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@ The Kid :
Re my mistakes:
First off thanks. For your feedback, and thoughtful words.

You're right, there was a big leap in my comment , which started where I said "'s how it works:"
It was in part a slip up, which often occurs during editting, when I insert lines later, forgetting context, although it was also clearly an overstatement of what I know.

That whole line, which starts with "I suppose... " and then goes on about Remo fiberskyns, was written last, after I'd written most of what follows. I added it later, as a lead-in, but forgot that I'd prefaced the part that follows with "Consider...", and also switched voice style to a "I'm a tell you how it is" rather than "here's a thought" mode.

Admittedly, "Consider..." is a minimal and ambiguous way of saying "this may not be fact, but here's a way of thinking about it for you to consider". I need to be more clear, it's not enough.
Re skins etc:
About my theory about air in skins, I'm basing this off my observations of how different skins sound, and how that seems to correlate to their density, or what I perceive to be the density.

Of course all skins are in fact dry, so I'm using the term "dry" to refer to the sound, as a metaphor. In the same sense as how, to me, wood usually sounds "dry" when struck, compared to metal, for example, and I attribute this in part to the presence of air in the wood. I think this in part because the more dense the wood is, the more it seems to sound similar to metal. (I realize there are other factors as well.)

It's been my observation that a skin which seems to me to be dense*, which I would describe as having less "air", has less of a "dry" sound, and more sustain, than one which I would describe as having "more air".

*: What do I mean "seems dense"? To me, the appearance and texture of a dense skin, at the extreme end of the spectrum, is sometimes relatively shiny**, sometimes partially or completely translucent, and very hard for it's thickness (stiff).

These to my ear ring cleaner, with a more focused, uniform tone, sometimes bell like or crisply metallic. If thin, they can be a bit "ringey".

Whereas a skin at the opposite end of the spectrum, which I suppose to have lots of air, often appears lighter, opaque**, and can be "spongy", almost as if it were made of wadded up felt, or layers of paper towels stuck together, and very flexible for it's thickness. These to my ear sound less clear and focused, with more of what I describe as "dry" overtones, i.e. separate and distinct overtones, which to me makes for a fuzzy and pallette of sound. I would describe the sound as having more "bark" to it (dog bark, not tree). To me this can also sound more like human speech, which is often full of dissonant overtones.
**: The presence or lack of shininess is not a reliable indicator, as a dry "airy" skin can have a shiny smooth surface from being played with oily hands, and a dense "airless" skins can be opaque. But it's worth mentioning as it seems to often go with density. It may be due to the presence of oil in the skin, or simply that the surface of the skin is less fibrous.

For example:
I had a soft/flexible skin (almost felt like suede at the edges) which sounded too "dry", not focused at all, and it didn't feel satisfying to play because the sound seemed to dissipate very quickly, with no definitive tone to it. I oiled it (with shea butter) and it sounded much more focused, had more "body" to the sound, and was more satisfying to play.
Later I decided that I had added too much oil, because it lost some of that "vocal/speech" character, so I removed some oil(will explain how in a new topic), and reached a perfect medium between the two ends of the spectrum. Neither too many overtones, nor too few.
It's something that I was only able to determine by playing the drum, and feeling what it's capable of. Without the oil, it just wasn't very powerful. With too much, it wasn't very expressive. Balanced, it sounds best compromise.

What is the oil doing? Partly I believe it's filling in the air spaces, making the skin less "dry". So the sound can travel through the oil, rather than having to leap the airgaps, which would cause it to change speed and lose energy.
There's probably more to it than that, but it seems plausible to me. It may also provide a softer interface for the soundwave to switch between air and solid/fiber.
This is related to how different chemicals in wood alter the sound, but that's a big tangent topic. (Lenke contains ~2% oil*, which I suspect may be partly responsible for the exceptional tonal qualities it has. *:According to a research paper I read, which I can dig up)
I got so focused on the responding to the rest of the post that I forgot to respond to the bit about the wood challenge, where you said:

"...but when fact is presented with out any proof then you have to get some slack for that, or be questioned or asked for proof, like in the 'guess the wood thread'. Nobody guessed right but it was prior stated it could be done. So then i'd say the prior statement was wrong and or misstated."

