How can I find the more comfortable key to sing?

Question

Given that I have the melody of a song, how can I find the more comfortable key to sing? I want to transpose the melody to be comfortable for the greatest number of people - with all voices (soprano, tenor, alto, bass) singing unison.

Answer 1

What you want to do is

1. Figure out the required range of the melody (such as for example a sixth, an octave, or an octave and a fifth). That means finding the lowest note and the highest note used for the melody (and determine the interval between those).

2. Fit the middle of that melody range¹ best possible to the middle of the average musically useful² singing range of the people who are supposed to sing the melody.

3. Figure out the resulting key. You figure out the resulting key by knowing that the key is transposed the same amount as you transposed the whole melody range. (Or the same amount as the lowest note, etc...)

Now, I assume that your question is about having a bunch of non-classically trained "Average Joe" and "Plain Jane" singers sing the melody in unison. So the actual question is: what is a musically useful range for average adults? (I've asked this same question but regarding children.)

Let's first state that, for "unison" singing, the women will (generally) sing one octave above the men.
I believe that we can assume that the average person has a range that can be classified as a baritone (for men) or a mezzo-soprano (for women) and that those who don't fit this classification still can handle most of the notes of these ranges. Wikipedia suggests ranges for these classifications as G2-F4 (baritone) and A3-A5 (mezzo-soprano). This leaves us with a common window of A2-F4 and A3-F5. (Remember that the women will sing an octave above.) In my experience the highest notes in these ranges can turn out strained, at least for men, so perhaps we can say that the ranges Bb2-C4 and Bb3-C5 constitutes our target range (although this might be troublesomely low for females used to singing in "head voice" only). This leaves us with F3 respectively F4 as the middle of our target singing range.

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So let's take a couple of examples:

Example 1: Somewhere over the rainbow
1. Figuring out the range of the melody:
Judy Garland sings the song in Ab major, and the lowest note is an F3 (three times) and the highest note is a Bb4 (once). This gives us the range of F3-Bb4 which is an octave and a fourth. However the bulk of the song is in the range Ab3-Ab4 (the octave interval of the first two notes).
2. Fitting the melody range best possible to the middle of the singers range:
Given this information, and the above proposed target singing range, a likely suitable range for the melody could be A2-D4 for men and A3-D5 for women, having a focus on C3-C4 and C4-C5 respectively. This choice means that the approximate middle of the song (F) aligns with the approximate middle of the target singing range.
3. Figuring out the key:
Since we have transposed the notes of the range up a major third the key for this song would then be C major which is a major third up from Ab major.

Example 2: We wish you a merry christmas
1. Figuring out the range of the melody:
(Disregarding the key change to Eb) Bing Crosby sings the song in C major and the lowest note is a G2 and the highest note is an F3. This gives us the range G2-F3 which is a minor seventh.
2. Fitting the melody range best possible to the middle of the singers range:
Given this information, and the above proposed target singing range, a likely suitable range for this song could be C3-Bb3 for men and C4-Bb4 for women. This choice means that the approximate middle of the song (F) aligns with the approximate middle of the target singing range.
3. Figuring out the key:
Since we have transposed the notes of the range up a fourth (or fifth) the key for this song would then be F major which is a fourth up from C major.
Perhaps though that G major would be a better choice in this case depending on your singers.

As you notice you can't say that a specific key is always (or generally) suitable for any song since the tonic root note can be in the middle of the register required for the melody just as well as it can be at the outer limits of the melody. What really matters is the required range of the melody, and you'll have to work out a suitable key - in regards to the singers' expected range - from there.

¹ _{If most of the important parts of the melody is in the upper end of this range you should probably aim for a key a couple of notes lower, and vice versa, in order to have the important parts not sound strained.}

² _{Aside of voice quality, musically useful is also subject to conditions regarding required voice loudness, such as if there are instruments playing that the singers need to be heard over, and/or if microphones are used.}

Answer 2

For my answer I will assume that you are intending to work with untrained voices since you want the greatest amount of participation.

An untrained voice typically has about an octave range of good, usable tone production. You won't be able to please everyone - some will probably switch octaves when it is comfortable for them to do so.

As a good rule of thumb, the key of "F Major" is generally friendly for untrained voices and will give the widest range for chord voicing possibilities for untrained voices. However, you're working in unison so that added benefit doesn't really apply. "C", "D", and "G" are all good keys too - particularly the first two if you keep the melody in check.

Apart from the above suggestions, here is another rule of thumb:

• For women, keep the melody away from the top of the treble clef - if possible, keep it in the lower 2/3rds (but try not to stray passed "middle C"!)
• For men, keep the melody away from the bottom of the bass clef - if possible, keep it in the upper 2/3rds (but try not to stray passed "E" above "middle C"!)

Hopefully the melody you're working with isn't too snake-like :)