The long awaited Windows? version of our popular LMS? analyzer software has finally arrived! Not only does it include all of the previous
well known features, but it also introduces many enhancements and new capabilities for both measurement and data processing.

? Color printing through any Windows Printer
? Curve Libraries now hold 99 Curves
? Direct Single/Multiple curve transfer into LEAP-5
? Multi Curve Copy/Paste using Clipboard for transfer
? Advanced Speaker Parameter Derivation
? Simulation of Loudspeaker Model Parameters
? Extensive Graphics Vector and Raster Export
? Manual real-time frequency sweep using mouse
? Maximum sweep resolution now 800 log points
? Macro Editor with syntax highlighting
? MDF Editor for creating/editing any mic file for external mics
? Curve Capture, distill actual curve data from raster images
? Curve Editor, create/modify curves by graphical editing
? Linear, Quadratic, and Cubic Interpolation routines
? Enhanced capabilities for Post Processing Math operations
? Enhanced capabilities for Polar Plot processing and resolution
? Operating System: Win98/SE/ME, Win2000, WinXP, Vista-32

A complete and affordable analyzer system that provides quality data for electroacoustic engineering work.

The LMS system provides a vast array of powerful computer based features which are specifically focused on the unique requirements of loudspeaker development and QC production testing.

LMS provides the ability to achieve very high log frequency resolution across many decades of frequency that typical FFTs can't match.

No other measurement package today provides as many outstanding features and capabilities at such an incredible price!

The rich graphical user interface provides a host of features which greatly enhance the ease of operation and power of the system.

All of the LMS hardware features can be controlled and modified through the Analyzer Parameters dialog.

The analyzer control parameters can also be saved to disk as QuickSet files, and recalled later to immediately reset all of the control panel parameters.

The user can save and retrieve previous setups for any number of favorite test measurements.

? Volts
? SPL
? Impedance
? Inductance

? Polar Volt
? Polar SPL
? RT60
? Capacitance

Unlike other analyzer software, LMS contains a Curve Library system. Up to 50 curves can be stored in each library of any mixed type.

Multi curve display was not an after thought in LMS, it was built in from the ground up. This also provides tremendous power and flexibility for post processing operations.

Single and multiple Curves can also be copy/pasted into other libaries.

The post processing features in the system enhance the user's ability to derive maximum use of the measured sweep data.  True power response can be computed directly by the software from a total set of off-axis response sweeps.  Individual weighting of the curves is also provided to allow the proper average to be computed.

The processing menu provides mathematical functions, data processing functions, and other specialized curve processing capabilities which can be applied to measured data or imported data. Smoothing, scaling, splicing, tail correction, phase generation, and math operations give the user complete control over the measured data without the need for using external data processing programs.

LMS provides a rich set of utilities for manipulating data and graphics.  Numerical data can be imported and exported from the program as simple ASCII text files. 

The graphic artwork can be exported as either vector or raster image files in many different formats including: BMP, TIF, PCX, PNG, EPS, AI, PDF, WMF, EMF. 

A powerful Curve Capture utility can distill numerical curve data from raster images.  These can be pictures from books, manuals, or scanned images of plotter output.  The Curve Editor utility allows you to graphically create your own curves, or edit the data of any curve in the library.

This dialog provides five different methods of generating speaker parameters.  Moreover, the parameters generated can be produced for two different models: Standard or LEAP. 

Full optimization of the model parameters to the original impedance curves is provided for maximum accuracy.  Native unit conversions are provided for all parameters. 

The dialog also provides the means to generate impedance curve simulations based on the derived parameters. This allows for easy viewing and comparison of the model to the measured impedance data.

The graph here shows a pair of typical impedance curves produced from a delta-mass measurement.

This was a 15 In woofer and 100 grams of mass was added to produce the delta curve.

After processing, the speaker parameters as shown below were produced.

The parameters will be generated with whatever units the user has selected.

The parameters can then be saved as a text file, transferred to the clipboard, or printed.

* LMS(TM) 4.1.0.249 Sep/15/2000
* (C)1993-2000 by LinearX Systems Inc
* ElectroMech Speaker Parameters
* Sep 28, 2000 Thr 5:17 pm
* Library=Spmtests.lib
* Reference Curve=15" in free air
* Delta M/C Curve=15" +100G DM
* Method= Double Curve - Delta Mass
* Domain= FreeAir, Model= LEAP
Revc= 6.200 Ohm
Fo= 27.962 Hz
Sd= 88.000m sqM
Krm= 19.137m Ohm
Erm= 0.709
Kxm= 6.816m Ohm
Exm= 0.740
Vas= 364.188m cuM
Cms= 331.186u M/N
Mmd= 82.812m Kg
Mms= 97.822 g
BL= 19.473 TM
Qms= 3.691
Qes= 0.281
Qts= 0.261
No= 2.700 %
SPLo= 96.395 dB

The graph here shows the simulation results based on the newly derived parameters.

The Red curve shows the free air simulation, and the Blue curve the delta-mass simulation.

A copy of the complete set of numeric parameters is also placed automatically into the note area of the graph. The parameters which created the curves are printed with the graph curves.

The new Transducer Model Derivation (TMD) dialog contains the ability to produce parameters for 3 different transducer models: Standard (STD), LEAP-4 (TSL), and LEAP-5 (LTD).

The LTD model was developed for LEAP-5 and provides extremely advanced behavior modeling capabilities for electrodynamic transducers. A comparison of the three different models and real driver behavior is given in the following link.

