Technology

I am writing this to answer a question posed by a friend of mine after he spent some time browsing my web site. His problem? The perception that I am using "70's" technology, and that I need more of the "latest" fashions in my speakers.

This is a very good question, since a lot of what I do has very deep roots in the work of some of the brightest pioneers in speakers, people who revolutionized the industry in the 60's and 70's, and even the 50's.

One part of the answer is to remember that change is not always desirable - say one designs an excellent speaker (the EPI 100 for example). After building it for several years, it will still be just as good but it will begin to appear "dated". Sure, its looks can be changed a bit, but the people who make their living writing about and selling music reproduction equipment need something new to write about and to promote! So eventually the market forces a change. Unfortunately this can result in the disappearance of a great product.

Another part of the answer is that some incredible technological marvels date back several decades. The Apollo moon missions which were accomplished before the end of the 60's were done with - get this - 60's technology! I still remember watching them on a black and white television.

Back then, much of the space program technology was just beginning to filter down to the consumer product market. However, at the same time, advances were being made in the design of loudspeaker drivers and speaker systems that would change forever the way music sounded in the home. The development of the "acoustic suspension" principle resulted in the reproduction of genuine low bass response from a reasonable size cabinet. the invention of the dome tweeter started the journey towards full 20 kHz and beyond reproduction, so difficult to attain with cone tweeters.

In the 80's, the space shuttle program generated a revolution in adhesive technology. We already knew how to build and throw a ship accurately into the outer atmosphere, but the tough part was getting it back without it burning up. Remember those original Apollo re-entry craft, streaming back to earth with a trail of fire behind them? The shuttle had to come in under control, and dissipate the heat of re-entry with reusable fuselage components. This led to the ceramic tiles covering the shuttle. These are glued on, and the same glues used in that process are available to the manufacturer today.

I have researched and experimented with modern adhesives to improve not only the durability of the drivers I build, but also the manufacturing tolerances and processes.

The third main point I would raise is the illusion of change and improvement created by advertising. Once advertising creates the demand for change, it has to feed it. How many "new, improved" soaps and toothpastes have we seen in our lifetime? This constant claim of improvement is often a marketing sham, but creates the illusion of many, many advances, often claimed to be technological, in many products. Usually they are just superficial, trendy, issues of fashion, but sometimes they throw out the baby with the bath water.

One example of this in loudspeaker technology is the use of polypropylene for loudspeaker cones. Trumpeted as the saving of the galaxy, these were embraced by large manufacturers as they are cheaper to make, look high tech, and can require less effort to build consistently. The truth, is, however, that the plastic material sounds no better than any other. A good designer can build a good driver from any appropriate material, vacuum deposited felted paper still being one of them. I still use paper because it allows me a much greater control over treatments, damping, adhesive use, and quality.

A brief chronology of loudspeaker breakthroughs...

50's:

Theile and Small determine how to correlate woofer and cabinet characteristics with low end frequency response.

60's:

The dome tweeter allows true 10th octave response.

70's:

Ferrofluid enables tweeters to have lower resonances and handle much more power.

80's:

Metal domes create the opportunity for flatter frequency response in tweeters with no "breakup" modes in the audible range.

The box becomes identified as the source of a lot of common speaker distortions, including diffraction at the edges, resonance, reflection from the baffle, and direct panel radiation.

Everything else has been the working out of these details. Sure, wire matters, as do high quality connections, well selected crossover components and proper internal damping material.

All these factors are taken into account in the design and manufacture of HUMAN loudspeakers. Just because they have a history doesn't mean they're dated.

And my friend? He has a pair of my eight inch woofers and aluminum tweeters in his Mercedes with a CD player and a hundred watts per channel. Loves to show it off to his friends.