FS: Concentric-6 Coaxial Drivers!

Discussion in 'Classified Section' started by Matt Grant, Jan 27, 2021.

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If you are interested in these which options would you choose:

  1. Just the raw driver - (don't select this option if choosing any of the others.)

    0 vote(s)
    0.0%
  2. + Baffle

    6 vote(s)
    85.7%
  3. + Crossover PCB

    3 vote(s)
    42.9%
  4. + Crossover Parts

    2 vote(s)
    28.6%
  5. + Assembled Crossover PCB (this takes the place of the above two)

    3 vote(s)
    42.9%
Multiple votes are allowed.
  1. #1 Matt Grant, Jan 27, 2021
    Last edited: Apr 9, 2021
    Update 4/9:
    5 coaxial drivers left.

    Bamboo baffles have Sold.

    Marble and White Corian Baffles Sold.

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


    I was recently doing some cleaning/reorganizing and remembered I had a bunch of these drivers that I had gotten from Erich. Unlike the Concentric-8's these never made it into kit form but they are really excellent sounding 6.5" coaxials. Much better sounding and measuring then any of the Volts, I am saving several of these for myself because I really haven't found anything in the 6.5" range that match them.

    D2H_3922-sm.jpg

    D2H_3923-sm.jpg

    D2H_3924-sm.jpg

    D2H_3927-sm.jpg

    D2H_3929-sm.jpg

    HF driver is a 1.75" titanium compression driver with copper cap on the pole.
    Woofer T/S Specs:
    * Piston Diameter = 134.6 mm
    * f(s)= 85.46 Hz
    * R(e)= 5.20 Ohms
    * Z(max)= 56.26 Ohms
    * Q(ms)= 7.551
    * Q(es)= 0.768
    * Q(ts)= 0.697
    * V(as)= 5.519 liters (0.195 cubic feet)
    * L(e)= 0.45 mH
    * n(0)= 0.43 %
    * SPL= 88.41 1W/1m
    * M(ms)= 17.87 grams
    * C(ms)= 0.19 mm/N
    * BL= 8.06
    Could be used sealed in a 0.25-0.5cuft box for an f3 of ~90-100hz.
    Or can be used ported 0.35cuft tuned to 70hz (f3 ~ 60hz)- 0.5cuft tuned to 60hz (f3 ~ 50hz).

    I had previously built four of these for a member on AVS forum several years back in sealed angled boxes for surrounds:
    DSC_6896-sm.jpg
    DSC_6898-sm.jpg
    DSC_6902-sm.jpg

    DSC_6903-sm.jpg

    Angled 6in Coax box.png

    I have 4 Bamboo Baffles for these: (Pretty sure they are 8" x 12")
    D2H_3936-sm.jpg
    D2H_3937-sm.jpg

    I also have 9 Corian Baffles, 2 White, 2 slightly cream or off white, two in a marble style, and 3 in a black/onyx look which also kind of looks like black brushed stainless in a way. The Black ones have some viable scuffs/scratches as can be seen in the photos. The backs of these corian baffles also have a plywood layer which is meant to be routed out to attach them to the box.

    D2H_3940-sm.jpg
    D2H_3941-sm.jpg
    D2H_3942-sm.jpg

    D2H_3944-sm.jpg
    D2H_3948-sm.jpg
    D2H_3950-sm.jpg
    D2H_3952-sm.jpg
    D2H_3953-sm.jpg
    D2H_3954-sm.jpg
    D2H_3956-sm.jpg

    I can also cut some MDF baffles for those who want them.

    Basically I can offer these as just the raw drivers ($120 + shipping) or with any one of these options:
    + Baffle (Limited Bamboo/Corian - Edit, I'll throw these baffles in for free, so first come first serve on these baffles.
    + Crossover PCB ($5)
    + Crossover Fully Assembled, ($55)


    Crossover Schematic:
    Concentric-6 Crossover Schematic.png
    Crossover parts list:
    C1:https://www.parts-express.com/Dayton-Audio-DMPC-2.7-2.7uF-250V-Polypropylene-Capacitor-027-416
    C2:https://www.parts-express.com/Dayton-Audio-DMPC-1.5-1.5uF-250V-Polypropylene-Capacitor-027-412
    C3:https://www.parts-express.com/Dayton-Audio-DMPC-7.5-7.5uF-250V-Polypropylene-Capacitor-027-429
    C4:https://www.parts-express.com/Dayton-Audio-DMPC-1.0-1.0uF-250V-Polypropylene-Capacitor-027-410
    -
    L1:https://www.parts-express.com/Dayton-Audio-AC201-5-1.5mH-20-AWG-Air-Core-Inductor-Coil-257-052
    L2:https://www.parts-express.com/Dayton-Audio-AC201-1.0mH-20-AWG-Air-Core-Inductor-Coil-257-048
    L3:https://www.parts-express.com/Dayton-Audio-IC181-5-1.5mH-18-AWG-I-Core-Inductor-257-552
    L4:https://www.parts-express.com/Dayton-Audio-LW18-40-0.40mH-18-AWG-Perfect-Layer-Inductor-257-814
    -
    R1:https://www.parts-express.com/Dayton-Audio-DNR-20-20-Ohm-10W-Precision-Audio-Grade-Resisto-004-20
    R2:https://www.parts-express.com/Dayton-Audio-DNR-25-25-Ohm-10W-Precision-Audio-Grade-Resisto-004-25
    R3:https://www.parts-express.com/Dayton-Audio-DNR-4.3-4.3-Ohm-10W-Precision-Audio-Grade-Resis-004-4.3
    R4:https://www.parts-express.com/Dayton-Audio-DNR-2.0-2-Ohm-10W-Precision-Audio-Grade-Resisto-004-2
    R5:https://www.parts-express.com/Dayton-Audio-DNR-12.5-12.5-Ohm-10W-Precision-Audio-Grade-Res-004-12.5

