The microphone boom/turntable Nor265 may be used as a stand-alone device to obtain the spatial average of sound level by moving a measurement microphone back and forth continuously. Main applications are building acoustic measurements (ISO 140-series), measurement of sound absorption in a reverberation room (ISO 354) and determination of sound power levels of sources using sound pressure (ISO 3741).


Due to the oscillating back and forth movement a normal microphone cable may be fed through the hollow main shaft without the need for slip rings thereby ensuring very low electrical noise levels are maintained. The unit may be equipped with a turntable plate or chuck for mounting of different test objects. In this configuration the main application is measurement of directional responses of acoustic transducers like microphones and loudspeakers. The unit is manually operated by the rotary switch on the front. As delivered from the factory eight of the switch positions (1, 2… 8) corresponds to ±90° and ±180° sweeps with different sweep speeds.

These settings may be redefined by using remote commands if the unit is equipped for remote operation. Extended control of the device is possible by remote commands from a computer by use of the optional serial interface. This allows accurate control of angular position, speed and acceleration. The unit is robust and constructed for years of maintenance-free operation. When a movement or sweep is started, the speed will gradually increase as specified by the acceleration instruction until the selected speed is obtained. The reversed speed-profile is used for deceleration. By specifying a higher value for the acceleration time, even a large or heavy object may be handled. Nor265 uses a digital signal processor (DSP) to obtain accurate positioning with simple and robust mechanical design. Accuracy in speed and acceleration are ensured by the use of a precision a crystal clock. The design allows a unique combination of specifications suitable for microphone boom applications as well as a general turntable. The sound emission from the unit is very low, especially when operated at the slower speeds.

Microphone Boom Nor265


  • Building Acoustic measurement in accordance with ISO 140
  • Reverberation Time measurements in accordance with ISO 354
  • Sound Power measurements in accordance with ISO 3740 series
  • Directional response measurements of loudspeakers and microphones


  • Sweep of ±90° and ±180°
  • User defined sweeps
  • Selectable sweep times
  • PC-control via RS-232 interface
  • User-defined fixed boom-positions
  • Accurate positioning of turntable angle
  • Low-noise design
  • No noisy slip-rings


The basic unit must be supplied either with option 1 (boom accessories) and/or option 2 Turntable accessories.

Option 1: Boom accessories

Microphone boom accessories for use with Nor265 main motor unit.
Includes adjustable rod (0.8 – 2.0 m), counterweight, 1/2″ preamplifier adapter, tripod, and tripod adapter.

Option 2: Turntable accessories

Turntable accessories for use with Nor265 main motor unit. Includes table plate (diameter 300 mm), chuck (2-13 mm), and table-plate mounting adapter.

Option 3: Remote control

RS-232 serial interface including 2m cable and Nor1029 Control Software
(Please note that option 3 must be ordered together with the Main Motor Unit as this option is installed at the factory)


Max sound level (re. 20 µPa): Diameter 202mm, Height: 171 mm
Size – main body: 6 kg
Mounting: Tripod allows inclined traverse plane
Diameter of tripod mounting stud: 3/8”
Main axle dimension: Outer diameter: 30 mm, Inner diameter: > 22 mm
Units to be mounted on turn axle:
Microphone boom (option 1)
Turn table (d=300 mm) (option 2)
Chuck (2 – 13 mm) (option 2)
Boom radius 0,8 – 2 m (continuously adjustable)
Rotation angle: -241592002° to +241592002° (more than 600.000 revolutions)
May also be set to rotate continuously at a specified direction and speed
Resolution: 0.01°
Angle accuracy (no torque): < 0.8°. Typical. < 0.05° if moved in one direction
Max load (any direction): 500 N
Max torque loading: 2 Nm
Typical error from loading torque: 0.3 deg/Nm
Power supply: 90 – 264V AC / 47 – 440 Hz
Fuses: 2,5 A slow blow (IEC 60127)
Remote operation (option 3): RS-232 interface: 9600 – 115200 baud
Noise emission: < 10 dBA at rest
< 23 dBA for all default rotations and sweep times (i.e. >20 sec/rev)
The noise is measured in an anechoic chamber with the moving microphone placed 1,5 m from the main body
Temperature range -10 to 50 °C
Humidity: 0 – 90 %RH


  • Product data: Nor265 Microphone boom / turntable basic unit