Falcate braced classical

[kiwigeo]

Okay I did a run of tap testing with the guitar held....lower waist on my knee and top edge against my chest. I held neck mid way with my left hand.

Heres a plot of data from guitar sitting on foam blocks and with the instrument held. Mic was around 50-60mm from bridge area.

[Trevor Gore]

Mic was around 50-60mm from bridge area.

Martin, try backing the mic off to ~50-60cm. I should have picked that one up last time I asked you! Sorry about that.

[kiwigeo]

Mic was around 50-60mm from bridge area.

Martin, try backing the mic off to ~50-60cm. I should have picked that one up last time I asked you! Sorry about that.

Got a huge piss up Geologists lunch on tomorrow but if I get time do another tap test run with mic further away as suggested.

[jeffhigh]

Just started french polishing mine yesterday and took some readings pre bridge
I'm getting around 79 and 178, with a small soundhole to support the low B string.
Bit lower on the top than I wanted, we'll see where it goes with the bridge on, I have a few ideas to bring it up.

[kiwigeo]

Ok I redid tap tests holding the guitar and with the mic at 50cm from soundhole. Peaks are still essentially the same but frequencies have dropped a few Hz. The interesting little peak at around 20Hz is interesting. I clamped G clamps to the headstock and gripped the neck to suppress vibration of same but it didnt have much effect on the peak. Ditto for the extra monopoles between T(1,1)1 and T(1,1)2 peaks. Plot shows data recorded holding guitar in normal fashion and with mic 50-60mm from bridge and 50cm from soundhole.

[Dominic]

Hey Martin, i was getting jaggy plots like yours at first and it turned out to be double tapping on a micro level. I started using the corner of the rubber so on contact it did not slap and my plots started looking like the book. Also light taps with a light touch so the hammer bounces right off. That might make the plot easier to read. More important for plate thicknessing.
Cheers
Dom

[kiwigeo]

Hey Martin, i was getting jaggy plots like yours at first and it turned out to be double tapping on a micro level. I started using the corner of the rubber so on contact it did not slap and my plots started looking like the book. Also light taps with a light touch so the hammer bounces right off. That might make the plot easier to read. More important for plate thicknessing.
Cheers
Dom

Dom,

Thanks for the suggestions.

I've paid close attention to my tapping. I try and keep striking pressure the same and I bounce the eraser off the board once. I let the hammer fall from horizontal to the board rather than letting my arm muscles provide the effort. Am using one corner of the rubber as well.

[kiwigeo]

Made up laminated bridge blank today. Discovered how tough CF cloth impregnated with epoxy is when I ran my plane over the blank.....left a dirty big nick out of the plane blade

[jeffhigh]

ouch
I use my disc sander or spindle sander for shaping anything Laminated with CF

Glad you survived the geologists lunch.

[kiwigeo]

ouch
I use my disc sander or spindle sander for shaping anything Laminated with CF

Glad you survived the geologists lunch.

Survived...but have been nursing a hangover for most of the day. Managed to doze off during this evening's pilates class

[Trevor Gore]

Discovered how tough CF cloth impregnated with epoxy is when I ran my plane over the blank.....left a dirty big nick out of the plane blade

It'll do the same to tungsten carbide, too!

[kiwigeo]

Well that's enough of that sh*t.

Got halfway through routing the saddle slot into the bridge blank and the blank came loose in the jig and I ended up routing half the top layer of wood off the blank. Blank is nuked so time to make up a new blank and start again......but not today. Time to have a drink....