Search found 1463 matches

by Trevor Gore
Mon Sep 16, 2019 9:16 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Complete guitar - frequency testing technique
Replies: 4
Views: 153

Re: Complete guitar - frequency testing technique

There's some new videos on Robbie O'Brien's site which show how I do all the tap testing etc..
by Trevor Gore
Mon Sep 16, 2019 9:14 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 3
Views: 68

Re: Frequency analysis GS Mini style build: improvement possible ?

Probably worth doing some Chladni testing to set what is actually going on around the 210Hz to 240Hz region, with and without added mass.
by Trevor Gore
Mon Sep 16, 2019 9:12 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Complete (almost) guitar - spectrum results
Replies: 3
Views: 87

Re: Complete (almost) guitar - spectrum results

String it and listen to it. With the added mass of saddle and strings the T(1,1)2 will drop and you may have to alter the side mass to hit 180 Hz for the T(1,1)2. You should end up pretty close to 180/226, which is not a bad place to be. With the sound port, the air resonance will always be higher t...
by Trevor Gore
Tue Sep 03, 2019 2:05 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: OOO without scallopping and live back
Replies: 1
Views: 177

Re: OOO without scallopping and live back

A live back will make your guitar sound about 1/2 a size larger, (i.e. a 00 will move toward a 000). This is because the coupling reduces both the main air and main top resonant frequencies and so the guitar sounds stronger in the bass than it otherwise would. The T(1,1)3 peak also helps reduce the ...
by Trevor Gore
Tue Sep 03, 2019 1:59 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Top Edge Thinning - Measurement of Thickness
Replies: 3
Views: 216

Re: Top Edge Thinning - Measurement of Thickness

My procedure for all of this is in Section 12.7 and I haven't changed what I do.

You will likely thin the edges a bit more when you clean up after gluing on the bindings, and maybe a bit more again in preparation for finishing. With a bit of side mass, you should be in reach of your 180Hz target.
by Trevor Gore
Tue Sep 03, 2019 1:49 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Equ. 4.5-1 and Equ. 4.5-2
Replies: 2
Views: 187

Re: Equ. 4.5-1 and Equ. 4.5-2

Bruce, check out this post: viewtopic.php?f=33&t=3626#p43983 . The error is small and fixed in the second edition.
by Trevor Gore
Wed Aug 21, 2019 9:44 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Veritas scraper plane in lieu of high angle plane
Replies: 13
Views: 1641

Re: Veritas scraper plane in lieu of high angle plane

I find that the fastest way to remove bulk wood from figured panels is to plane cross grain with a curved edge standard angle plane. Then finish in line with a high angle plane. See pages 6-3 and 6-5 in Build.
by Trevor Gore
Sun Aug 18, 2019 11:10 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Veritas scraper plane in lieu of high angle plane
Replies: 13
Views: 1641

Re: Veritas scraper plane in lieu of high angle plane

Appologies all but just to move slightly off topic. I've just made a high angle Bailey No4 using Trevors method with the 12mm round bar. I'm waiting for an A2 blade and a honing guide to appear in the mail before I try it out. My question is what angle should the micro bevel be? I was thinking abou...
by Trevor Gore
Tue Aug 13, 2019 10:34 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Carbon Fibre or not
Replies: 2
Views: 337

Re: Carbon Fibre or not

Omitting the CF makes for easier assembly but you lose out on some cold creep resistance in the middle of the guitar. I routinely use the CF as it also makes the area pretty well split proof.
by Trevor Gore
Tue Aug 13, 2019 10:28 am
Forum: Instrument Builders Forum
Topic: Veneer Softener
Replies: 5
Views: 949

Re: Veneer Softener

I bought some veneer softener from Carbatec years ago (price on my bottle $22, vs. $42 for what looks like the identical bottle now). I found it didn't work nearly as well as the fabric softener I was using. Maybe the formulation has changed???
by Trevor Gore
Sun Aug 11, 2019 8:55 am
Forum: Instrument Builders Forum
Topic: Luthier on Luthier - Michael Bashkin talks to Trevor Gore
Replies: 2
Views: 934

Re: Luthier on Luthier - Michael Bashkin talks to Trevor Gore

Dave M wrote:
Sun Aug 11, 2019 2:03 am
Some of Michael Bashkins other podcasts are also worth seeking out.
Definitely!
by Trevor Gore
Fri Aug 09, 2019 5:52 pm
Forum: Instrument Builders Forum
Topic: Luthier on Luthier - Michael Bashkin talks to Trevor Gore
Replies: 2
Views: 934

Luthier on Luthier - Michael Bashkin talks to Trevor Gore

When I was over in the USA in July presenting the Modal Tuning Course at Robbie O'Brien's , one of the participants was Michael Bashkin . Michael periodically contributes a podcast called Luthier on Luthier to the Fretboad Journal where he interviews other guitar makers and he was kind enough to inv...
by Trevor Gore
Fri Aug 09, 2019 10:44 am
Forum: Instrument Builders Forum
Topic: Finish (shellac?) repair suggestions on Spanish classical
Replies: 8
Views: 1098

Re: Finish (shellac?) repair suggestions on Spanish classical

The darker patches look like a water stain - the sort you get under varnish when wood has been left in damp conditions for a long while. So that makes me wonder if some sort of re-hydration was attempted with water spilling inside the guitar. I don't know of any finish that fails with white dots lik...
by Trevor Gore
Thu Aug 08, 2019 1:44 pm
Forum: Instrument Builders Forum
Topic: Finish (shellac?) repair suggestions on Spanish classical
Replies: 8
Views: 1098

Re: Finish (shellac?) repair suggestions on Spanish classical

Looks very weird!

