Music description 

1 - Sources of  musical inspiration
The compositions of Himalaya form a tissue in which improvisations and written parts are interwoven. The principal sources of inspiration are Indian music and jazz, in which improvisation takes a primordial place. Filled with the essence of these cultures, the music of Himalaya gives large space to developpements of themes conceived over unusual rythmic  structures (for the actuel occidental listener), through elaborated improvisations.
Other  sources are Africa with the multirythms and repetitive hypnotical forms that can provoce trances (in a different way also found in Indian culture), and several kind of Eastern as well as Western folk music. You will also hear some reminiscenses of Occidental medieval and Renaissance music. This all is seasoned with actual music styles like the large palette of rock, pop, … among others by the use of specific psychedelic effects and sounds.

2 - Some notions concerning the form of the compositions
Many of the Himalaya compositions are based on the classical construction of ragas. This  concerns the modes as well as other particular caracteristics.
Thus, several compositions begin with an alap - an alap is the presentation and the progressif developpment of the modus and the sentiments (rasa) of the raga. The character of the raga is so to say slightly unveiled. Next this alap is followed by a more rythmical developpment that on his turn is followed by one or several melodical themes (gats), improvisations on these themes by the solists, accelerations of tempi, …
Another exemple is the use of tihai's (asymetrical phrases played three times, ending on the first beat of the next cycle) at the end of an improvisation and/or before passages leading toward other tempi, solists or themes.

3 - Rhythms and metrics  
Himalaya often uses uneven metrics. The rythm patterns and bass lines are build naturally and the audience is not disconcerted by it, all on the contrary, the non-informed listener will probably not even remark that it is not a usual 4/4. On the other hand the particuliar sensations these  rythms provoce will not loose their effect.
Many of these uneven metrics have an Indian origine like rupaktal in 7 beats (3+2+2), jhaptal in 10 beats (5+5). There is also dadratal in 6 beats (3+3), teental in 16 beats (4+4+4+4). Also other kind of rythms, for exemple in 9 beats or in  3½ beats are used. The traditionnal 4 beat rythm is of course also present.
4 - Instrumentation
The very particular and original sound of Himalaya is among other factors a result of an  uncommon instrumentation : sitar, harp, guitar and bass concerning the string instruments, flute and saxophone for the winds, synthesizer (used in the alaps) and drums, tabla, mridingam and other percussions to complete the rythm section on one hand and on the other the main male voice with the typical Indian vocals in Bengali, accompagned by the traditional harmonium and using the specific turns of phrases and particular techniques of different Indian musical styles.
In some compositions one or two feminine voices are added to this.The combination of these instruments and voices creates a very rich and profound soundscape.