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Large Signal Identification (LSI)

Features and Benefits

Force factor Bl(x) Shows an offset Xoff in the voice coil rest position.
  • Identification of large signal model in real time
  • Electrical and mechanical state variables (displacement, temperature, …)
  • For woofers in free air, sealed and vented enclosures
  • For micro‐speakers, headphones, mini‐loudspeakers, tweeters, shakers
  • Measures signal distortion on‐line
  • Full thermal and mechanical driver protection
  • Finds dominant sources of distortion
  • Locates weak points in design and assembly

The module LSI3 identifies the elements of the lumped parameter model of woofers, micro‐speakers, headphones, tweeters, shakers, mini‐loudspeakers and other electro‐dynamical transducers. It allows to measure transducers mounted in an enclosure or in free air. The transducer is operated under normal working conditions and excited with a broadband noise signal. Starting in the small signal domain the amplitude is gradually increased up to limits admissible for the particular transducer. 
The maximal amplitude is determined automatically using the identified transducer parameters and general protection parameters describing the thermal and mechanical load. The identification of the model parameters is performed in real time using an adaptive system. It is based on the estimation of the back EMF from the voltage U(t) and current signal I(t) measured at the electrical terminals. The identified model allows locating the sources of the nonlinear distortion and their contribution to the radiated sound. The dynamic generation of a DC‐part in the displacement, amplitude compression and other nonlinear effects can be investigated in detail.


Specification

Specification for LSI Tweeter and Woofer (Distortion Analyzer 2)
S1 LSI


Requirements

Hardware
KA3 - KLIPPEL Analyzer 3 

Software
dB-Lab 210

Accessories
Power amplifier
Laser sensor (optional)
PC 


Products

LSI3 Woofer
The LSI3 Woofer allows to measure woofers and other electro-dynamical transducers operated in free-air or coupled with an additional mechanical or acoustical resonator (vented enclosure, horn, panel) giving a total mechanical-acoustical system of 2nd or 4th-order. There are three working modes: Free air, sealed enclosure and vented enclosure.

LSI3  Micro-speaker
This module is dedicated for micro-speakers, tweeters, and horn compression drivers and which may be modeled by a 2nd-order mechanical system with a resonance fre-quency between 400 Hz and 1.5 kHz.


Standard

IEC Standard IEC62458 Sound System Equipment – Electroacoustic Transducers - Measurement of Large Signal Parameters



Standards

Consumer Electronics Association
CEA-2031

International Electrotechnical Commission 
IEC 60268-5, IEC 60268-7, IEC 60268-22, IEC 62458, IEC 62459, IEC WD 63034

European Standards
BS EN 54-24

Audio Engineering Society 
AES2

Institute of Electrical and Electronics Engineers
IEEE 269, IEEE 1206, IEEE 1329, IEEE 1652


Patents

Germany: 10 2007 005 070; USA: US8,078,433B2; China: ZL200810092055.4; Japan: 5364271; India: 162/DEL/2008; Germany: 10 2012 020 271 7; USA: 10,110,995; China: 201380054458.9;Korea:10-2015-7012390;Taiwan: 102137485;India: 844/MUMNP/2015

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