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Author: Paul Morton Click HERE to view our complete list of auto sound related articles. Originally appeared in the March 1997 issue of Truckin' magazine. © All rights reserved. |
In the past, we've discussed the importance of mating your woofers to the appropriate enclosure and touched on a handful of methods to determine just what that appropriate enclosure is. Using the specifications that are provided by the manufacturer, or calling the manufacturer for even more detailed enclosure information are both excellent ways of determining the right enclosure for your particular subwoofers. But when it comes time to model several different enclosure variations to determine a design that is best suited to your personal needs, you're either going to need a bachelor's degree in math or one serious computer program. A professional installer can rely on just such a program to simplify, quicken and even improve the construction of the speaker enclosures they build. They are fortunate enough to have one of the most comprehensive enclosure response modeling programs available - Term-PRO from Wayne Harris Enterprises. You've heard us mention this program before, and with good reason, so we figured it was high time to show you exactly what Term-PRO is all about. Thanks to both his vast computer knowledge and auto sound savvy, Wayne has put together a computer program that allows even the novice user to easily tweak any and all of the variables of a particular speaker enclosure.
Term-PRO will run on IBM or compatible computers with a 386 or higher processor, 640 KB of RAM, VGA color monitor, 3.5-inch high-density drive and a Microsoft compatible mouse. Once you have loaded and started the Term-PRO, it will take you into its driver library. More than 1,000 of today's most popular drivers are already on file and more can be added at your discretion. Alphabetical index tabs make driver selection quick and easy. Once you have chosen the driver that you want to model an enclosure for, it's off to the enclosure selection screen. At this point you can choose between 12 different enclosure types including sealed, vented, single-reflex bandpass, dual-reflex bandpass chambers plus isobaric and three-chamber variations of each.
With the desired chamber selected you can move onto the enclosure design screen where you can actually create and see the response of the enclosure you want to build. It is here where you have complete control over all design parameters. For example, you could see how ell your speaker will work in various sized enclosures, and compare each response curve on the same grid. There are even buttons on this screen that will plot the best curve for a normal response, a purist response or the ultimate bass curve for you boomers out there. At this point, anyone who is designing a ported or bandpass enclosure can move on to the vent design screen so that they can determine the optimum length, diameter and number of ports for their chamber. Term-PRO will even calculate the area for rectangular vents, circular vents and Aerovents.
What is truly amazing about Term-PRO is the fact that you have complete control over all of the variables and the fact that they can be adjusted in real time. Let's say, for example, that you want to change your port's diameter. When you increase or decrease this value the port's length will reciprocate with the appropriate value. This feature is found throughout both Term-PRO and Term-CAD 3D. What is Term-CAD 3D you ask? That just happens to be Term-PRO's companion software that will generate blueprint perfect enclosure diagrams of your sub design right down to a material usage report. Remember to use the right tool for the right job - even if that tool is a computer!