After a year, the bar suspension using the insulation foam was again not really satisfying. The insulation foam still made a scraping noise when hit with a heavier mallet, and the sound was also a bit dull: fast deacay, no warm marimba sound.
So I tried a new material: foam rubber (Moosgummi in German). The result is simply great: longer decay, clearer sound, no more scraping noise on mallet impact. So if this stuff holds its form, this is really an alternative to drilling. I used a sheet of foam rubber that was 10mm thick, found it under the motorcycle-seat cushion category.
I've also rechecked the bars' tuning, and it was exactly as I measured it a year ago. I took the opportunity to put the fundamental into exact 443Hz based tuning, again applying a result from I. Bork's paper: The area where only the fundamental goes down is at 42% of the bar's lenght. A small incision here with a hand saw, at most 1mm deep, drops the fundamental by 20cent.
What still remains to be done are the resonator tubes. Let's see!
