I just got off the phone with John Dunlavy. Of course being the designer of the Dunlavy speakers he strongly defends his selection of parts used in the crossover. This should not come as any surprise, but let me tell you how he defended his selections.
He did acknowledge that he could have used more expensive parts, but he said he selected his parts on their performance and not on cost. The capacitors he uses are polypropylene and have the best measured values of any capacitor on the market, there are simply not more accurate capacitors available. The Inductors he uses are not an iron core because they simply do not perform as well, they tend to saturate at very low levels, thus they are less constant in their values. The air core inductors used again are the most accurate and constant he has measured. His goal is not the "most expensive parts, it is using the parts that produces the best fidelity."
As I stated earlier, his goal has always been to create the most accurate speaker possible. He not only uses his ears to test the speaker's performance but judiciously measures every speaker to within +/- 1 dB with a full set of measurements made in his world renowned anechoic chamber. "Every speaker" built is thoroughly measured for all aspects of performance and only then are released to the client. "No other speaker in the world is put through such stringent testing" all in the name of accuracy.
John reminded me that the IVa is used in all the major recording studios around the world. This is the speaker that most music today is sounded to, so altering its accuracy with other components will add distortion or otherwise lessen the realism of this speaker. John had commented that he sometimes thinks "people would rather hear distortion or otherwise inaccurate sound rather than the truth."
Again I think that remembering the goal of Dunlavy speakers is important, to produce "accurate speakers." I was reminded of a story John has told me before where he sets up a pair of IVa speakers in his large anechoic chamber along with real instruments. The piano is the story he tells where they play a grand piano or a digital recording at 24 bit was played through the speakers. The people they bring in were to detect which is playing cannot identify any difference between the two.
If you do choose to modify your speakers you are choosing to modify the accuracy of these speakers, which may be to your personal taste but it is not the goal of Dunlavy speakers. Dunlavy wants to "reproduce music as exact as possible." If the measurements and the listening tests are to be believed then the IVa has succeeded, and any alteration will only lessen those measurements.
It is an interesting topic, I guess those who do choose to alter their speakers are trying to solve another problem in their system. I would recommend people look at what other weaknesses might exist in their stereo before looking at the speakers as the issue.
As a side note I spent sometime discussing JA and Stereophile. This is a whole other post some day!
