LOUDSIM : Version 1.4
LOUDSIM is a Windows based loudspeaker simulation program. It can be used to calculate the response of a moving coil drive unit mounted in a closed or a vented (reflex) enclosure or on an infinite baffle. The driver (Thiele) parameters, which may be obtained from the manufacturer, are first defined together with the cabinet dimensions. The program will then calculate the speaker amplitude response (Sound Pressure Level - SPL), impedance, phase shift and efficiency at any given frequency, and it will also give the optimum vent loading for a reflex enclosure, as illustrated in the screenshot below.
The program also provides a graphical output showing the loudspeaker or woofer bass response over the frequency range of 10 to 500Hz together with the speaker impedance (lower trace). These curves may be plotted in colour and the response for differing enclosures or drive unit parameters may be superimposed for ease of comparison. The screenshot below shows the predicted performance of the driver, defined in the above example, mounted in a vented box with optimum vent volume. The amplitude response is essentially flat down to 40Hz and then falls away rapidly at 24dB per octave. The impedance curve exhibits the characteristic double hump with a minimum at 30Hz - the Helmholtz frequency.
The next screenshot shows the step response of the above speaker which exhibits considerable ringing at around 30 Hz.
The program is easy to install and use. Many examples of popular drive units and loudspeaker designs are included together with full documentation. The speaker details and program settings are stored on exit to allow the same parameters to be used on restarting. The minimum hardware requirements are any IBM 386 compatible PC with coprocessor running Windows 9x/NT/Me/XP or Vista. This is an EDA - Electronic Design Automation - product.
Click here to purchase the full registered version of LOUDSIM.
Peter M. Montgomery, Downings, Bells Hill, Stoke Poges, SLOUGH SL2 4EG (UK)
Telephone : 44(0)1753643384
For more details see program documentation or contact the author.
LOUDSIM : Copyright © 2003 - 2010 P.M. Montgomery
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LOUDSIM : 09/04/10