README.HTM --- Part of Manual for Driver Parameter Calculator --- by Claus Futtrup.
Created 13. July 1997, last revised 2. May 2004. Ported to XHTML 1.0 on 2. October 2004. Last modified 29. October 2004.
Contact info updated for web publishing 17. June 2014.

Table of Contents:

  1. Disclaimer
  2. The Author
  3. Distribution
  4. Nota Bene for this release
  5. Description of Distributed Files


No warranty on anything. This software is free, but copyrighted by Claus Futtrup, 1996. It is not public domain. All calculations are without any kind of warranty as well. No reliability can be guaranteed, at all.

The Author

A Danish "do it yourself" speaker builder, who thought that the Internet could be a great place to have data for all kinds of electro-dynamic transducers. This calculator is intended to expand to a full-featured database and could become a great source for data, not only for myself, but any speaker builder with Internet access (and we're quite many!).

Since 1997 I have been working as a professional R&D Engineer at Dynaudio A/S, Denmark.

My e-mail address :

My homepage is at :

Comments and criticism are very welcome. They're actually essential to the further development of this product.

The development of DPC is partly based on my own needs and interests, but also from what you suggest (if you are kind enough to mail me your thoughts). DPC is made to make your and our everyday life easier and more fun, so there is no reason to hesitate with your comments.


This software is free software and may be used freely for commercial and non-commercial use. It is illegal to distribute it for profit. The software may be sold only at the cost of distribution, eg. the price of a floppydisk + necessary postage.

All files in this package (see below Description of Distributed Files) must be distributed together. It is illegal to distribute selected parts of this package.

This software is copyrighted © by Claus Futtrup.

Nota Bene for this release

                                    |----- major changes
                                    | |--- minor changes
                                    | | |- patch releases
                                    | | |
This is an Pi-release, version 0.6.1. It might happen that the
program does something, which it should not or which is "undocumented
behavior," in these cases, please inform me.

The "history" of this software is described in HISTORY.HTM.

If you get any runtime error-messages, please inform the author and tell him how to replicate.

At the moment I think very few runtime errors should occur, if any. Well, except if you save your driver data to a diskfile you may get some errors (if the drive is full, I do not know whether DELPHI protects against this kind of errors).

This Pi release has been compiled and tested on Intel Pentium II only with the Delphi Commandline Compiler, running 32 bit.

Intel 286 computers and compatibles are therefore not supported. In this case you will need to get one of the older versions of DPC.

The "major changes" release so far is reserved for a GUI implementation in MS-Windows (probably using Delphi) when I get a grip on Delphi/Windows programming and a closer look at OOP. I realize users must be sighing for a Windows interface, but currently I need response from people on bugs, peculiar behavior and inclusion of further parameters---the current format of the source code (and this implies the simple DOS-like user interface) gives me the perfect playground to rearrange the parameters, add or change parameters etc. You will notice that the Windows interface has started popping everywhere but at the main window(s).

Besides my own homepage the software is available for download at like the former published releases. The pages are managed by Brian Steele (, or

Description of Distributed Files

DPC.EXE         - The executable file
DPC.INI         - Initialization (Configuration) file (ASCii text)
FILE_ID.DIZ     - A short description of DPC (in PCBoard format)
MKSA.CU         - Custom Units file, MKSA/SI
EURO.CU         - Custom Units file, Western/European units
UK.CU           - Custom Units file, UK/USA units
MKSA.DIG        - Custom DIGits file, for MKSA.CU
EURO.DIG        - Custom DIGits file, for EURO.CU
UK.DIG          - Custom DIGits file, for UK.CU
MAX.DIG         - Custom DIGits file, for MAXimum number of digits
DPC.HTM         - The manual frame page
CONTENTS.HTM    - The table of contents part of the manual
TEMPLATE.HTM    - The standard/default template for generating reports
DPC.PNG         - The DPC icon for the (HTML) manual
DPC.URL         - Internet Shortcut to the DPC webpage (for updates etcetera)
MANUAL.HTM      - Manual for DPC (how to use, main part)
INTRO.HTM       - The introduction to the manual pages
MEASURE.HTM     - A recipe on how to measure driver parameters
REPORT.HTM      - Describes the report facility and its configuration
RESISTOR.HTM    - About measuring impedance with the "compare resistor" method
AIR.HTM         - An academic description of the properties of air
AIRMODEL.HTM    - More documentation on air properties
VOLUMES.HTM     - How to calculate volumes of various shapes
DIGITS.HTM      - About significant digits and how to make your own .DIG files
FORMULAS.HTM    - Documentation of parameters and equations used in DPC
README.HTM      - This file
INSTALL.HTM     - Installation and setup instructions
HISTORY.HTM     - Describes the development process of the software
BASICS.HTM      - A basic tutorial on loudspeaker drivers
DATAINFO.HTM    - Information and personal opinion on some data/parameters
INVENTOR.HTM    - The invention of the electro-dynamic loudspeaker
BOX_AIR.HTM     - Distortion calculation for a closed (measuring) box
MULTIPLE.HTM    - Multiple drivers, lumped parameter calculation method
POWER.HTM       - About thermal power handling
XMAX.HTM        - About Xmax and its definitions

The documentation consist of .HTM files and is more than 400 kb of plain text. I suggest that you print the MANUAL.HTM file plus which ever parts of the documentation you may find interesting. Totally it will add up to more than 100 pages of printed text.