I saw a first prototype of this " gizmo" many years ago ( about 8 or 9) back then it was only applicable to a saxophone and maybe a clarinet and it was a pice of metal which was placed in a section of the neck cork which was cut out to allow this piece of metal (aluminum) to be placed there between the mouthpiece and the metal of the neck.
The place I saw it was Matthews in Edam where Hans Kuijt was often a guest and where I've met him several times and we had friendly contacts back then (until I declared my position on this matter, I have no personal grudge with Hans who is, in fact, a very nice person in many ways we just disagree on acoustics matters).
I did try the awkward prototypical gizmo ( hoping it wouldn't scratch the shaft of my mouthpiece) and I found it a pain in the proverbial derriere and completely useless.
Then years later 2011, they came up with this improved version a piece of metal (a " sound" bridge!) to connect all and any disconnect-able parts of any wind instrument ( some have really many parts!) which would carry the sound around.
The funny thing about this is that all that many years ago the owner of this gizmo design were two people Ton Kooiman ( a well known repairer and maker of several add-on things in the woodwind world, like the " forza" thumb rests) and Hans Kuijt a saxophone player , at least their name is still together on the patents (
http://patents.justia.com/assignee/le-freque-holding-b-v) , however Ton Kooiman seems to have dropped his participation in this enterprise.
I wonder why that was, I remember to have asked him but he didn't say.
The same year or the one before I had met Hans Kuijt at the Frankfurter Musikmesse where he went to plug this product ( some would say " push") . He was demonstrating this gizmo in a hall full of people trying all sorts of woodwind and brass instruments.
There was Nothing to be heard although he did his best ( unconsciously affecting his sound) while showing ( not blindly playing but just showing how to place it and take it off) that the gizmo did what he said he did. He asked me to stand in front and listen. I did I heard nothing, smiled and walked away.
Yet, I wasn't and still am not thinking that he had done this in bad faith, on the contrary, I am sure that he really believes in it, but like all the inventors, they become so focussed on their thing that they lose contact with objectivity.
When Hans came here to SOTW to present his product, he was met with obvious criticism to which he responded not being amused.He presented a large part of annedoctical " evidence"
He talked of many tests ( among which public performances that you can find on you tube) and also blind tests that he and his followers have carried out ( those I've never found on line). He also said that he was going to have this tested at an institute of learning but I am still waiting for any publishing of a paper from the technical university of Delft, for example, attesting the result of double or triple blind tests.
Lacking this still, so many years after they patented their gizmo, it is very difficult to me to still believe in the good faith of anyone who makes money on an object which promises and effect based on a so-implied scientific and Physics effect, that has never been scientifically tested.
Where is the beef? ( real one not pretend beef like these, all " tests" where the player is aware whether the lefreque is on or off).
Perhaps should I ask: " Where is the wolf?". Since time immemorial, crying " Wolf!" carries with it the burden of proof, if one says that there is something to observe based on science he has to provide the science to be observed. I suppose by this time the profits are such that LeFrque could pay for an independent test carried out from independent scientists and an internationally recognized institute of learning. Pick any!
These are NOT tests! The lefreque appears to be a method to turn any metal into gold (the money that you pay for it).
https://www.youtube.com/results?search_query=lefreque+test