I tried to measure my Alpha 8s to see if the specs are closer to the "new" ones or the "old" ones (specs are quite different!). I knew I wasn't going to get accurate specs but I was hoping that they would indicate which of the Eminence specs to use.

I used a fairly good Fluke Multi meter and the signal generator software I mentioned before.

I first made a calibration table in Excel to compensate for the meter not being able to accurately measure RMS voltages at low frequencies. I made a table for 1V across my 0.5 ohm resistor and a table for 0.1V. They were pretty close and showed that the meter is accurate down to about 30 Hz (5% off) and looses it by 10 Hz (35% off)

I tested with 2.8 V across the driver and measured at every 5 Hz from 100 Hz to 10 Hz. The results were put in a table, compensated and graphed. The results around 50 Hz (resonance) were too grainy (5Hz increments) so I decided to zoom in on the 40 to 60 Hz area and use 1 Hz increments.

I also placed another 0.5 ohm resistor in parallel with the test resistor giving me a total test resistance of 0.25 ohms in series with the Alpha 8.

The results were:

Measured Alpha 8

Qts=0.13, Qd=7.7
Fr= 51 Hz
Zmax= 79 ohms
Zmin= 5.3 ohms
Vad= 0.67 cuft

"New" Alpha 8

Qts=0.53, Qd=1.887
Fr= 76 Hz
Zmax= 45 ohms
Zmin= 5.3 ohms
Vad= 0.5 cuft

"Old" Alpha 8

Qts=0.5, Qd=2
Fr= 75 Hz
Zmax= 125 ohms
Zmin= 5.34 ohms
Vad= 1.5 cuft

I was disappointed that my results didn't correspond with either!
Any interpretations would be welcome.

Cheers,
Jeff

I'll try again with a larger series resistor...

Cheers,
Jeff