Search found 484 matches

by johnparchem
Wed Feb 17, 2021 12:49 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Monopole mobility again...!
Replies: 7
Views: 203

Re: Monopole mobility again...!

Sounding good is somewhat subjective. What do you like with the Martin that is missing in your guitar? It would be interesting to do a bit testing on the Martin, both spectrum and specific mobility to see if you can associate any difference to what you are hearing.
by johnparchem
Tue Feb 16, 2021 5:57 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Monopole mobility again...!
Replies: 7
Views: 203

Re: Monopole mobility again...!

No excel only a calculator

1kg = 9.81 N

I made a mistake the following is the correct calculation.
So in a calculator .. 9.81 / .16 = 81.75 X 1000 = K= 81750

mass = 81750 / (2 * 3.141 * 170)^2 = 0.07167 m(kg)

1 / square root (81750 * 0.07167) * 1000 = 13.064 In the range for a SS.
by johnparchem
Tue Feb 16, 2021 3:31 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Monopole mobility again...!
Replies: 7
Views: 203

Re: Monopole mobility again...!

Not from only those 2 measurements. You would also need the weight of the load used for the deflection. Do three calculations even with a calculator. K is the stiffness K is N/M so get your load into Newtons then divide that by your deflection times 100000 (turning your deflection into meters) get m...
by johnparchem
Sat Jan 30, 2021 11:55 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Intonation and Flamenco guitars
Replies: 4
Views: 388

Re: Intonation and Flamenco guitars

Thanks Trevor, I was overthinking it and missed the obvious. A simpler example for your point than either the capo or bar chord is fretting a string in two positions which is also normal. If I am fretting with my ring finger and place my index finger on the same string a couple of steps down the nec...
by johnparchem
Sat Jan 30, 2021 9:40 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Intonation and Flamenco guitars
Replies: 4
Views: 388

Re: Intonation and Flamenco guitars

I am no expert in compensation, but someone (don't remember who) mentioned something which I am still digesting. If you compensate the nut and you put a capo on a fret, the total length of the string is still shorter compared to a non compensated. So the nut compensation will make a difference with...
by johnparchem
Sat Jan 30, 2021 6:16 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Intonation and Flamenco guitars
Replies: 4
Views: 388

Intonation and Flamenco guitars

or Intonation and capos A flamenco player gave me a 650 scale Flamenco guitar that has really good flamenco tone, but with intonation problems. He had a luthier friend who worked on it and made it somewhat better, using the limited amount of saddle intonation available and removing some to all of th...
by johnparchem
Thu Jan 28, 2021 12:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Headstock - Ears or not
Replies: 4
Views: 299

Re: Headstock - Ears or not

I have done it both ways. If wide enough I generally do not add the ears. I do not mind showing the scarf on the sides. I did have one instrument where I added ears and I also managed to carefully place the back end of the scarf right under the volute. The headstock transition had a very clean look
by johnparchem
Mon Jan 18, 2021 7:12 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Plate target thickness of non rectangular plates using deflection testing
Replies: 11
Views: 4748

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

I did do the cross grain at exactly 5 cm but I picked 5 cm because I had that much. I was not following any guidance. We rely on the stiffness of wood at 6 mm wide when we use it for braces, so it seems like 30 mm or so should be OK.
by johnparchem
Mon Jan 18, 2021 1:16 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Plate target thickness of non rectangular plates using deflection testing
Replies: 11
Views: 4748

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

I would square up the upper bout and do a deflection test on the squared portion for the long grain. It seems like a deflection tests on a rectangular 3 cm strip should work. Use less mass for the deflection test. Or if you have sides from the same wood take a strip off one end of the sides. nonrec ...
by johnparchem
Tue Jan 12, 2021 8:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Richlite & primary bracing
Replies: 4
Views: 776

Re: Richlite & primary bracing

Hi, and happy new year! I have 2 questions 1. Has anybody tried Richlite for a bridge material ? Felt very light and should be strong enough, i guess. 2. Before i rabbet the part of the primary braces that goes over the bridgeplate, is there suppose to be space between the underside of the primary ...
by johnparchem
Sun Jan 10, 2021 1:26 am
Forum: Instrument Builders Forum
Topic: Yet another bracing issue...
Replies: 6
Views: 1288

Re: Yet another bracing issue...

