How gigbrain scrolls a chord sheet in time with the recording
Auto scroll moves a chord sheet while you play, so your hands stay on the instrument. In most apps it is a speed slider you nudge during the first verse. It never quite holds, because choruses repeat, bridges are short, and outros run long. gigbrain times the sheet to the recording instead.
How does gigbrain know which song it is?
When you paste a chord sheet, gigbrain suggests a title and artist. It uses the name at the top of the sheet, or matches the lyrics against public lyric catalogues. You can change it before it is saved.
The rest depends on the recording. "Hallelujah" by Leonard Cohen and by Jeff Buckley have different lengths and tempos.
Where do the tempo and length come from?
gigbrain asks several public music catalogues for the recording's length and tempo, since each knows different songs. Auto scroll needs the length most. The tempo drives the metronome and the count-in. You can edit both on the song. Set your own tempo if you play slower than the record.
What are timed lyrics?
Timed lyrics are files that say when each line of a song is sung, to the second. gigbrain looks one up and lines it up with your sheet. Different line breaks or a few changed words still mostly line up.
When this works, the sheet moves line by line as the singer does. Before the first word and after long gaps, a bar fills so you see the entrance coming.
What you see on the song
A dot next to the title shows what auto scroll will do. Green means it found timed lyrics, a tempo and a length. Yellow means one is missing.
What happens when a song has no timed lyrics?
Auto scroll uses the length of the recording and of your sheet, so the page reaches the end when the song does. A sheet with 40 lines and a four minute recording moves about one line every six seconds. Sections with more lines get more time.
Songs with a long instrumental section can run ahead or behind. You can scroll by hand without stopping playback, and the scroll picks up from there. Manual mode scrolls at a steady speed you set.
How does the count-in work?
The count-in uses the song's tempo, or your own if you set one. If the count feels wrong, halve or double the tempo, since catalogues sometimes list a slow song at twice its speed.
Which tempo numbers look wrong?
Most pop and rock songs sit between 90 and 130 beats per minute. Ballads usually sit between 60 and 80. A slow ballad listed at 140 is almost always counted double, and a fast punk song listed at 85 is counted half. If the number looks off for the feel of the song, halve or double it before you trust the count-in.
Why does my live version run longer than the record?
Live songs stretch. You hold the intro while the room settles, play the solo twice, or sing one more chorus because the crowd wants it. A three and a half minute record can become five minutes on stage. If you always play a song longer, set your own length on it, so the sheet does not reach the end while you are still in the last chorus.
If the band skips a verse on the night, scroll past it with a finger. Playback keeps going, and the scroll carries on from where you put it.
Does auto scroll work for songs I wrote myself?
Yes, with one extra step. An original song has no recording in any catalogue, so there is no length, tempo or timed lyrics to find. Give it a length yourself and the sheet scrolls over that time, with more time for the longer sections.
To get the length, time a full run-through at rehearsal, from the count-in to the last chord. Do it twice and use the longer one, because songs run a little longer in front of a room. Add the tempo too if you want a count-in. If you would rather not time it, use manual mode and set a steady speed.
What can go wrong, and what do I do?
- Wrong song. Change the title or artist. The lookups run again.
- Length is for a different version. Edit the length by hand.
- Timing drifts in one section. The sheet usually has an extra or missing chorus compared to the recording. Fix it in the sheet and the timing is rebuilt.
- Your arrangement differs from the record. Set your own length and tempo.
What does gigbrain send to other services?
The lookups send a song title and artist to the catalogues, and the text of a pasted sheet to the service that identifies it. They never get your email address or your setlists. The privacy policy lists every service by name.
Check it before the gig
Public timing can be wrong. Press play once at home. If the dot is green and the first chorus lands, it will land on stage too.
To make the sheet easier to follow while it moves, see the post on chord sheets for a dark stage.