Direct Draw Drivers [if you are not running 98 or NT] CIRCAD for Windows NT, Windows 98, and Windows 95B - CIRCAD boasts the highest run-time performance of any PCB CAD package on the market today. Schematics, netlists, circuit boards, and gerber plots are all at your fingertips awaiting your beck and call. For the more advanced users, CIRCAD even has a "reverse engineering" feature that enables you to start with a scanned image of a PCB and work backwards to the schematic.

DC CAD (tm) Electronic Board Design - DC CAD combines the ease and versatility of a pixel-oriented drawing program with the specialized tools and funtions of a CAD program to give you an uncommon level of control in creating schematics and double-side board layouts.

DC Circuits Training System v2.10- 13 exercises to help you learn or teach electricity or electronics. Features random problem generation, extensive graphics, context sensitive help, and instant scoring.

DPC - Driver Parameter Calculator - and it utilizes the simple Thiele-Small loudspeaker parameter model to calculate unknown parameters from a minimum of known parameters. Besides the simple Thiele-Small parameters, it can also assist you (the DIY speaker builder) in measuring loudspeaker parameters, and you can pick between the normal two methods (added mass or closed box). With the closed box method it uses a slightly improved Thiele-Small model where leakage losses are included, so you should get some really nice and reliable data. In DPC everything is documented, formulas, theory, everything. A newbie in loudspeakers could learn a lot from the documentation. DPC supports any kind of units you would like to apply - and files for UK and SI units are included.

DesignWorks Schematic Capture for Windows [Lite]- DesignWorks offers you the Best User Interface, bar none, for schematic capture. The program is designed to minimize the number of mouse clicks and key strokes needed to complete a task. Most common operations, like placing a part or drawing a signal line, require no menu selections and no command typing. The powerful scripting system provides seamless integration with all your engineering tools. DesignWorks doesn't just provide an environment for a single goal. It is flexible enough to handle all your design goals, be the goal a PCB design, Spice analysis, or FPGA design. You are not locked in to one PCB or simulation vendor.

EENG2.ZIP - Archive file contains: DC CIRCUIT ANALYSIS, v1.1 - This program can create and evaluate computer circuits. TSHOOT.ZIP - Troubleshoot a two-stage amplifier program.

ELCAD Version 1.0 - Elcad is intended primarily for the electronic hobbyist or tinkerer. Although, it will save an electronic engineer a lot of time in calculations, too. ELCAD can be used to compute resistance, wattage, capacitance, inductance, filter capacitance, timing circuits, transistor circuits and a host of other things. ELCAD is very straightforward and easy to use (it is all menu driven).

ETF Energy-Time-Frequency - ETF is a software application that greatly reduces the cost of taking these measurements by using your existing PC hardware, sound card and microphone to record a test signal played through your sound system (supplied on CD). ETF imports and analyzes the resulting wave file to graphically illustrate the three critical parameters in small room acoustics. ETF produces three-dimensional graphs that illustrate room resonances, early reflections and later reflection diffusion. All graphics are automatically scaled to give the best possible resolution and quality of results. ETF is a visual tool that enables even beginners to do effective room analysis with a minimum of effort.

Filter - A real-time variable audio filter Windows utility

Filter CAD - Computer aided filter design! FilterCAD was designed to be easy to use as well as being a very power filter design tool.

FILTRY v 1.10 - Nearly everytime you construct a new piece of equipment you have to design some filter. It's exactly the same for me! Now there are several ways to solve this problem: to look in catalogues and handbooks, to ask a colleague, etc. The quickest way, however, is to say your computer: "I need an active low-pass filter with no more than -0.32 dB up to 3.25 kHz and with more than 22 dB attenuation at 4.06 kHz.". "And should it be Tchebychev or Butterworth ?", it replies. "Butterworth!", you answer. The schematic diagram then appears on the screen instantaneously. It would be nice, wouldn't it ? But it IS nice! This program is in your hands. Its name is FILTRY (plural for 'filter' in Czech). It's a kind of "autonavigation program" and it needs no manual. Just type the word 'filtry' and then let the program guide you. You can print out the schematic diagram - hit <PtrScr>. You can also store the picture on the disk and print out it sometime later - by using the program "ZOBRAZ" (it means 'represent').

