This is like an alternative sectone .
The Dropstart tone works in conjunction with the Intro time on the next piece of audio to be played in DPS auto mode.
Any cut with a DropStart tone should have a sectone at the usual place. The DropStart tone is able to modify the sectone, to fire off the next cut early so as to best fit the next intro.
The best place to use DropStart tones is towards the ends of voiced sweepers or promos. If the sweeper has a mostly musical or noisy background, but has a dry voice at the end that may safely overlay the next song, set the dropstart tone to the very end of the noisy background. Set the segue point to the end point of the dry voice (ie when the sweeper actually fades out or ends).
Then, if the next song in automation has no intro, DPS will wait for the sectone, so as to avoid a vocal crash. But if there's an intro on the next song, DPS will effectively fire the next cut slightly early; just early enough to avoid a vocal crash. This is an effective technique for slick, vocal-crash free automation!
To test, load Michael Jackson's Thriller into Editplayer. Set the segue point (Sectone) to the very end of the spooky laugh at the end. Save it.
Now reload into editplayer, and set the dropstart tone to the very beginning of the spooky laugh. Save again.
Play this song in a cart with the sequencer on into various songs with differing intro lengths. You will notice that the spooky laugh now overlays the next songs intro, without a vocal crash (provided you set the intro correctly on the cut that plays next!