Canberra Modal Tuning Course

[Clancy]

Well, us locals donned our beanies & welcomed a great bunch of guys to our frosty little corner of the world.
Straight up I'd like to thank Dom, on behalf of everyone, for organising the course AND for opening up his house & workshop to a bunch of guitar geeks. Cheers mate.
I'd also like to thank Trevor, not only for coming down here to present his knowledge, but for being so open and receptive to questions, queries and confusions.
Finally, I'd like to thank everyone for bringing their instruments with them for us to 'peruse without pressure'.
Damn you guys do some good work!

TG1 - Modal Tuning.jpg (49.05 KiB) Viewed 28343 times

TG2 - Monopole Mobility.jpg (57.43 KiB) Viewed 28343 times

TG3 - Bridge Rotation.jpg (53.03 KiB) Viewed 28343 times

TG4 - Motley Crew.jpg (54.78 KiB) Viewed 28343 times

Note: All persons depicted in the above photos are 'stand in actors'.

Oh, and I think the local Indian Restaraunt is going to miss you lot.

[Mark McLean]

It was a fantastic weekend. I experienced a quantum leap in understanding how a guitar works and how I might try to build one that works better. Trevor is a great teacher as well as a very good luthier. We had 9 guitar nerds, a shit-load of beautiful guitars/ukes (and a bouzouki), 3 whole days to do nothing else but loofery, and Dom's fantastic workshop to poke around in. What else would you want from a long-weekend? Best of all, it was great to meet some ANZLF characters in the flesh.

Thanks for organizing and hosting Dom

Are we doing it again next year?
Mark

[woodrat]

Apart from the beanies it looks pretty much the the same as our 3 great days we had with TG back in January in sunny Toronto ....tired but contented looks on the loofiers faces!....I am sure you guys will benefit in the months and years ahead as all that info percolates through the system.....
Did your visitor from the States end up coming?

Thanks for posting Craig.

John

[kiwigeo]

Bugger......missed a great opportunity.

[Nick]

Sounds like a great weekend for all! Not sure about a number of curry's the night before when working in a confined space though!
Can we get a few names to the line up in the last pic Craig? I see your names on the forum everyday but it's quite nice to be able to put a mugshot to the name when the opportunity such as this (when all suspects are assembled in one place) arises

[ScottC.]

No I didn't make it cause I heard rumor TG might be coming to the U.S. I really hope so!!! I am soooooo jealous of you guys who got to attend.

Apart from the beanies it looks pretty much the the same as our 3 great days we had with TG back in January in sunny Toronto ....tired but contented looks on the loofiers faces!....I am sure you guys will benefit in the months and years ahead as all that info percolates through the system.....
Did your visitor from the States end up coming?

Thanks for posting Craig.

John

[68matts]

It was a great weekend, my brain is a bit fried at the moment but hopefully all the knowledge that was rammed in will be retained enough to be put to good use.
Another big thanks to Dom for not only hosting the course but for giving me a room for the weekend ( in his mighty impressive wood room no less ), it was very much appreciated.
The bottom photo from left to right shows Trevor (with his head cut in half), Bruce, myself, Frank, Nick, Dom and Mark. The next shot up shows Craig and the back of Nicks head. The only one missing from these shots is Graham.

[kiwigeo]

The bottom photo from left to right shows Trevor (with his head cut in half), Bruce, myself, Frank, Nick, Dom and Mark. The next shot up shows Craig and the back of Nicks head. The only one missing from these shots is Graham.

Is Dom the one with the tea cozy on his head?

[Bruce McC]

I agree wholeheartedly with Craig, Mark and Matt. Thanks to Dom for making
his house available for the venue and to Trevor for putting on the course and
sharing his knowledge so patiently.
The course gave me a greater understanding of the design concepts in
Vol.1 of the "Book, I found the practical demonstrations particularly helpful.
The two guitars that I took along for testing did not fare so well, but at least
I now know how to try and remedy the short comings of each one.
It was also a great chance to socialise with other forum members.

[kiwigeo]

In photo 1 Nick's mouth appears to be exhibiting a classic dipole response

[Trevor Gore]

And I very much enjoyed it, too. Plus I can no longer say I know nothing about ukes. We shook one of Craig's (yes, THAT one) and it showed every indication of operating just as I would expect a small guitar to operate. Funny, that.

Thanks specially to Dom for his hospitality and to everyone for making the whole thing so enjoyable. I guess you all know what to do now if any of you guys want another.

[kiwigeo]

And I very much enjoyed it, too. Plus I can no longer say I know nothing about ukes. We shook one of Craig's (yes, THAT one) and it showed every indication of operating just as I would expect a small guitar to operate. Funny, that.

Dont tell anybody on the UU forum that...

[Trevor Gore]

I think it was Graham who asked me about the software parametric equaliser I used for filtering guitar sounds. The one I use I was able to cobble together using VST (Virtual Studio Technology). I downloaded it from here. Needless to say, I'm using an old version...

If there's anything else I promised to do - please remind me!

Oh, and if anyone has my memory stick (thumb drive) still stuck in their computer, please PM me!

[Dominic]

Is Dom the one with the tea cozy on his head?

Yes that's me Martin, green jumper. I was bloody cold. I've never spent so much time in my workshop just sitting.

A few guys had problems with VA 2009. I updated to the 2011 version and it seems quite stable. Holds the settings and won't crash. They have moved on to beta 2012 now so perhaps 2011 is settled. Hope it works for you guys if you try it.
Cheers
Dom

[kiwigeo]

That workshop's come along way since you posted pics of the start of the fit out some time ago.....looking good.

