Hi Stefano and C-Bag! It is good to hear from you both and glad you are over the flu...there was a nasty one going around here too.
I like C-Bags idea for the buffer ball/cones. Generally they are mounted on twisted wire which you will need to be careful with. Probably wrap it with several layers of tape and maybe some foam too? I was also thinking of using a boring bar type that you could mount on the cross slide and compound to work it in with some pressure...although if you use your compounds wisely you shouldn't need a bunch of pressure.
I took a look at the medianet program and looks pretty good but they don't give a lot of details. When I did my sound table I used TrueRTA (24 octave version) for my spectrum analyzer and found it quite easy to use, accurate (as you can be with a sound card) and mainly it has a capture feature that ports the data to Excel which was what I wanted. Lots of good settings and options but it is important to create a configuration file with your equipment to give it a base line.
As far as the mic goes I pointed it downward into the flat table. Not sure if this was correct but the db level dropped off drastically when it was perpendicular to the table. The tricky part is placement distance IMHO. For my application I needed to take 3 different heights from the table face (1", 3" & 6") in a 4" grid pattern over the table surface. Speaker measurement is another story and believe the optimum measure distance is either 1" or 1' (C-Bags friend would know better I'm sure). Room measurement is a whole other ball game!! The other most important part is what you are driving it with and how. I drove the transducers with the HP 4ch signal generator through the Art4 amp while monitoring at the transducer on my O'scope for input levels.
The direction curve for the mic is quite good and in reality it is well suited for room correction work but there is hardware/software and algorithms for analyzing the acoustics levels for optimum placement based on the responses to specific frequencies, pulsed, sweeps, pink/white, etc. My Marantz system has the feature built in and came with a mic. The interesting thing is it has multiple algorithms and storage options. Hard for me to get my head around it. Although I played around with building a voice analysis system to identify frequency/db ratios by octaves and to show harmonics as a subset...had to put it down finally but still think it's doable and may be worthwhile for determining stresses within the body/spirit/mind. Tuvan throat singers can actually create a binaural beats and IMHO is why it "feels" so relaxing or invigorating and adding that to an instrument or other singers in harmony or "disharmony" can invoke an amazing "well being" or health.
Ha!! C-Bag...I'm with you on the Pantograph. Ever since I saw Keith Fenner creating the boat rudders I have been on the hunt for how to do that!!
Looking forward to what you come up with Stefano...Plasma...Oh, My...shocking!