I understand why you would feel this way, and if I ever said, as you say I did, that I definitely "can"reliably identify wood from hearing the djembe, then I agree, it was overstated. I certainly notice differences, and I'd be happy to try again properly, in person, at my closest real Djembe store (DrumSkullDrums), although my life doesn't grant me the ability to travel there at the moment.

However, the challenge run by Djembefeeling was in no way a definitive test, and I certainly never asserted that I could guess the woods with those recordings. I appreciate his effort, but there were multiple factors that made it almost impossible to hear differences. I would have mentioned them on that thread, but it felt rude. He went to trouble to make that happen, and I want to support him for that.
But I believe it led to an inaccurate assessment of my claims.
I have written a list of the criteria that were missing, which would be required for a more fair test, but it doesn't seem like this is the place to post it, nor does it feel right to post it on his thread.
I would say there are tonal differences between the woods for sure but the limitation is the human ear in noticing them. We get a sense of feeling about the woods sound characteristics but actually saying which is which in a blind test is very difficult perhaps impossible . I think the speed at which the sound moves/bounces multi directional y through the drum is too complicated to really understand what elements are contributing to the sound we hear. Plus putting a skin in there between the hand and the wood is totally confusing the issue. Slowing down the sound with a sampler or examining visual representations of the sound wave could give some clue as to sound differences and then again all the waves could be so similar as to be indistinguishable. You slow down bird calls and it provides way more rhythmical information to our ears.

You take wood on wood like a balafon and it is easier to describe the sound of different woods. I seen a cool demo instrument which had native irish woods all with the same shape of a balafon key. Hitting them with the same mallet produces different sound on each key. Totally evident the different characteristics.

Take it easy. If ya want any off board conversations or discuss other ideas on it i use 'Wire Swiss'
for chat mail or file sharing. later. pm me if you want to get my address. Nsa won't crack that encryption lol. well they probably can but noone else will.
I agree theres way more going on in a Djembe, due to the design and skin, so the wood tone is part of a complex system of sound. As Michi often says, the most important factor is the skin, assuming the shell is the right basic shape and dimensions, and the head is tuned up. Not sure if you saw my other response above about skins, (long and wonky I know) but it sort of addresses one of the factors which affects how different skins sound different.
As for wood, it's always a debate on instruments forums. Usually a large vocal contingency insisting that wood type makes little or no difference, and that construction is more relevant in sound.
I dont think its either/or. Putting aside construction, which no one questions the importance of, I think for some people wood type makes less difference. Surely wood type matters to some, which is why certain woods are the most chosen for a given instrument, but to most it may be of minor or no importance.
I may give up trying to convince anyone, whats the point anyway, but I can describe the differences between the djembe woods, their strengths and weaknesses etc. It requires controlled testing to tell them apart for sure, many factors affect the djembes sound. But its clear to me they are different.
As for wood, it's always a debate on instruments forums.
Yes but for an example we can hear the difference between a rose wood martin guitar and a mahogany one. The strings and build measurements are so standard, that the differences in projection, attack, delay and sustain of the sound emitted is due to the different woods sound characteristics.

We can't so easily do that for djembes as they are all different and the skins has to be different unless we go and machine the drums to be identical and use synthetic skins. There is the conversation that wood species from different soils is different and this is a fact, and that wood from different areas of the tree are different density etc. So you might get a lenge leaning on one end of the spectrum of hardness sounding one way and one with a different hardness sounding different again.
Surely wood type matters to some, which is why certain woods are the most chosen for a given instrument, but to most it may be of minor or no importance.
Pretty much yea, tropical hardwood from west africa is the stuff. Makes a njaang when you slap it. But i'd love some chip board drum if it sounded good no doubt about it. Dununs sound class from a steel barrel. No body is discriminating against materials, it is just i never heard a good djembe that wasn't of the high quality wood.