Combining waves - Schumann resonances

Working on combining frequencies. Is it best done with (sim [beh1 beh2 …])? Or with a table of harmonics added together?
http://www.cs.cmu.edu/~rbd/doc/nyquist/part8.html#index612
http://www.cs.cmu.edu/~rbd/doc/nyquist/part2.html#index25

Trying to emulate Schumann Resonances in audacity. These are a set of spectrum peaks in the extremely low frequency (ELF) portion of the Earth’s electromagnetic field spectrum.
https://en.wikipedia.org/wiki/Schumann_resonances
https://commons.wikimedia.org/wiki/File:Schumann_resonance_spectrum.gif
7.83 Hz (fundamental) 14.3, 20.8, 27.3 and 33.8 Hz

Thanks.

Difficult to say which is “best” as that depends on what you are doing.
(sim [beh1 beh2 …]) is possibly easier to understand and use.
build-harmonic would be quite tricky for extreme low (and non-integer) frequencies.

As a simple example, to create a waveform that combines 7.83, 14.1 and 20.3 Hz:

(mult 0.3
  (sim
    (hzosc 7.83)
    (hzosc 14.1)
    (hzosc 20.3)))