Falcate #2 Tapping Results

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chrisbaer
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Falcate #2 Tapping Results

Post by chrisbaer » Fri Nov 09, 2018 11:47 am

Hello again, everyone! So, my second Falcate guitar is well underway... The box is closed and bound and the BO/BO neck fitted.

Carpathian Spruce top with a target thickness of 2.67mm - I think I may have gone a touch thinner after leveling the rosette.
EIR back and sides with a target thickness of 2.26 - I believe I'm right on the money here.
I have only the bolts in the side mass blocks, but they're heavy at 20g each.

So, here's the results!
Falcate 2 Top Bound.png
T(1,1)1 is 100Hz, which I take as a win!
T(1,1)2 is 187Hz which I think is a bit high, yes? Some more side mass, maybe?
T(1,1)3 is 211Hz (the back tapped at 209), so I think I actually have a live back, yes?? The main back brace is only slightly scalloped, so I do have room to work.

Any suggestions, or does it look like I can proceed to finishing and putting the bridge on?

Thanks!!

Chris

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kiwigeo
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Re: Falcate #2 Tapping Results

Post by kiwigeo » Fri Nov 09, 2018 12:34 pm

I wouldn't be playing around too much with everything. Once bridge is on I'd expect a few Hz drop in main top frequency. I sometimes stick a bit of mass on the top roughly equivalent to the bridge mass to see where things might go with the top frequencies. I'd probably be aiming to keep the bridge as light as possible.

Have you thinned the top around the periphery of the main bout as per G and G? If you haven't yet done this then I'd leave this step out as it will also alter top frequency.

Back frequency looks a little low to what I normally get but looks to me like you're getting some coupling going on.

Trevor will no doubt pop in and add some (more) learned comments.
Martin

johnparchem
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Re: Falcate #2 Tapping Results

Post by johnparchem » Sat Nov 10, 2018 1:54 am

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 I see a drop of about 10 Hz in the top resonance from just closed with no bridge to strung up.

chrisbaer
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Re: Falcate #2 Tapping Results

Post by chrisbaer » Sat Nov 10, 2018 3:43 am

Thanks, John and Martin!

I only thinned the perimeter of the top very slightly, given that I had already gone a touch below the target thickness.
The bridge is walnut and is pretty light at 18g with holes drilled and the saddle slot routed.

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

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Re: Falcate #2 Tapping Results

Post by johnparchem » Sat Nov 10, 2018 4:40 am

chrisbaer wrote:
Sat Nov 10, 2018 3:43 am

... 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 spectrum with more spikes (like yours) providing an almost choir like voice. I would not do anymore tuning of the back or the back resonance will get too low. I follow Trevor's guidelines of three semitones above the top.

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Trevor Gore
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Re: Falcate #2 Tapping Results

Post by Trevor Gore » Sat Nov 10, 2018 11:26 am

johnparchem wrote:
Sat Nov 10, 2018 4:40 am
chrisbaer wrote:
Sat Nov 10, 2018 3:43 am

... 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 spectrum with more spikes (like yours) providing an almost choir like voice. I would not do anymore tuning of the back or the back resonance will get too low. I follow Trevor's guidelines of three semitones above the top.
I recommend 4 semi tones but no closer than 3.

With the T(1,1)3 already at 211Hz, 4 semi tones separation is T(1,1)2 = 170Hz and T(1,1)3 = 214Hz. So leave the back and proceed to finishing. Trim to 170Hz with side mass after you've got it strung.

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