Here's what I do to create the legendary tweaked Mellow Dog: I remove the whistlehead from a mass produced whistle. I make a new wide body, key of D tonebody. I stabilize the whistle's response and clean up the sound by filling the cavity under the whistlehead windway using a special, acoustically transparent lattice I've developed for the purpose. I laminate a thickness of plastic under the soundblade to adjust it to the correct position. I place the lamination differently in different whistles to achieve the different voicings that distinguish each model of Freeman whistle. Where the windway floor connects with the voicing chamber, I correct the manufactured square edge by working a radius onto the end of the windway floor. Different keys and models of whistles require different radii. I press a brass ring around the whistlehead socket to protect it from cracking from the pressure of the tube inside. That has always been the demise of mass produced whistles. Occasionally you see a performer playing an old whistle with electrician's tape wrapped around a cracked socket. It bears mention, some of these adjustments are interrelated. If I change one of them, another adjustment will need to be modified to make it work correctly. If you were to only do one or two of the tweaks, even if you could duplicate them exactly, you would not get the same result.