[Dominic]

Hey guys, I've got some results from the cooked tops we tested during the course.

For those not there, we tap tested 2 Englemann tops to determine the final plate thickness and then I cooked them for about 1.5 hours at 100c then let them cool and stabilise them back to 45% humidity, then I retested the other day. Interesting results.

The tops lost about 10gms each which must be drying resins in the wood because they had stabilised at 45 for a while before cooking and weighed several times so it was not water loss. The drop in mass raised the tops frequencies in all 3 directions slightly which offset the reduced weight and the El, Ec and Glc where around the same values and there was little change in the calculated plate thickness. The real improvement came from the lighter final plate mass. saving around 15gms each half plate.
I'll keep checking other plates as I go to get a clearer idea of what is happening
Interesting though.
Cheers
Dom

[Tod Gilding]

Did You Use an Oven Bag Dom? A few Vegetables and let it roast in its own juices?

But seriously, what result do you expect when the tops are subjected to higher RH say 90% and then returned to 45% to stabilise? Do you think the tops would still have less mass?

[Dominic]

No bags, but after cooking they stayed out of the dry room for a week or so and it was raining so they weighed more than pre cooking mass. These top had been sitting around the house for 3 years and then in the dry room for about 2 months at 45% before testing.
So if what you mean is 'have they been cycled through high then low humidity' Yes.
Cheers
Dom

[charangohabsburg]

The tops lost about 10gms each which must be drying resins in the wood because they had stabilised at 45 for a while before cooking and weighed several times so it was not water loss.

I'd rather think that the loss of eight at the same RH as before is due to decreased ability of humidity adsorption.

Check out the adsorption / desorption curves (and the related text) in this document (page 26, respectively p. 42 of the pdf). Similar curves about the same phenomena in this pdf(p.7, 8 ).

[Dominic]

What i am saying is they had stabilised at 45% and mass was constant over time. I cooked the tops then left them in a high humidity area until they weighed more than the stabilised weight. Then back into 45% again and this time they have stabilised at a lower weight. Actually about 10gms each half plate, from ~ 170 to 160 . I've seen plates fluctuate by a few gms in high humidity but not 10gms.

We tried to approach this scientifically and control for all variables. The point was to test the theory, not prove it. So I am reasonably confident I am not just measuring a lower water content in the plates. Resins had bled out of the tops and hardened on the surface so I expect these tops will be even lighter once that outside surface is cleaned up. I will keep an eye on these plates and make some more measurements in the future and report back.

Cheers
Dom

[Dominic]

Sorry if i was dismissive of your thoughts Marcus, do you mean that cooked wood takes on less water stabilised under the same conditions as an uncooked piece? I didn't read your links yet but a quick summary would be of interest I think. Does it shrink the cell walls so the water spaces are smaller? What do you recon is happening?

As I said, as a test of the theory, our interest was scientific, not voodoo. I do think there is something in the hardened resin idea but perhaps it can only explain a small part of the weight loss. Its important to determine the dominant effect so the cooking can be fine tuned. Then determine if there actually is any long-term benefit from doing it or is it just a short-term loss of water that humidity cycles will unwind, but slowly over time.

What do you think? Perhaps I should a separate thread.

Cheers
Dom

[charangohabsburg]

No problem Dom.

I don't know what exactly happens when repeatedly drying/humidifying wood. I only read (not very scientific, I know) that the ability of absorbing moisture decreases with every full cycle. I don't even know if someone knows the reason why this happens, I did not read enough! I could postulate some conjectures though, but I think this would be a bit silly to do without having read before all I can find about this phenomenon.

As I said, as a test of the theory, our interest was scientific, not voodoo. I do think there is something in the hardened resin idea but perhaps it can only explain a small part of the weight loss.

I think it would be interesting to know

1. the percentage in weight of fresh resin in a spruce top (which may be less than the percentage in just "spruce wood" which normally contain resin pockets)
2. the percentage in weight of volatile substances in fresh resin

Its important to determine the dominant effect so the cooking can be fine tuned.

I'm not sure if I understand what you mean with "fine tune cooking".
I think that having available some empirical data, e.g. those adsorbtion/desorbtion curves for each wood species would already be a nice leap towards understanding better what "aged wood" or "cured wood" really means.

I think that it would be very interesting to understand what exactly happens on wood cell level or maybe molecular level. But such a detailed understanding will only of practical value if we were able to determine the exact amount of components in that piece of wood we are going to use with the next instrument.

Cheers,

[Dominic]

Its important to determine the dominant effect so the cooking can be fine tuned.

I'm not sure if I understand what you mean with "fine tune cooking".


Cheers,

What i mean is that drying out resins may require higher/lower temp, longer/shorter cooking and/or different cooling than if we are just trying to super dry the wood to impact on cells. I have no idea which but it seem a good idea to know more accurately how to optimise the process if in fact it does produce meaning ful improvements.

The only way I can see to obtain data is to try out before and after measurements of a number of plates, and over time and collect it ourselves. So that's what I'll do and I'll put up results as I go. If i had a couple of days i could go through and square up and thickness all my plates (about 40) and then measure them all at once. Something to do on a sicky.

Cheers
Dom

[jeffhigh]

Besides any effects on resins, you are probably seeing some "sorption hysteresis" and also removal of bound water from the wood which is not then able to be take up again by normal exposure to humid conditions.
All good things for a soundboard
Baking to higher temperatures can however result in losses of strength which are found in some commercially heat treated timbers used in Europe for the increased durability imparted.

[Trevor Gore]

There's a really good thread on wood seasoning/baking/sorption hysteresis etc. here. It's long and you also need to follow the links, but heaps of great stuff.