Use of a super tweeter worth the investement ?

chorus,

I don't have the knowledge to know the reason why, but the little I have read suggests that no one really knows exactly why, but we are able in some way to perceive the supertweeters contribution.

carlsbad,

What you said is true, but the point is that even though we definitely can't hear 18khz or even less, supertweeters are still audible within the fabric of music, and it's not exactly known why that is so. 

carlsbad,

Say and think what you will, bottom line - they work.

jasonbourne52,

How would you know if you haven't tried them?

That's interesting information Alex.

Good question. My speakers have a horn in the center and a 12" bass driver above and below the horn. I tried it on top of the speaker at first as Townshend recommends, but I suspected that  it would be better to try to align it with the horn, so I built a simple pair of wooden stands that were the height of the horn, and then in an attempt to time align them, I moved them back a bit farther than the distance from the mouth of the horn to the dome of the compression driver in the horn. The result was immediately noticeable.

I think that Townshend and their dealers (one of whom I spoke with) should amend their placement recommendation and encourage users to experiment with placement. On top of the speaker might be good for some if the top of the speaker is at ear level and the tweeter of the main speaker is near to the top, but in my case, the top of the speaker is far above my ear level, and if you're using a ribbon supertweeter like the Townshend, you need to consider that they don't have wide dispersion like dome tweeters, so they should be at or near the level of your ears and pointed toward you. 

I bought a pair of supertweeters that were the EMIT type, and I wasn't satisfied with the sound and stopped using them. Two years later I bought the Townshend ribbon supertweeters and have been very happy with the result with no plans to get rid of them. I agree with emailists that they have an effect across the audible range, including the bass definition.