"Do materials have an effect?" - ChrisC
Chris, when it comes to theremins, one cannot say anything with certainty! - If you seriously asked "Does the phase of the moon have any effect" I would, 3 years ago, have laughed at your sillyness.. Now - well, im not so sure! ;-)
I heard a tale somewhere (not sure how true it is) That some thereminists were playing with a pitch antenna, and put an insulating sleeve or something like that over it - They all agreed that the tone quality (or something - I think it was tone quality) altered dramatically.. Apparently this was at some exhibit or whatever, and Bob Moog was nearbye - when he was asked about this effect, he apparently said it couldnt happen..
But, it can happen - Coupling of the antenna to internal circuits in the theremin can alter its tone (marginally) - and placing an extra dielectric over the antenna can reduce this coupling - highly unlikely - highly improbable - but, with theremins, well, expect the unlikely and fear the improbable! ;-)
But no - I see no reason why the antenna material (provided its metal and not latinum or radioactive) should affect the theremin or the player.
- With one other proviso.. Some metals have a greater thermal expansion than others - expand the antenna area, and you increase the capacitive coupling.. so this can contribute to thermal 'drift' I think, but unless one has extreme temperature change (I noticed drift on one of my H1 theremins when a spotlight was beaming onto its aluminium+steel antenna, which was getting quite hot, as it was covered in black sleeving) I doubt that it is of great significance.
Worst to best: micrometre / metre / 1 degree K:
Zinc =29.7 ; Tin =23.4 ; Aluminium =22.2 ; Silver = 19.5 ; Brass =18.7 ; Bronze =18.0 ; Stainless Steel (304) = 17.3 ; Copper = 16.6 ; Stainless Steel (316) =16.0 ; Gold =14.2 ; Stainless Steel (310) =14.4 ; Nickel = 13.0 ; Pure Iron = 12.0 ; Stainless steel Ferritic (410) =9.9 ; Tungsten =4.3
Unfortunately, tungsten is too expensive, and a pig to work with! - So stainless steel 410 looks like the best metal for antennas - perhaps
Fred.
>> Just looking at those numbers, and doing some sums - I dont think thermal expansion of the antenna caused the drift on my H1, even with aluminium.. So I wonder if the heat radiating from the antenna possibly altered the dielectric properties of the surrounding air... Or, perhaps the spotlight was expanding!