SDA Driver Mystery

Bubblehead

I recently bought a set of SDA-SRS2 speakers. They're the pin/blade model. I decided to install the RD0194-1 tweeters. While installing them, I found the positive lead to the right speaker's bottom tweeter was unhooked and dangling down into the cabinet. In order to get at the lead I had to remove a main driver. I was surprised to find it was a MW6502 model, which was never used in SDA speakers. I checked all of the stereo and dimensional drivers and they're all 6502s. I sent an inquiry to Polk Audio, but haven't heard back yet. The serial numbers of my speakers are 1972 and 1979, which make these compatible with the amplifier interface. I'm not using an interface, but this, along with the fact that the interconnecting cable is pin/blade, confirms, for me, that these are 4th generation speakers and should have 6511 and 6510 drivers. The 6502s are close enough in specification that they're probably OK to keep in the stereo positions. The speakers sound fine and the sound stage sounds as it should, at least, to me.

I suppose someone must have been in these sometime in their history. I've attached an image of the date stamp from one of the drivers. It's hard to read, but it looks like August 98.

Gardenstater

Those 6502 are pretty far off in TS parameters:

Driver: MW 6500 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 31.0000 Hz (Free air resonance)
Vas: 2.6486 ft^3 (Compliance volume)
Qts: 0.2190 Total Q
Qms: 1.3000 Mechanical Q
Qes: 0.2640 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5000 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power


Driver: MW 6501 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 31.0000 Hz (Free air resonance)
Vas: 2.7545 ft^3 (Compliance volume)
Qts: 0.2790 Total Q
Qms: 1.4700 Mechanical Q
Qes: 0.3440 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 7.7500 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power


Driver: MW 6502 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 44.0000 Hz (Free air resonance)
Vas: 1.2360 ft^3 (Compliance volume)
Qts: 0.2790 Total Q
Qms: 1.9700 Mechanical Q
Qes: 0.3250 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 3.5200 ohms (DC resistance)
Znom: 4.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power


Driver: MW 6503 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 29.8600 Hz (Free air resonance)
Vas: 3.0017 ft^3 (Compliance volume)
Qts: 0.3100 Total Q
Qms: 1.7680 Mechanical Q
Qes: 0.3760 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5400 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power

Driver: MW 6517
BrandL Polk Audio
* Size / Type = 6.50" treater paper cone woofer
* SPL = 91 db @ 1w/1m
* Wattage = 125 Watts RMS / 250 Watts Peak
* Treated cone woofer, rubber surround
* Response = 40 Hz. to 10 kHz.
* Weight = Right a 4 pound ea.
* Magnet = UnShielded
* VC = 1" ( 25 mm)
* Ohms = 4 ohms
* f(s) - 55 Hz.
* Q(ms) - 7.261
* V(as) - 14.60 liters ( 0.516 cf. )
* n(0) - 5.02%
* M(ms) - 18.38 grams
* R(e) - 1.86 Ohms
* Q(es) - 0.048
* SPL - 92 dB @ 1W/1m
* C(ms) - 0.44 mm/N
* Z(max) - 281.50 Ohms
* Q(ts) - 0.048
* L(e) - 31.08 mH
1 Driver Type Q BL Compliance DC Resistance Fs

3 MW 6501 1.470 5.96 N 3.250 E - 3N/M 7.750 Ohms 31 Hertz
4 MW 6502 1.970 5.16 N 1.470 E - 3N/M 3.520 Ohms 44 Hertz
5 MW 6503 1.820 5.24 N 3.550 E - 3N/M 6.540 Ohms 29 Hertz
6 MW 6509 2.100 4.57 N 3.540 E - 3N/M 8.970 Ohms 30 Hertz
7 MW 6510 1.390 6.32 N 3.410 E - 3N/M 6.570 Ohms 31 Hertz
8 MW 6511 1.405 4.34 N 3.496 E - 3N/M 3.130 Ohms 29 Hertz
9 MW 6512 1.905 4.99 N 1.588 E - 3N/M 3.466 Ohms 40 Hertz

F1nut

That's 1988. Polk no longer made SDA speakers after 1992.

xschop

I've substituted 6511's for 6502's.