What do you call all the pieces of a song minus the lyrics

I think there must be a good word for this, but can't think of what it might be.

Harmony and Melody are pieces of it, beat seems simplistic, Instrumentation seems too scientific and dull.

Any Ideas?

Instrumentals — TFD
plural noun of instrumental

It's very commonly used to refer to music (minus the lyrics)

noun Music
A composition for one or more instruments, usually without vocal accompaniment.

"the opening tune is an instrumental"

adjective Music
Performed on or written for an instrument.

"They played instrumental music at the wedding."
"an instrumental version of a song"

Or called backing tracks, karaoke, etc.

For further reading, here's a quote from a highly-upvoted and accepted answer to a similar question on ELL:

Instrumental can mean two things:

1. a "karaoke" version with the vocals removed; or

2. a song which was written without vocals in the first place.

From both the legal and writing process standpoints, the components that make up a song (by "song" I mean a musical piece that includes vocals, and may (often) include other musical instruments that accompany the vocals, with the vocals almost always including words in a specific language) are almost universally divided into music and lyrics.

When those two words are used in this sense, the word lyrics refers exclusively to any and all words that are sung or spoken or rapped as part of the song, and it does not refer to the melody or rhythm or any purely musical aspect of the vocals for the song. Often the word words is used in place of lyrics.

When used in these senses, the word music refers to everything but the lyrics (in the sense above) themselves, and therefore music in this sense does refer to the vocal melody, harmonies, and rhythms.

One visual way to separate lyrics from everything is to look at how a song is most commonly written down.

Image source

The top line of the music represents the vocal melody (and often includes vocal harmonies), and shows, in musical notation, the rhythm and pattern of notes that are to be sung. Right underneath the top line of music we see the words or lyrics written out, with each syllable aligned underneath the musical note that is to be sung at the musical time and on the pitch and for the duration indicated.

Is is clear in this case that music and lyrics (or words) separately refer to those two elements as written. In practice, especially among song writers, those words are used in the same exact way for the sounds as well.

Note:

• Music usually refers to all of the musical elements, including vocal notes and rhythms, but not any words or lyrics.
• Beat and instrumentation refer to the music played by any musical instruments along with the singing, with beat being used more often in the contexts of techno, rap, hip-hop, and R&B. Instrumentation can also refer to music played by instruments when there is no singing involved, or it can refer to simply the instruments chosen to play, without any reference to the music that is played.
• Backing track is often used as a synonym for beat or instrumentation, but sometimes includes any harmony vocals (along with the relevant lyrics) and sometimes omits solo and/or lead parts played by instruments.

Addendum

I randomly remembered the lyrics to a "Weird" Al Yankovic parody of George Harrison's Got My Mind Set On You this morning. In the parody, "Weird" Al refers to the "music" and the "words" and "lyrics" as separate parts of making a song.

Relevant excerpts:

You really need words
Whole lotta rhyming words
You gotta rhyme so many words, mm-mm
To do it, to do it, to do it, to do it
To do it, to do it right, child

Later:

Oh, you gotta have-a music
You need really catchy music
This song has got plenty of music
But just six words, child

And so I'll sing' em over
And over and over and over
And over and over and over, mm-mm
And over and over and over
And over and over and over again

Source: https://www.youtube.com/watch?v=tI4oRt7PLnc

I'd go for 'music'.

Bing defines a 'song' as:

a short poem or other set of words set to music or meant to be sung.

The Free Dictionary describes a song as:

a piece of music, usually employing a verbal text, composed for the voice...

Oxford Dictionaries take on the word:

short poem or other set of words set to music or meant to be sung.

which is exactly the same as Bing's.

And Merriam-Webster say:

a short musical composition of words and music

So, without words, a song becomes just music.

I want to draw the distinction between the tune and the accompaniment.

If we take away the lyrics we are definitely left with one thing, the tune (or melody) and may be left with another the accompaniment.

I claim that it's not a song unless there is a tune to be sung. There are examples of pieces of music that are called songs by their creators, but which do not have words; Felix Mendelssohn's Songs Without Words being a well known example.

Not all songs have an accompaniment, many folk songs are sung unaccompanied. However in many cases the instrumental accompaniment is intrinsic to the character of the song. This seems very much the case for concert music such as Schubert's Lieder, but also in popular music the riffs, or intricate acoustic guitar parts are a formal part of the song.

Considering songs by Rogers and Hammerstein, Rogers is referred to as the Lyricist and Hammerstein as the composer. Hence we could argue that everything of the song except for the lyrics is the composition. However I don't think I've ever heard "composition" used in this way. I would say that a song has three elements: Lyrics, Tune and Accompaniment, so no single term for what's left when lyrics are removed.

[instrumental] accompaniment

A musical part that supports or partners a solo instrument, voice, or group.

Oxford Dictionaries

(music) Instrumental part.

Gwen sang for us, with Muriel providing accompaniment on the piano.

WordReference