Loose Particles Sequence

This sequence demonstrates how to use SoundCheck to detect loose particle defects in loudspeakers

Introduction

This sequence demonstrates how to use SoundCheck to detect loose particle defects in loudspeakers. Loose particles typically reveal themselves as randomly spaced impulses, so they may not be detected when performing frequency based measurements such as THD, even though they can be clearly heard as undesirable artifacts. The loose particle algorithm, which is an available function in all analysis algorithms, analyzes a time waveform to detect these impulses. The user sets a customized threshold level for detection.

This sequence uses a low frequency 1/3rd octave stepped sine sweep and a HarmonicTrak analysis step with the loose particle option enabled. There is also a limit step, which outputs a pass/fail result based on the number of impulses detected during the sweep.

Required Hardware

• Reference Microphone – Listen SCM-3 or similar
• Audio Interface – Listen AudioConnect or similar (note: AudioConnect provides bias voltage for the SCM3 microphone. If you use a different microphone or interface, you will likely need to add a microphone power supply such as the Listen SoundConnect to your hardware setup.)
• Power Amplifier – Listen SCAmp or similar

Setup Diagram

Hardware Setup and Calibration

1. Calibrate the amplifier as instructed in the SoundCheck manual.
2. Calibrate the reference microphone as instructed in the SoundCheck manual.
3. Connect Output 1 of your audio interface to the input of the amplifier.
4. Connect the output of the amplifier to your loudspeaker.
5. Position your reference microphone at the desired test distance from the loudspeaker, and connect it to the microphone power supply.
6. Connect the output of the mic supply to Input 1 of your audio interface

Get Sequence

This sequence is included in the Sequences folder of your SoundCheck installation.