Search found 391 matches

by johnparchem
Mon Jan 14, 2019 2:18 am
Forum: Instrument Builders Forum
Topic: Disaster I think
Replies: 4
Views: 345

Re: Disaster I think

I could not see that it was cracking the finish. If it was cracking at all the finish would be cracked. I just had a very figured cocobolo back this did move not even crack on a grain line and it open a finish crack. I refinished but told the owner that the finish my crack there again.
by johnparchem
Thu Dec 06, 2018 12:39 pm
Forum: Instrument Builders Forum
Topic: Disaster?
Replies: 15
Views: 1250

Re: Disaster?

I think you are good; whats a thin strip of top relative to the mass of the bridge? Just a thought, if you are OK with the current width of the saddle slot, glue in a strip of rosewood just thick enough to give you the correct slot depth into the slot. Then there is no need to reroute. You have it e...
by johnparchem
Fri Nov 30, 2018 11:58 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Prototype Gore Guitar Freq Request
Replies: 21
Views: 2799

Re: Prototype Gore Guitar Freq Request

The guitar looks great and I bet it has a good voice as well. I just round the end of my fret boards off short of the 19th fret.
by johnparchem
Tue Nov 13, 2018 12:45 am
Forum: Instrument Builders Forum
Topic: Acacia dread build thread
Replies: 109
Views: 7303

Re: Acacia dread build thread

The acacia top looks great, I never thought to use a flush cut saw like you did on the purflings. This will be a fun guitar build to watch.
by johnparchem
Sun Nov 11, 2018 8:42 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

Re: 8 String bocote falcate braced nylon string crossover guitar

Thanks guys! ... I shall certainly try your technique. Dave make sure you check out Greven's description as well. http://www.grevenguitars.com/retopping-demo.html the source I used for the process. Today I handed the guitar off to the young guitarist who had me build it. He was thrilled, he may perf...
by johnparchem
Sat Nov 10, 2018 4:40 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Falcate #2 Tapping Results
Replies: 8
Views: 592

Re: Falcate #2 Tapping Results

... I think my main focus with this guitar is that the back be as "live" and resonant as I can make it. What are some hallmarks of a truly live back? Higher dB on the T(1,1)3? Thanks again for all the help! Chris To me it is the way it couples with the top also I get a much more complex final tap s...
by johnparchem
Sat Nov 10, 2018 1:54 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Falcate #2 Tapping Results
Replies: 8
Views: 592

Re: Falcate #2 Tapping Results

I am with Martin, I would not touch anything now until you see where you are at with the guitar strung up. On my classical guitars the top resonance goes up a bit when I glue on the bridge and down a bit when I string up the guitar, so not a big change from the point you are at. On my steel strings ...
by johnparchem
Fri Nov 09, 2018 10:23 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

Re: 8 String bocote falcate braced nylon string crossover guitar

Thank you for the previous kind comments I am FINALLY ready to deliver this guitar Saturday. I finished the top with post catalyzed Royal Lac sprayed on top of a shellac wash coat. I originally French Polished with an amber shellac hoping to give the instrument an older feel to it but I hated the co...
by johnparchem
Wed Oct 17, 2018 4:45 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 3 piece pernambuco back
Replies: 6
Views: 1309

Re: 3 piece pernambuco back

John, I am assuming you're going for a live back because you're computing a target panel thickness. Check what the back panel mass will turn out to be and then compare that with other live back guitars you have made. I'm suspecting that the pernambuco might be too dense and therefore have too low a...
by johnparchem
Sat Oct 13, 2018 9:34 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 3 piece pernambuco back
Replies: 6
Views: 1309

Re: 3 piece pernambuco back

Thanks Simon, those posts were really helpful as I like the way Jim laid out the three piece back.
by johnparchem
Fri Oct 12, 2018 3:53 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 3 piece pernambuco back
Replies: 6
Views: 1309

3 piece pernambuco back

I am making a new classical guitar with pernambuco sent to me by my client. I have never used it before. I need to make a three piece back as you can see in the picture. pernambuco.jpg I tap tested the wood as I was getting very clean tap tones. I have not tried it on this narrow of a piece. I could...
by johnparchem
Wed Oct 03, 2018 1:32 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Three Random Questions
Replies: 3
Views: 459

Re: Three Random Questions

I built a falcate braced 14 fret to the body Martinish 00 on commission. The owner loves the sound and has recently bought a falcate brace classical guitar of mine as well. I like the the deep or more full bass sounds that I get from 12 fret joins. I tried to talk him into the 12 fret but all of his...
by johnparchem
Mon Aug 27, 2018 3:38 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

Re: 8 String bocote falcate braced nylon string crossover guitar

John, That looks great! How were you able to drop the main air that low? I'm primarily building with a Hauser plantilla and my air resonance is usually around 102 HZ and I would like to drop it some. Looking at Trevor's sensitivity analysis it looks like sound hole diameter and back stiffness are m...
by johnparchem
Fri Jul 06, 2018 8:05 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

