A few Western Electric prototype speakers, plus........
Prototype for 596A/597A...very similar, DCRs seem consistent.
This one has a very short horn.
The article below is from early 1931. So this particular speaker could be 80 years old!
Read the full article where I got the two screenshots above here:
Another article by Bostwick from the October 1930 Journal of the Acoustical Society is:
AN EFFICIENT LOUD SPEAKER AT THE HIGHER AUDIBLE FREQUENCIES
You should be able to download a free PDF of this article here.
Twelve thousand cycles in 1930! Amazing.
The patent for the tweeter was filed in 1929, four years before the patent for the woofer was filed.
On left, shown with 594A compression driver. The woofer's magnet structure seems very similar to that of the 594A.
I weighed this speaker- 41.5 pounds, and that's without a cast frame.
Patent number 1,967,223, L G Bostwick, filed in 1933.
Either a prototype for the original 555, or for the later permanent magnet version.
Pictured with a 555 or a 555W on the right.
The 500 below is 6 inches. My most photogenic ruler!
Diaphragm assembly from speaker above.
VC= 12 ohms.
In fact the resistance of the field coil bounced between .1 and .0 ohms.
The graduations are thousandths of a foot, so I am guessing from the photo about 1/15 inch.
I need to find my micrometer for an exact measurement.
Weight: over 25 pounds, about 11.5 kilos.
I needed the 2x4s because the magnetic field of the speaker affected the reading
if it was any closer to the scale.
Here is a photo album of a recording machine, not labeled W.E.,
but full of W.E. parts. Western Electric never made it big in tape recording.