The Speaker Guru speaks: David Ralph

Speaker Designer Questions

1. Without giving the standard "weakest link" answer, how important would you rate speakers as component?
Speakers are the most important in my opinion, especially given the availability of inexpensive power amps. But it still should be balanced with the rest of the system. That is, don't go all out on the speakers and get cheap on rest. The front end should match the speakers in quality. Note the word quality, not price.

2. How have speakers changed in the past 25 years?
From my perspective, more along the lines of continued refinement. My reference for this time period is the set of Dahlquist DQ-10s I purchased as my first speakers. It was 12 years+ before I was willing to spend money again on speakers (I wasn't building them then). It took ribbons to do that, but they had their limits as well.

3. Do we have to spend a lot on woofers and tweeters to get good sound?
Good sound, no, great sound, yes.

4. What are the top three design parameters you use? (or the top three things you worry about most)
Adequate driver bandwidth, linearity in the passband and lack of resonances (relates to distortion).

5. Do you design on measurement or sound?
Both, of course. I may live with a design for months or more, then decide to try to improve upon it again if I happen to think of something that had not occurred to me before.

6. What to you think is that "special something" is that makes some speakers sound so good?
Relaxed, open sound that let's you hear deep into the recording that makes the speakers disappear and makes you want to tap your feet or sing along reflexively. I feel that this comes primarily from the midrange and lower treble. I spend most of my time on this part of the crossover. I don't subscribe to the theory that the crossover must stay out of the midrange, though it inherently seems correct. The best sound I have achieved uses a 2500Hz 2nd order, 1" tweeter. Still, it is close to the sound I had from a 4000Hz 4th order, 3/4" tweeter. I do think that it takes physically aligning drivers to fully optimize this response, though.

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 most difficult part for me is knowing whether what I hear as a weakness is my design or the recording (or both).

8. Do you have a theory on crossovers or use whatever seems to work?
It's all about what works, but that leaves open a lot of room for personal preferences and taste as well as the application requirements. There is no single "best" crossover for any set of drivers or application.

9. Do we overstress the bottom octave and area above 20K Hz?
Yes, especially the former. Accuracy of reproduction in this area is too often ignored.

10. What one piece of advice would you give every new speaker builder?
If you want to design rather than just build kits, read and re-read as much as possible. Buy "The Loudspeaker Design Cookbook" by Vance Dickason, "Testing Loudspeakers" by Joe D'Appolito and any other recommended books. Just keep in mind that it's a long term process of nearly continual learning.

11. When you get cornered at a party by a speaker builder, what is the question they ask most often?
Never happened, I don't go to parties very often. ;)

12. Will we ever find the Holy Grail in sound reproduction?
No, not in our lifetimes.

13. So, which is it, tubes or SS?
SS, given the quality possible today.

14. What does the future hold for speaker design?
For DIYers, I think that it will be digital crossover emulation in a PC or devices with native DSP. These my be fed by a PC that streams a digital signal. But I think that the old standard CD is not going to be replaced by SACD nor DVD-A nor anything else soon, since CD can be ripped and copied onto a PC.

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Copyright: Peter J. Smith 2005 Return to