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Max Fidelity MF165/77L8

Amanda grabbed these off the door prize table last October, and this weekend expressed an interest in doing a design of her own. So I decided to go ahead and break one in and take some T/S parameters to start with. Based on the parameters, I will order a pair of the PE 0.56 cubic foot knock downs. Of course, I will be re-testing them with her when she is ready to start her design. 

Without further ado.

Loudspeaker parameters:

Fs  = 54.84 Hz
Re  = 5.46 ohms[dc]
Le  = 92.39 uH
L2  = 648.31 uH
R2  = 29.03 ohms
Ke  = 0.087558 sH
Qt  = 0.52
Qes = 0.67
Qms = 2.21
Mms = 15.38 grams
Rms = 2.397945 kg/s
Cms = 0.000548 m/N
Vas = 15.76 liters
Sd= 143.14 cm^2
Bl  = 6.550822 Tm
ETA = 0.37 %
Lp(2.83V/1m) = 89.45 dB

Added Mass Method:
Added mass = 20.00 grams
Diameter= 13.50 cm

Sample 1 is what I used to derive the T/S parameters. There are some minor differences in the resonance peak indicating some differences in motor strength, but that is probably not worth worrying about. 

There is a type on the above image - it says MF135/77L8 twice, in point of fact the second MF135 should read MF165. As I have come to expect from smaller and/or boutique manufacturers, actual versus claimed specifications are different enough to warrant a caution should one purchase these. 

These are available at Solen. Mfr website:

I have a signature.


  • that's a really flat line... I wonder if they actually measure like that.
    deadhorse - leviathan - harbinger - shockwave (wip)
  • I will update when we measure.
    I have a signature.
  • These are really attractive drivers on paper and upon inspection. I look forward to knowing more.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • They look beefy
  • Nice driver.  Reminds me a lot of the Dynaudio 17W75ext but with a much better frame.
  • Did you ever measure the frequency response of this driver? 
  • Possibly in the next few weeks. 
    I have a signature.
  • edited September 2018
    The Max Fidelity website is dead and the 165mm drivers are on sale at Solen, other models "on backorder" so they may be the last of their kind. They look like great performers, get them while you can!

    Max Fidelity is/was a division of Fabian Acoustics, which I think has closed its doors.
    I'm not deaf, I'm just not listening.
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