Polar Plot (Outline ET250-3D Turntable) Loudspeaker Sequence
This sequence measures the polar response of a loudspeaker in both the vertical and horizontal planes.
This sequence measures the polar response of a loudspeaker in both the vertical and horizontal planes. It is designed to work with the Outline ET250-3D turntable and contains all the necessary commands to automatically rotate the turntable’s platter when the SoundCheck host PC is connected to the turntable via an Ethernet/LAN connection. The sequence uses a log sweep stimulus with the Time Selective Response algorithm so that the measurements can be made in a non-anechoic environment. Note that the analysis step’s time window needs to be adapted to the user’s measurement space. The ET250-3D custom control step will also need to be configured prior to running this sequence. The sequence plays the stimulus and measures at 10 degree increments from 0 to 180 degrees. This process is repeated with the speaker positioned horizontally. The two results are mirrored to display full 360 degree polar plots for each axis. A directivity index curve is also calculated for each axis and is displayed at the end of the test.
- Audio Interface – Listen AudioConnect or similar
- Power Amp – Listen SCAmp or similar
- Reference Microphone – Listen SCM-3 or similar
- Linear X LT360 Turntable
- 2006 – Time Selective Response
- 2011 – Polar Plot
Hardware Setup and Calibration
- Calibrate the reference microphone as instructed in the SoundCheck manual.
- Calibrate the amplifier as instructed in the SoundCheck manual.
- Connect the output of the microphone power supply to Input 1 of your audio interface.
- Connect Output 1 of your audio interface to the input of the amplifier.
- Connect the output of the amplifier to your loudspeaker.
- Position your reference microphone at the desired test distance from the loudspeaker, and connect it to the microphone power supply.
- Connect the Ethernet port on the ET250-3D to your LAN or directly to the SoundCheck PC’s Ethernet port using a suitable cable.
- Configure the network address of Steps 5, 11, and 19 as instructed above to communicate with your Outline Turntable.
You are ready to start the sequence.