Filter Lab 1.0.39 - FilterLab is an innovative software tool that simplifies active filter design. Available at no cost, the Fil-terLab active filter software design tool provides full schematic diagrams of the filter circuit with component values and displays the frequency response. FilterLab allows the design of low-pass filters up to an 8th order filter with Chebyshev, Bessel or Butterworth responses from frequencies of 0.1 Hz to 10 MHz. Users can select a flat passband or sharp transition from passband to stopband. Options, such as minimum ripple factor, sharp transition and linear phase delay, are available. Once the filter response has been identi-fied, FilterLab generates the frequency response and the circuit. For maxi-mum design flexibility, changes in capacitor values can be implemented to fit the demands of the application. FilterLab will recalculate all values to meet the desired response, allowing real-world values to be substituted or changed as part of the design process. FilterLab also generates a spice model of the designed filter. Extraction of this model will allow time domain analysis in spice simulations, streamlining the design process. Further consideration is given to designs used in conjunction with an ana-log-to-digital converter. A suggested filter can be generated by simply input-ting the bit resolution and sample rate via the Anti-Aliasing Wizard. This eliminates erroneous signals folded back into the digital data due to the aliasing effect.

FORMULAS.XLS - A spreadsheet approach to crossover design.

FREQ Version 5.0 - Freq, a spectrum analyzer program for DOS, Linux, Linux/X, and Sun Copyright (C) 1995 Philip VanBaren Contents: dos/freq.exe For DOS, with PAS-16, SB, or VESA-AI sound cards linux_svga/freq For Linux with SVGA graphics linux_srgp/xfreq For Linux running X Windows sun/xfreq For Sun Sparcstations running X Windows. FREQ.EXE is a program for the ProAudio Spectrum/Studio 16 sound cards, Soundblater compatible 8-bit cards, and cards supporting the VESA audio interface BIOS extensions. The program samples the input, performs an FFT, and graphs the output. INI file and command line options provide the user with the ability to select linear/log frequency and amplitude scales as well as sampling rates, length of the FFT, and windowing functions. Graphics is done using the VGA 640x480x16 video mode, so a VGA compatible card is required. The program will only run on computers with an 80386 or above processor. A coprocessor is recommended, but not required. FREQ.EXE also works with 8 bit Soundblaster and compatible cards. It looks for the environment variable "BLASTER=A220 I5 D1" to set the Soundblaster address, IRQ, and DMA. If this variable is not available, the default values (220,5,1) are used.

LinearX's LMS Loudspeaker Measurement System Version 3.72

This requires that you own the software/hardware package by LinearX (formerly ATI for some of the old users) and upgrades the software to current standards and drivers. 

This requires that you own the software package by LinearX (formerly ATI for some of the old users) and upgrades the software to current operating standards, printer drivers, and the like.  

LOUDSPEAKER ENCLOSURE DESIGNER (LED) v2.20 LED generates up to 3 discrete sophisticated speaker/enclosure models using widely availa- ble Thiele-Small parameters. Models are displayed with richly colored graphs. LED re- quires As Easy As spreadsheet v5.50 rev. C or newer to run. (also works on other spreadsheet programs.) Written by David Kakenmaster of Definitive Technology fame.

Loudspeaker Modeling Program LMP v1.25 - LMP is a computer program designed to model 2-way loudspeaker systems. The resulting frequency and phase response curves predict the on-axis sound pressure level produced by the interaction of your choice of crossover, drivers and enclosure design. LMP assumes that the impedance curve of the drivers in the modeled system have been made reasonably flat by way of Zobel and/or impedance correcting networks. LMP also assumes that the drivers modeled have a flat frequency response from the low frequency roll-off point to the high frequency roll- off point. Quality drivers on the market today meet this criteria. LMP assumes that the user has had some experience with loudspeaker systems and crossover networks and is familiar with the terminology commonly used to describe the various parameters involved.

Loudspeaker Attentuator Design Version 2.0 Lets you provide exact attentuation.

