Guitars sound like guitars. No matter how poorly or bizarrely they are made, you'll never confuse the natural sound of an acoustic guitar with that of a banjo, a mandolin, a drum or a flute
Yes, I did read the entire article and I did see that bit and my response (I don't think it was actually out loud) was
"Duh"! That's like saying a cat meowing and a dog barking don't sound the same.
The tone of a guitar lies more in the hands of the builder than in the materials from which it is constructed. With increased experience, the level of craftsmanship increases. As the quality of the luthier's instruments goes up, the tonal difference between the instruments goes down."
Well this might be designed to get me to say "Well what do I know? I've only got Larrivees and Morgans. Maybe they just have more quality than, say, a R3000 Tanglewood but that's not really quality is it?"
This morning this seems to me to be a bit like the Emperor's new clothes. What? With the type of instrument you play you CAN hear the difference between mahogany and rosewood? My dear fellow, you simply do not have guitars of the highest quality from a luthier out of the top drawer.
See, I've been through an interesting process recently. A friend of mine left a Larrivee OM, with mahogany back and sides at my house a few months ago. I decided to do the decent thing and humidify it for him whilst it was in my house. Then one evening I took it out of it's case and played it a bit. It sounded different from my Morgan, in fact I quite liked the difference. I ascribed that difference to the tonewood. Sure that's not the only thing that effects tone, but in this case the guitars were very similar in their overall philosophy and design. I started GASing for a good mahogany bodied instrument because I liked that tone so much. It was a very useful and attractive alternative to the darker sound of the Morgan. I don't suddenly dislike that Morgan and it's dark sound - this is like covering bases by having a Telecaster and a Les Paul.
Eventually I bought a Larrivee LV05. In the Larrivee scheme of things the "05" indicates mahogany tone wood, and the "L" indicates the body shape - in this case L for "Larivee", their own shape which is curvier than a dreadnought and, in fact, kind of like a classical body rendered larger and beefed up for use with steel strings.
So now my friend and I sit in this situation where he has a Larrivee with an L body and rosewood back and sides and a Larrivee OM with mahogany back and sides. I sit with a Morgan (heavily Larrivee influenced) OM with rosewood and an L body Larrivee with mahogany. So we didn't set out to to do this, but we have played each other's guitars a lot (whenever he comes to my house he always asks "can I play your Morgan?" to which I reply "sure. But only if I can play your Larrivee") and we can hear correlations between sound and bodyshape as well as sound and woods. There are definitely qualities in the sound of the mahogany guitars that are not present in the rosewood guitars, and vice versa.
I used to lap up the story of Bob Taylor and his palette guitar (made, so the story goes, from wood taken from shipping/stacking palette lying around the Taylor factory). I'm less convinced now.
Last year I got to play a guitar, from a very good maker with an excellent reputation, with very unusual woods. Pine top. Oak back and sides. All wood previously used in whisky distilleries (which in the case of the oak probably means that it was also used for maturing port or sherry). I was less than convinced by the tone of these guitars. They are striking to look at, but I rather suspect that's the point. I notice that the all the signature editions from this maker, designs that correspond to those used by professional players, all use much more conventional woods. I was actually a little saddened when I played one of these "single malt" guitars because I'd heard so much about this brand. I then played what I think is the cheapest instrument in his range - mahogany tone wood, cedar top and a thousand pounds less in price. Suddenly we were talking!