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Showing results for tags 'tap-tuning'.
A couple of weeks ago I watched as the plates of my current build were put through the loudspeaker and tea leaf routine and we established the M1 M2 and M5 frequencies Now, out of curiosity, I have got hold of a microphone (Behringer ECM 8000 measurement mic), downloaded Audacity and started doing some tap testing. I have found that I get good clear correlation for M5 on both plates. But when I tap the top plate in the locations for M1 and M2, although I can find peaks at the same frequencies as the Chladni patterns, if I didn't know those frequencies in advance I would have no confidence that I was on the correct peak. When I tap the back plate I can find M1 but there is basically nothing at 156Hz, which was where the M2 pattern occurred, and the nearest I get is 180 Hz (M5 is 350). Is this just my inexperience, or is that the way it is? This is a bit of a diversion because I'm happy to stick with tidy graduation, the feel of the plates and a nice clear ring to the sound for M5.
Hi everyone! Haven't posted for a long time, but have still been lurking and in the last few months getting back into making violin number #3. I am most of the way through hollowing out a spruce top and have been trying to follow along with a working method that Davide Sora has been so kind to put online https://davidesora.altervista.org/videos/belly-back/ Currently my spruce top is 74 grams and the wings of the upper and lower bouts seem to be getting closer and closer to the flexibility I'm happy with. Not much flex longitudinally, but plenty of twist. The mode 5 tap tone is currently at around 289hz. This is where I am very far from the model that Davide is working with. I still have a little thinning out to do in-between the C bouts and would like to be somewhere in the 60-70g mark for the top. Davide's model at this stage has a mode 5 of 350-370hz. I obviously cannot put more timber back on and I'm not sure I'd want to even if I could. I have attached a few pics, one has the graduations marked on it. A few things I'm thinking could have me where I am currently: - I don't have stiff enough spruce for the weight - my model is wider in the C bouts than I'd originally intended, perhaps this is pushing mode 5 down and the weight up - my arching could be very weird - I live in an area with high humidity Anyways, the biggest questions I have now are: - What should I do with this spruce top now? Should I keep thinning down to where the numbers seem reasonable, or should I stop and cut the f-holes and keep moving. - What did I do wrong and how can I improve for next time? I know comparing Davide's model to mine is diamonds to gravel, but it is nice having a reference point to learn from. Thanks in advance for any ideas and thoughts.
I use a 'home brew' hard felt hammer at about 7 grams +/- ..it is non resonant and won't mar the finish ... a striking mallet from a piano would also work ...the convention is to soften it with olive oil on old mallets (I like 3 in 1 oil...it doesn't harden up as much) The thinking is that with a hard mallet you also hear the striking head resonance (and the impact) I find a knuckle to be variable Edit...I use this for evaluations mostly Jim