Search found 31 matches

by JamesO
Wed Nov 30, 2016 2:27 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: How to tap the coupled top and back
Replies: 3
Views: 2834

Re: How to tap the coupled top and back

Fantastic. Thanks, Trevor. :cl

I see the targets in the book. Should I aim for those targets without the neck and bridge on, or with the neck and bridge on? I had assumed that I should have the neck and bridge on.
by JamesO
Tue Nov 29, 2016 12:52 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: How to tap the coupled top and back
Replies: 3
Views: 2834

How to tap the coupled top and back

I have another Gore-method noobie question, guys. I'm ready to pore fill my current build and start the finish process. I've left the brace that spans the lower bout full height, and I'd like to begin the testing process so that I can sand in the notch and tune it appropriately. The Technical Note o...
by JamesO
Tue Nov 29, 2016 12:30 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Top Deflection rig
Replies: 37
Views: 17106

Re: Top Deflection rig

I'm trying to understand why and how we test top mobility, but I'm having trouble finding it in the table of contents in Design and Build. Can someone point me to it? Thanks. :oops:
by JamesO
Wed Feb 24, 2016 3:33 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Ervin Smoygi Books
Replies: 17
Views: 5646

Re: Ervin Smoygi Books

I don't see the forum either. I've had the books, but I let them go. I do miss them. I scanned a few pages, but if I had the extra money, I'd try to pick them up again. I don't remember them being earth-shattering, but I do believe Ervin is one of the best, and it would be great to have that little ...
by JamesO
Thu Feb 18, 2016 11:58 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Brace dimensions for live backs
Replies: 10
Views: 3983

Re: Brace dimensions for live backs

How strong does a back need to be? It's not taking much load! I've wondered this. Using a floating brace to connect the four ladder braces has become popular, and Rick Turner used carbon fiber to reinforce the arch of the back on a number of guitars, though I'm not sure if he still is. The purpose ...
by JamesO
Tue Feb 16, 2016 8:06 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Brace dimensions for live backs
Replies: 10
Views: 3983

Re: Brace dimensions for live backs

I like it! Thanks, Trevor. I noticed that scoop on the back you posted to my thread on the OLF, too (the thread regarding using different species for back joint reinforcement strips).
by JamesO
Tue Feb 16, 2016 8:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Measuring top and back frequencies while voicing
Replies: 21
Views: 7448

Re: Measuring top and back frequencies while voicing

Excellent. Thanks, Trevor. That actually makes it much simpler, too.
by JamesO
Sat Feb 13, 2016 6:05 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Brace dimensions for live backs
Replies: 10
Views: 3983

Re: Brace dimensions for live backs

I realized I'd been measuring the frequency incorrectly anyway. See here.
by JamesO
Sat Feb 13, 2016 5:54 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Measuring top and back frequencies while voicing
Replies: 21
Views: 7448

Measuring top and back frequencies while voicing

I was just going through the books to look for the process of measuring tops and backs while voicing. Build page 11-48, for example, gives a number of different measurements for a falcate braced top. Build 11-7 gives a rough target for a live back (rough because we know it needs to be four semi-tone...
by JamesO
Sat Feb 13, 2016 5:13 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Brace dimensions for live backs
Replies: 10
Views: 3983

Re: Brace dimensions for live backs

Thanks for being helpful as always, Martin. I ended up prepping some blanks a little over width yesterday, and nearly full height. They're 1.8cm tall x 1.2cm wide. I understand the implications of the cube rule and now the added width won't make up for the lost stiffness, but I'll give them a try.
by JamesO
Fri Feb 12, 2016 5:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Brace dimensions for live backs
Replies: 10
Views: 3983

Brace dimensions for live backs

Hi all! Going by the book, back braces for a live back should be 2cm tall x 1cm wide. After shaping mine ended up being 15mm tall x 1cm wide (5/8" in American terms). I planed them off before class this morning and plan to finish scraping off the residue this afternoon. My brace stock is .75" tall, ...
by JamesO
Fri Dec 18, 2015 6:04 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Radial back braces for live backs
Replies: 2
Views: 3127

Radial back braces for live backs

Howdy guys Getting ready to brace up a back. In Fig. 11-3 (Build), the radial braces are 115mm long, 50mm from the center of the third ladder brace, and according to the text on pg 11-7, should end about 10-15mm from the inside edge of the linings. So, should I make the brace however long it needs t...
by JamesO
Thu Dec 10, 2015 10:42 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Testing irregularly shaped tops and back
Replies: 1
Views: 1037

