Scrolling Music Game Track Design

Alright, so I've been working on a music game for about the past 1.5 months now. I had a basically playable version, but I realized - after reexamining games such as DJ MAX, Rock Band, and Osu!'s "Mania" mode, that I had been dealing with the track design incorrectly.

I had a static track - notes spawned N ms before they needed to be played and moved down. This kind of works but isn't the most efficient or flexible way of doing things - plus too many notes and the game lags easily.

Really, it appears that the track has the notes placed, and the track scrolls towards the player / down the screen at a speed that allows the notes to be hit in time with the song. There's also the horizontal lines that appear - I believe these are some indication of the BPM of the song? This screenshot from one of the BeatMania's illustrates some of this.

These games also have varying speeds (well, Rock Band only has normal speed and Breakneck speed but the idea is the same) allowing for a greater increase in challenge should the player desire so.

So really, my question, dear Unity Answers is how would one go about creating this type of scrolling track? I'm looking for concepts that I can apply to code, because I have been conceptually blocked with the actual nitty gritty of how this system works.

For example getting the notes to move at the right speed has been quite challenging (I posted on the forums to no response see: here).

• TL;DR How would one go about beginning to code a music game track that scrolls like Beatmania or DJ MAX in Unity using C#? Not looking for a handout, just key-concepts to get started with. -,- **