Search found 435 matches

by johnparchem
Tue Jan 07, 2020 3:17 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA plots for tap test on plates
Replies: 13
Views: 1050

Re: VA plots for tap test on plates

Thanks John. Having identified the better tops i have now started on the sides as i want to be in a position to use the top or back as soon as its built. Auckland has permanently high humidity so i don't like leaving the plates hanging around for too long. If you don't mind me asking, for the brace...
by johnparchem
Sun Jan 05, 2020 10:52 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA plots for tap test on plates
Replies: 13
Views: 1050

Re: VA plots for tap test on plates

I would do what you did and put an average value or 1 for the 6.9 for the G for plate ls002. Your results will be a lot close to correct and make for a better comparison. With that low cross grain stiffness the fdiag might be really low.
by johnparchem
Sun Dec 29, 2019 1:01 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Unusual Panal Size
Replies: 5
Views: 380

Re: Unusual Panal Size

I just had to do this, and I posted the steps I took earlier this month. I at least tried to use the information from the Book. Link: viewtopic.php?f=33&t=8707
by johnparchem
Mon Dec 09, 2019 4:34 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Spectrum change with age
Replies: 5
Views: 707

Re: Spectrum change with age

I noticed that the resonance frequency shift with changes in the string height off the top in the saddle position. So if you ever needed to adjust the action, you might see a change.
by johnparchem
Sat Dec 07, 2019 10:57 am
Forum: Instrument Builders Forum
Topic: First Flamenco Guitar.
Replies: 6
Views: 2460

Re: First Flamenco Guitar.

I did a bit more analysis of the guitar after having it for 4 months. All of the flamenco players that have tried it have been shock at its sound. I watched them go from skeptical to slightly interested when they felt how light the guitar was, to very engaged when they started playing and spending a...
by johnparchem
Sat Dec 07, 2019 10:51 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Plate target thickness of non rectangular plates using deflection testing
Replies: 2
Views: 333

Re: Plate target thickness of non rectangular plates using deflection testing

I am trying to match my results from my first Flamenco. It is an amazing sounding instrument. All of the flamenco players that have tried it have been shock at its sound. I watched them go from skeptical to slightly interested when they felt how light the guitar was, to very engaged when they starte...
by johnparchem
Fri Dec 06, 2019 5:41 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Plate target thickness of non rectangular plates using deflection testing
Replies: 2
Views: 333

Plate target thickness of non rectangular plates using deflection testing

I am starting a new flamenco blanca guitar with spanish cypress back and sides. The Gore plate thicknessing method using tap tones as described The Book requires evenly thicknessed rectangular plates. Often times with nice back and side sets the plates are non rectangular taking advantage of the fac...
by johnparchem
Sat Nov 23, 2019 4:40 am
Forum: Instrument Builders Forum
Topic: Bending Sides issue
Replies: 17
Views: 1839

Re: Bending Sides issue

I bend both on a fox style and a bending iron. I never soak the wood, rather I lightly spritz it with the goal of initially quickening the heat transfer into the wood. On a pipe I like to bend very hot with only a light spritz, I always thought that wet wood would try to limit the temperature in the...
by johnparchem
Fri Nov 15, 2019 2:38 am
Forum: Instrument Builders Forum
Topic: Amateur mess up, do I start over or make raised fretboard...
Replies: 6
Views: 927

Re: Amateur mess up, do I start over or make raised fretboard...

First off, when sanding it is really easy to take more off the edges than the center. One has to fight it and check constantly. This issue exists for sanding straight or sanding with a radius board. I think that the friction of sanding tends to place a downward force on the leading edge of the sandi...
by johnparchem
Wed Oct 16, 2019 9:51 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Classical Bridges using CF
Replies: 16
Views: 1723

Re: Classical Bridges using CF

I machine the bridge blanks on a small micromill. The CF presented no problems. I wear a dust mask. I use 3K 5.7 oz plain weave fabric. (Sorry about the imperial measurement.)
by johnparchem
Wed Oct 16, 2019 2:19 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Classical Bridges using CF
Replies: 16
Views: 1723

Re: Classical Bridges using CF

I take some from the top and some from the bottom (including the radius) until I get the thickness that I want. I am considering simplifying my classical bridges. Like the steel string I will include a 1mm bridge patch and a layer of CF fabric under the the braces. When I make the bridge I will sand...
by johnparchem
Sun Oct 13, 2019 8:55 am
Forum: Instrument Builders Forum
Topic: First Flamenco Guitar.
Replies: 6
Views: 2460

Re: First Flamenco Guitar.

Thanks guy! The guitar was French Polished. I have been spending a bunch of time learning how to sort of play Flamenco guitar. I might find a real teacher.
by johnparchem
Wed Aug 28, 2019 9:36 am
Forum: Instrument Builders Forum
Topic: First Flamenco Guitar.
Replies: 6
Views: 2460

First Flamenco Guitar.

