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Thread: 'MACHINE' level up! (...frankenstein)

  1. #1
    Senior Member demon's Avatar
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    'MACHINE' level up! (...frankenstein)

    hello!

    as some of you might know, i have currently a four-way diy system going with the great 2360 as the centerpiece.
    since the new arrived subs are working great, i now want to start reworking the satellites, the front-cabinets.

    ----------------------
    information about the current state:
    (links=pdf):

    *the horn plays wide range ~8ooHz to ~1okHz, its the centerpiece of the system: JBL 2360 with 2"compressiondriver JBL 2450.

    *above it plays the ol' JBL 2405, but it will probably be replaced with the 2404, after testing.

    *bass is handled by the JBL 2206, reaching from ~69Hz to ~8ooHz in CB internal volume ~6o litres (XO has to change to ~1ooHz, thats important)

    *subbass, provided by 2 subwoofers (stereo) with 2x18 each in BMC RiPol. (no idea about sensitivity here...)

    *controlled by 2xbehringer DCX2496 digital XO.

    ------------------------
    lets discuss some sketches and ideas that haunt me:

    first, id like to modify a pair of JBL 4310-cabinets to house the 2206 and maybe tweeters. ports closed of course.
    since i would like the crossoverpoint not lower than 1ooHz, this could probably work out. but im not sure...
    ---> QUESTION: does anyone know the exact internal volume of the 4310??

    since i like the woofer nearly on earheight, the small box would have to be liftet. under it i can imagine putting all the electronics.
    sketches seen here:
    (i didnt ask, but: thanks ratitifb! i used your iconic picture for this grafix)


    ------------------------


    thinking about it, building new from scratch could bring some advantages. here is a design based on the 4350 (tweeter could be swapped around like seen obove):


    partially used kenricksound-pictures to work with: www.jbl43.com.

    going further, i could also use my beloved JBL 2123. i know it well and always enjoy hearing it. but adding a 1o-inch to a 12-inch?
    thats small steps... better think 15": i always liked the easy of big 15" two-ways play. got class! i would get a new JBL 2226 starting at 8oHz going to maybe 3ooHz, then the 1o" to 1kHz at the max.

    pros:
    fast attack, solid bass: efficient and snappy!

    cons:
    another XO point in the voice area, costs a lot of money, costs a lot of space...

    misc. thoughts:
    highpass the 15" above 8oHz is mean, pointless, but necesarry doe to the subwoofer concept (different story). on the other side, lowpassing the 1o" around 800Hz isnt very smart either.
    with this setup i would have to reduce ingenuity on at least one of these three brilliant drivers: the 15", the 1o" or the magic horn, and thats all not very promising.

    anyway, here some sketches based on the 4344:



    another thing i cant get off my mind is a horn or maybe waveguide added to the 12".
    based on the A7 design, i played around a little not caring much about the right proportions of the waveguide or int. volume of the box.
    you get the idea:



    thanks for any thoughts on this, im really looking forward to discuss this next step for me and my little system.

    cheers,
    mikey


    ps: yes, i know theres already a thread about my system, but i need a new start. so...

  2. #2
    Senior Member jerv's Avatar
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    Hi, Mikey!

    My system looks a lot like yours. I also use the 2360 horn, but with the 2445 driver. 2405 slot for the highs. 2204 in 50 ltr closed cabinets for midwoofer, and 2245 in closed corner cabinets for bass. See pictures.

    These are prototypes. I am not yet done with finishing and mounting, and the crossover networks are not finalised. I'll use the dbx DR260 for the bass and the midwoofer. The 2445/2360 and the 2405's will get passive networks. Measurements indicate possible crossover frequencies at about 80 Hz, 600 Hz and 8 kHz. Amplifiers are a mix of MOSFET and tube units, all DIY.

    Cheers,
    Espen
    Attached Images Attached Images    

  3. #3
    Senior Member Loren42's Avatar
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    The biggest challenge I see is time alignment of the drivers. Ideally, the throat or voice coil for each driver should be the same distance from the listener's ear so that all wave fronts arrive coherent.

    An example where that is going to be a problem is the last rendering you show. Here the tweeter is way forward of the mid tweeter driver. It also interferes with the horn and will cause diffraction distortion.

    One solution is to use a digital crossover with a DSP to allow precision setting of the time alignment for each driver.

    The next challenge will be how the horns and the conventional front mounted drivers play together. A flat front panel can cause a step function in gain for the tweeters of 3 dB. That is a little more complicated to work out.

    The ideal driver alignment when stacking drivers is one over the other in a vertical alignment. There are rules of thumb as far as distances from the center of each driver to the next, but the horns will prevent you from following that road.

