Bhagavad Gita Verse 19, Chapter 1

sa ghosho dhaartaraashtraanaam hridayaani vyadaaryat |
nabhascha prithvim chaiva tumulo vyanunaadayan || 19 ||
 
That tumultuous sound resounded through the earth and the sky, shattering the hearts of the sons of Dhritraashtra.
 
sa : that
ghosho : sound
dhaartaraashtraanaam : of the sons of Dhritaashtra
hridayaani : hearts of
vyadaaryat : shattered
nabhascha : sky
prithvim : earth
chaiva : and
tumulo : tumultuous
vyanunaadayan : resounded
 
During college years my classmates and I used to participate in inter-college music competitions. Teams from various colleges competed with each other for the "best music team" prize. Usually the teams would all be waiting backstage to be called on to perform, but in the interim they would do "mini rehearsals" where they would sing one or two lines of their song to warm up. What was interesting is that most teams knew who would win just by hearing that two line sample of the song, because it provided a glimpse of that team's talent and preparation.
 
Similarly, when the Pandavas blew their conches, their sound was much louder and spirited than the Kauravas, even though the Pandava army was a fraction of the Kaurava army. That sound provided a window into the Pandava army's determination and preparation, which had the effect of injecting fear into the hearts of the Kauravas.