Celestion 15" buyout and SEOS12/DNA360

Discussion in 'DIY Speakers and Subwoofers' started by BillWaslo, May 9, 2013.

  1. Is the woofer completely dead or just not working properly when the resistors are connected. A shorted woofer cap would place the 3 ohm resistor across the woofer terminals and cause a very low output from the woofer.
  2. I also suspect the woofer cap. Try disconnecting the cap and 3 ohm resistor at one of the ends and see what happens. If you have a multimeter handy measure for continuity across that cap as well (there should be none).
  3. when the resistors touch the grounding cable (the negative line between the tweeter and woofer neg in the picture) the woofer doesn't respond...we found out by accident that if the 3 resistors come OUT of contact with that negative grounding line then the woofer gets sound..... I'll see if I can check the capacitor... I thought you COULDN"T test a capictor with a regular multimeter? I thought it needed an ESR multimeter to test those, but yes, the 7.5 ohm resistor or the 20uf capacitor was my thought as well. I'll see If I can test it
  4. You can't measure capacitance with a basic multimeter, but you can find out if that capacitor has infinite DC resistance (good) or zero resistance (bad).
  5. ahhh, gotcha.. just set it to measure dc resistance and see what it gives back
  6. It might do that if the big inductor is open, too (or one of its connections isn't really making it). You can check that with a DC resistance check across it.

  7. Bill, on AVS forums there was discussion in an unrelated thread that testing by folks here revealed the tweeter polarity in the crossover design of the Eminence pro / SEOS design (Karma 12) and possibly this one (?) may be reversed for slightly better measured response. In the thread over there Erich said you were in the hospital at that time and you were going to look into it when you got out.

    First and foremost, we hope it was nothing too serious, and you are doing well. Have you had a chance to do any more measurements or consult with others about the tweeter polarity issue? Which designs are in question?

  8. Hi, I'm Michael and I lurk a lot. I built a set of speakers using these drivers and crossover. For cabs I kinda chopped up some old Pioneer CS-63 cabinets. They are ~2.5cf and built like tanks. The horn is front mounted on a 3/4" piece of plywood that I glued to the front of the original baffle. The woofer is rear mounted on the original baffle so it is a bit behind the horn. I did all this just as a quick and dirty job to see what it might sound like and because I didn't have time at the moment to build some nice boxes.

    I've been listening to them for a few weeks now. To me they seem quite laid back, maybe too laid back for me. Very clear highs but I'm missing a little bit of sparkle. I've heard other speakers with this same sort of signature up high and I think it is probably good for some folks. I'm 41 and have abused my ears when I was younger so I like a little bit of extra zing -- a little bit, too much is still too much. They also seem to lack clarity in the lower mids (well below the XO point) and this is my real gripe with them.

    Is there a chance that I might like these woofers better in some different cabinet or with some other change? I have an electronic XO that I can play with but my impression is that what I am hearing that I don't like is below the XO point. I got the horns and compression drivers months ago and did some experimenting with them and was duly impressed with them at that point. I am pretty sure I that if I keep at it I they will find a home in something that is right to my ear.
  9. hey michael, these speakers were MEANT to be crossed over with a sub at 70-100hz ... that's why it has the high crossover point, and probably why you're not liking the sound below the crossover point.
  10. You are going to have some issues with the excessive offset between the woofer and the waveguide. That aside, I built mine with the big QSD waveguides with Dayton CDs in a similar volume. I think, because these cones are relatively light for high sensitivity, and are large in surface area, they are prone to the lower mids being re-radiated through the woofer cone (leaking if you will). I ended up with the box lined with 3.5 in. fiberglass and the contents of a Walmart king size pillow fluffed behind the woofer. I could not be more pleased with the result. The QTC is about .65 in the 2.5 ft3.
  11. I understand that they are meant to be used with a sub but I don't really understand why adding a sub would make anything sound clearer. I compare them to other speakers where the bass roll off is at about the same freq and can tell a difference in midbass clarity and congestion.

    My cabs are lined with fiberglass and stuffed with polyfill.

    Based on post #8 I don't think the offset between my drivers is such a terrible thing. I've listen from many different positions and none of them alleviate the clarity issue.

    I'm not giving up. Just gonna take some time to try them in a different way (better box, experiment with electronic XO).
  12. Michael, have you thought about pulling the polyfill to see how it affects the clarity? I have foam sheets lining my boxes Pure 10s with no polyfill. As you and I discussed "off the air" I am still trying to wake up the woofer in the Pure 10s (low volume output).

