Sample 1
Fs = 59.16 Hz
Re = 7.26 ohms[dc]
Le = 211.55 uH
L2 = 560.53 uH
R2 = 19.06 ohms
Qt = 0.55
Qes = 0.63
Qms = 4.27
Mms = 9.30 grams
Rms = 0.809374 kg/s
Cms = 0.000778 m/N
Vas = 5.73 liters
Sd= 72.38 cm^2
Bl = 6.330997 Tm
ETA = 0.18 %
Lp(2.83V/1m) = 85.13 dB
Sample 2
Fs = 57.50 Hz
Re = 7.26 ohms[dc]
Le = 210.13 uH
L2 = 521.34 uH
R2 = 17.65 ohms
Qt = 0.55
Qes = 0.64
Qms = 4.14
Mms = 9.92 grams
Rms = 0.865260 kg/s
Cms = 0.000772 m/N
Vas = 5.68 liters
Sd= 72.38 cm^2
Bl = 6.396310 Tm
ETA = 0.16 %
Lp(2.83V/1m) = 84.66 dB
Added Mass Method:
Added mass = 20.00 grams
Diameter= 9.60 cm
Quick box model:
F3/6/10 in a dinky box is 61/48/40. Low Vas + medium Q (Qts is 0.55) = vented enclosure with excellent cone control. See how the excursion flat lines below tuning? If a guy wanted to, say, load a pair in a slim tower they will easily pull F3/6/10 of 51/45/40. Very flexible TS parameters.
The two samples are reasonably close to one another.
OK, so these have a very nice molded frame with venting below the spider. A slightly raised spider, and gobs and gobs of throw. Plus, I could not get them to bottom out by pushing - so the soft parts are doing their job.
The cone is so-called "HOP" material, which Sony claims is an acronym for "Highly Oriented Poleofin" or some shit. Looks and feels like plastic/poly to me. Has a slight texture, is curvilinear, and the dustcap is very soft. Rubber surround with a shiny material added along the edge where it meets the cone. Tap test yields a fairly soft sound, and the lack of wrinkles above 3K in the impedance sweep indicates that the driver has minimal breakup. It appears to be a very well behaved driver, at least on response.
The motor looks bread and butter - but the measured Le is not very high at all, and the impedance swing looks fairly controlled. I suspect the driver was designed to have a lot of "bump" in a small cabinet, and run with a minimal crossover. In fact, the Sony speakers are undersized - I am guessing on the order of 0.15 cubic feet and tuned to 80 Hz. As these drivers are NOS and not pulled from a pair I found, I will never know for sure. I have listened to one pair years ago, so I am basing my estimate of that design on an old experience.
I digress.
So we have a well built little driver with an excellent cone and an interesting motor. I suspect it is manufactured by Bravox for Sony, but that is only because the frame is similar to a bunch of those Bravox buyouts from years ago. While it ultimately does not matter where they are sourced, it is always fun to speculate. I found these for $25/pr shipped.
Just FYI - these will be getting used in my AMT monitor rather than the MCM. They model better on the low end.
I have a signature.
Comments
My only concern is the impedance blip around 1200 - that might indicate a shelf in the response.
InDIYana Event Website
Im pretty sure the ads in the back of LSDC is how I found PE, lol
InDIYana Event Website