Transducer Model Comparison

Extensive parameter fields are provided in the TMD dialog. Multiple impedance curves are input by the user taken under different drive conditions, delta mass, and temperature. Numerical optimization techiques are used to fit the parameters to the data curves.

The results of the model simulation are compared directly against the imported measured data. Each measured impedance data curve can be compared to the matching model curve.

The parameter graph tab provides a graphical view of various key parameters of the transducer. Many of these parameters are both frequency and/or level dependent in the case of the LTD model.

For production testing applications the LMS software can be controlled by user written Macro programs.

The LMS Macro programming language allows for messages to be written to the screen to prompt operators, control test sweeps, run utilities, control printing of graphs, export data, and conduct Pass/Fail tests.

A custom macro editor is also provided as shown here which features syntax highlighting and color printing.

The analyzer parameters can be saved to disk as QuickSet files, and recalled later to immediately reset all of the control panel parameters.

When the macro program is running, the dialog as shown here is active. Messages, prompts, and other data can be displayed for the operator. Menus can also be created.

The dialog provides PASS/FAIL indicators which can be utilitized by the macro script programs.

The Scale Parameters dialog consists of two principal groups of controls: Horizontal and Vertical Scales. 

This powerful dialog enables plotting of curve data in almost any possible manner.  A different scale is defined for each type of curve units. 

The horizontal panel provides control over the frequency, time, or angle unit scales.  The vertical panel controls a wide variety of different types of unit scales.

Scale labels can be automatically generated bythe system, or modified by the user for special applications.

This utility is very useful for manually constructing polar plot data, from a group of normal frequency response measurements.

Each frequency response curve is taken at a different location radially around the transducer.

Using this dialog the representative locations of each curve are entered, and then an output list of curves is established with specific frequencies for which the polar curves will be generated.

A series of ground plane measurements were made by rotating the mic by 7.5 Degree increments through the entire 360 Degree circle. This resulted in 48 frequency response curves measured across 10Hz-40kHz.

The curves were then normalized to the on-axis 0 Degree curve. This was accomplished by dividing all curves by the 0 Degree curve. In this way the response at each location around the transducer is relative to the on-axis response.

It was desired to produce 5 polar curves for the higher frequencies of 2kHz, 5kHz, 10kHz, 20kHz, and 40kHz.

The graph plotting system automatically calculates the beamwidth in degrees, Q factor, and the directivity index DI for each of the polar curves.

This is the normal full sweep Sound Pressure Level frequency response.  Since LMS measures automatically in absolute dBSPL, no level scaling or determination of absolute levels is required. 

You can measure the sensitivity of any transducer directly by simply setting the drive level from the power amp to 1 watt.  The curves below show a woofer in Yellow, a midrange in Red, and a tweeter in Blue.

With LMS, taking accurate impedance measurements is as easy as connecting two wires to a speaker. LMS uses a built-in 500 Ohm output resistance to form a voltage divider with the load. 

LMS then automatically resolves this equation and produces the actual impedance of the load in true Ohms.

For more accuracy and capability the VI-Box can be used. This will allow impedance measurements at any power level.

By using one of the processing features, LMS can perform an inverse FFT on any frequency domain data, and produce a time domain response. 

Both Impulse and Step response curves are generated.  LMS has many powerful post processing functions which allow easy manipulation of curve data. 

The step response is shown below in Red, and the Impulse response in Blue.

The scale system allows almost any data to be displayed on either rectangular or circular grids.  When magnitude/phase data is plotted using polar coordinates, a Nyquist plot results. 

Any LMS data curve can be displayed in this polar representation.  True polar display is provided for easy viewing of the radial data with either linear, log, or dB scales.

The gating system in LMS allows for quasi-anechoic measurements to be taken in any environment. 

The adjustment of gate time parameters prevents reflections from local nearby boundaries from affecting the measurement.  LMS does not produce any erroneous false data below the gate frequency limit.

LMS can also be used to measure environmental noise vs. frequency using the Bandpass filters.  This type of sweep will indicate where the significant energy is located. 

The effectiveness of isolations or damping materials can be quantitatively evaluated.  Adjustments and/or improvements can be made.

The LMS filters can also be configured to perform Rub/Buzz type testing very effectively.  By setting both filters as Highpass with a tracking ratio of nominally 7 times the oscillator frequency, the buzzing sounds of a defective transducer can be measured.  Electrical as well as acoustic R/B setups can be tested. 

The curves here show some defective drivers, and demonstrate that the defects can present themselves at different frequencies.  The Violet shows rubbing sound at 25Hz, while the Grn and Blue curves rub at much higher frequencies.

LMS produces excellent polar plots for viewing the response from all directions of a transducer or cabinet. 

LMS also provides automatic calculation of the 6dB coverage angle, Q, and the directivity index DI.  Two different methods are available in LMS for generating the Polar Plot data.

LMS provides direct measurement of inductance and/or capacitance vs. frequency.  This mode allows measurement and evaluation of passive crossover components to determine frequency dependency.

This graph shows a 9mH ferrite bobbin (Violet), 5mH ferrite bobbin (Blue), 4mH iron bar (Orange),  1.5mH air core (Brown), and a 0.7mH air core (Green).  The rise at low frequencies is due to the DCR of the inductor, and the fall at high frequencies is due to the shunting capacitance of the windings and/or the changes in core permeability.

This graph shows an example of measuring the cone excursion of a loudspeaker tested at 1 Watt. 

It was produced by attaching a lightweight accelerometer to the base of the cone, and then measuring the acceleration vs. frequency. 

The  processing features of LMS where then used to convert this data into velocity, and then finally excursion.  The sharp dip near 50Hz shows the effect of the port on reducing the cone excursion.