Search found 36 matches

by JurgenV
Sat Mar 28, 2020 1:07 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 1. falcate braced classical
Replies: 4
Views: 503

Re: 1. falcate braced classical

Ok, old top off, new top on. Actually easier than I thought. Thanks the advice Jim. New values after binding and sanding: T(1,1)1= 90Hz T(1,1)2=195Hz T(1,1)3= 244Hz I had been wondering why the T(1,1)1 is so low until I checked the diameter of the soundhole... Great! Instead of 85mm I have just 79mm...
by JurgenV
Wed Mar 18, 2020 4:59 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 1. falcate braced classical
Replies: 4
Views: 503

1. falcate braced classical

After my actually quite nice results with a steel string falcate braced 000 style guitar I thought I can easily adapt a classical guitar to falcate bracing. Little did I know :) I should have believed John Parchem build description and stayed with the bracing height for steel strings. What I did was...
by JurgenV
Wed Mar 18, 2020 4:45 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

The answer is not easy. Depends strongly who you ask. In the mean time I had someone else try both of them and this guy preferred the x-brace a lot more than the falcate. How do you describe sound with words. I always had problems with that. Both sound quite open, you don´t have this boxed in sound....
by JurgenV
Sun Feb 02, 2020 8:23 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

Actually this is up to now the longest time it took me to finish a guitar. Problems at the company when they had been firing 500 people and then when the rest had to do the same work as before. Building some additional jigs. Girlfriend breaking up with me also didn´t increase the mood for guitar bui...
by JurgenV
Tue Jan 21, 2020 5:02 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: compensation spreadsheet question
Replies: 5
Views: 1933

Re: compensation spreadsheet question

The jig is more or less the same as described in the book on page 4-107: plank of wood with a bolt and screw on one side to hold the string and a pulley on the other side. Distance between the locking nut and the bridge is 650mm and at middle there is a hinged fret. For the compensation calculation ...
by JurgenV
Tue Jan 21, 2020 6:14 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: compensation spreadsheet question
Replies: 5
Views: 1933

Re: compensation spreadsheet question

Thanks Jeff. Yepp, you´re right. It had been a year ago when I put the spreadsheet together so I just mixed it up. I found one more mistake: at one point I used the wrong unit (m^2 instead of ^2). To get more stable measurements I played a bit around with g-tune: with a higher sensitivity setting an...
by JurgenV
Sun Jan 12, 2020 6:29 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: compensation spreadsheet question
Replies: 5
Views: 1933

compensation spreadsheet question

A year ago I started with my compensation spreadsheet. I stopped when the optimization seemed to work with some data I found in the forum thanks to woodsy23 (Richard). The last few days I tried to get the complete calculation including string stiffness measurements and neck curve model running. It l...
by JurgenV
Wed Oct 23, 2019 8:13 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 2113

Re: Paulownia fas bridge material?

With the Padouk Ißm down to 18.6gr. Should be fine
by JurgenV
Mon Oct 21, 2019 4:39 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 2113

Re: Paulownia fas bridge material?

Thank you for the fast reply Trevor.
Means I can save my time and leave this wood for some other project (whatever that will be). Let´s see how far down I will get the weight of the padouk bridge.
by JurgenV
Sun Oct 20, 2019 7:00 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 2113

Re: Paulownia fas bridge material?

is there any way of correcting the text or title of a posted thread?
That´s already the second time I made a mistake in the title and couldn´t find a way to correct it
by JurgenV
Sun Oct 20, 2019 4:35 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Paulownia fas bridge material?
Replies: 5
Views: 2113

Paulownia fas bridge material?

I wasn´t sure if I should start a new thread for this or if I should post in the old thread with the two OOO I´m building. I had some problems to get the weight of my bridge under 23gr with my walnut blank so I ordered Padouk at my wood supplier. I asked for a blank with low density and explained to...
by JurgenV
Tue Oct 15, 2019 5:56 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 2314

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

Hi Trevor, I finally got to check this one again: I hadn´t been able to reproduce the spectrum. This time I stuck the coins from the outside to the back as I was a bit lazy to loosen the strings so that I could put them inside the guitar. I hope that doesn´t make a big difference otherwise I can rep...
by JurgenV
Sun Oct 06, 2019 9:48 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

