Muswell

I heard John Tomlinson, bass, sing the title role of the Minotaur at the Royal Opera House in 2013. It was the 35th anniversary of his debut at the ROH and there was a small celebration on stage. Antonio Pappano and Tony Hall gave speeches and then handed the microphone to John Tom who, after a few words, said he would be better off without it and then completely filled the space with his speaking voice, which was a deep rumble which seemed to come from below his feet.

That's a neat solution.

You need to keep off that spirit varnish mate, it's proper dodgy

The quality as evidenced by the reliability?

Thanks Don for pointing out that about the wave lengths. As I wrote to Davide, I have tried with the mic closer. I'm not going to get bogged down in this. The tea leaf testing was done immediately after I had got down to 350 and I can see that there are some spots where I want to tidy up the graduations anyway. I'll be interested to see if it makes much difference then I'll stop. I only did this out of curiosity because someone did the tea-leaves and then I was loaned the microphone. After this I'm going back to the basic tap tone and Mk 1 earhole which has worked quite well so far, and for guitars too. The numbers are interesting but I am reminded that when I was working there were people who got lost in the analysis for its own sake while we just had to get the drawings of something, which worked, out of the door.

Thanks Davide. I watched your video before I started on this and, like them all, I found it very helpful. I have tried holding the plate as close as possible, about 25mm, from the microphone and the result is clearer. It was not very obvious at 4096 but quite clear at 8192.

Encouraged by your screen shot I've been experimenting and found that the response is very sensitive to the exact postion of holding the plate but have now been able to get a peak at 151 compared with tea leaves at 156. I also found that it was much more pronounced if I kept the recording level low and gave the plate a good wack. My peak is not as clear as yours and is not really picked up at 4096 ; I have a feeling that the transition of the graduation in the upper and lower bouts into the waist is not quite right yet so I'll see how that working that affects the response

Thanks Don that's very helpful, I get nothing like that. I'll post what I'm getting after I take this computer down to the workshop.

Marty, I didn't draw the nodes when we read the tea leaves because it wasn't until I got home that I had the idea of trying Audacity. Don, I tap with my ear next to the plate and then repeat with the mic. The tea-leaves showed M1 107, M2 156, M5 351. My Audacity result at 4096 shows peaks: 124Hz -50.7dB, 185Hz -56.5dB, 256Hz -45.7dB, 343Hz -41.8dB at 16384 it shows 109Hz -57, 127Hz -54.4, 180Hz -60.2, 205Hz -60.8 and there is a little pimple of 148Hz -60.2 on the slope down from the 127 peak. The pimple would seem to relate to the tea-leaf 156 but at 4096 it's not visible. If it's of interest I'll learn how to send a copy but the computer in my workshop is in isolation after being infected with malware so I'll have to get this one down there. It is a "copy" of the Salabue and at 18mm the arch is high. Could this be having an effect?

I'm holding at about halfway along the 45 degree radius in the upper bout and tapping at the bottom block position, albeit with a bit of moving around to get the clearest tone. My hammer is a well worn technical eraser impaled on a scalpel and the microphone is about 100mm behind the plate in the same location that I strike. Off to bed now.

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.

We bought a new build apartment 6 years ago, entirely lit by 40 LED GU10. We only use it 1 week in 6 and in effectively 1 year of use all those lamps have failed, some after only a few months. I have been replacing with Phillips, who are leaders in the technology, and none have failed. I have had a similar, but not so extreme, experience in our house where bulb type LED lamps were bought locally and I replace those with Phillips too. Buy cheap. buy twice.

I think it is designed for guitars because of the flatness of the guide, just like the Ibex bending iron isn't good for violin making. I modified mine with a file to the shape it should be.

I think maybe you aren't using the tool correctly. You insert the blades so that the backs touch, and the bevel is out, then you shim between the blades to get the exact width you want. A piece of purfling plus a thin shm gives the correct spacing.

I did . I once had a project to design a large meditation hall for a buddhist monastery and suggested to the architect that we use green oak. That's what we did and the monks love the way it has aged and moved over the last 20 years. Traditional oak building was to cut down the tree and immediately make the components in-situ in the forest. The quicker you shape the wood and cut the joints, the easier it is and then you transport the least weight. The building was then assembled ASAP.