Versatility for a broad range of applications
The M 51 is the reference monitor of choice for many small studios and broadcast vans around the world for several reasons. Where space is at a premium, the M 51 offers the distinct advantage of being extremely compact, taking up a volume of only 1,8 liters (4-3/4" x 6-7/8" x 4-5/8" / 120 x 173 x 116 mm). Yet it offers a flat frequency response, making it ideal as either a control monitor in live broadcast or as a mix monitor in the smaller recording studio. The fact that this monitor can be powered by a 12-volt battery opens up new application possibilities in small broadcast vans or video editing stations. As a multimedia monitor, the versatile M 51 is ideal for both permanent and mobile applications.

Remarkable sound
The enclosure, which is constructed entirely of aluminium, offers the maximum interior volume for its size, and inner wall bracing adds a stiffness that eliminates resonant colorations. These factors help the 3" (75 mm) high-performance neodymium broadband driver deliver outstanding sound for an enclosure of this size, with very low distortion and a frequency response that is flat across the entire spectrum.

Practical features, professional connections
The volume knob is located on the front of the monitor for quick and easy adjustment. If needed, the knob can be removed to prevent unauthorized operation. The floating transformer-balanced input (+6 dBu) offers a Common Mode Rejection ratio of over 50 dB. The M 51 is fitted with an XLR input jack for secure, professional connections.
The M 51 is so lightweight that it can be mounted on a microphone stand. The bottom panel includes a 3/8" threaded socket expressly for this purpose. The monitor can be connected to with the LH 11 table stand with adjustable side-mounted screws that allow the M 51 to be tilted at any angle for optimal monitoring. The power switch, mains connector, fuse holder, and a pair of ½" blade terminals for battery operation (12 - 14 volts) are all located on the rear panel.

Magnetic shielding
The speaker chassis is magnetically shielded so that placement next to video monitors or hard-disk drives will pose no problem.

Free field frequency response 2	100 Hz - 20 kHz, ± 5 dB
Self generated noise level at 10 cm	< 20 dB(A)
Max. SPL in half space at 3% THD in 1m	100 db/SPL
Max. SPL averaged between	100 Hz and 6 kHz
Electronics
Woofer amplifier, cont. output power (THD < 0.1%)	14 W
Woofer amplifier, peak output power	25 W
Controller design	Analog, active
Input, analog
Impedance, bal. floating	20 kOhm
Input sensitivity	+6 dBu
Attenuator	0-Infinite
CMRR	> 50 dB @ 15 kHz
Displays, indicators - power on	LED "red"
Mains	230 V AC; 120 V AC available 12-14 V DC
Power consumption - idle	2 VA; 90 mA
Power consumption - full output AC; DC	27 VA; 1.7 A
Mechanical Specs
Cabinet surface	Painted finish
Color standard	Anthracite (RAL 7021)
Special (add-on price)	On request
Baffle cover	Metal grille, fixed
Drivers	Magnetically shielded
Woofer	3"
Mounting points	3/8" thread on bottom, 2 x M6 on sides
Height x width x depth	6.8 x 4.7 x 4.6"
Net volume internal	1.8 liters
Weight	5.7 lb