LSPCad - Loudspeaker Computer Aided Design is a software that helps you to construct and simulate loudspeaker boxes, passive and active crossover networks. With the box utility you are able to model 9 different kinds of loudspeaker boxes with dynamic loudspeaker units. These are: Closed box, Bass reflex, Double tuned bass reflex - Two types, ABR (passive radiator), Bandpass 1, Bandpass 2, Bandpass 3, and Bandpass 4. The passive crossover utility can model 2-way and 3-way loudspeaker systems. Besides the rudimentary filter calculator existing in most loudspeaker modelling software the user can import measured SPL and impedance data and thus model a real system. One or two drivers per network is supported, there also exist and vertical off axis simulation capabilities. Also is available a music filtering function that allows you to filter a music sample through the loudspeakers frequency response, after that you can listen to the result with a pair of high quality headphones.

Magnetic Designer v3.1 Lets you design with transformers in mind. Windows based simulation includes a sample to guide you through the design of a 50 watt feed forward transformer.

MicFFT v1.2 - MicFFT is a program that samples data from a sound card or addressable analog-to-digital (ADC) port, and plots out the spectral features of the sampled waveform. The program utilizes a Fast Fourier Transform (FFT) algorithm to transform the sampled data (in the time domain) to the frequency domain. The program gets 256 Pulse Code Modulated (PCM-see below) samples from the ADC at a defined sampling rate, and then plots the transformed data. MicFFT continuously loops between sampling and plotting. Thus, the program acts somewhat like a realtime spectrum analyzer, and on fast machines with fast sound cards, is capable of impressive performance. MicFFT can be likened to spectrum analyzers found on some audio equalizers, and can provide detailed information on the spectral components and relative intensities of continuous waveforms.

Mobile Design Version 1.0 - Freeware from Mobile Dynamics, the car audio installation experts and trainers. It works great if you are trying to design sealed or isobarik enclosures (selectable Qtc), even with multiple drivers. This program is designed only for figuring true "optimum" ported enclosures. MD1 also displays the drivers EBP, and recommends an enclosure type to best fit the driver.

NOISE ANALYSIS TOOLS - Spreadsheet with macro formatted to work in Microsoft Excel 4.0 or greater.

Sample Champion - Champion is an accurate and easy to use audio measurement software. It has been designed for acoustical technicians, sound engineers, scientists and students. With this software you'll be able to easily perform Impulse response measurements, FFT analysis and much more.

Oscilloscope for Windows v. 2.51 - Oscilloscope for Windows uses the sound card as an analog-to-digital converter, providing complete oscilloscope and spectrum analyzer functionality in Windows95 environment.

Ohms Law Visual Aid Can't remember OHM's Law - here you go.

Power Audio Database [Ver. 3.0.19 - Win95/NT] - The program provides a wide range of features, including a designer which you can use to create and print your own tape and CD inlays, and a Music Trivia Quiz - you can even create your own quizzes! Link video (.avi files), audio (.wav files) and pictures and photographs (.bmp files) to any of your albums or songs. You can view your collection - records of albums, songs, artists, musicians etc. - in many different ways, including specialized view screens, grid views and printable reports. With the program's excellent search facilities, you will never again give up trying to remember the name of a song in your collection, or wonder which album it's on. You can even search according to how a name sounds! Make sure your albums never go missing, by recording every time you loan an album to a friend. Also easily calculate the value of your entire collection and, for insurance purposes, increase all values in line with inflation in seconds.

PC Audio Lab for Windows 95/NT Version 1.0 Beta [Microacoustics] - Using a Soundblaster card you can provide a Spectrum Analyzer, Real time Analyzer, Oscilliscope, and VU meters that can be used with inputs [line or mike inputs] from your sound card. Full version will include standard DOS version features like MLS, FFT, Loudspeaker Tests, Distortion analysis and more.

PCB[- This is a small printed circuit board cad package. It consists of three programs: an autorouter, a board viewer, and a board printer.

PCTrace v5.0 - PC Trace is a circuit board layout tool. It also includes SCAD for schematic capture.

Peerless Boxsimulation Version 1.1 for Windows.

This is a Windows 3.+ based program from Peerless that is provided at no cost to those interested in using Peerless drivers in a project. Thanks to Mr. Bill Spillaine, Vice President of Peerless, for offering this valuable tool for download at this site. The files are compressed with PKZIP and must be extracted to a 3.5 diskette for installation. 