Has a soldering iron been used to try to steam out dings?
by Trevor Gore
Tue Aug 06, 2019 11:12 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Practical degreee of accuracy thicknessing panels
Replies: 2
Views: 298

Re: Practical degreee of accuracy thicknessing panels

The +/- 0.05 is practical for me, using planes. On the occasions that I've used Gerard's wide belt sander, the variation is a lot more than that, though, as it also is on the (few) typical-style cantilevered drum sanders I've had experience with. In order to get good tolerance with a plane, you need...
by Trevor Gore
Tue Aug 06, 2019 9:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Wallnut Density for SS Falcate Bridge
Replies: 4
Views: 374

Re: Wallnut Density for SS Falcate Bridge

I've used between 550 and 650 kg/m^3. Black walnut has a wide spread in density, but 730Kg/m^3 is on the high side. Bootle (a wood reference) quotes 600 kg/m^3 for American Black walnut; the Wood database quotes 610 kg/m^3 as an average.
by Trevor Gore
Mon Aug 05, 2019 1:32 pm
Forum: Instrument Builders Forum
Topic: Now more difficult to export
Replies: 12
Views: 1508

Re: Now more difficult to export

I suppose that's why they want you you rock up at a desk. THEN they tell you you need 100 point ID. So then that's another 2 hour round trip....

Has anyone had the courtesy to tell you why we need this extra red tape and how it benefits the SME?
by Trevor Gore
Fri Aug 02, 2019 5:07 pm
Forum: Instrument Builders Forum
Topic: Now more difficult to export
Replies: 12
Views: 1508

Re: Now more difficult to export

Makes you wonder if the people who think this stuff up have any idea how a SME really works.
by Trevor Gore
Thu Aug 01, 2019 2:56 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Advice on Resonances
Replies: 7
Views: 516

Re: Advice on Resonances

Good to hear that the suggested fix worked for you! :D
by Trevor Gore
Thu Aug 01, 2019 10:27 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA, opening saved files
Replies: 7
Views: 446

Re: VA, opening saved files

VA 9.0.6 doesn't save files that are re-openable in VA. It just saves a .txt file that can be used in Excel (or similar) and a .wmf file which is just a picture of whatever was on your screen when you hit save. The files cannot be re-loaded into VA and be zoomed etc. so you can read peaks. If you wa...
by Trevor Gore
Tue Jul 30, 2019 11:07 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Advice on Resonances
Replies: 7
Views: 516

Re: Advice on Resonances

The biggest resonance by a long way is at 98Hz.... The main issue I had was the G on the 6th string and the open G string notes not sustaining.... That was because the the G on the 6th string is at 98Hz, matching the T(1,1)1 resonance. For a 180Hz T(1,1)2, ideally you'd want the T(1,1)3 at 226Hz an...
by Trevor Gore
Tue Jul 30, 2019 10:55 pm
Forum: Instrument Builders Forum
Topic: Back joint prep
Replies: 15
Views: 1629

Re: Back joint prep

The usual problem when trying to shoot panel edges and having trouble is that the plane sole is not flat enough. The usual out-of-flatness is that the sole is concave and I would say that ~90% of Stanley/Bailey pattern planes have this problem. A secondary problem is that even if you flatten the sol...
by Trevor Gore
Mon Jul 29, 2019 8:02 pm
Forum: Instrument Builders Forum
Topic: Size of Steel String guitars
Replies: 2
Views: 1027

Re: Size of Steel String guitars

The falcate steel string in the book is "medium" size, about the same size as a Martin 000 and quite a bit smaller than a J45, J200 or Dread. A standard classical is very similar in size to a Martin 00. The amount of bass you get out of a guitar is related to where you position the T(1,1)1 and the T...
by Trevor Gore
Wed Jul 24, 2019 9:59 am
Forum: Instrument Builders Forum
Topic: Black marks/stain in grain
Replies: 7
Views: 1627

Re: Black marks/stain in grain

That looks like staining due to a mix of iron and carbonate ions in your water reacting with the tannins in the wood (i.e. hard water plus iron plus tannins). A certain fix for that is to wash it down with a mild solution of oxalic acid in pure (de-ionised) water. Oxalic acid is available in crystal...
by Trevor Gore
Sun Jul 14, 2019 3:20 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 836

Re: opinion about my frequency spectra

You write that when you talk about characteristic frequencies T(1,1)1, T(1,1)2 and T(1,1)3 you mean the fully coupled frequencies. So I have to look at the unplugged spectrum. Yes. The "air" and back peaks easy to identify because they disappear in the plugged spectrum. In the unplugged spectrum I ...