My friend, disappointingly, just left to go somewhere without telling me. He was supposed to produce my classical techno-fusion jazz metal rap album! Instead, he left me four riddles, each with two-letter-long solutions, to piece together his whereabouts. He already gave me the solution to the last riddle, "NK."
1) I'm truly the first two in "go back to the start";
Obey me you must if you've mastered the art.
Halting's not smart;
It hasn't ended;
Please let me remind of the part I appended. _ _
2) I can show imagination, I can show you what's real;
Let me show you the unheard, it's what I reveal.
I frequently wander,
And pass time as you ponder;
How all that you've heard is only piecemeal. _ _
3) "Press" on those keys, oh "tug" on those strings;
Do both and you'll make a rise and tide out of things;
Now split them in half;
That's it, don't laugh;
Or flip "down" two-fold like it's a drum stick spinning. _ _
Can you help me solve the first three and tell me where he went? It better have been worth it - studio recording time is expensive.
1) A phrase's first two letters;
3) Two letters borne out of splitting either of two words in half. Using either word should suffice.
There's a vague theme across this entire riddle, including the non-highlighted text. Solving #3 first might engender ideas on what #1 and #2 may be.
Riddle 2 is by far the hardest. I want to draw your attention to the idea that every sound you hear is almost never just one "sound". A pure sine wave is the exception. A mathematician, of all things, may be most qualified to solve this.