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Design System Summary

This site assists in the rapid and accurate design of superior speaker systems for music and home theater utilizing conventional drivers and passive crossover circuitry. Depending on your selected drivers, it suggests enclosure types, rough dimensions, port configuration, and crossover points and components. It predicts and suggests components to compensate for baffle diffraction loss. It estimates polar sound intensity (lobing) at specific frequencies due to driver spacing, acoustic center, and electrical phase differences. It can alert the astute builder to design flaws before beginning component purchasing and construction. Speaker projects can include multiple enclosures, and each enclosure can include multiple drivers. Driver parameters can be manually entered, or imported from our database of hundreds of popular drivers. It takes into account more subtle variables such as the resistance of series inductors and component interaction in 3-way systems (affecting the band-pass section). No software installation is necessary -- it works over the web. Projects can be saved and reloaded at a later date, and a project parts list can be generated to speed and simplify the purchasing process. The parts list can be used to purchase from any supplier you wish, or conveniently direct from us in a kit or finished form.

Intended Audience

The speaker design system assumes that the user has considerable knowledge of speakers and their variables. In keeping with the "garbage in -- garbage out" philosophy of computer use, it is entirely possible to use this system to design an outstanding speaker system, or one that that would should be put out of its misery, depending on your personal knowledge, skills, tools and resources.

Compatibility

No software installation or configuration is required. This system should work with any conventional computer connected to the Internet using a common web browser like MSIE, FireFox, Safari, etc. Javascript and cookies must not be deactivated (don't complain to us about our software if you've broken your own computer). We do not provide technical assistance on how to use your computer, but if you do need help using this system or building speakers from components purchased from us, we will do our best.

Cost

There is presently no cost to use this system. We are considering requesting donations for use.

Why was this software created?

We desired a software tool that would do the following:

  1. Work from any computer
  2. Manage systems of multiple speakers, not just individual boxes
  3. Combine the various, useful-but-individual calculators into a comprehensive system (and improve some of them in the process)
  4. Include box panel drafting, driver and port locations
  5. Predict and suggest compensation for baffle step loss
  6. Estimate polar sound lobing
  7. Tie-in with shopping systems to ease purchasing (none of the parts-suppliers we contacted responded to our request for methods of integrating with their systems, so we decided to start stocking our own inventory)
  8. Estimate total materials, labor and project costs

It is relatively easy to design a single or stereo speaker system with paper, pencil and a calculator. There are plenty of stock designs and formulas available that, combined with decent building skills, surpass many commercial/consumer systems. But once one starts attempting to trial-test different combinations of drivers, enclosures sizes, etc., the calculations quickly become tedious, time-consuming and error-prone. There are many tools available on the Internet that handle individual parts of the problem, but many advanced issues cannot be easily solved on a hand calculator or the simplistic internet speaker calculators that are available. There are software programs that can be purchased and installed on particular computer systems, too. These are all suitable for some purposes, but none really met our own design needs and desires.

  Design image of MTM custom speaker layout and sound presence.

Limitations/Caveats

We purposefully flip between metric and English units. In our own shop most of our drivers arrive with physical measurements given in centimeters and liters. However, we do our enclosure construction using materials that are typically measured in inches. Consequently, driver data is entered in metric units, and enclosure data given in inches.

Though the system allows surprisingly-sophisticated configurations, there are some options missing. Fourth-order and above crossovers, for example. Dual-coil and other complex speakers have to be entered very carefully, and figures should be manually double-checked. In addition, I'm sure it is possible to enter a configuration or data set that was not anticipated and end up with a really whacky result. If in doubt, manually double-check everything!

The software uses fundamental physical acoustics and electronics formulas from a variety of sources (including the author's own college physics and electronics texts). Though a great deal of research goes into the development and application of these formulas, in the final analysis they are merely attempts to approximately model highly-complex, real-world phenomena. The difference between the mathematical model and actual results of a particular project can be significant and depends upon the accuracy of entered data, the degree to which your design differs from the system's assumptions, and any number of other, unmeasurable or unanticipated factors.

Frankly, we are not convinced that one or even five percent accuracy is necessary (or perhaps even useful) when it comes to component, volume, and similar measurements and calculations because individual driver variations, the room in which speakers are finally placed, the proximity to walls and corners, and the 'stuff' in the room will have at least a 5% effect upon the perceived sound. There is little point in obsessing to get three significant digits of precision when the at least last two will be wiped out by variables entirely beyond your control. Consequently, most calculations are reduced to two significant digits.

For these and other reasons, this service/software is provided as is, without warranty or promise of usefulness for any particular effort; actual results may vary significantly from those predicted mathematically. The user urged to double check all figures manually, and accepts full responsibility for the final product. The software makers accept no responsibility for any costs experienced as a consequence of using this site. We welcome feedback for improvement, but cannot answer all e-mails. Preference is given to those who have financially supported the development.

Future

As time and funds allow we will continue to improve this system by (1) listening to your feedback, requests and suggestions, (2) adding a larger variety of crossover types, (3) adding additional drivers to the library, (4) massaging the calculations, and (5) improving the system's integration with our shopping system.




Copyright 2005 Simple Way Limited Partnership DBA Arpeggio Music and Sound. All Rights Reserved. http://speaker.rosaryshop.com/index.php Terms of Use

Arpeggio Music and Sound, 805 NW Alder St, McMinnville, OR, USA. 97128
Telephone 503-472-0688; FAX 503-434-5803; Hours 10 AM - 5 PM Pacific Time, Monday through Friday
Visits by appointment only.