Perfect Box 4.50

PERFECT BOX is a Computer Aided Design (CAD) program for the simulation of loudspeaker performance. PERFECT BOX is a very powerful tool for the amateur or professional speaker builder. It is a shareware program that is provided for your evaluation at no cost for a trial period. 

P.E.T. Ported Enclosure Toolkit v1.69 - A DOS based speaker enclosure design program.

PHYMOD 2.0 - A new method used for the creation of innovative electronical sounds is the Physical-Modeling-Synthesis which can be used to create virtual resonance bodies. Phy Mod 2.0 is a Physical-Modeling-Programm which can create virtual resonance bodies, i.e. defined by the programm as "sound-sculptures", on the screen. Not just sound-bodies can therefore be simulated in an astonishingly visible way but swinging compositions can also be described. Hardware requirements are: - CPU 486 66 Mhz with coprocessor, preferably Pentium - Hard disk with space for Sounds - Windows 3.11, Windows 95 or Windows NT - 16-bit stereo sound card

PreWalls - A simulator of room acoustics for arbitrarely-shaped rooms and source-receiver directivities

PROfft version 1.0 release date 29.4.1992 - PROfft stands for PROject Fast Fourier Transform and is the result of a project developed by five students learning C++ at the Norwegian Institute of Technology spring 1992. The program allows to transform bitmap (.BMP) pictures using the fast fourier transform. The resulting pictures will be displayed as according to the mathematic formula [Grayscale Intensity]=LOG10(1+ABS(Z)) where Z denotes the complex number after transforming the picture. There is an option which allow the transforms to be shifted to the center of the window (centered lower frequencies). You can also filter the pictures using lowpass, highpass, bandpass, bandstop, butterworth lowpass and highpass filters. In addition there is a "freehand" filter which allow you to zero out certain frequencies in the transformed picture. Finally the manipulated complex pictures can be transformed back again. The program requires Windows 3.X to run, and preferably with a 256 colour driver installed (although it will work perfectly with standard VGA). The transformed pictures can be saved to disk or pasted into other applications by using the clipboard.

PXover - PXover calculates component values for different orders and mathematical approximations (i.e. Butterworth, Linear-Phase, ...) of passive crossover networks. A schematic of the network is displayed with component values. All inductor values are in milli-henries(mH) and all capacitor values are in micro-Farads (uF).

RCC v2.1 - Resistor Color Code From TC Electronics, the makers of ACL: Just match the colors to get a fast easy readout of coded values on resistors or input the values to get the colors for resistors. Calculates total ohms value on parallel & series connected resistors. Calculates usable tolerance range. Handy and simple to use. Speeds service work and hobby construction.

Rockin'Box v1.13 - CAD Speaker design program for vented and sealed enclosures. Aimed at the car stereo enthusiast.

ROOM OPTIMIZER - A room optimization software that combines computer image model room simulation techniques with powerful multi-dimensional optimization tools. Room Optimizer™ is the first program that automatically determines the optimum listener and loudspeaker locations in a rectangular room, by evaluating the combined, weighted standard deviation of the speaker-boundary interference and modal responses. All you need to do is enter the room dimensions and the search ranges for the listener and up to 20 loudspeakers. Room Optimizer™ automatically and intelligently searches hundreds of possibilities for the optimum locations. During the search you can view the listener and loudspeakers, in the Room View; the room response spectra, in the Spectra View; the weighted error, in the Error View; the room configuration, in the Configuration View; the geometrical reflection points for mid/high frequency image control, in the GRP View; and most importantly the answer (listener and loudspeaker coordinates), in the Data View.

Room Acoustics Simulator Version 1.0 Audio group W.C.L. University of Patras. A rectangular room response simulator based on the image method with a Windows interface.

Room Augmentation Analysis for Loudspeakers - A spreadsheet written by Roy Allison to plots room boundary augmentation curves for loudspeakers in real rooms.

ROOMODE.BAS + WKS file - Since I'm not wild about using a BASIC interpreter every time I want to plot room modes, I took his published (unenhanced) program and created a .WKS spreadsheet to perform the calculations. It will also plot the modes graphically. This spreadsheet was created using version 5.50C of As Easy As, a widely available shareware spreadsheet program. I suspect that it will work well enough in other Lotus compatible spreadsheets, even with the large differences in macro languages and graph descriptions. The graphs that this spreadsheet template creates simply plot the frequencies at which modes will occur.

