Zilch's AK Design Collaborative - Econowave Speaker

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

  1. EarlK

    EarlK Active Member

    Messages:
    459
    Location:
    Richmond Hill, Ont.
    [​IMG]

    It appears the waveguide mentioned ( the PT-D95HF-1 ) in the above schematic is the one seen in the following pic

    [​IMG][​IMG]

    :)
     

     

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  2. turnitdown

    turnitdown Well-worn member Subscriber

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    [​IMG]I believe, then, it was this..
     
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  3. turnitdown

    turnitdown Well-worn member Subscriber

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  4. Ross6860

    Ross6860 AK Subscriber Subscriber

    Messages:
    1,461
    Location:
    Ohio
    I have to ask...

    Instead of tearing up a nice pair of NL Advents, I have a pair of EPI Magnus 1200 cabs with the following woofers.

    Are these a decent candidate for Ewaves? They have plenty of efficiency and HF extension. Should I use the >95 dB Woofer generic crossover, or is there a better crossover to try? They are 4-ohm woofers...

    The cabs are marginal (just a wee bit shallow, so volume is a little under the 1.6 ft^3

    Model DL-1250-4
    4 ohm
    96 dB 2.83V/1m
    Fs 33 Hz
    DC ohms 3.18
    LE inductance 0.84 mH
    Qms 6.94
    Qes 0.46
    Qts 0.43
    Vas 5.03 ft^3
    Cms 0.38 mm
    BL 9.18 Tm
    Mms 58.4 g
    Xmax 5 mm
    Sd 511.8 cm^2
    Sealed Volume 1.6 ft^3
    Sealed F3 66 Hz
    Vented Volume 5.1 ft^3
    Vented F3 36 Hz
     
  5. Katalyst

    Katalyst AK Subscriber Subscriber

    Messages:
    622
    Location:
    Indianapolis, Indiana
    The eWave crossover is usually for 8 ohm woofers. You will have to adjust the values to a 4 ohm woofer. If you mount the wave on top of the boxes .You will keep as much volume as available. When you like them, build the vented box.
     
  6. Ross6860

    Ross6860 AK Subscriber Subscriber

    Messages:
    1,461
    Location:
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    I thought I saw a 4-ohm woofer Ewave crossover out there...I'll keep looking.

    I've run these vented and sealed in the Magnus 1200 cabs, and actually like them better sealed. I've run them as two-ways with a Dayton "Silkie" tweeter, and as three-ways with the same tweeter and an Infinity polydome mid-range. The two-ways were actually pretty decent. Way too much mid-range with the polydomes, and I don't want to add L-Pads at this point.
     

     

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  7. turnitdown

    turnitdown Well-worn member Subscriber

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    4 ohm, I believe, entails halving the inductor and doubling the capacitor values for the woofer.
     
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  8. turnitdown

    turnitdown Well-worn member Subscriber

    Messages:
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    BTW - tear 'em up. They never sounded so good..unless you intend to sell them...to finance more Ewaves...yep
     
  9. Ofir Yaloz

    Ofir Yaloz New Member

    Messages:
    15
    Location:
    New York
    Sorry in advance if this question is stupid but- when looking on most of the schematics for the crossover, the HF section (8ohm) and the LF (8ohm) are connected in parallel, so I’m guessing that my amp will see 4 ohm total?

    Is that why this project can’t be done with
    4 ohm speakers? As most amps won’t handle
    2 ohm in total...
     
  10. turnitdown

    turnitdown Well-worn member Subscriber

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    It's baked in. You're good
     
  11. Ross6860

    Ross6860 AK Subscriber Subscriber

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    Location:
    Ohio


    I'm no electronics whiz, but I've had some electrical training. Speakers are not just a simple DC circuit with two resistors in parallel. It's an AC circuit with a varying voltage supply and frequency, and the drivers themselves are inductive loads as well as having a DC resistance value.

    Lots of two-ways built with "4-ohm" drivers.
     
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  12. Ross6860

    Ross6860 AK Subscriber Subscriber

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    It is tempting, just for the experience if nothing else.
     
