My Interests

One of my interests is Hi-fi. My system consists of the following:-

• Audiolab 8000C pre-amplifier and 8000P power amplifier
• Rega Planar 3 turntable with Rega Bias cartridge
• ATC SCM20 loudspeakers
• Arcam Delta 170.3 CD transport & Black Box 5 DAC

As a sideshoot to this interest, I have started getting interested in building loudspeakers. So far I have only build a sub-woofer based on a kit although I had to change the kit design so I could get the speaker into my living room.

Testing a sub-woofer can be disconcerting. When I tested mine, I used a 20Hz signal and couldn't tell if it was working until I turned the level up and all the doors and windows started rattling!

I have also invested in some test kit and software for designing and testing speakers. Firstly, I have a Liberty Instruments IMP unit and a Mitey Mike test microphone. The IMP is a black box which connects to a PC and generates short test signals which can be fed to a speaker. The microphone is used to pick up the loudspeaker output and the IMP converts the signal back to digital form so that a PC can analyse the signal. The system can be used to carry out all the measurements you need to make on a loudspeaker to get a nice flat frequency response.

Secondly, I have a program called Calsod which is a loudspeaker modelling program. It can be used to simulate both the impedance characteristics and the output of each drive unit. Using this information, the program can automatically calculate crossover component values.

I have used the IMP and Calsod to design a crossover for a friend. I used only the data sheet for the drive units, but the crossover I designed worked exactly as expected much to our surprise.

If there is anyone in the East Anglia region of England is interested in building themselves a loudspeaker, let me know - I'll be glad to help out doing some measurements.

A link for advice on loudspeaker building

Free Software!

Another pastime is porting various Unix utilities to Windows 95 or Windows NT.

Spice Circuit Simulator

I have also ported both Spice2G6 and Spice3F5 (electronic circuit simulators) to run under Windows 95, Windows 98 and Windows NT 4 SP5.

Visit one of the following pages to download the simulator.

The main web site is at WinSpice3 web page.

Alternatively, click here to download from this web site.

Spice2G6 will also run under plain DOS since it has been compiled to run under the Borland PowerPack DOS extender.  It is fairly basic, having no graphical post-processor.  However, it comes with my pre-processor which handles libraries of components and file inclusion.

Spice3F5 is ported to run in a window as a native 32-bit application.  It can generate waveform plots to individual floating windows and contains a powerful scripting language (see the included example files). This is very much work in progress - I want to add a proper windows help file, schematic entry and an improved windows interface at some point in the future.  However, it contains several enhancements over the original Berkeley Spice3F5 e.g. better compatibility with Spice2 and PSpice circuit files, such as handling for POLY statements in non-linear sources and the ability to extract models from PSpice-style libraries.  I have also included a manual and a simple tutorial, both in Word for Windows 2 format.

Note that Spice2G6 will work under MSDOS, Win3.1, Win95 and Win98.  Spice3F5 will only work under Win95, Win98 or WinNT.