Sage - From RPS Software - SAGE is a shareware program which automatically calculates the graphic equalizer settings that give the most realistic playback of sound, compensating for both your sound system and the acoustics of the room. It has a simple wizard interface, and will work with both hardware and software equalizers such as the one in Winamp. It can also balance the stereo for your listening position and correct for damage, such as a defective tweeter.

SB_OCT - a 100kB DOS program that uses SoundBlaster(R)-compatible soundcard to evaluate 1/3 up to 1/24 octave spectra. Supports full calibration of mixer (result independant of mic/line input and input gain) and allows soundcard frequency response compensation (separate for mic and line). As SB_OCT is fully key operated it is especially interesting for mobile applications (tested with a wide range of laptop soundcards).

SINUSGEN - is a simple sinus generator program. The frequency is adjustable from 20 to 10000 Hz and the output level of the sinusoidal signal can be lowered. For signal generation the FM chip of the soundcard is used. For frequencies above 4000 Hz the sine signal might sound a bit distorted depending on the FM chip/soundcard! The program SINUSGEN.EXE should run with all AdLib®-compatible soundcard (which means nearly any soundcard) under MS-DOS® or under WINDOWS® (in DOS box or direct).

Speaker Design Package - Loudspeaker Enclosure program predicts box response.

SPEAKER ENCLOSURE CALCULATOR v1.0 - This little program will calculate a nice sounding enclosure for all types of dynamic speakers. The good thing about it is that you don't need a PhD in acoustics to use it.

SKEM 1.1 - was developed to fill the need for a simple, easy to use schematic drawing and printing program. SKEM 1.1 is only intended to be used to draw and print schematics (nothing else). It is not a CAD program. A professional looking schematic can be made in minutes. Printing a schematic is performed using an HP laser printer (or equivelant).

Snell Computer Assisted Room Analyzer and Listening Environment Optimizer - has been developed to make two powerful mathematical tools of scientific acoustics accessible to home listeners. Using these tools, the pitch and relative audibility of low frequency sonic colorations can be determined for any rectangular room. In addition, woofer locations for minimal excitation of these colorations can be determined.

SPEAKERS.EXE - This procedure and worksheets have been evolving since 1978. The worksheets implement a combination of the methods Thiele suggested in "Loudspeakers in Vented Boxes: Part II", and Ashley & Swan described in "Experimental Determination of Low-Frequency Loudspeaker Parameters". Over the years, numerous refinements have been added. The arithmetic involved is straightforward but tedious. By automating the calculations, the worksheets eliminate com- putational errors and minimize many of the other sources of error. Additionally, these programs direct the process of making the measurements, do the unit conversions, and print the results in a convenient format.

Speaker Workshop - Speaker Workshop is a Windows 95 based program designed to test speaker drivers and design speakers. The program is based on a tree structure (folders and "files") for a loudspeaker design. All charts, tests, alternate designs, etc. are saved in one single document - easily accessible with names that can be long and descriptive. The program has full multi-step undo/redo capability. Speaker Workshop can test and measure: Driver Impedance, Passive Components, Transfer Function, Driver Acoustic Response, and Harmonic Distortion. Speaker Workshop can help you design Enclosures, Stock Crossovers, Custom Crossovers, and Impedance Compensation Circuits. Speaker Workshop includes a Signal Generator that uses your sound board to play standard audio signals. Speaker Workshop has a wide range of analytical tools, including FFT, Inverse FFT,Scaling, Splicing, Filtering, and Charting Speaker Workshop requires a computer running Windows 95 and a full-duplex sound card (for testing)

SpeakerWorx Version 1.1 - SpeakerWorx automatically calculates the optimum hi-fi speaker position based on your room's dimensions. Based on the Audio Engineering Society's specifications, this software computes optimum speaker position within the room and also analyzes your current speaker positions and recommends changes to improve the situation and reduce the negative effects a room can have on sound. Requires Windows [any version]

Spectra Plus - The program works in conjunction with the sound card on your computer. Plug the audio signal to be measured into the Line-In or Microphone jack on the back of the sound card. Spectra Plus then uses the card to perform an "Analog-to-Digital" conversion on the audio signal. This digitized audio is then passed through a math algorithm known as a Fast Fourier Transform (FFT) which converts the signal from the time domain to the frequency domain. The CPU on your computer is used to perform this transformation.

