Beomic BM4

 

Product : Beomic BM4

 
Produced : 1962
Designed by : ———————–
Finish : ———————–
Desirability : ———————–

The Beomic BM4 and Beomic BM3 from Bang & Olufsen were pressure-gradient full-bass microphones. They were shock- and blast-proof and included ball-swivel tilting to any position.

BM4

Beomic BM4 Details:

Dimensions 195 mm high, 30 mm diameter
Impedance, switchable 50 ohms, 250 ohms and 40 Kohms balanced
Response M position: 20-11000 c/s +/- 2,5 dB
T position: 10 dB lower at 100 c/s
Sensitivity M position, 50 ohms: 88 dB below 1V/µbar
M position, 250 ohms: 81 dB below 1V/µbar
M position, 40 Kohms: 60 dB below 1V/µbar
T position, 4 dB lower

Response Frequency characteristics: 

M (Music) Position: From 20 till 11,000 c/s +/- 3 dB 

T (Close Talk) Position (8-16″) Rolled off below 100 c/s: 12 dB 

RTMA Microphone Rating GM (sensitivity): -158dB; Hum Sensitivity (RTMA) GH: -145 dB. RTMA Standard SE - 105. BM 3. Open Circuit Voltage Level: -88 dB, OdB = 1 Volt per Microbar 

Output Impedance: Nominal 80 ohms 

Rating Impedance: 150 ohms 

BM 4. Open Circuit Voltage Level: 

“L”-Position: -88 dB 

“M—Position: -81dB 

“H”-Position: -60 dB 

OdB = 1 Volt per Microbar 

Output Impedance: 

“L”-Position: 

Nominal at 1000 c/s; 100 ohms 

Rating Impedance: 150 ohms 

“M”-Position: 

Nominal at 1000 c/s; 450 ohms 

“H” position:  

Nominal at 1000 c/s; 60 k ohms 

Rating impedance: 40 k ohms 

Size: 7,75″ x 1 3/16″ 

Weight: 15 ozs approx. 

Cable: supplied with 20 feet twin cond. shld. 

Transformer type: 8016-JS for matching BM3 to a high impedance amplifier input available on special order 

Mounting: Bayonette detach to 5/8″ x 27 thread

(Taken from BM Specifications’ Sheet)

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