1. Step: Analysis of the Sound Spectrum

 

If you want to make your bars for a vibraphone, then these should later sound like vibraphone and not like something else. Therefore, the sound analysis of good sounding vibraphone bar set is at the beginning of the considerations.
Furthermore, the aim of the analysis is to determine only the influence of the sound bars, i.e. without the influence of the resonance tubes.

In the first step we tried to determine the sound target for our bars.
We used Fast Fourier Transformation (FFT) to measure and analyze the sound spectrum of several bar sets that were available to us. Those were:
  * Musser M55 Gold
  * Musser M55 Silver
  * ROSS Concert R715 Silver

 We analyzed each bar of all sets similarly as shown below and noted the results.

Suitable FFT software is even available as freeware for cell phones (spectroid, phyphox, ...) and they are not even bad.
 		  
With simple freeware programs, it is advisable to determine the individual overtones individually.
 
However, we used a more precise but more complex program from the university.

 With this program we can simultaneously record the amplitude spectrum of the frequencies to each other in a single recording.
 		  

The result can be shown graphically for one bar set:

The first harmonic overtone remains up to F5 at 4 times of the fundamental and then decreases linearly up to 3.5 times in the highest octave.
The second harmonic overtone decreases continuously from 11 times the fundamental to about 6.5 times.

We have set this sound spectrum as the goal for our bar set.