  13. Gary_L

    Gary_L Member

    Messages:
    54
    I've used both the Eminence Beta 8A and Fane Sovereign 225-8 with the 18Sound XD120 as per Zilch's original mini ewave, but was wondering how the Faital Pro 8FE200 would compare - it's about half the price of the 8A and has 95dB sensitivity (8A has 95.1) 4.67mm XMax (8A is 3) but the FS is 80 (8A is 62) . The Fane seems better than both with those measurements (I don't know about the other specs but others here can probably say what's bad about it), so I was wondering how well the 8FE200 worked. Has anyone tried it? I might try the Faital Pro with the P-Audio PHT 408 or 411 to see if the cost of an ewave can be brought down lower still without losing too much in the process. Both those parts cost about the same as a single Beta 8A

    Any thoughts or comments on the 8FE200? :)

    http://www.faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=401030100
     
  14. Ofir Yaloz

    Ofir Yaloz New Member

    Messages:
    15
    Location:
    New York
    I see, but can I actually measure it like I measure a DC circuit? I.e- testing The speaker terminals with a meter and see the actual correct impedance my amp sees under load? It’s probably more complicated then this..
     
  15. donprice

    donprice Wound up workin' at a gas station.... Subscriber

    Messages:
    2,280
    Yes, more complicated. Do a google image search for "speaker impedance curve" and you will see examples of how impedance changes with frequency. An "8 ohm" speaker may, in fact, almost never measure at 8 ohms at any frequency.
     
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  16. 300Z

    300Z Leo

    Messages:
    74
    Location:
    Recife, Brazil.
    A note about the X-max on the Faital, Faital specifies their X-max as [(winding depth - magnetic gap depth)/2] + (magnetic gap depth/3), so the actual geometric X-max on this driver is only 2mm (winding depth - magnetic gap depth)/2.
     

     

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  17. Gary_L

    Gary_L Member

    Messages:
    54
    Thanks - that's the kind of thing I had no idea about so appreciate the info. So although it's only 1mm less than the Beta 8A, it's a 50% difference. I guess I'll have to see how they both model and compare using a program like WinISD. Other than that, do you think it may be OK to use as an alternative? It seems cheap enough to try just to see, but don't want to waste my money if it's really a no go.

    Cheers.
     
  18. 300Z

    300Z Leo

    Messages:
    74
    Location:
    Recife, Brazil.
    Faital makes really nice stuff, but with only 2mm X-max I would not expect much in the bass region, the more you try to push it the higher the distortion. I would only use this as a midrange.
    If the budget permits I would try the new B&C 8CL51. It has 4.5mm of geometric X-max but it has enough motor force to drive it linearly to 6mm, give it 17L and Fb@63hz will produce an F3 of 60hz, F10 at 47hz.
    My small E-wave set is coming up to 10 years since I built it, I went with the B&C 8PS21 and never looked back, it does an excellent job.
     
  19. donprice

    donprice Wound up workin' at a gas station.... Subscriber

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    I used the Alpha 8 in my minis when I built them. I eventually swapped them out for the Beta 8 since that was what the rest of the design was based on. It drove me nuts thinking that I had compromised the original design. Of course if you are changing the CD/waveguide (and crossover?) then you might as well experiment with the woofer.
     
  20. Gary_L

    Gary_L Member

    Messages:
    54
    Thanks for the recommendations etc.

    I was looking more for 'econo' to see what might still get reasonable results without breaking the bank - I'm trying to keep things to a tight budget. The Fane Soveriegn 225-8 measures very similarly to the Beta 8A and is a little cheaper - specs look a tad better too but as you can see, I don't know how that measures up in real terms.

    I've a spare box that I can use for the experiment, so as Don says, I might as well give it a go. I'm getting to grips with XSim and crossover design but only on a veryt simple level. I'm just enjoying learning and getting some reasonable results as I go :)

    How do I determine if a waveguide is truly 'constant directivity'? Do you have to measure the off axis performance at varying degrees and the results will tell me? I also wonder how they compare to the various other types of waveguides out there (tractrix, exponential etc) so I could see what the differences are. I picked up a chinese CD type waveguide for approx $7 including delivery so would like to know if it really is. It looks like the two P-Audio tweeters I mentioned but only one of those says its CD so who knows.

    Thanks.
     

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