Did the test with the added mass to the back and ended up with a drop of 2Hz in T(1,1)2 when I adjusted the T(1,1)3 to 214Hz. So I think the lighter bridge could do the work. With the x-brace I´m a bit confused. I get a value that seems too high. The deflection is quite high according to my jig. As ...
by JurgenV
Sun Oct 06, 2019 8:00 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

Thanks Trevor. I will have a look at the two bridges and see if I can get the weight a bit further down. The density of the walnut I used is around 655 kg/m3. Somewhere you posted a range of 550-650kg/m3 for the walnut you are using, so that would be at the upper end. But at the moment I don´t have ...
by JurgenV
Tue Oct 01, 2019 4:45 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

ohh. Correction: x-braced OOO: T(1,1)1 = 99.5Hz T(1,1)2= 202.7Hz T(1,1)3= 226.4Hz I forgot to say that the binding data was taken before scraping the binding and before sanding. After the final sanding there are further changes in the spectra of both guitars. I put in a graph which shows the changes...
by JurgenV
Sun Sep 29, 2019 8:15 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

Ok, I finished the binding yesterday during the night. Hmm actually it had been morning when I finished (1:30am). I should really think about doing something else instead of tinkering with guitars... Ok, here are the results for the x-braced OOO: binding x-brace OOO.JPG T(1,1)1 = 99.5Hz T(1,1)2= 193...
by JurgenV
Sat Sep 28, 2019 2:16 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

Re: cosed box Frequency response falcate OOO

Ok, finally closed the x-braced OOO as well. As I promised here´s the next spectrum: closed box x-brace OOO.JPG Actually I had to shave the braces because the top frequency had been quite high. I think I miscalculated the height of the braces. Next time I should take more care to check the wood prop...
by JurgenV
Wed Sep 25, 2019 6:37 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: cosed box Frequency response falcate OOO
Replies: 10
Views: 3158

cosed box Frequency response falcate OOO

Hi, it´s me again. This time again some frequency spectra. I finally managed to close the box of my falcate steelstring OOO version, trimmed the back and top and couldn´t wait to see the spectrum. Here it is: closed box falcate OOO.JPG My peak detection excel sheet finds 7 peaks in the range from 10...
by JurgenV
Sat Sep 21, 2019 8:16 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 2314

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

Ok, I have some pictures to show. First Chladni experiments in my life and most probably not very helpful. I actually checked with all three cases: without mass mass at the sides mass at the back at and around the resonance frequencies from the spectra 52gr at sides: 106Hz: 52gr at side 106Hz.jpg 19...
by JurgenV
Tue Sep 17, 2019 7:15 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 2314

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

As soon as I´m back from my business trip I´ll try to put something together. Up to now I don´t have anything to do a chladni analysis. So it may take a while.
by JurgenV
Mon Sep 16, 2019 2:11 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 2314

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

I forgot to include a picture. As you can see nothing fancy but still ...
gs mini.jpg
by JurgenV
Mon Sep 16, 2019 1:59 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Frequency analysis GS Mini style build: improvement possible ?
Replies: 6
Views: 2314

Frequency analysis GS Mini style build: improvement possible ?

As at the moment the humidity rose by 10% to 56% I am at the moment blocked. with my two experimental builds I´m at the stage where I could start closing the box but looks like I have to wait a few more days. This led to a situation where I had too much time while being in guitar mode. So I started ...
by JurgenV
Sat Aug 31, 2019 6:09 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: OOO without scallopping and live back
Replies: 1
Views: 1921

OOO without scallopping and live back

Hi again, I finally started with my two experimental builds. One will be a falcate braced OOO and the other one a x-braced OOO where I aim for the frequency response of a guitar I built earlier. Here I will change from the original scalloped bracing to straight braces as they are used for the J45 in...
by JurgenV
Fri Jul 12, 2019 7:50 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 3488

Re: opinion about my frequency spectra

Hi Trevor, I fear I might get annoying but I´m a bit confused so I need to ask to get the spectrum interpretation the next time right: 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...
by JurgenV
Fri Jul 12, 2019 3:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 3488

Re: opinion about my frequency spectra

Ok, finally back form work. If Trevor always refers to the fully coupled frequencies the numbers actually are no longer as good... the unplugged spectrum with the peak positions: top_va_spec_pos.JPG In this case I´m not only a few Hz too low. 162.5Hz for T(1,1)2 and 215Hz for T(1,1)3 doesn´t sound s...