daugaard's Avatar
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    This is the formula for capacitors in series:
    https://en.wikipedia.org/wiki/Series...its#Capacitors

    In this case, we have 1 / (1 / 30.61F + 1 / 10.2F) = ca. 7.65F

  7. #22
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    Quote Originally Posted by Jan Daugaard View Post
    This is the formula for capacitors in series:
    https://en.wikipedia.org/wiki/Series...its#Capacitors

    In this case, we have 1 / (1 / 30.61F + 1 / 10.2F) = ca. 7.65F
    Thank you my friend

  8. #23
    Senior Member edgewound's Avatar
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    Quote Originally Posted by Jan Daugaard View Post
    This is the formula for capacitors in series:
    https://en.wikipedia.org/wiki/Series...its#Capacitors

    In this case, we have 1 / (1 / 30.61F + 1 / 10.2F) = ca. 7.65F
    Thanks, Jan.

    It's interesting because this is the same formula for parallel impedance.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  9. #24
    Senior Member turnitdown's Avatar
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    Where does one acquire the Everest horn from the DD66000? I love their looks and obvious sonic contribution.

  10. #25
    Dang. Amateur speakerdave's Avatar
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    There is a sound reinforcement near-equivalent which shows up from time to time on the second-hand market from sound system tearouts in churches and the like.

    2346 horn from the 4660A system.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

  11. #26
    Senior Member turnitdown's Avatar
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    Thanks Dave

    I was surprised to see the PA version uses readily available drivers.

    I have never heard the horn. Its lower loading frequency aside, does it have that big sound of the 2344?

    On the surface it would seem a nice home build on top of a 2235.

  12. #27
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by speakerdave View Post
    There is a sound reinforcement near-equivalent which shows up from time to time on the second-hand market from sound system tearouts in churches and the like.

    2346 horn from the 4660A system.
    I am curious, what was the 4660's purpose? What type of SR?


  13. #28
    Senior Member turnitdown's Avatar
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  14. #29
    Senior Member RMC's Avatar
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    If my memory is correct, this is an invention by Don Keele while at JBL to cover a rectangular area. Clever.

    Please see:

    D. B. Keele, "A Loudspeaker Horn that covers A Flat Rectangular Area From an Oblique Angle", AES, 74th Convention, 1983, October 8 -12, New York. Available on the Net.

    Page one explains the purpose and SR use of it, and on pages 9 and following you can see Don's sketches and preliminary pictures of the defined coverage horn... to which they added a 2225H (4660) and later on a 2226 HPL (4660A).

    Richard

  15. #30
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    Quote Originally Posted by Lee in Montreal View Post
    I am curious, what was the 4660's purpose? What type of SR?

    Big-Azzed ceiling speakers.

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