    Concentric-6 crossover.jpg

    Frequency response 0-90 degrees off axis:
    0-90 degrees off axis.png
     
    Brinkman likes this.
  2. Those look familiar!! I’m still using them as surrounds. How would they work as LCR? Rearranging my family room soon, was going to go with in wall speakers but I don’t think they’ll work. The wall I want to mount my tv is shared with the laundry room. I’m afraid of hitting water lines, electric etc... Not sure if these would be a food LCR option or if I should look at HT-6 or 8’s? Maybe could mount those to the wall for LCR?
     
  3. These could be used for LCR especially in a family room setup where the single 6.5" can usually give more then enough output for normal people. They would probably be best used in ported enclosures for LCR to extend the bass response and minimize cone excursion, though that does increase the required enclosure size a little.

    I'll have to double check the driver depth to see what could be done to make something shallow for wall mounting.
     
  4. So then the answer really is no ;)
     
  5. #5 Matt Grant, Feb 23, 2021
    Last edited: Apr 9, 2021
    Finally got around to testing all of these coaxial drivers.

    Update 4/9:
    5 coaxial drivers left.

    Bamboo baffles have Sold.

    Marble and White Corian Baffles Sold.
     
  6. I am interested in 4 Concentric-6 with baffles.
     
  7. Would these blend well with the ht8?
     
  8. They would likely work ok with the HT8, no worse then the volts which many people use together with the HT series with good results.
     
  9. Do you have any baffles left?
     
  10. The 3 Black and 2 off white corian baffles are still available.
     
  11. I’ll take two with black baffles and two PCB’s.
     
  12. I don't have the PCB's yet as I am waiting until I verify the crossover values but will post here when they are available.

    I'll send you a PM for payment details.
     
  13. I now have the PCBs for these and in case you missed it I posted the crossover information as well as the measured frequency response at the end of the original post.
     
    Brinkman likes this.
  14. Matt. I received the PCBs today. Thank you.

    Question: what do you think of using a top-mounted variovent with these drivers? I’m replacing my four sealed-box volt-6 surrounds with these and wanted to do something a little different.
     
  15. It could be interesting to try, through the f3 on these is already quite high when sealed and using the aperiodic vent to decrease the Qts would increase it further to some degree.
     
  16. That was a concern; trading LF extension for transient response. A little googling wasn’t too enlightening as to how much LF surround speakers typically see. I never noticed much bass from my Volt-6 surrounds with the exception of the pod-racing sequence from The Phantom Menace and even then the mix was more midrange and HF. I don’t think I’m listening at reference levels, lol.
     
  17. Would these fit in the slanted and ported enclosures that come with the Volt-6 kits? Are they 8-ohm and high efficiency, similar to the Volts, so that they can be powered by a typical AVR?
     
  18. They would work in the slanted Volt-6 flatpacks but obviously the stock Volt-6 baffle isn't compatible with this driver. It should also be used sealed in that enclosure.

    They are 8 ohm and efficiency is decent (~90dB @ 2.83v) so a normal AVR should have no issue driving them.
     
  19. #19 Charles Collins, Mar 30, 2021
    Last edited: Mar 30, 2021
    I definitely want four, with assembled crossovers and16” x 8.5” mdf baffles that would fit the Denovo 0.56 cubic foot enclosures that Parts Express stocks 300-7064 (which I could order from them). I just need to figure out the proper port size for that enclosure. Please PM me if this is something you can do. Thanks Matt.
     
  20. I've previously cut some baffles designed to fit that box for another member, it was designed to use the 2.5" flared port that PE sells, the port should be cut to 5" which should give a tuning a little below 65hz and an f3 in the mid-low 50's. Let me know if that works for you?

    16x8.5 baffle.png
     
  21. Matt, thanks that looks perfect. I tried to reply to your PM but it wouldn’t accept it. Please do send an invoice for everything. Thanks.

    Edit: I finally got the PM to work.
     
  22. I am interested in a couple of these with the black baffles and crossover parts if possible!
     

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