4540 ND is the ultimate BMS driver in its class - for now

the smallest and lightest in its class
the loudest in its class
the most impressive of all is the superior sound
Unique patented design
Neodymium magnet assembly
114 dB sensitivity 1W / 1m
Extended high frequency response up to 30 kHz
Very small size and low weight
38 mm voice coil
1" 3/8 - 18N screw or 1" flange adapter
BMS 4540 ND is a powerful 1" professional compression driver that
delivers superb sonic quality in a very small package.
The unique BMS annular diaphragm together with the high energy neodymium magnet achieve very high sensitivity and linear frequency response up to 30 kHz.
The sound of 4540 ND is extremely transparent and detailed, it has an exceptional dynamic range and produces even the most complex music signals with depth and definition.


4540 ND - 1" compression driver is designed for a wide variety of applications including high level professional reinforcement systems, studio monitors and high-end audio.

Durability and reliability are key in heavy-use professional applications. Therefore each driver is systematically tested to strict standards to ensure highest possible quality.

BMS Elektronik GmbH located in Hannover, Germany is a leading manufacturer of compression drivers. BMS products are used by professional speaker and high-end companies globally.

The patented BMS design remarkably reduces diaphragm weight and inertia. There is no loss of energy required to drive conventional diaphragms.
That is why BMS drivers have higher sound pressure level and less dynamic compression than conventional designs.

Specifications 4540 ND
Throat diameter 1" (25,4 mm)
Nominal impedance 8 or 16 Ohm
Power capacity (AES) 60 W
Peak power 300 W

Sensitivity in:
CD Horn 90°x75°, 1W / 1m 114 dB
Plane wave tube, 1 mW 118 dB
Maximal SPL (cont.) 132 dB aha_at 60 W
Frequency range 1.200 - 30.000 Hz
Recommended crossover 1.900 Hz
Voice coil diameter 1,5" (38 mm)
Magnet material Neodymium
Flux density 2,2 T
Voice coil material Cooper Clad Aluminium
Voice coil former Kapton
Diaphragm material Polyester

Mounting information
Overall Diameter 72 mm (+/- 0,1 mm)
Depth 45 mm
Net weight 0,530 kg
Mounting 1" 3/8 - 18N screw or 1" flange adapter