The dance of their hands with the Gubal the PANArt tuners call a bal. Therefor “Deep Bal”, “Bal so” and “Bal 5/11” are not different Gubal versions as someone suppossed in an Internet forum, but three Gubal dances, three Gubal grooves.
PANArt presented the improved Gubal during the Gubal Days in May in Bern. It has a stronger Gung. This central bass tone is composed of the Helmholtz resonance of the vessel (Gu) and the partial tones of the ringding. PANArt succeeded in tuning two additional modes of the ringding to a harmonic partial tone. The gugel side is made of a thicker Pang sheet and has a higher resonance frequency. So less energy is drawn from the modes of the upper side.
You need good headphones or speakers for the playback of the powerful bass of the Gubal.