The Hub

I did a pretty big update to my web tools last week. These are updated from the older versions I had up on celestialinstruments.com. There’s an updated FFT tool now, plus mode detection for guitars and plates, wolf note detection, played-note energy transfer, monopole mobility, plate thickness calculation, and 1/2/3/4 DOF modeling that can be prefilled from FFT data. The part I’m most excited about is being able to fit a measured guitar re…

Initial frequency analysis of this D28 copy (done with a temporary 35g bolt-on bridge and the back plate taped on) is VERY LOW. Main air resonance 83.5hz and top monopole 156.6. It's standard Martin scalloped X-bracing with a torrefied Adirondack top. Since I can still easily access the bracing, I'm thinking of going in and laminating wood on top of the X brace to stiffen it. Other options would be a very light bridge, though I'm not…

Hi, I just glued the bridge on the dreadnought I'm building and generated some Chladni patterns. I have the monopole at 188 Hz, long dipole at 335 Hz and cross dipole at 378 Hz. I would expect the cross dipole to come at a lower frequency than the long dipole, but they seem to be reversed. Does anyone know why this happens? Pictures attached. Any comments about things you can see on them, good or bad, are welcome :) Thanks! Jorge

I was thinking it would be kind of cool to have a community spread sheet for guitars. Repair guys see a huge variety of instruments. We could include a REW spectrum as Well as maybe the T(1,1)1 and T(1,1)2 labeled. A monopole mobility measurement and bridge rotation measurement would be great too. All who have Giulianos book can make these measurements easily. It would just be a willingness to share and input data for the community.