Jer, the difference between you and me is that you "think" and I "know". =)
Objection!
I'm sure there are a lot of differences between you and I....but heck it's an internet message board. I don't take it that seriously.
1. A brace can be loose without causing a loss in structural integrity.
That's debatable. I guess it would depend on the location of the brace and how loose it is. I don't completely disagree. I'm sure it's possible that it could happen with no ill effects. However, the braces ARE there for a reason. It would depend on the particular instrument and situation.
In my extreme example though, I was talking about taking all the bracing off completely, to prove the point I was making.
2. A thin top will not always vibrate more freely than a thick top.
I don't disagree with that either. If you put super thick braces on the thin top but brace the thicker top lightly, you could get similar results.
Here's a good article talking about that sort of thing and more:
http://www.masterguitars.com/Article1.htm
That said, if you have two tops that are identical in both thickness and stiffness and brace one while leaving the other un-braced, the one that is not braced will move more easily.
Also, a brace can be loose and not even make a buzz or rattle.
Crazy, right?
Right!
I don't disagree with that either, for the record.
3. An unbraced top will not vibrate more freely, just the opposite.
Maybe I should throw out the word "vibrate" here. I'm wondering if I'm even using the appropriate word for what I'm trying to say.
What I'm trying to say is maybe most easily seen and heard in a banjo:
If you have your typical old-time open back banjo (not resonator), the only thing touching the top is a very thin and light bridge. Of course the top is under a good bit of tension, but it is really thin. The sound is loud without much sustain. Stick something underneath the top of the same banjo (similar effect to a brace) and the volume starts decreasing. Put a heavier bridge on it, or even one of those metal "mutes" that sits on the bridge and the added mass lead to far less volume but more sustain. So volume goes down and sustain goes up.
The lighter an instrument is built, the more vibrant and loud it is.
The only instruments I've built personally are home-made instruments more in line with cigar box guitars and other various things. I noticed the same principles I'd heard talked about for years apply to those too. I have one that I did use an instrument grade top wood I got from Stewmac on. I built my own box using that wood for the top and back. The same thing happens with these types of instruments, as in the more you brace them, the more the sustain goes up but the more the volume goes down.
If you're saying a braced top can sustain more, I don't disagree. I guess it depends on if you consider "vibrate" and "sustain" to mean the same thing. I was speaking in terms of volume, so maybe I shouldn't have even used the word "vibrate" up there. I'm not sure.
Another, maybe odd example, of what I'm getting at is this: Think about a kite. I think most everyone has played with one of those at some point. I used to have the cheap ones as a kid. You pull it out of the bag and it's a floppy sheet of plastic that resembles a good garbage bag. You then put braces on it and the material doesn't flop around as much. Bracing restricts movement (and volume). That's what I'm getting at.
Now, go practice on your uke. =P
Sound advice...and you can go fly that kite!
I'm going to shutup now because this probably isn't helping the person who started the thread at all, even if it is entertaining... You can present your closing arguments and let the jury decide. ha.