Well it has been great fun watching this thread, particularly as it teeters on the edge of incivility.
In my previous post, I proposed that the supertweeter operates by interacting with audible frequencies. It does not need to be in the audible range itself to so this. However, if there is some overlap, that would not change my proposition as to what is happening.
I found Stanwal's information from Martin Colloms to be quite interesting. I haven't read the source material of Mr. Colloms, so I will rely on Stanwal's report to be an accurate reproduction.
In the report of Mr. Colloms, it is stated: "the test for response extension benefit will only be valid if the extended response is achieved without affecting
the performance in the existing audible range'." He then goes on to state some reasons why audible range performance is, in fact, affected. This would support my propostion that despite the supertweeter being inaudible itself, there are interactions that produce effects in the audible range, although there seem to be more effects than I originally thought.
This is good stuff, and I am happy to see these comments from a person who is certainly more authoritative in the science of audio than I am.
The report further states: "Testing for a subtle effect, which may well be barely audible, is a manifest nonsense if it changes the uniformity and loudness in the already operative treble range. Yet this is what is happening in these tests. So far, no commercially available add-on tweeter and matching crossover can avoid
this fundamental error."
He appears to be stating that one cannot properly evaluate the effect of the supertweeter because of the interference of the supertweeter with the audible treble range. In other words, the variable is not isolated so its true effect is undetermined. I would agree with this. However, scientific niceties aside, to my mind, that's the whole point of the supertweeter. It is interacting with the audible range. And many people hear and report this as being an improvement to their system.
Mr. Colloms seems to regard this as unsatisfactory: "Sadly, some critics are so pleased to have heard a difference they are tempted simply to judge it as an improvement." This criticism also appears to have an element of cynicism behind it: "It is not surprising that audio professionals dismiss such published subjective
results, which often seem to be produced in support of media and equipment marketing."
My conclusions, based on the posts to date, are as follows.
Supertweeters affect the audible range through a variety of ways. Mr. Collums, who I would acknowledge as an expert, appears to confirm this.
I would agree that this is an "error" in evaluating the effects of the supertweeter in an objective sense in that the variable is not fully isolated.
I disagree that this "error" means that reports of system improvements through the use of supertweeters are to be dismissed. Whether somebody thinks something is a subjective improvement is ultimately their own personal taste. It does not require scientific affirmation or the approval of anybody else, no matter what that person's level of expertise is. If I like the colour blue, it doesn't really matter what colour you like, or who you are, or what you're an expert in, if anything at all.
The final comment of Mr Collom's, which I've already quoted, is: "It is not surprising that audio professionals dismiss such published subjective results, which often seem to be produced in support of media and equipment marketing".
This appears to place Mr. Colloms in the camp of the objectivists, those who think that if it can't be measured, it doesn't exist. Or the corollary: if it measures the same, it sounds the same. Many people would have difficulty with this.
Like some of the other posters on this thread, I also have a doctorate. My field of expertise is in the social sciences. Unlike the pure scienctists who work with test tubes and heavily controlled experiments, I have a rather healthy regard for the human variable. They cannot be experimented with in test tubes or in controlled conditions with their prior experiences, attitudes and beliefs wiped clean. (And unlike rats, we don't kill them after they've been experimented on because their experimental experience would affect their performance in furture experiments!) Neither is there full knowledge of their psychology or the physiological basis for their psychology. For a "scientist" to cynically dismiss the effects of such possible variables as being merely in support of media or marketing is rather sad. Many pure scientists appear to forget their training when confronted with the human subject in an open system experiment.
At any rate, to get back to the original post that started the thread, I think the regretable answer to the question is this... A supertweeter may be worth the money you pay for it, or it may not be. It depends on whether you like what it does or not. Nobody else can tell you this. You have to try it for yourself. In this sense it no different than any other change to your system. The financially prudent approach would be to try to audition one before purchasing, if possible.