This is my first Flamenco Guitar built following the Paco Chorobo video class offered by Robbie O'Brien. It was a fun course to follow as it include a lot of slide visits and interviews in the Spanish flamenco community. Paco Chorobo is an outstanding flamenco guitar builder and a wonderful flamenco...
by johnparchem
Thu Aug 08, 2019 12:48 pm
Forum: Instrument Builders Forum
Topic: Finish (shellac?) repair suggestions on Spanish classical
Replies: 8
Views: 2038

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

I have never seen that with shellac even from heat. It seems like on the way to refinishing you can try and sand it out. I have used behlem qualasole for repairs on top as it sticks to nearly anything and can be padded on. I have done whole tops with it and it builds quickly and looks great. I think...
by johnparchem
Thu Aug 01, 2019 6:41 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA, opening saved files
Replies: 7
Views: 1250

Re: VA, opening saved files

Whoops,

you can always hit the capture spectrom button and after the buffer fills it will open a window that should allow you to open a file. That is one of the ways I get a window.
by johnparchem
Thu Aug 01, 2019 2:25 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: VA, opening saved files
Replies: 7
Views: 1250

Re: VA, opening saved files

If you want to open a .tee file (waveform) On the bottom right hand control panel, I select the more tab and then spectrum.
va file open 2.JPG
va file open.JPG
va file open.JPG (23.21 KiB) Viewed 1243 times
by johnparchem
Sun Jul 28, 2019 2:09 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Advice on Resonances
Replies: 7
Views: 1428

Re: Advice on Resonances

In general do not look at the amplitude of the peak as your test setup really is not accurate in terms of relative peak amplitude. It is really showing you the locations of the resonances on the frequency spectrum. The resonance frequency values and bridge rotation are better indicators of stiffness...
by johnparchem
Sat Jun 22, 2019 11:27 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Gore method/Tap tune/Siminoff...help!
Replies: 13
Views: 2494

Re: Gore method/Tap tune/Siminoff...help!

I have a bit of trouble answering a question about "the Gore method" as I think it mischaracterizes the Design volume as it is not a method book. Also the Design volume is not about "Gore type guitars". What is taught in that volume has a lot more inclusive has more depth and is more applicable than...
by johnparchem
Sat Jun 22, 2019 12:32 am
Forum: Instrument Builders Forum
Topic: Guitar top and back radius position
Replies: 13
Views: 4020

Re: Guitar top and back radius position

If the side template\profile is correct and the are sides cut very close to the profile and the waist is bent in the correct place, one can have the sides very close to the correct size and radius with minimal sanding by driving the bus.
by johnparchem
Fri Jun 21, 2019 7:30 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Gore method/Tap tune/Siminoff...help!
Replies: 13
Views: 2494

Re: Gore method/Tap tune/Siminoff...help!

Thanks for your comments on the website. As you see I photo document all of my projects. I think that a lot of the big (factory) boys, have a bunch of parts made to pretty exact dimensions and assembles guitars from those parts in a constant way. The parts are probably sized to hit the center of the...
by johnparchem
Thu Jun 20, 2019 8:57 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Gore method/Tap tune/Siminoff...help!
Replies: 13
Views: 2494

Re: Gore method/Tap tune/Siminoff...help!

When I read your three choices, from your descriptions it seems like there is only one choice. "1". I never understand when i hear that Siminoff is more doable than processes in The Book. I read 'The art of tap tuning" and watched the DVD that came with it. There is no prescriptive method and in the...
by johnparchem
Mon Apr 29, 2019 12:07 am
Forum: Instrument Builders Forum
Topic: Finished Pernambuco/WRC contemporary classical guitar.
Replies: 4
Views: 1366

Re: Finished Pernambuco/WRC contemporary classical guitar.

Here is a video my guitar instructor Doug Rice tring this guitar. His main guitar now is one of my falcate classical guitars. Here is his description of the sound he hears from this falcate bracing pattern. " Their superb basic tone color and resonance, especially their high overtones presented a ha...
by johnparchem
Sat Apr 20, 2019 6:45 am
Forum: Instrument Builders Forum
Topic: Finished Pernambuco/WRC contemporary classical guitar.
Replies: 4
Views: 1366

Re: Finished Pernambuco/WRC contemporary classical guitar.

I do have spectrum graphs of the tap for this and the Osage Orange guitar I posted last week. You will see they are very close. The Pernambuco has a sound port which accounted for the higher Air resonance. I am not sure what the cutaway does to the air resonance T(1,1)1, I do know the sound port wou...
by johnparchem
Fri Apr 19, 2019 9:14 am
Forum: Instrument Builders Forum
Topic: Finished Pernambuco/WRC contemporary classical guitar.
Replies: 4
Views: 1366

Finished Pernambuco/WRC contemporary classical guitar.

My last complete instrument for a short time (I promise.) It is just that I had two going on and the scheduled Ukulele class. In any case this is a "Contemporary Classical" Guitar. I get it, an oxymoron. The basic body shape is a Hauser 37 with the cutaway added. The contemporary features are a bolt...
by johnparchem
Tue Apr 16, 2019 9:52 am
Forum: Instrument Builders Forum
Topic: Acoustical effect of back woods
Replies: 25
Views: 5337

Re: Acoustical effect of back woods

I held off giving my own from my hind side comments on blind listening tests mainly because of where I am pulling them from. Here goes ... Part of the context for my point is that humans are not like a microphone and a computer, we do not hear reality rather we have learned through evolution and in ...