Zilch's AK Design Collaborative - Econowave Speaker

Discussion in 'Speakers' started by Zilch, Feb 23, 2008.

  1. jackgiff

    jackgiff Super Member

    Messages:
    1,045
    Location:
    Prescott, Arizona
    Cool, that will work out good for me.

    I received my CX-3400, but don't have cables yet. And I would rather work with a new set of waveguides and drivers than get up and unload my garage speakers.

    In the meantime, I have to finish my latest furniture project, a redwood slab based sofa table. Just finished oiling it with Watco Natural Danish oil, and now it needs a few coats of polyurethane varnish. Pics here are before oil and after.

    Edit: OK, the Seleniums are on the way. It will be good to see what he thinks of the EconoWave.
     

    Attached Files:

  2. ttan98

    ttan98 Member

    Messages:
    56
    Hi,

    Some of you chaps are very familar with JBL bass drivers, I have 2 (15")woofers extracted from left-over of a JBL outdoor speakers 2 way speakers. The model is:MR825

    The model no of woofer is 2032H, with t/s
    qts:0.54
    qes=0.6
    qms=5.5
    fs=57Hz
    vas=133l
    spl=98dB

    will the woofer work well with the SElenium and PT-F95HF horn? I think so but
    I suspect the bass would not be that strong, ie go very low.

    any comments
     
  3. GordonW

    GordonW Speakerfixer Subscriber

    Messages:
    18,312
    Location:
    Marietta/Moultrie GA USA
    You might be able to make it work... with a LC "shelf" filter.

    This would, in essence, reduce the sensitivity of the driver in the midrange.

    I'd probably go for a frequency of about 150-200 Hz for the transition (ie, pick a resistor to reduce output about 2 dB, and an inductor that would give a low-pass crossover at about 150-200 Hz with THAT value of resistance).

    With this, I'd then tune the woofer lower than expected, in a normal alignment... say, about 20% lower in frequency, in a box that's maybe 10-20% bigger than normal tuning.

    This should give an effective bass rolloff, quite a bit lower than would be predicted for those woofer parameters. I'd expect to get at least down to around 40 Hz or so, probably...

    Regards,
    Gordon.
     
  4. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    What Gordon said.

    They're in the box modeling databases for you to work with.

    Tuned low, they'll play low, but you've gotta give up ~10 dB in efficiency to get there.... :yes:
     
  5. Greyhawk17

    Greyhawk17 Well-Known Member

    Messages:
    886
    Location:
    Fountain Hills, Arizona
    E-Waves........

    Skywave-rider,
    JBL's, cool, thought about that too, but had no 'extra' 12's without taking
    appart a set of speakers...Have a pristine pair of 82' K-22"K"'s, but decided
    on the EF's because of the deeper bottom end, and the extended top end
    to better fit the 'project' parameters.....Poly-fil is spun polyester, works
    great, and NO allergic problems as with fiberglass......I decided to initially
    stay with the Nova 8B cabs, inspite of the 1.8 cuft, if after testing they
    don't 'dig' deep enough, I can cut out the bottom of the cabs, and extend
    them, possibly another 6" or so.....On the crossovers, going with the 4/05
    /08 post/schematic, using the 1.5, because the K-22EF's are 95.5-98.0....
    Appreciate the nearfield offer, I'll see how things progress later this week.
    Take Care, T
     
  6. Greyhawk17

    Greyhawk17 Well-Known Member

    Messages:
    886
    Location:
    Fountain Hills, Arizona
    Great work Jack!...........

    Howdy Jack,
    Your table looks great! I built one out a 6.0' redwood burl some years back,
    and this may inspire me to build another this summer......Manzanita is a nice
    desert wood to work with, though sometimes tough on blades, Cheers,T:thmbsp:
     
  7. skywave-rider

    skywave-rider Slumming in Akihabara Subscriber

    Messages:
    1,717
    Location:
    Akihabara, Tokyo
    Duh! How could I not figure that out.:stupid:
    OK, I see it around on-line in 12 oz. bags.
    Let me know if you have a bulk supplier.

    I like the Klipsch stuff, not the k-77 tweeter, though.
    You won't have that issue, however. :)
     
  8. Greyhawk17

    Greyhawk17 Well-Known Member

    Messages:
    886
    Location:
    Fountain Hills, Arizona
    E-Waves........