    You really want to the higher frequency drivers closer to eye level (in your listening position) due to beaming. Woofers really have a much better off-axis response than tweeters (even horn loaded), so I tend to place them lower in the stack. You still get some ground coupling with the woofers, but you have so many drivers that you either need to build an amphitheater as your living room or live with the compromises.

  4. #4
    Senior Member 1audiohack's Avatar
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    Hi Mikey;

    I have done all the bottom four designs you have there, with all the same drivers, and then some. The 2404 - 2405 works great where you have it drawn.

    Here is some opinion on how to do it. Active crossover and electronic delay. This allows you to minimize the baffle step issues and get the timing right and that will go a long way in making it sound good on and off axis. That is more important than many believe, I believe.

    Since we have all the same stuff, when you get closer to a final plan with phisical measurements I can give you a very close approximation of the cross over and delay requirements.

    Currently mine is five way active, dual mono.

  5. #5
    Senior Member demon's Avatar
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    hello!

    thanks for the info.
    espen: your system looks very nice now!! cool sub, too.
    but long distances between the drivers -wich is a problem i share too, because i have the subs all around the room and, of course, the long throat of the horn. luckily i got programable delays.
    oh yeah: thanks for the heads up, but i use a digital XO for the whole system since i started it. its just very comfortable for testing and offers so many possibilities, like the delays and EQs and whatnot.

    ++++++++++

    back to *leveling-up*, lets discuss the drivers for the lower voice-area:
    i chose not to use the 2123 and i will not buy a 2226, though it would become quite a cool monster... the 12" 2206 will perfectly fit my situation (i must build another system for the beloved 1o"), beeing surrounded by the subs and the horn. everything fits nicely here. only thing special thats on my mind currently is a different type of enclosure for it. im really interested in a VOTT-A7-kind-of-cabinet instead of the closed box.
    --> QUESTION:
    did anyone ever try to use the 2206 in a cabinet like the A7? tried something similar? since i got no woodshop, i just cant built prototypes to test, though i sure would like to.
    the frequencies it will have to handle are ( + - ) 1oo Hz and 8oo Hz.

    ++++++++++

    yes, the tweeters will be placed on ear height (or maybe a little higher aiming down), but that depends on the heigt of the cabinets to come.
    mounting them inside the big horns would sure be good for stereo-imaging, but it would refract the horn of course. this i will test anyway, i can imagine that some damping behind the tweeter could work out. i think the lower, (stereo-) outer corner of the horn (where the mounting holes are (horn upside down)) will be a good spot to try the tweeter.


    thanks for sharing your thoughts,
    cheers,
    mikey

  6. #6
    Senior Member richluvsound's Avatar
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    Hey Mikee!

    this thread is really interesting. You have great eye for design. The images
    are wonderful. If you need any box help let me know !

    Rich

  7. #7
    Senior Member demon's Avatar
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    hey rich!

    thanks. i enjoy designing speakers a lot, and i had some fun dooing the crude doodles above. they are mostly made from the great www.jbl43.com picture sets.
    im awaiting a calculation from a friend concerning the 2206 in a short front loaded horn. im really interessted in building a small horn for it. maybe a backloaded scoop would work out, too?
    ..if not, CB will still work great.
    anyway, i will share any news.

    cheers,
    mikey

  8. #8
    Member tinnitus's Avatar
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    2360a Horns

    First post. Please take it easy. I too have 2360a horns and was thinking of adding a bass cabinet below the horn that was slightly larger than the horn. Initially I'm envisioning an Altec 3184 in a modified Altec 817 cabinet. Close off the side vents but put in the reflex ports. The stock 817 cabinets is around 11 cf so growing it to 12 cf shouldn't be that difficult. Here is a conceptual of the cabinet. The horn flares would extend over the driver a bit (though not shown). I'm still learning SketchUp. THoughts?
    Attached Images Attached Images  

  9. #9
    Senior Member demon's Avatar
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    I'm still learning SketchUp. THoughts?
    yes: i should learn sketchup too!
    thanks for this -first post in my thread, i feel honored. for what i found out now is that i have to let the basshorn pass. simply to big for my apartment...

    but CB will be nice, too. i will present further sketches when i have time, maybe see some sketchup!

    cheers,
    mikey

  10. #10
    Senior Member demon's Avatar
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    so, appearantly i will get a pair of 4435 and just put my horns atop. the original 2344 will be tested of course, but i expect the 2360 will stay the centerpiece of my system, for it beeing a little to amazing to let go.
    when i find the time, i will provide some sketches again. for now im drowning in work...

    cheers,
    mikey
    I'm selling a pair of JBL 4435 in Vienna, Austria

  11. #11
    JBL 4645
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    I think we’ll just have to call you, Frankenstein Mikey.

    I like the last one the horn loaded enclosure with the 2360A mounted on top it fits so nicely.

  12. #12
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    I think, I like the way you think, good luck, looks great.

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