These have the rare 604E2s in them.
The Audiomarketing Ltd. 604E2 was a special 16 ohm OEM version 604-8G... essentially a non-catalog 604-16G
16" Duplex Speaker
Magnets: Alnico V
rest of spec assumed to be same as 604G except 16 ohm
Power Rating: 65 watts continuous pink 20Hz-20kHz (AES)
Sensitivity: 100dBSPL/1W/4ft
Free Air Resonance: 30Hz
Response: 20Hz - 22kHz
Crossover: 1500 Hz
Network: used with Mastering Lab 16 ohm crossover as implemented in the Big and Super Reds by Audiomarketing ltd..
Impedance: 16 ohms
Phase Plug: Circumferential initially - moved to Tangerine phase plug in 1976
HF horn: 6-section sectoral-style horn with divider vanes - 90° horizontal and 40° vertical
Cone: paper cone with an "accordion edge" cloth surround
Frame: 16" die cast aluminum frame dark gray paint
Weight: 34 lb.
comment: 604E2 had the new 16" cast basket that came in with G in 1974 - G was 8 ohm nominal - E2 is 16 ohm - the only place these appear as E2's are in Audiomarketing Ltd. "Big Red" speaker systems that used the Mastering Labs Crossover that was nominal 16 ohms. Cabinets for Big Red's were front loading. Since the original Mastering Labs monitors and crossovers were based around a 16 ohm 604E it made marketing sense to call this driver an E2.
Note the
604E2 label is not an Altec label
In the recording studio before I bought them:
One-off professional electronic crossover:
One-off eq units:
The oversized grills covered the recesses they were mounted in in the recording studio in the first pic.