Search found 29 matches

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: 523

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: 523

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: 523

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: 523

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: 769

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: 6
Views: 735

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: 6
Views: 735

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: 6
Views: 735

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: 6
Views: 735

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: 6
Views: 735

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: 6
Views: 735

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: 769

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: 769

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: 769

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: 769

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: 664

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: 1555

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: 1555

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...
by JurgenV
Thu Jul 11, 2019 8:41 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 1555

Re: opinion about my frequency spectra

Cladni testing could be a possibility but I have already given the guitar back to its owner :)
In addition I would have to start putting the equipment together as I didn´t start into this direction
by JurgenV
Thu Jul 11, 2019 4:51 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 1555

Re: opinion about my frequency spectra

Hmm, but that means I aleady have a T(1,1)3 with 214Hz as this is the peak which vanishes from the spectrum when the soundhole is plugged. So I have to raise the top frequency? Ok, I will check the peak positions of the unplugged spectrum as soon as I´m back form work and post the values. The top an...
by JurgenV
Thu Jul 11, 2019 5:56 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Excel spreadsheet and summary page
Replies: 2
Views: 981

Re: Excel spreadsheet and summary page

Hi Dave, I saw that you didn´t get an answer. I can give just give you my opinion: Actually I´m quite new to the books of Trevor and Gerard but I never heard about a simple summary. The thing is that you have to work through the math. You don´t have to understand all derivations for the different fo...
by JurgenV
Thu Jul 11, 2019 2:55 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 1555

Re: opinion about my frequency spectra

Hey Trevor, thanks a lot for the confirmation of my data. It does sound nice, but that doesn´t mean there´s nor space for improvement :) As I wanted to use this guitar as a test object I can try to aim for a back frequency you suggested. Btw. just to be sure: when you talk about the target frequenci...
by JurgenV
Tue Jul 09, 2019 4:38 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: opinion about my frequency spectra
Replies: 10
Views: 1555

opinion about my frequency spectra

Hi, it´s me again. I finally got my old guitar back from it´s new owner to do some frequency analysis and to check the values for the specific mobility. This was my second steel string build where everyone had been totally surprised when they heard I built it myself. And I never came near the sound ...
by JurgenV
Tue Jul 02, 2019 4:27 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Flexural rigidity & Co
Replies: 3
Views: 1161

Re: Flexural rigidity & Co

Thanks for your comments Trevor. This helps to get further. Concerning the braces with and without carbon fibre... yeah, I should have checked that first instead of just guesssing. According to my spreadsheet it´s around 0.6mm I would have to remove. With the MOR would guess one needs a good statist...
by JurgenV
Tue Jun 25, 2019 5:34 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Flexural rigidity & Co
Replies: 3
Views: 1161

Flexural rigidity & Co

Hi. I´ve got a question concerning flexural rigidity for falcate steel strings and classical. But first quite a long text to show that I most probably managed to get my spreadsheets working After a quite long break due to my job I continued work through the Book to start with the excel sheets for ta...