Re: A few specific questions about testing wood influence on tone
Here's an anecdote of relevance from my shop some years back.
I had a particular client with a Veleno-style aluminum neck guitar. One piece neck to bridge, with a wood body surrounding it on the sides and butt end. The guitar originally came with the pickups hard mounted to the aluminum frame - no cushioning or springs, and the owner simply could not use it on stage due to the high pitched squeal an feedback it woul generate at moderate volume.
The I do not recall the make of the pickups, but they were epoxy potted and not microphonic in the least. Just to be clear, I know pickups quite well. I learned to wind my first pickups with time with Seymour (and some time with Lindy Fralin and Jim Rolph) starting back about 20 years, and I know how to test for microphonic properties. Given that this was a suspect cause I can assure you I tested quite thoroughly, and they were as solid and unshakable as they come. Likewise for all the original mounting hardware. No microphonics, uncontrollable high squeal feedback.
After milling suitable recess in the aluminum frame, I experimented with spring and cushion mounting to the aluminum, and finally settled on installing brackets to the wood for a more traditional mount. The final effects compared to the original were absolutely night and day. Where originalally you could not turn the amp up above 3 without piercing squeal, now this was gone and you could crank up to 11 and sustain fundamentals and low overtones forever. It went from unusable to wonderful, simply by changing what part of the chassis the pickups were mounted to. There were no loose components or microphonics, and the changes were not the sort of thing that could be affected by expectations or bias.
Now this is a bit different from the topic at hand, as it does not involve comparing woods, but rather an extreme change in pickup mounting. It does demonstrate a few things quite poignantly though.
First - pickup vibration can affect tone, even in absence of any microphonics. I'm not saying that changing from springs to tubing on your Strat is going to turn your world upside down, but in extreme cases pickup vibration induced by components it is attached to can affect changes in performance. So the question is not one of can it happen at all, but rather where does the difference limen or relative threshold lie? Will pickups mounted to a floppy diaphragm of single ply pickguard vs hard to a wood body cross this threshold of just noticeable difference? I think that's a good question (if I do say so myself). What about then, pickups mounted to two different woods with different characteristics of resonant feedback? Maple vs African mahogany? I really don't know, but given the enormous difference witnessed between aluminum and alder mounting, I would not be so cocky as to say there were no chance of any change at all until I did some controlled testing to base that claim on.
Second, it should serve as a clear reminder that feedback starts in the chassis. Whether the end results of my comparison had anything to do with pickups being driven relative to the strings by the wood, or it was simply because they were better isolated from the high frequency vibrations present in the aluminum neck, I really can't say. Still, feedback starts primarily in the wood. It's the primary driver of the strings at this point,. It's not just for wild screaming solos, but modest volume sustain, how easily you can coax out swells in the lower harmonics or fundamentals. Can you bring in the heavy squeals with ease, or do you have to lean right up against your cabinet?
Feedback, feedback, feedback. It's not just an occasionally used gimmick, but present to some degree in your final tone once you get anywhere near stage level. Properties of chassis woods may or may not have some level of influence on the initial damping and reflection at low volumes, but once you turn up the wood becomes an active component which drives the strings depending on how it resonates (and few would be foolish enough to argue that different woods do not respond differently with sympathetic vibration).
With all this in mind, I hold it to be quite plain that those who advocate wood type to be entirely irrelevant may be holding the more extraordinary claim, and therefore the greater burden of proof in their argument.
Of course this example is not an isolated source on which I base my position, just one of the more dramatic. I've built a few hundred guitars, worked on many thousands, taught over a hundred students and mentored and handful of apprentices over the years. I used to win bets all the time on identifying the model, back and sides, and top woods of acoustic guitars played behind my back, and can regularly identify smaller changes in potentiometer and cap values than most can blind, so I feel confident that I have a decent ear.
I'm also a dedicated skeptic though. Although I've worked my entire adult life full time in lutherie, I do not underestimate the potential of subjective interference in my perceptions. I've studied physchoacoustics as a side interest over the years, and am quite familiar with limits of human perception. I do employ diligent and standardized methods of testing when I am engaged in a serious test, and try to keep a reasonable mind when considerig my own anecdotal experiences, but have yet to embark on any well controlled tests on this topic.
For these reasons, although I have a strong opinion based on far more extensive experience than many, I keep my certainty in check and will not declare any absolutes until suitable controlled evidence can be demonstrated. Until then I am equally as ready to accept that my ears have been fooled all this time if the evidence demonstrates such, as I am to having my current position verified. To take any other stance in absence of suitable evidence would simply be unscientific.