Testing irregularly shaped tops and back

I received a set of LS redwood today, but it's shaped a bit irregularly. I know this can be an issue with some back sets as well. It tapped well enough (an understatement). What do we do in these situations? Length: 535mm Width: 214mm Thickness: 4mm Weight: 212g Long: 82 hz Cross: 42 hz Twisting: 44...
by JamesO
Thu Dec 10, 2015 10:10 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Initial results from 14 tops and backs
Replies: 4
Views: 1530

Re: Initial results from 14 tops and backs

Actually, I'm sorry, Martin. I don't believe I do have the Youngs values. I thought I did, but they seem quite a bit higher than what you posted in the lutz thread. This is a screenshot of the calculator I'm using.
Screen Shot 2015-12-09 at 3.07.54 PM.png
by JamesO
Wed Dec 09, 2015 2:07 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Initial results from 14 tops and backs
Replies: 4
Views: 1530

Re: Initial results from 14 tops and backs

They're display on the calculator I'm using. How would I use them?
by JamesO
Wed Dec 09, 2015 5:59 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Initial results from 14 tops and backs
Replies: 4
Views: 1530

Initial results from 14 tops and backs

I'm enjoying the first tastes of freedom as I took my last fall exam last night. This morning I got to work testing 12 top sets and one set of koa with my new found ability to accurate get cross-grain results. I have an LS redwood top on the way that should be here within the next few days. Looking ...
by JamesO
Sun Dec 06, 2015 5:55 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

I'm doing a happy dance! Thank you. I was starting to feel like I'd never figure this out. Martin's tip to pinch closer to the center really did it. I'm looking forwarding to running through 10-12 tops next week (Sitka, Cedar, Redwood, LS Redwood), and I'll share my results. I'm particularly looking...
by JamesO
Sat Dec 05, 2015 11:26 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

Hi everyone I am clearly the issue. I received six new sitka tops yesterday. The plan was to test them using Trevor's method, then join and thickness them to get a range of deflection measurements as I work them all the way down to .075". The point is to see how deflection data corresponds with diff...
by JamesO
Sat Nov 07, 2015 6:26 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Altering the value of F
Replies: 1
Views: 1391

Altering the value of F

Hi all My apologies for not updating my results regarding the cross grain testing. I've made my mallet, but had an exam earlier this week and haven't done any re-testing yet. As I was driving around this week, thinking about this approach to building, a question came to mind. When we adjust the valu...
by JamesO
Fri Oct 30, 2015 5:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

Trevor Gore wrote:
JamesO wrote:I tried to hold the top right where the stars are in the book...
I hope that's just a typo. Hold on the dots, tap on the stars...
Ha! Yes, typo. Sorry. I got them mixed up. I held at the dot (node), tapped at the star (anti-node).
by JamesO
Thu Oct 29, 2015 12:04 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

Thanks for all of this, Martin :cl I've had a busy day today, so my apologies for not responding sooner. I'm finishing up a draft of a paper I'm writing with a professor and need to be done tomorrow morning. :shock: The Apogee MiC I'm using is a condensor mic with a built-in preamp. It's runs to the...
by JamesO
Wed Oct 28, 2015 1:28 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

James, I haven't got the books with me at the moment so I can't check but my recollection is that the point where you hold the board to generate the cross grain vibration is further from the edge of the board than indicated by your marks. I may be wrong but it's worth checking the books. Hey Woodsy...
by JamesO
Wed Oct 28, 2015 1:26 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

James, What wood are you testing? Ive got a library of tap tests on Swiss, Engleman and Sitka tops in my stash so should be able to pull up a screenshot of what you should be looking for. Also what hardware are you using? (ie mic, pre-amp? etc). Thanks for the help, guys. This is redwood, and I'm u...
by JamesO
Wed Oct 28, 2015 10:02 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Cross-grain tap test advice?
Replies: 29
Views: 8615

Re: Cross-grain tap test advice?

Cross is where I run into trouble. There isn't an obvious peak that jumps out as the leader. It seems like it could be 50-ish, 125-ish, or 175-ish. The clearest audio results were when I held it in positions 5 and 6, which correspond best with where that node should be as pictured in the book (Buil...