I am planning to sing a song and which has a vocal range of D3-D4.
I want the crowd to join in too. Should I raise or lower the tune of this song to better fit the crowd's range?
Which key or vocal range is recommended for a crowd (comprising of men and women)?
Just about everyone can manage an octave from B♭ to the one above. Women and men will find their own octave. Take it up to C if you like. By D some will begin to fall out, but this should be compensated by the louder tone of those who CAN get up there!
Having said that, crowds enjoy 'going for the high note' in some types of song. Keep 'All things bright and beautiful' in an easy range. But 'Walk through a storm' NEEDS at least an E♭ or F, even if some of them can't quite make it! (Not G though. That gets ugly.)
One other place where we find large crowds of people singing songs together is worship music- so perhaps we can find relevant advice there.
The general consensus* is that the most friendly keys for congregational singing will be the keys which place the melody in the range of C to C, roughly. It doesn't technically matter which C's, really, as men will generally sing C3 to C4 and women will generally sing an octave up, C4 to C5. For readability, you should notate C4 to C5 on a treble clef. You can reach beyond this range a little if necessary but go too far and you'll start to lose people...
Oddly enough, I was reading an analysis of this a couple of weeks ago: Finding The Best Keys For Congregational Songs. (That page is for worship leaders and analyses lots of popular worship songs; but I think the principle applies equally to most sorts of contemporary singing.)
Its conclusion is that the average singer's basic range is the octave-and-a-fourth from A up to D, with the most comfortable part being the octave C–C. If necessary, the occasional top E♭ may be allowed; but many people will struggle to exceed that range in either direction. And a song that spends time near the top of that range will be tiring for many singers even if it doesn't go over D.
So: stick to C–C where convenient, and to A–D if at all possible. That may mean some compromise between what's best for you, and what's best for the average member of your audience, if you want them to join in.
I'm going to take a different tack on this...
Listen to a crowd singing along to a big ballad - one that springs to mind is Robbie Williams' Angels. They'll go for it whether they can reach it properly or not. The money note in that is an E5 with a more throwaway [or swung at & missed] F♯ after that.
The commonly returned-to bottom note [not literally the lowest but the others are fleeting & throwaway] is a D4, so only just over an octave, but pitched for a pop singer not an opera singer.
I wouldn't use hymns as any kind of reference - there's a different purpose in how they are pitched.
So, make your money note reachable by most. There's a reason it's a money note - it's the one people want to join in on. I think you're probably in safe territory with a D… but D3 to D4 feels like an odd octave for a pop song.
…or maybe it's not a pop song, you didn't say.
The vocal range of people is an important topic to vocal science and speech pathology, and has of course received much research attention.
TL;DR
A2-C4 (adult males) and A3-C5 (others) normally work for most people, in line with both answers from Edward and Laurence Payne quoting standard practice. It's called standard for a reason.
Summary of results
Studies which are not open access are not included. Note I'm specifically going to take the most inclusive range, i.e. approx -2 stdev or 5th percentile for upper limit and +2 stdev or 95th percentile for lower limit.
Dienerowitz et al., 2021 [1], studying 1578 mostly untrained children, report A3-C5 for most, except about A2-C4 for older boys. Wuyts et al., 2010 [2], with 74 younger children report A3-E♭5.
In adults, Hunter and Titze, 2005 [3], reported 4 untrained subjects at G2-G♯4 (male) and D3-E5 (female). Siupsinskiene, 2010 [4], reports A2-G4 (untrained male, n=38; Table 2) and G3-D5 (untrained female, n=89; Table 3). Ma et al., 2007 [5], reports E3-G5 (non-dysphonic female, n=35; Table 2). D'Alatri and Marchese, 2014 [6], reports F♯3-B♭4 (non-dysphonic female, n=40; Table IV - mean used for upper limit).
Remember most of these are reporting extreme ranges, so going straight to the edge is not going to be fun for most people.
Figures
High and low voice limits of children. Figure 1 from [1].
From [2].
Vocal and hearing ranges of single subjects. Figure 1 from [3].
References:
[1]: Tobias Dienerowitz, Thomas Peschel, Mandy Vogel, Tanja Poulain, Christoph Engel, Wieland Kiess, Michael Fuchs, and Thomas Berger. "Establishing Normative Data on Singing Voice Parameters of Children and Adolescents with Average Singing Activity Using the Voice Range Profile." Folia Phoniatrica et Logopaedica: in press, 2021.
[2]: Floris L. Wuyts, Louis Heylen, Fons Mertens, Marc De Bodt and Paul H. Van de Heyning. "Normative voice range profiles of untrained boys and girls." Journal of Voice 24(2):153-160, 2010.
[3]: Eric J. Hunter and Ingo R. Titze. "Overlap of hearing and voicing ranges in singing." Journal of Singing 61(4):387-392, 2005.
[4]: Nora Siupsinskiene. "Effects of Vocal Training on Quantitative Voice Parameters in Healthy Voice Adults and Children." In Laryngeal Diseases: Symptoms, Diagnosis and Treatments, Oldrich Nemecek and Viktor Mares (eds.), Nova Science Publishers, 2010.
[5]: Estella Ma, Jennie Robertson, Claire Radford, Sarah Vagne, Ruba El-Halabi, Edwin Yiu. "Reliability of Speaking and Maximum Voice Range Measures in Screening for Dysphonia." Journal of Voice 21(4):397-406, 2007.
[6]: Lucia D'Alatri, and Maria R. Marchese. "The speech range profile (SRP): an easy and useful tool to assess vocal limits." Acta Otorhinolaryngologica Italica 34:253-258, 2014.
The key is of no relevance, unless the range of the song is known. Then, it's of paramount importance! The range is, as already mentioned, the lowest and highest notes in that song.
OP asks about 'a crowd' singing. Quite different scenarios between a football match and a hen night, for starters. Or a kid's birthday party and a gathering of OAPs!
Most people - 'non-singers' included, will have a range of an octave or so. C3 to C4 for males, C4 to C5 for females, as a (very) rough approximate. Well oiled with alcohol, probably a little more at each end, and often with greater volume. Those who are outside this range will often compensate by dropping/rising an octave for the notes outside that range.
Now, back to key. Not all songs have the tonic as the lowest and highest notes. So that's not a god criterion - on its own. A common example will be 'Happy Birthday' - well crafted for all to sing - and why not?
In my 60-odd years of playing it, keys F and G have been the most accepted. The tune happens to have its 5th as the lowest, and an octave above that as its highest note. So, assuming C-C is an 'average' range, key F is perfect. OP's tune may use the same criteria, thus revealing the 'perfect' key.
This is a very good question. Until a little more information is given, this should help.
The range you have given, D3 - D4, falls into the tenor vocal range. As such it also overlaps with the bass vocal range and the alto vocal range, however some notes will be hard for the basses and some notes will be hard for the altos. Roughly speaking, the basses will have difficulty with the D4; the altos will have difficulty with the D3; sopranos can not sing in that range; please read on for more on this though.
Will this be sung as a single unharmonized line? If so, most people automatically sing in their own octave (they will sing up or down an octave from the original singer) and therefore there is theoretically no problems regarding range. However, in practice, it is not that simple. Some melodies seem more inclined to octave transposition than others.
In order to fit better within each range, you might want to try the key of G:
Soprano: G4 - G5 (Perfect fit); Alto: G3 - G4 (stretch on G3); Tenor: G3 - G4 (stretch on G4); Bass: G2 - G3 (Perfect fit).
(the key of A would also be good; generally speaking the key of D is not good for untrained male singers. They have difficulty with low D.)
