FS: Concentric-6 Coaxial Drivers!

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


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)
  2. + Baffle

    4 vote(s)
  3. + Crossover PCB

    2 vote(s)
  4. + Crossover Parts

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

    1 vote(s)
Multiple votes are allowed.
  1. #1 Matt Grant, Jan 27, 2021
    Last edited: Feb 26, 2021 at 1:01 AM
    Update 2/26:
    14 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.






    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:


    Angled 6in Coax box.png

    I have 4 Bamboo Baffles for these: (Pretty sure they are 8" x 12")

    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.



    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(just the bare PCB), ($5)
    + Crossover Fully Assembled, ($55)

    I don't have the PCBs made up yet and I still need to throw the old crossover design together to make sure it measures correctly. I will post the crossover details and more measurements once I have tested it and verified it's good to go.

    Here is the on axis response from the design I did years back:
    sample coax v1.01 crossover.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 at 9:38 PM
    Last edited: Feb 26, 2021 at 1:00 AM
    Finally got around to testing all of these coaxial drivers.

    Update 2/26:
    14 coaxial drivers left.

    Bamboo baffles have Sold.

    Marble and White Corian Baffles Sold.
  6. I am interested in 4 Concentric-6 with baffles.

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