SPICEMOD - SpiceMod can be used to model: * Diodes * Bipolar Transistors * Darlington Transistors * Zeners * Power Transistors * Power Mosfets * JFETs * Small Signal Mosfets * IGBTs and SCRs. SpiceMod is a powerful addition to the other model library packages available from Intusoft (described after the demonstration) and provides a extremely fast and versatile method for supporting your model generation requirements.

Speaker Box Design 2.0 - Loudspeaker Box Design program written for DOS.

THE CROSSOVER DESIGNER V1.5 - This is a little program I wrote to do quick and dirty crossover crossover calculations for my loudspeaker building projects. The formulas used in this version are from Vance Dickesons, "The Loudspeaker Design Cookbook" (fourth edition) excluding a few typographical errors I found. It designs crossover networks based on a resistive load.

TC X-Over - This program was designed to assist users in calculating cross-over values for specific slopes at specific impedances. The formulas were taken from Vance Dickason's Loud Speaker Design Cookbook. The 24 db crossover formulas are for the Linkwitz-Riley versions. This only does two-way systems because there seems to be some controversy when you get to three way designs.

THX Room Calculator Version 1.0 - This file has two Excel spreadsheets in it. One for McIntosh and one for PC. It will calculate Room Modes and allow the user to position listening chairs to avoid severe suck-outs in response realted to the room.

Triode Gain Calculator 1.0 - Author: César D. Bazzi - Freeware

Tube.EXE is a small program to help calculate the basic parameters of a push-pull transformer coupled output stage. It works for all modes of operation and on triodes or pentode. The math is from an RCA transmitting tube manual written in the late thirties.

Tube DataBase III - A Vaccum Tube cross reference program. The user is allowed to update, add, delete, edit and print the tube data they select of the whole data file.

TRANSMISSION-LINE MODEL - Uses a model of a transmission-line loudspeaker system to predict small-signal response, input-impedance or maximum input voltage.

Unmask Resistor Band Reader - A simple DOS program that allows you to read reisitor color codings.

VISUAL AUDIO v1.0 - Sixteen band left and right channel real-time spectrum analyzer. Left and right channel peak analyzer (oscilloscope). Compact disc player with all the necessities including shuffle play, continuous play, and elapsed/total track displays. Mixer with complete control over your sound card's mixing abilities including bass, treble, load, enhanced, and 100 levels of mixing for available inputs/outputs. Save and load your favorite settings to/from one of eight presets.

Visual Ears - Speaker Placement Program - Your room, and where in your room you have chosen to locate your speakers and prime listening position, can make a very significant difference in the quality of reproduction. Visual Ears helps you find positioning for yourself and your speakers which can reduce the effects of the room by as much as 15db.

WATTS v2.1 - Stereo Wattage Calculator WATTS was written to aid the electronics technician in finding the output wattage of an audio amp or stereo quickly and efficiently. This program will display the output RMS wattage at a glance. You should find the programs interface simple and easy to use. Speeds service work and hobby construction.

Wave Generater v1.1 - Generates sine, square, triangular, and step functions as well as custom functions (waves) using the mouse cursor. Features allow for wave editing as well as saving and loading signal parameters and data to a user defined file. The signal amplitude, phase delay, and offset are all changable.

WinISD - is freeware speaker designing software for Windows 9x/NT environment. You can design Closed, Vented and Bandpass boxes with this program. It also allows you to calculate few different types of filters. Written by Juha Hartikainen, JJ Richard, Choong Kiat Yian

Wire Gauge Spread Sheet [Excel] - All you need to work with wire

ZA2 AudioDrome AudioMeter - This program will turn your computer into a stereo audio-meter, using your ZA2 as input & output.

Wave Generater v1.1 - Generates sine, square, triangular, and step functions as well as custom functions (waves) using the mouse cursor. Features allow for wave editing as well as saving and loading signal parameters and data to a user defined file. The signal amplitude, phase delay, and offset are all changable.