dB Drag Racing Magazine - August/September 1997

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Originally appeared in the August / September 1997 issue of Car Sound magazine.

'Tis The Season

Its amazing how much Sound Pressure Levels have increased over the past few years. In fact, according to my records, SPLs have been increasing at an average rate of about 2 dB per year since 1984. That may not seem like a lot until you realize that a 3 dB increase in SPL represents a doubling in acoustic output power!

At first, you might be tempted to attribute these higher scores to bigger sound systems. Looking back over the years, however, you would quickly realize that the systems of today are not really that much larger than those found in show vehicles from a decade earlier. In fact, some of the loudest vehicles in history have had sound systems that are substantially smaller than those found in some of the earlier competition vehicles.

This presents us with something of a paradox. Sound Pressure Levels are rising at a rate that is disproportionate to the size of the system. How is this possible? What has enabled SPL competitors to increase their scores by 26 dB over the past 13 years? I think the answer to these two questions can be summed up in a couple of simple phrases; "better equipment," and "better science."

Better Equipment

In the early eighties, high-end performance auto sound was still in its infancy. High-powered amplifiers were available, but they were expensive and temperamental. Reliability was always a concern. When it came to sub-woofers, the only ones available were those that were originally intended for sound reinforcement applications. Unfortunately, the enclosure volumes required for these drivers usually resulted in a box that was larger than the vehicle itself! Nevertheless, early competitors did the best they could with the equipment available at the time.

As sound off contests became more and more popular, auto sound manufacturers started to take notice. Some of these companies even started manufacturing products that were intended for use in the sound off arena. The rest, as they say, is history.

Competitors demanded better products and the manufacturers responded. Amplifiers became more reliable. Specialized signal processors were developed. High-performance woofers with extremely long excursions were introduced. In fact, almost every auto sound component in existence today has benefited in one way or another from the innovations originally developed to win trophies in the competition arena.

When it comes to SPL systems, advancements in speaker technology are the primary factor affecting the tremendous gains we have seen over the years. The box requirements for many drivers on the market today are less than half of that required for an equivalent sized driver from 10 years ago. Reliability has also improved dramatically. New adhesives and cone materials allow drivers to withstand devastating abuse without failure.

The important point here, is to realize that sound-off competitions, specifically SPL based contests, continue to drive the manufacturers to produce better and better components. These improvements eventually benefit everyone.

Better Science

It takes more than good components to win these days, however. It takes science. Just one look at a winning vehicle and you'll be convinced that the system was engineered from the ground up. Everything is taken into account during the design process. This includes the engine, electrical system, amplification, sub-woofer enclosures, and even the vehicle itself.

Today's installers are unquestionably better informed than their counterparts from a decade ago. There are many factors contributing to this ongoing phenomenon. Publications like this one continue to help educate competitors and consumers alike. Installation schools and training seminars have also played a major role in escalating the knowledge base of the typical installer. And now, with the proliferation of auto sound related web sites and news groups on the Internet, anyone with a computer has access to a world of car audio related information.

So, what does the future hold? Well, I'd be willing to bet that the 170 dB SPL mark gets thrashed before the year 2000. Who knows, you may be just the person to do it!

If you have questions, comments, or suggestions regarding dB Drag Racing or this publication, please write to:

dB Drag Racing Magazine
6 Manhasset Avenue
Port Washington, NY 11050

Wayne Harris is President of Wayne Harris Enterprises, Director of Research and Development for Rockford Corporation, and President and Founder of the dB Drag Racing Association.

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