Polar Plot (Outline ET250-3D Turntable) Loudspeaker Sequence
This sequence measures the polar response of a loudspeaker in both the vertical and horizontal planes.
Introduction
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.
Required Hardware
- Audio Interface – Listen AudioConnect or similar
- Power Amp – Listen SCAmp or similar
- Reference Microphone – Listen SCM-3 or similar
- Linear X LT360 Turntable
Required Software
- 2006 – Time Selective Response
- 2011 – Polar Plot
Setup Diagram
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.
Get Sequence
Download Sequence (zip file)
Download Sequence documentation (PDF)
