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Granadillo/Port Orford Cedar

Posted: Fri Oct 16, 2020 1:35 am
by Dave Bagwill
I made a prototype of this guitar a while back and liked it a lot, so I'm making another with an eye to selling it.
The difference is, I'm using the A-frame bracing that Lutaio Mottola recommends, based on the Tacoma line of guitars. It taps out nicely, so I'm very keen to hear how it sounds.
No special pix here - a view of the bracing, a view of the gluing-on of the back, and a lousy picture of the box. Better pix to follow hopefully.
So far so good, no major goofs.
What do you fellas do at this point in the build in regards to voicing? Are you all done at this point, or is there some magic of resonances and such that you use to assess the box?
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Re: Granadillo/Port Orford Cedar

Posted: Fri Oct 16, 2020 9:43 am
by John Parchem
Looks really good. Once bound I generally like to see a peak around 180-190 Hz at this point in my build process. Adding the bridge and string tension drops the tops resonance into the 170 or 180 Hz target I look for in a steel string. I like the bracing pattern.

Re: Granadillo/Port Orford Cedar

Posted: Fri Oct 16, 2020 12:17 pm
by Dave Bagwill
I have the Peterson strobosoft program, and nothing more sophisticated than that. How would I test this body using that, do you think?

Re: Granadillo/Port Orford Cedar

Posted: Fri Oct 16, 2020 12:57 pm
by John Parchem
I do not use Peterson strobe tuning a lot but it has a tap function and can be set to Hz. When tapping the body near the bridge location you will generally get two or one of two different numbers that come up; the lower one 90 to 110 at this point and a number close to 200 Hz 190-250Hz. The first is the air resonance, mostly affected by the sound hole size and the body volume, the second is the top resonance which is affected by the mass vs the stiffness of the top. Peterson may have a way to set the trigger higher than the air resonance letting you see the tops resonance.

I mostly use a free PC software Visual Analyzer. Trevor gore has a description on how to set up the tool, use it and understand where to look. https://goreguitars.com.au/attachments/ ... 018_A4.pdf

Re: Granadillo/Port Orford Cedar

Posted: Fri Oct 16, 2020 1:07 pm
by Dave Bagwill
Okay, thx.
Anyone else had luck with the Peterson?

Re: Granadillo/Port Orford Cedar

Posted: Sat Oct 17, 2020 10:54 am
by Herman
I use the Peterson for intonation purposes. Not for tuning.
At this point, when the box is closed,I don't do specific tuning anymore.
The only thing I do, if the top sounds to stiff to my ear (If the top does not "bounce" and say "poinggg"), is taking material from the perimiter. Lets say the outer 2 inches.
A little sanding can do a lot, so go slow.
2cts.
Stay safe. Corona is going fast here.
Herman

John thanks for the link. I will take a serious look at it.

Re: Granadillo/Port Orford Cedar

Posted: Sat Oct 17, 2020 12:04 pm
by Dave Bagwill
:D