"Once" by OSI was released on April 21, 2006. Since Once is still less than 10 minute long, it is still considered a pretty long duration song compared to the average song length. This song does not appear to be explicit due to the lack of the "E" tag. The song is number 10 out of 20 in Free (Deluxe Edition) by OSI. The popularity of Once is currently not that popular right now. Although the tone can be danceable to some, this track does projects more of a negative sound rather than a postive one.

Once テンポ

The tempo marking of Once by OSI is Vivace (lively and fast), since this song has a tempo of 166 テンポ. With that information, we can conclude that the song has a fast tempo. The time signature for this track is 4/4.

Once キー

This song has a musical key of B♭ Minor. Because this track belongs in the B♭ Minor key, the camelot key is 3A. So, the perfect camelot match for 3A would be either 3A or 2B. While, a low energy boost can consist of either 3B or 4A. For moderate energy boost, you would use 12A and a high energy boost can either be 5A or 10A. However, if you are looking for a low energy drop, finding a song with a camelot key of 2A would be a great choice. Where 6A would give you a moderate drop, and 1A or 8A would be a high energy drop. Lastly, 6B allows you to change the mood.