In the past, I have written about relaxing music and what makes it relaxing. The words that I come up with over and over again are spacing and open-ness. Most of my previous posts focused on these traits in regards to the harmonies(chords) and rhythms.
In ‘Un Bal,’ Berlioz uses another technique in addition to these, orchestration. One of my favorite aspects of composing and listening to music is that of orchestration. The combination of instruments and timbres(sounds). When in the hands of a master, I believe, that even inferior melodic/harmonic music can be made great.
Berlioz often uses sparse groups of instruments including solos. When the music does get more dramatic he tends to feature the strings and woodwinds over the heavier brass timbres, of the later Romantics such as Mahler and Wagner. The use of a harp adds to the dulcet nature of the piece.
The creator of the embedded video supplies some great commentary. For those of you trying to gain insights into classical music make sure you check out their other videos, as well.