The bracing looks fine to me. Under tension the neck is going to pull forward a bit. I even allow a millimeter at the saddle when I do calculation for string height from the top at the saddle when setting the neck angle. That normal movement under tension will reflect itself in the top as the neck b...
by johnparchem
Tue Dec 22, 2020 2:21 am
Forum: Instrument Builders Forum
Topic: Building a flamenco guitar
Replies: 9
Views: 1937

Re: Building a flamenco guitar

A great video I enjoyed watching and a fine looking guitar.
by johnparchem
Sat Nov 21, 2020 11:19 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bridge rotation too high... countermeasures?
Replies: 3
Views: 773

Re: Bridge rotation too high... countermeasures?

On some of my classical with tops close to 2 mm I can see the the main falcate braces through the top. I have not had over rotation of bridge, except one time I found the bridge was lifting off the top on the trailing edge.
by johnparchem
Sun Nov 15, 2020 4:03 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Collecting Spectrographic data
Replies: 62
Views: 47221

Re: Collecting Spectrographic data

I just reinstalled a version of visual analyzer and thought I would post what I had to do to get it to launch without errors. After running the setup exe in the file explorer in C:\Program Files (x86) I changed the properties of the folder visual analyzer -> security tab -> Users -> to full control....
by johnparchem
Sun Nov 01, 2020 11:59 pm
Forum: Instrument Builders Forum
Topic: Falcate Classical #2 Build (in NZ)
Replies: 5
Views: 1981

Re: Falcate Classical #2 Build (in NZ)

Nice, I love the rosette design. I have yet to make my own classical style rosette. Are you showing how it looks when all are stacked during installation or is that one, two or three tiles?
by johnparchem
Sun Nov 01, 2020 11:44 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 1. falcate braced classical
Replies: 17
Views: 7683

Re: 1. falcate braced classical

Jurgen, It looks like your classical falcate braces worked out. What attributes of the sound seem different? My falcate guitars all have a characteristic sound that includes long sustain, clarity of each note played and a balance across the strings. Richard, I personally am happy if I have some brid...
by johnparchem
Sun Nov 01, 2020 3:07 am
Forum: Instrument Builders Forum
Topic: Double V Neck Acoustic
Replies: 23
Views: 11369

Re: Double V Neck Acoustic

Wow, amazing that you built it and really good work in the construction. It seems like it would be a bit awkwards to play, unless there was a right and left hand couple playing it together.
by johnparchem
Tue Oct 20, 2020 3:26 am
Forum: Instrument Builders Forum
Topic: Fretting, Michael Bashkin
Replies: 2
Views: 1471

Re: Fretting, Michael Bashkin

I have it and I agree with your assessment. Well worth it.
by johnparchem
Tue Oct 20, 2020 12:06 am
Forum: Instrument Builders Forum
Topic: Wood bending fail - looking for advice
Replies: 11
Views: 2385

Re: Wood bending fail - looking for advice

I also bend as hot as my iron goes. I have found as you mentioned the wood becomes plastic relatively quickly with a very hot iron. I have also found it possible to cook the the wood such that it takes a rather brittle set. There is a lot of gluing service so you may be able to use CA. A fix might n...
by johnparchem
Sat Sep 12, 2020 11:52 pm
Forum: Instrument Builders Forum
Topic: Guitar bridge as a brace
Replies: 4
Views: 1818

Re: Guitar bridge as a brace

Adding the bridge to my falcate braced classical guitars without a lower transverse brace raises the top frequency (T(1,1)2) nearly 10 Hz. My bridges are generally around 18 grams. So the bridge in this case has added enough stiffness to the top to more than make up for the added mass. I haven't use...
by johnparchem
Sun Aug 30, 2020 11:15 am
Forum: Instrument Builders Forum
Topic: french polishing courses/tutorials?
Replies: 7
Views: 1735

Re: french polishing courses/tutorials?

Robbie has a French Polish online course; it is much like the Milburn method but optimised. The best FP finishes I have seen are not really French Polished. It is the slow application of shellac with a FP like pad (no oil) over some weeks. The surface is leveled every day or couple of days. When the...
by johnparchem
Fri Aug 07, 2020 3:49 am
Forum: Instrument Builders Forum
Topic: Removing Lacquer
Replies: 8
Views: 1777

Re: Removing Lacquer

A respirator, good ventilation and lacquer thinner or stripper?
by johnparchem
Sat May 23, 2020 12:46 pm
Forum: Instrument Builders Forum
Topic: Test post
Replies: 9
Views: 3149

Re: Test post

kiwigeo wrote:
Sat May 23, 2020 11:33 am
[youtube]https://www.youtube.com/watch?v=JBM5r5WnPOs[/youtube]

You still need to to it like this

Code: Select all

[youtube]JBM5r5WnPOs[/youtube]




youtu.be/JBM5r5WnPOs