Re: 8 String bocote falcate braced nylon string crossover guitar

As always nice looking work John. As always I am interested in the falcate bracing. You presumably beefed it up a bit for the extra strings so I wonder what height you ended up with? I wonder if you have had time yet to look at resonant frequencies, and perhaps particularly with this one, the bridg...
by johnparchem
Fri Jul 06, 2018 6:35 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

Re: 8 String bocote falcate braced nylon string crossover guitar

Thanks Mark, The neck wood is mahogany, I think the light hit it funny in the picture. I build for a customer, but take no deposits. My thoughts are I will try and if I succeed and they still like it they can buy it. If not well it was just like a private build. It has been awhile but she is all str...
by johnparchem
Sun Jun 03, 2018 6:05 am
Forum: Instrument Builders Forum
Topic: 8 String bocote falcate braced nylon string crossover guitar
Replies: 17
Views: 2415

8 String bocote falcate braced nylon string crossover guitar

I am ready to start cleanup and finish prep on this Bocote\Lutz spruce 8 string crossover commision. The 2 extra strings will be bass strings. I will have to play to see how low to go. The player would like to go down in fourths from the low E. I know I can make the 7th string a D and the 8 string a...
by johnparchem
Fri May 04, 2018 6:23 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Measuring top and back frequencies while voicing
Replies: 21
Views: 9009

Re: Measuring top and back frequencies while voicing

I am not sure it is Q, but when I took a voicing class from Jeffery Elliott a Portland Oregon classical guitar builder, he taught that he consistently thicknesses all of his top spruce panels for evaluation. Then on tapping he wanted to hear it ring for 5 seconds. It seems like the sustain would be ...
by johnparchem
Sun Apr 15, 2018 3:31 am
Forum: Instrument Builders Forum
Topic: Australian Guitar Making School - Students blog
Replies: 4
Views: 1169

Re: Australian Guitar Making School - Students blog

Nice work on this guitar. It was interesting to see it built on a work board instead of an outside mold.
by johnparchem
Wed Feb 07, 2018 11:44 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: falcate Failure with an unexpected result
Replies: 22
Views: 9763

Re: falcate Failure with an unexpected result

I was feeling groovy, All and all it was a easier process. When I carved away parts of the braces I found no gap between the brace and the CF or the CF and the top.
by johnparchem
Sun Feb 04, 2018 8:24 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: falcate Failure with an unexpected result
Replies: 22
Views: 9763

Re: falcate Failure with an unexpected result

On my latest guitar I am slotting the bottom of the falcate braces for the carbon fiber. It really made the glue up process go a lot better for me. At the Guild of American Luthier auction I bought a router base\table called the Otter by the maker of Luthiers friend. http://www.luthiersfriend.com/aO...
by johnparchem
Sat Jan 27, 2018 8:04 am
Forum: Instrument Builders Forum
Topic: Audio comparison of 2 falcate SS and an X brace all mine.
Replies: 1
Views: 709

Re: Audio comparison of 2 falcate SS and an X brace all mine.

Too much room noise

I tried again this time with the mic a AKG C1000S, about 250 mm away pointing at the 12th fret

https://soundcloud.com/johnparchem/gore ... take-two-3

here is the Martin 00 sized falcate through the K&K pickup.

https://soundcloud.com/johnparchem/kandk-pickup
by johnparchem
Wed Jan 24, 2018 12:30 pm
Forum: Instrument Builders Forum
Topic: Mask the bridge glueing area
Replies: 11
Views: 2193

Re: Mask the bridge glueing area

I have been go back and forth between no masking and masking most of the bridge area and clearing to a scribed cut. Of those two options I am leaning toward mask most and cut to the line. My experience: If you mask inside 2-3 mm and after finishing you scribe the bridge outline with a sharp scalpel,...
by johnparchem
Sat Jan 20, 2018 7:52 am
Forum: Instrument Builders Forum
Topic: Audio comparison of 2 falcate SS and an X brace all mine.
Replies: 1
Views: 709

Audio comparison of 2 falcate SS and an X brace all mine.

I am about ready to ship my latest Falcate braced steel string so I thought it worthwhile to record the difference between the two falcate SS guitars that I still have: My WRC\Cocobolo Martin sized 00 and my Spruce\Koa Gore medium sized SS guitar. As an additional bonus I recorded the same tune on a...
by johnparchem
Fri Jan 19, 2018 10:48 am
Forum: Instrument Builders Forum
Topic: Cocobolo\WRC Falcate 00 12 fret to the body
Replies: 19
Views: 6865

Re: Cocobolo\WRC Falcate 00 12 fret to the body

Whoops forgot to post the final spectrum graph. Everything is not exactly where I had hoped but the guitar sounds great, my target T(1,1)2 was 180 Hz and I am at 181-182 Hz with no mass. Also nothing is right on a note (but the air is close). The back is not super responsive but it does couple. I go...
by johnparchem
Fri Jan 05, 2018 2:52 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: 1st box closed - spectrograph result
Replies: 2
Views: 1051

Re: 1st box closed - spectrograph result

I am still a novice looking at these but here are my thoughts. If I look at the red it looks like your top and back are pitched close together with that double peak. If the peak around 220 Hz is the top resonance, it will move away from the back when the bridge is glued on; a good thing. If the back...