[Hallicrafters] PM-23 speaker specs

[Ken Kaplan]

I think I remember someone asking a question about the speaker in a PM-23. If so, 
here are the specs as measured from my very good but old condition PM-23 
speaker. The paper cone is 60+ years old which means dry & a bit brittle. Until the 
time machine is repaired, I guess we'll just have to assume that these measured 
numbers are kinda close to original.

Fs = 55 Hz
f1 = 49 Hz
f2 = 65 Hz
Qms = 7.37
Qes = .602
Re = 3 ohms
Le = .375mH

Sorry but I didn't measure Vas. These were free air tests using good quality test 
equipment (Wavetek, Fluke). If you want an impedance curve, just holler. How does 
this speaker compare to newer ones of similar size? Fs is a bit high but that probably 
came with age. Otherwise its ok. I just wouldn't dump any rap (or Tchaikovsky's 1812 
Overture) into it or the cone would probably shred.

73 Ken kb7rgg