    I am now building the Cheap Thrill XOs, so I may experiment with that to see if it has any effect on the woofer. I just feel like with such a robust XO design and the Eminence Delta 10A woofer, I shouldn't be able to talk louder than the speaker can play.
  13. Something up with your Fusion Pures wvu80? Maybe I can help.

    They should certainly play louder than you can talk. When I tested them I had to plug my ears on the other side of my house. But I don't think stuffing would cause that kind of problem.
  14. how much volume would be needed to get these down to full range territory? maybe like 35Hz?

    i was thinking of a Cornscala using these. what would 6 cubic feet look like?
  15. VB=6
  16. VB=10
  17. The problem with going the large ported route is that you can only feed it about 10 watts if you want to keep it anywhere near xmax. Granted, with 10 watts you're still above 106 db @ 1 m in either configuration. But it's still something to keep in mind.
  18. 10 watts?! hmm. that changes things for sure. that makes these very room dependent. in a smaller room it would be fine, but then big ass enclosures dont pair up well with smaller rooms as far as waf.

    maybe the Sentinel would make for the better Cornscala?
  19. [​IMG]
    I'm not sure I can help, but I've got my Cheap Thrill in full "experimental" mode, and I'm listening to the speakers in their most natural state. I have the two 15" Celestions hung by a zip tie from a metal shelf (with XO's at the moment) and the two 360's just above that on a shelf, sitting on a rubber mat.

    I am running them in stereo from my PC headphones OUT to a 15 watt amp.

    I haven't come close to playing these close to the entire 15 watts, because I don't want to blow out my hearing. They play incredibly clean with the 360 on the top end, and have a VERY wide mid-range to my ears, playing musical instruments, like bari sax, and the slap bass is incredible. I also really like how male spoken voice sounds thru them. The music part starts around 1:40.

    Beach Boys Sloop John B - Youtube

    I ran a speaker test from Youtube and I could hear a small rumble at 40Hz, and these really started to work at 80 Hz. Remember, this is open air, no cabinet.

    I hope that helps.
  20. I still don't have my Cheap Thrills put together due to a lack of woodworking skills/equipment, and the lack of an available flat pack. Over on the AVS DIY discussion board, LDT02 suggested that the SEOS 12 waveguide can be mounted externally.

    If this is feasible, what do you think about my getting a sub or PA sealed flat pack and mounting the SEOS 12 on top?

    Sealed 15" (14" cutout) PA trapazoid box 2.75 cu ft - $84

    Sealed 12" sub box, 2.0 cu ft - $73

    Sealed 15" sub box, 3.0 cu ft - $90
  21. The trapezoid birch enclosure looks like it would work well. Just turn it upside down from the picture so that the woofer and waveguide are as close as possible.
  22. Wow, thanks Mr. Flyer, you are fast! 8)

    I also posted this on the AVS discussion board, in the DIY speaker section:
  23. After my attempts to find someone to cut boards for me for months, things are now going fast and I need some help to finalize my dimensions as the cut will be made tomorrow (Friday). The kit baffle is 26x17. The DIY website Notes says:


    In the beginning of this thread, Bill said he did his original box for this with a "2.0 cuft" enclosure, sealed. On the DIY Sound Group site, 2.5 is the minimum recommended.

    26x17x14 = 6188 inches. The converter I used says that translates into 3.5 cuft.

    Just to make things complicated: I have the room to lengthen the box to 31 inches, which would make 7378", converts to 4.3 cuft. I could really use some help in nailing down these numbers.
  24. I am also in the process of building my first pair of CT's. From what I understand if you are running these sealed w/subs and crossing 80 or higher, the size difference is somewhat negligible. Running ported, larger is better, but not by much, and more difficult to blend smoothly with subs. These drivers just don't dig deep. The kit dimensions are external, meaning a 17x26x14 box made out of 3/4" material is approx. 2.75 cu. ft. net volume (subtract 1-1/2" from all three dimensions) . Subtract driver volume and bracing and you are somewhere around 2.5 cu. ft.....add a little lining and stuffing, whatever. The external depth of my pair with the double baffle is 14 3/4".

    I had a local young entrepreneur I met last year build mine out of 3/4" Arauco ply with double baffle fronts, with the woofers inset 3/4". By my calculations that should bring the sweet spot down about 4 degrees, to about 6 degrees above horizontal. Mine will be crossed at about 100 Hz to a couple of 15" ported pro subs, which do the heavy lifting between 35 and 100 Hz.
  25. Wow, that makes a good deal of sense. It never even occurred to me. I just figured I was doing the math wrong.

    I do plan on putting some 2" braces in there, and if I need to if I make that slightly larger box, I could pad it somewhat with foam lining if need be.

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