At the risk of being called stupid (again) by one of SOTW's regulalr contributers who delights in flaunting his superior knowledge of acoustics to everyone on this forum and others and belittling those who have the audacity to disagree with him, I am going to resurrect the dead horse one more time. (Let's call the horse Lazarus or Lacquerus might be more appropriate).
There has been a longstanding difference of opinion between scientists and musicians (people who actually play music on real woodwind instruments outside of laboratories) of the effects of materials and finishes on the sound of instruments. The scientists design their experiments to isolate and measure variables to come up with their conclusions. The musicians actually perform music on the instruments often for a lifetime to gather their "unscientific" anecdotal evidence.
Clearly either one group or the other is right on the subject of whether materials and finishes have any effect whatsoever on the sound of a woodwind instrument. They can't both be right, or can they?
1) I strongly believe that the factor that has the greatest influence on the sound of any woodwind instrument is the concept of tone in the mind of the performer, given that the player has a high enough level of skill on the instrument to have maximum control of the sound that is humanly possible.
2) The next most important factor would be the mouthpiece and reed, quality and design of the headjoint, or reed alone in the case of the single reed instruments.
3) Following this would be the dimesions inside the bore of the instrument, tonehole size and placement, key height opening, absence of leaks, etc.
I think most players and researchers would be in agreement up to this point although perhaps the non-performing researchers would not have the same depth of understanding of factor #1 as would a professional musician. Now is where the two sides diverge.
4) Is there a #4? Does the wall material, thickness of the body, plating, or lacquering have any effect whatsoever on the tone or sound of the instrument when the dimensions are otherwise identical? Data from acoustics experiments (primarily on flutes) suggest that no, these factors do not have any significant measurable effect. Clarinet and oboe players who compare wooden clarinets to plastic say "yes". Flutists who spend vast amounts on top end flutes made of precious metals say "of course". Many sax players say "even the color of the plating makes a difference---let alone a few coats of lacquer, dude". (Question-how do you lower the value of a Mark VI tenor by at least $3000?)
If there is anyone still reading this diatribe---I am finally getting to my point!
In my opinion, the question that should be asked of the player is "was the feedback you got from that instrument the same, or different than the one with the different material/plating/finish/coating etc., etc." This is something science presently has no way of accurately measuring for each individual player? The closest they could come might be to blindfold a flutist and have him randomly select one of two identical flutes made of silver and gold and ask "was the second instrument the same or different than the first"? Or "did you play the second flute the same or differently to achieve the same sound"?
An accomplished player will either consciously or unconsciously adjust the aperture of the throat, speed and volume of the air, shape of the tongue, pressure of the abdominal muscles, firmness or shape of the embouchure, force of the tongue during articulation etc. etc. in order to make the sound and response of that instrument conform to the tonal concept in the player’s mind. To do otherwise is contrary to years and years of practice and extremely difficult to do. Performers select their primary instruments based upon this feel or response of (feedback from) the instrument.
Another way to describe this criteria is “how hard the player has to work to produce the sound and response that is desired.” Thus instrument A and B may sound identical to a trained listener, and even show the same pattern of harmonics when shown on a spectrograph, but the performer may have to work much harder on one instrument over the other to reproduce the desired tonal concept. In this example, did the plating have and effect on the tone? No. Did it have an effect on the feedback of the instrument to the performer and the response of the performer to that feedback? Certainly. Do performers sometimes “confuse” the feel and response of (feedback from) an instrument with the sound of the instrument or combine the two to form a gestalt. I believe they do. Does this mean they are being deceived by their senses as in an optical illusion? Or does it mean that they are stupid, incompetent, or self deceived as some would have us believe? Or does it mean they are interacting with and responding to the instrument in a wonderfully personal and complex way that transcends the measurements of scientific instruments and listening surveys. Rather than ask "does the lacquered sax sound different than the unlacquered one", I think the more valid question is "on which finish is it easier for you to sound the way you want to sound". To a musician, what else really matters?