Linear Parameter Measurement (LPM)
- Thiele / Small parameter
- Identifies linear transducer model
- Measures suspension creep
- Single-step measurement with laser sensor
- Two-step measurement with additional mass or test enclosure
- Monitors ratio signal to noise + distortion (SNR+D) and noise floor
- Automatic validity check
This module identifies the electrical and mechanical parameters of electro-dynamical transducers by measuring the voltage and current at the speaker terminals. Using an optional laser displacement sensor, the identification dispenses with a second measurement and avoids problems due to leakage of the test enclosure and mass attachment. This kind of measurement also identifies the parameters of the suspension creep giving more accuracy of the loudspeaker model at low frequencies. The measurement indicates insufficient signal to noise ratio and malfunction operation due to nonlinear effects of the driver or amplifier limiting.
Specification
Standard Measurement performed by LPM Module
Requirements
- Distortion Analyzer 2 hardware
- dB-Lab software
- Power amplifier
- Laser sensor (optional)
- PC
It is recommended to use coating spray for micro-speakers and tweeters with transparent and shiny diaphragms. More information.
Added mass perturbation technique
Test box perturbation technique
Laser technique
Multi-tone Measurement
Templates coming with the LPM module:
LPM multitone distortion SP1 | Multi-tone distortion at high amplitudes (see Application Note AN 16) using standard current sensor 1 |
LPM Microspeaker T/S (SP2) | Linear parameters of micro-speakers using sensitive current sensor 2 |
LPM Subwoofer T/S (Sp1) | Linear parameters of subwoofers using standard current sensor 1 |
LPM Subwoofer T/S (Sp2) | Linear parameters of subwoofers using sensitive current sensor 2 |
LPM Tweeter T/S (SP2) | Linear parameters of tweeters using sensitive current sensor 2 |
LPM Woofer T/S (Sp1) | Linear parameters of woofers using standard current sensor 1 |
LPM Woofer T/S (Sp2) | Linear parameters of woofers using sensitive current sensor 2 |
LPM Woofer T/S added mass | Linear parameters of woofers using added mass method |
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