Music Maker III

Review — notes and instruments 5 min

• Every key has a number. 60 is middle C.
• Each sprite has its own instrument. The tempo is shared.
• Our sing block plays a note and shows its letter.

Quick-fire

Last week the Studio Theme was 16 blocks. You want to change the sixth note. How do you find it?

Today’s Topic 3 min

• Two lists kept in step: notes and beats
• One loop, with i walking down both lists
• A 0 in the notes list means a rest
• Changing the tempo between a verse and a chorus

Learning outcome

By the end of this lesson you will be able to:

1. Store a song as two lists that line up row by row.
2. Play any song in those lists with one loop.
3. Change a song by changing the lists, not the script.

Learnt — a song in two lists 28 min

1 · Two lists, in step

A note needs two things: which key, and how long. So we keep two lists. Row 1 of notes goes with row 1 of beats, row 2 with row 2, all the way down. That is what in step means.

A 0 in notes means “rest here”. Nobody plays key 0 in a song.

2 · Fill the lists

1. Make two lists, notes and beats, for all sprites. Their boxes appear on the Stage.
2. Click the + at the bottom of the notes box. Type 60 and press Enter.
3. Keep typing. Enter makes the next row.
4. Do the same in the beats box, so both lists have the same number of rows.

3 · One loop plays it all

A variable called i says which row we are on. It starts at 1, and goes up by one after every note.

set [i v] to (1)
repeat (length of [notes v])
  if <(item (i) of [notes v]) = (0)> then
    hide
    rest for (item (i) of [beats v]) beats
  else
    sing (item (i) of [notes v]) (item (i) of [beats v]) :: custom
  end
  change [i v] by (1)
end
            

4 · A new song is new lists

Change the numbers in the boxes and run it again. The script did not change at all, but you hear a different tune.

Basic — a verse and a chorus 24 min

Songs often play the same part twice — slowly first, then faster. You are going to play the Studio Theme as a slow verse and a fast chorus.

Step 1 — the lists

1. Use your letter sprite and sing block from last lesson.
2. Make notes and beats. Fill them with the Studio Theme: the table from Lesson 10, with 0 for the rest.
3. Check both boxes say length 15.

Step 2 — a play song block

1. Make a Block called play song.
2. Put the loop from the Learnt under its define hat.

Step 3 — verse, then chorus

1. Make a variable bpm. Under the green flag, set it to 90 and set the tempo to it.
2. say [Verse] for (1) seconds, then play song :: custom.
3. Set bpm to 140 and the tempo to it.
4. show, say [Chorus!] for (1) seconds, then play song again.

define play song
set [i v] to (1)
repeat (length of [notes v])
  if <(item (i) of [notes v]) = (0)> then
    hide
    rest for (item (i) of [beats v]) beats
  else
    sing (item (i) of [notes v]) (item (i) of [beats v]) :: custom
  end
  change [i v] by (1)
end

when flag clicked
set instrument to [(1) Piano v]
set [bpm v] to (90)
set tempo to (bpm)
say [Verse] for (1) seconds
play song :: custom
set [bpm v] to (140)
set tempo to (bpm)
show
say [Chorus!] for (1) seconds
play song :: custom
            

Backwards

Play the song from the last note to the first.

• Do not change the lists.
• i starts at the length of the list and goes down by one.

set [i v] to (length of [notes v])
repeat (length of [notes v])
  if <(item (i) of [notes v]) = (0)> then
    hide
    rest for (item (i) of [beats v]) beats
  else
    sing (item (i) of [notes v]) (item (i) of [beats v]) :: custom
  end
  change [i v] by (-1)
end
            

A key change

Pop songs often finish higher than they started. Make yours do it.

• The song plays once as it is.
• Then it plays again with every note 5 keys higher.
• A shift box on the Stage shows 0, then 5.

A round

In a round, a second singer starts the same song a little later. Two singers, one pair of lists.

• Duplicate the letter sprite. Call it Note 2 and give it a colour effect and the Flute.
• Both sprites play the same lists, starting on one broadcast.
• Note 2 says “wait...” and starts 2 beats later.
• Neither singer skips a note.

when I receive [go v]
set [color v] effect to (100)
set instrument to [(12) Flute v]
say [wait...]
rest for (2) beats
say []
play song :: custom
            

A recorder

Join last week’s keyboard to this week’s lists. Whatever you play is saved, so you can play it back.

• The green flag empties both lists.
• A to K play C to C, and add the note and 0.5 to the lists.
• The space bar plays the recording back with the play song block.
• C empties the lists so you can start again.

when flag clicked
delete all of [notes v]
delete all of [beats v]
set tempo to (120)
say [Press A to K to record. Space plays it back.]

when [a v] key pressed
say []
add (60) to [notes v]
add (0.5) to [beats v]
sing (60) (0.5) :: custom

when [space v] key pressed
say []
play song :: custom
            

Summary 5 min

• A song can live in two lists kept in step: notes and beats.
• One loop with i walks down both and plays every row.
• A 0 in notes is a rest.
• A new song is new lists. The script stays the same.
• Two sprites reading the same lists each need their own i.

In step

Two lists where row 1 goes with row 1, row 2 with row 2, and so on.

Verse and chorus

Two parts of a song. Here they are the same notes at two tempos.

Key change

Playing the whole song a few keys higher or lower.

Round

The same song sung by two voices, one starting later.

Hand in

Save your song. Next lesson the lists become a grid of pads you click — a beat machine, and the end of the arc.