The Speaker Guru speaks: Geoffrey Dillon

Speaker Designer Questions

1. Without giving the standard “weakest link” answer, how important would you rate speakers as component?
I would say that loudspeakers get you about 75% of the way there. The importance of good electronics is grossly underestimated.

2. How have speakers changed in the past 25 years?
Cone materials have improved which has helped. Design techniques are better and faster.

3. Do we have to spend a lot on woofers and tweeters to get good sound?
No, good sound can be achieved with low cost drivers although excellent sound usually means high price points.

4. What are the top three design parameters you use? (or the top three things you worry about most)
On axis frequency response, the speaker should sound balanced. Driver integration, you should never be able to "hear" individual driver in a speaker system. Using driver within their proper frequency with attention to frequency response, off axis response and driver resonances.

5. Do you design on measurement or sound?
Good measurements are very, very important but this only gets you so far. My ears are always my final judge, this is how loudspeakers get really good!

6. What to you think is that “special something” is that makes some speakers sound so good?
The disappearing act, if you close your eyes, you should not be able to localize where the music is emanating from. The music should evoke an emotional feeling.

7. What are your speaker audition strong points and weak points, i.e., what problems do you find most difficult to pick up in listening tests?
The cause of brightness is sometimes difficult to locate, it may not be seen in the frequency response. Making a speaker sound “natural” is also difficult.

8. Do you have a theory on crossovers or use whatever seems to work?
There are many ways to design a crossover and achieve good sound. Crossover topology is also driver dependant. I like to use as few parts as possible. Drivers that are "forced" into a system using many components usually don't sound good. I tend to use low Q, high order, transitional slopes; the results are predictable and sound good!

9. Do we overstress the bottom octave and area above 20K Hz?
20Hz to 20k are a good cut off points.

10. What one piece of advice would you give every new speaker builder?
Start out with a kit or some type of proven design. You will thank me for this advice!

11. When you get cornered at a party by a speaker builder, what is the question they ask most often?
I have never met a speaker builder at a party but when I tell people what I do I hear "You design speakers" "You mean like Bose” My reaction will depend on how many cocktails I have had.

12. Will we ever find the Holy Grail in sound reproduction?
Everyone should read the book "The Da Vinci code", the Holy Grail may not be what you think it is but to answer your question, no, not with 2 channel audio.

13. So, which is it, tubes or SS? Tubes, what else is there?
I have no love for tube amps, they just sound better than SS.

14. What does the future hold for speaker design?
DSP is where everything is headed although this may be a double-edged sword. Very cool processing can be done but I believe that the overall system sound quality will suffer from the application of these new technologies.

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Copyright: Peter J. Smith 2005 Return to