Search found 1481 matches

by Trevor Gore
Wed Nov 06, 2019 9:48 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 714

Re: Bridge Rotation at 2.3deg

John, do the before and after tap responses tell you any more about what changes happened?
by Trevor Gore
Mon Nov 04, 2019 9:24 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum results
Replies: 3
Views: 197

Re: Spectrum results

Good to hear it all worked out. Well done!
by Trevor Gore
Sun Nov 03, 2019 10:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: My Second Build
Replies: 12
Views: 657

Re: My Second Build

Your bridge looks the same size as mine (presumably made off the book drawings). Mine stay on! Them peeling off is as much about the bridge plate design as it is about the glue area, and you have the standard falcate bridge plate.
by Trevor Gore
Sat Nov 02, 2019 10:32 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum results
Replies: 3
Views: 197

Re: Spectrum results

95,170, 214 is a great result. Carving the back brace to reduce the T(1,1)1 and T(1,1)2 sufficiently will bring the T(1,1)3 down way too far and cause acoustics problems that you don't need because you no longer have the 4 semitone separation. Stringing up will possibly drop the T(1,1)2 a little bec...
by Trevor Gore
Mon Oct 28, 2019 8:25 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 714

Re: Bridge Rotation at 2.3deg

I haven't spoken to Charles about a future class. Maybe an idea for another occasion!
by Trevor Gore
Sun Oct 27, 2019 10:14 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 714

Re: Bridge Rotation at 2.3deg

Eric, there's the possibility of another class at Robbie's 10/11/12 Jul 2020. Please contact Robbie if you're interested.
by Trevor Gore
Sat Oct 26, 2019 10:30 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 714

Re: Bridge Rotation at 2.3deg

My rotation ended up at 1.3 degrees... Let me refer you to this post from a while back: http://www.anzlf.com/viewtopic.php?f=33&t=6321&p=71613#p71613 Don't get too hung up on the bridge rotation if the modal frequencies and the monopole mobility are right. However, if the modal frequecnies are too ...
by Trevor Gore
Sat Oct 26, 2019 10:09 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: saddle location
Replies: 4
Views: 211

Re: saddle location

The problem I find is that leaving only1.2mm on the back of the saddle, 6th string, tends to lead to too much crushing and wear on the saddle, especially if Tusq is used. Obviously this is also a problem when using the traditional narrow saddle. As the contact point only ever moves forward as the br...
by Trevor Gore
Fri Oct 25, 2019 4:01 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: saddle location
Replies: 4
Views: 211

Re: saddle location

What am I missing? ...that I say in the last two lines of para 2 Section 20.3.2 (both editions) that you work it out for the string that has the shortest distance (typically the first string). The longest distance is typically ~ 3mm more, so that gives you ~2mm "land" of saddle on a 5mm saddle for ...
by Trevor Gore
Fri Oct 25, 2019 3:33 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge Rotation at 2.3deg
Replies: 15
Views: 714

Re: Bridge Rotation at 2.3deg

John, I've seen some seriously "roller-coaster" tops that have sounded fine, so that in and of itself doesn't appear to be sufficient criteria for less-than-best sound quality. Similarly, "print through" of the bracing pattern is pretty normal on highly responsive guitars. One of the things that I'v...
by Trevor Gore
Wed Oct 23, 2019 8:22 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: My Second Build
Replies: 12
Views: 657

Re: My Second Build

DavidS wrote:
Tue Oct 22, 2019 8:09 pm
I am trying to figure out whether I am going to be able to achieve a finished T(1,1)2 close enough to 170Hz given I am starting at 180hz closed box.
Provided you remove very little wood on binding and clean-up and use a very low mass bridge (< 15 gms), you should be close.
by Trevor Gore
Sun Oct 20, 2019 10:12 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 299

Re: Paulownia fas bridge material?

The Paulownia I've had is only one step removed from balsa and quite soft. I doubt it would hold up using the designs in the books. With some very cunning design work it might work, but I suspect some pretty complicated manufacturing would be required.
by Trevor Gore
Wed Oct 16, 2019 9:08 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Classical Bridges using CF
Replies: 16
Views: 795

Re: Classical Bridges using CF

... Dimensions Fig 20-2 in the Build volume shows typical dimensions for the classical bridge with the height at 8mm Section 20.2 discusses the make up of the bridge and calls for three wood plies of 2,3 and 4mm thickness with two layers of CF between these plies. I haven't got the CF yet but it pr...
by Trevor Gore
Tue Oct 08, 2019 8:51 am
Forum: Instrument Builders Forum
Topic: RIP Graham Caldersmith
Replies: 3
Views: 666

Re: RIP Graham Caldersmith

Sad news indeed. Graham was a pioneers in musical acoustics and guitar function, starting as an academic with a PhD in physics before moving to instrument making. One of the finest classical guitars I ever heard was one of Graham's. As Peter mentioned, a lot of the procedures and concepts in the boo...
by Trevor Gore
Sun Oct 06, 2019 12:37 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 553

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

It is almost impossible for me to determine what is going on from the pictures, but I suspect that some type of dipole activity was excited when you tapped with the back mass added; either because of the way you tapped on that occasion, or because the added back mass precipitated that type of respon...
by Trevor Gore
Sun Oct 06, 2019 12:24 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Tertiary braces -- need for carbon fiber?
Replies: 2
Views: 445

Re: Tertiary braces -- need for carbon fiber?

I have always put CF above and below all the braces. That doesn't mean that you have to...
by Trevor Gore
Sun Oct 06, 2019 12:21 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 6
Views: 522

Re: cosed box Frequency response falcate OOO

Sorry for the delay in responding. I've been overseas. A couple of things: Remember that the T(1,1)3 is the back response as seen in the top, rather than just the back response. So if the top is too stiff, which may happen with X bracing, you might not see much by way of the T(1,1)3 because of that....
by Trevor Gore
Sun Oct 06, 2019 12:05 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Case for 000
Replies: 2
Views: 247

Re: Case for 000

The medium sized steel string (as per the plans in the book) fits into a Hiscox OM case.
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: 504

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: 6
Views: 553

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: 467

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: 496

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: 587

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: 430

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: 2262

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.