David Answers Pjay's Questions for the Speaker Guru


1. Without giving the standard "weakest link" answer, how important would you rate speakers as component?

They are the key, whereby all of the other things people fuss about hardly matter. But the really critical issue is matching the speaker to the room environment in which it lives, and in my view too little attention is often paid for this, with the goal instead being to design a speaker that will sound right in any room. Thatís impossible. A related issue involves matching speakers to electronics. In general speakers were designed to work well with electronics from the same time periodóvintage speakers go with vintage gearómodern speakers with modern gearÖoccasionally itís possible to find modern speakers that perform well with vintage gear and vice versa, but itís difficult. Iím underwelmed by all the discussions on wires, cabling and electronics.

2. How have speakers changed in the past 25 years?

Iím deeply saddened by what has happened to so many of the great commercial speaker companies from the 70s. I spend a lot of time listening to speakers built in the early 70s from companies such as Advent and EPI, and I continue to be amazed at what these people were able to accomplish with drivers of moderate cost and simple crossover designs, through careful voicing be ear. But then Henry Kloss, who founded Advent, and Winslow Burhoe, who founded EPI, are my heros in the speaker building world. I have had a chance to chat a bit with Winslow on his message board and take note that his fundamental philosophy about how speakers should be built has not deviated significantly in 35 years. Winslow Burhoe can be contacted at his Web sitewhere he sells a speaker related to the EPI 201 at www.directacoustics.com. Huw Powell, the self-described ďchief cook and bottle washerĒ for EPI, runs the Web site at www.humanspeakers.com, rebuilds and sells drivers and other parts for EPI owners, as well as supports a DIY business using these drivers.

 

Recently, Ken Perkins has had some interesting conversations with Andy Petite, who largely voiced the original Large and Small Advents as well as designed the 2nd generation Large Advent Woofer. (Ken was kind enough to post some of these on the audio asylum vintage message boards). Andy Petite (now Kotsatos) was the lead speaker designer at Advent through 1978 and co-founded Boston Acoustics with Frank Reed in 1979, whom he'd known since his days at KLH. Andy did most of the detailed voicing and designed the 2nd generation Advent woofer that eliminated the Masonite ring. These people are all major players in the so called East Coast ďBostonĒ sound that started with EdgarVillchur at Acoustic Research.A recent Stereophile article interviewing Edgar Villchur and Roy Allison (who worked for Villchur before founding his own company (now back in business selling high end Allison speakers) is at

http://www.stereophile.com/interviews/105villchur/index1.html

 

Given a choice of living in a world in which the options in speakers and drivers are what we have today versus 25-35 years ago, I would take a time trip back to the 70s in a heartbeat. Speakers were just a lot more diverse and fun then than now.

3. Do we have to spend a lot on woofers and tweeters to get good sound?

I wish there were currently available woofers that rolled off as smoothly on top as the larger 8-12 inch paper cone woofers commonly used in the grand commercial designs of the 70s did. I do feel that the current generation of modestly-priced textile dome tweeters are an improvement in terms of dispersion properties relative to the commonly used cone designs from the 70s. Spending more on a woofer does not necessarily get you a woofer with either a smoother not more extended upper end. As it is, you donít have to spend a lot on woofers and tweeters to get good sound, but I hate it when the crossover parts end up costing more than the woofer cost.


4. What are the top three design parameters you use? (or the top three things you worry about most)

1. Simple is often good, and often simpler is better.In general, I think the fewer things you must put between the speaker input terminals and the drivers, the better. 2. Choose drivers on the basis of how well matched they are output wise, and avoid drivers that require lots of crossover parts to tame. 3. Keep the design efficient so 20 watts is adequate or better. Power eaten up by (especially parallel) crossover components is power that is not going to make music for you.


5. Do you design on measurement or sound?

Iím primarily an ear person. Occasionally I will test a speaker, but only to see whether the measurements indeed can confirm what I hear.


6. What to you think is that "special something" is that makes some speakers sound so good?

Primarily simple, straightforward, classic design using bigger, paper-cone woofers. I regard an 8-inch woofer as small, and generally prefer 10- or 12-inch woofers. Did I mention I like three way designs with big woofers in addition to my love for early Advent and EPI?

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?

Getting the position in a location similar to where it will live on a daily basis with appropriate electronics.


8. Do you have a theory on crossovers or use whatever seems to work?

I love the classic EPI crossover, in which the woofer and tweeter are so well matched acoustically that the woofer just smoothly rolls off on its own, and the tweeter has a single series capacitor. Iím constantly on the prowl for drivers that will work with such a simple design. Sadly, other than drivers salvaged from vintage speakers, I seldom find them.


9. Do we overstress the bottom octave and area above 20K Hz?

As a lover of pipe organ music, of course not! But, we Large Advent guys think that the Large Advent continues to set the standard for bass extension that has never quite been equaled in conventional current designs for a reasonable price. Modern tweeters do tend to be more linear and better dispersed on top--especially between 15,000 and 20,000 Hz. I like the clarity that gives to brushes, hi hat cymbals etc., but I also lament the fact that so many speakers have no level adjustments on the tweeters, erroneously assuming that all rooms absorb high frequencies equally well.

10. What one piece of advice would you give every new speaker builder?

I think building a kit is a poor way to learn about speaker design. Building a kit teaches you very little about the nuances of speakers design. If you want to learn how to build a speaker, pick out some moderately priced drivers that appear to be well matched output wise, build a box and see what happens. In the process of building your speakers you will learn a lot, and begin to understand how the pieces fit together as a whole.


11. When you get cornered at a party by a speaker builder, what is the question they ask most often?

Why donít most modern speakers sound as good as they did in the 70s?

12. Will we ever find the Holy Grail in sound reproduction?

Not until we quit trying to place the listener on the stage among the musicians rather than out in the audience where he or she belongs.

13. So, which is it, tubes or SS?

I am a big fan of solid state designs from the period 1970-1985. One favorite setup of mine pairs a 40 watt Sherwood 7300 from 1971 with a pair of Epicure 11ís The Epicure 11ís use a 6 Ĺ inch EPI paper cone woofer along with the EPI inverted dome tweeter, all in a quite large (1 Ĺ cubic foot plus) ported box. These speakers just blow away most modern small-woofer, small-box, two-way designs


14. What does the future hold for speaker design?

Iím saddened by the lack of imagination and risk taking in so many current designs, both commercial and DIY, which seem to largely be relatively inefficient small-woofer MT or MTM designs that are made to be placed out in the middle of a room. While subwoofers have a place in home theater, they donít do anything for me in stereo music listening. I hope we can get back to designs that use 10, 12 and even 15 inch woofers. I would like more choice in mid-tweets, that is, tweeters that can be crossed over below 2000 Hz without the need for a mid-range speaker. And I wish speakers now came in the variety of shapes they did in the 70s.

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