    I bought several large bags on sale at Michael's Arts & Crafts supply, and
    as I remember it was a 'fraction' of PE's price,....Think Michael's has a web
    site, Google it.....As for the Klipsch tweeters, Bob Crites has a good drop in
    replacement, Recommended........Take Care, T
     
  9. ttan98

    ttan98 Member

    Messages:
    56
    It looks like I am the only one from DIYAudio who found that a cheap JBL horn that can give excellent performance is coming to this forum is curious enough to ask more questions here?

    Where are the rest? Not interested in cheap but excellent horn?

    I am waiting for Gedlee to find out whether it has any limitations eg. off axis response performance.

    This horn is too cheap not to try a pair no matter what the outcome of Gedlee's findings are. I am from overseas(Australia) hence I made request to JBL spare parts department to buy a pair, request turned down(This is the truth). Anyone wants/volunteers to send me 1 pair(new or used) of PT-F95HF, I will pay the costs of the parts plus all postages incl. local & USPS International, I prefer to pay you via Paypal.

    Also, I found the RCF, H100 horn to be very good too $28 each. I am using it with B&C DE250 without equalizing, it gives me relatively flat response if you are fussy some eq. is reqd. above 9Khz. My X-over is around 1.7KHz.

    cheers.
     
  10. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    There have been maybe 1000 "extra" views in the last 24 hours. DIY folks are looking.

    I am confident that Earl will find the waveguides good, but not as good as his. ;)

    I will order you a pair tomorrow....
     
  11. ttan98

    ttan98 Member

    Messages:
    56
    Zilch,

    Many thanks...

    Tell me the total cost, USPS postage is about $35-$50(costs more than the horns) depending on the weight. I will pay you prior to you posting. Once you are ready to send, you can message me (address from my profile), I will send you details of postal address.

    cheers.
     
  12. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    Let's hope there's still some stock left. :p:

    Note: The part you posted, PT-F95HF, calls out the 1.5" throat heavy composite version, not the 1" thread-on economy one. Try again locally with the correct part number, if you didn't already, 338800-001.... :yes:
     
  13. ttan98

    ttan98 Member

    Messages:
    56
    Maybe I misunderstood, I prefer the 1" throat version.
     
  14. Jerv

    Jerv New Member

    Messages:
    4
    Not the only one...(though this is my first post here)

    I have both the Geddes 10" waveguide and the JBL econowaveguide on order. And a couple of JBL, B&C and Beyma drivers (for starters) to try them with.
     
  15. ttan98

    ttan98 Member

    Messages:
    56
    When you have to evaluate the econowaveguide, please give us you opinion, particularly in comparison to Gedlee waveguide, most viewers here would be most interested.
     
  16. Russellc

    Russellc AK Subscriber Subscriber

    Messages:
    5,776
    Location:
    KC MO
    Would it be possible to post aphoto of the 10" Geddes waveguide? Is there a site that shows them, and pricing?

    Russellc
     
  17. Jerv

    Jerv New Member

    Messages:
    4
    Will do when I get them. :yes:
     
  18. skywave-rider

    skywave-rider Slumming in Akihabara Subscriber

    Messages:
    1,717
    Location:
    Akihabara, Tokyo
    Might be something like this:
    http://www.ai-audio.com/products_esp15.html

    Look here:
    http://www.ai-audio.com/waveguides.html

    Can't find a better picture yet:
    [​IMG]

    The foam suggest something in the middle -- it's actually an open cell phase plug, I assume denser in the center. Theory, as read above, to reduce diffraction effects in the horn. Sound bouncing from "side to side" within the horn itself.
     
  19. skywave-rider

    skywave-rider Slumming in Akihabara Subscriber

    Messages:
    1,717
    Location:
    Akihabara, Tokyo
    More info on Geddes conical with foam attached.
     

    Attached Files:

  20. skywave-rider

    skywave-rider Slumming in Akihabara Subscriber

    Messages:
    1,717
    Location:
    Akihabara, Tokyo
    Getting There

    Hi,
    I have crossovers done, no new baffles yet. Check this RTA. I had a hole around 2 or 2.5 kHz, reversing polarity only moved it down to 1.5 or so, and looked worse, so I kept designed polarity and moved the waveguide. This is the best I got so far, about 2 inches out from front of current baffle. Given that the JBL 123A-1 has a shallow depth, does this seem reasonable? I estimate that the voice coil of the Selenium is now approx. 2 3/4" back from the baffle.

    This is somewhat critical because if I am to keep this physical arrangement, I won't mount the waveguides in the new baffles. I'll have to keep them on top.

    Ideas, suggestions???
    :scratch2:
    RTA at 1 meter, on axis:
    [​IMG]
    LF on dummy load:
    [​IMG]
    Waveguide forward of baffle:
    [​IMG]
     

    Attached Files:

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