Believe it or not, you do not need to formally compose or buy sheet music for your a cappella group. The old-fashioned way is to make it up! Improv-ing songs is all about the "out-of-thin-air" singing method. This song puzzle process is the science of pulling notes out of nowhere, singing off the top of your head and jamming on your toes…whatever you want to call it, I'm here to tell you it is possible even if you don't understand a lick of musical theory. The technical, proper way to improv a song is to follow the chord progressions, then layer loops of the rhythm line. Next you add riff phrases, create harmonies and complete it with someone singing the lead. If your members do not come from extensive musical backgrounds, that procedure is too complex. My approach below will train your ears and give you the skills of reflection, mocking, matching, copying, pretending and duplicating…basically, you're about to become a professionally aca-certified kickass copy-cat.
My first rule is to know your place. If you're not the girl that normally does belty diva runs at the end of a song…then don't attempt it. Stereotype the voices in your group. Stick with what you know. So, I'm sure you are asking, "How am I supposed to figure out which part of the original song to imitate?" Read below:
-Sopranos, you lucky ones get those floaty melody lines, but don't hog all the easy stuff. Wander out of your comfort zone. Add in long vowels that stretch out over time. Also emulate the violin, cello, flute or upper pitch instruments. Stay on top of the pitch. Keep your vocal placement poppy bright so if the overall group pitch falls flat, you have the power to bring it back up. Be the rock!
-Mezzos, analyze the soloist and play a game of call and repeat or follow the leader. Echo their words, be a verbal mime, harmonize over their phrases and do dramatic riffs that are afterthoughts of their melody. Also focus on filling in the silent spaces. If the group is on the same rhythm wavelength, change it up by singing on the off-beat. Make it your goal to cover in the gaps, group breath marks and general long pauses.
-Altos, hit up those piano lines and chunky mid-section meaty parts. Find the measure pattern loop and stick to it.
-Tenors, mimic the guitar line. If you get bored, partner up with other voice parts to thicken up their sections. Also do some humming, show off your falsetto, echo others and jam out on those instrumental breaks.
-Baritones, keep to the time signature of the song, be the metronome for everyone else and have a consistent syllable on-top of the beat that keeps the song moving.
-Basses, I know you normally get the degradingly easy parts, therefore, you should use this creative freedom to show off your inner star! Keep to the standard resonating low end movements but also sink into those bass guitar notes while playing around with traveling walking phrases. For example, sing lines that slide up and down your register but still always consistently fall on beat count 1 so you can crisply lead other singers into those beginnings, tricky transitions and clipped endings.
-Beatboxers, just do your thang! Characterize the drums and play off the basses whenever you can. Cover up any of the group's inconsistencies or problems that arise, especially in those tricky transition sections.
The second step is to play the song over and over on very loud speakers. (Sometimes stereos have settings where you can turn bass, treble, pan, balance, fade, equalizer and sub sound volumes up or down. Mess around with those volume options so people can hear their instrument lines clearer if need be.) Let everyone jam out to themselves, no pressure. Right now, it's not about blend, dynamics, accuracy or making the song sound like the original song. It's just about getting familiar with the background instrumental lines. If you are confused about syllables, imitate the instrument sound, echo important soloist lyrics or pick up on the soloist's vowels. For example, if the lyrics are "Walk with me baby, I want ya to always laugh", then mimic a repeated "a" tone to compliment your soloist's words.
The third step is to hone in on your voice part emulations and get all your ideas out loud. When you think you have nailed down a decent loop, stop yourself and do it over and over. Engrave it in your memory. Don't get all fancy, make it simple at first; stop and rewind, go through the song in chunks. Intro, Verse 1, Pre Chorus, Chorus, Verse 2, Pre Chorus, Bridge, Finale Chorus, Outro. Sing it as many times needed with the original song playing so you can get the groove of where you belong. Singing along to the song can also cue you into the next section if you lose creativity, get lost, can't hear a certain instrument or forget stuff. Once you get confident, try it without the original song playing.
My fourth rule is to always think ahead. If you're following along with an instrument line, try to predict the transition changes (for example Chorus 2 into the Bridge).
The last rule is that you need an authoritative music director to control dynamics, nit-pick and meld the voice parts together. If your entire group chimes in with opinions every five seconds, then your rehearsal will last six hours instead of two. The icing on the cake will be the music director editing improv sections that sound junky. When there is an intricate section that is not coming together, just go back, listen to the original song and mimic it phrase by phrase. Don't make it rocket science, break it down.