# Why are time signatures needed?

Days ago, I think I got something that I want to confirm with you.

This is my reasoning:

• If you play an instrument that can only play one note at a time, like a trumpet, you don't really need the time signature, since you always have to play one note completely to play the next note.

• If you play an instrument that can play more that one note at a time, like the piano or guitar, or play more than one instrument (like in a band), you need the time signature because without it, you can't know when to play the next note.

For example: you have a piano score. In the first measure you have 4 quarter notes all of them different notes in that measure. The tempo is "quarter note equals 60." In this way, you can play the first note at t = 0 s, the second note at t = 0.25 s, the third note at t = 0.5 s and the last note at t = 0.75 s. The four notes are held exactly one second. Or you can play the first note at t = 0 s, the second note at t = 1 s, the third note at t = 2 s and the last note at t = 3 s.

So without time signatures, in the last case, an ambiguity arises and the whole purpose of the time signature is to eliminate this ambiguity.

• This doesn't make any sense. The time signature is about the beat and fully independent of the tempo, and neither depends on the type of instrument. – delete me Apr 17 '15 at 19:46
• I'm somewhat unsure: possibly mean chord notation? Whether notes are played at the same time or not, is typically seen from the fact, that they share the note stem... This rule finds its exception in very tightly set chords, where notes in smaller intervals than a third may be squeezed aside. – guidot Apr 17 '15 at 19:53
• I voted for closing. It's nothing personal, but I find the question, the way it is phrased, to be absurdly confusing and would probably not help much somebody who read it. I had to reread it 10 times. I fear it would confuse the hell out of anybody who came here wondering what a time signature actually here. – Some Dude On The Interwebs Apr 18 '15 at 13:06
• @SomeDudeOnTheInterwebs Ideally we'd take out the whole polyphonic instruments thing, which is a red herring, but unfortunately then the accepted answer would make no sense. It would arguably be better if the OP had just asked "Why are time signatures needed?", and left the wording of the question simpler. But we also expect people to show that they have done their own research, and I suspect If he'd kept it simple we'd have people voting to close for that reason. – topo Reinstate Monica Apr 18 '15 at 15:34
• @topomorto No, we specifically do not close based on lack of research here. That's what downvotes are for. All: I've cleaned up some comments. Comments are for clarification and on-topic info/explanation that doesn't constitute a full answer. If you want to talk about downvotes and the merits of closure, head to Meta or Chat. – delete me Apr 19 '15 at 22:16

Your basic premise is incorrect. Both of the examples you describe are represented through the notation, and are not captured in the time signature.

In the image below, the first bar represents your first case, and the second bar your second case.

The basic point of a time signature is as an organizing principle for music, to give the music a sense of structure and to help performers in understanding how to play it. The first beat of a bar is usually accented; which other beats should be accented is often explained through the use of the time signature. (For instance, in a 4/4 pattern, the third beat often carries a weaker stress than the first, but stronger than the second or fourth beats.)

• @aeismail First, your notation is horrifying. Second, your ideas of "accented" beats are entirely contextual. You should only accent certain beats if it is historically or stylistically necessary. Otherwise, you should play the music as written. – jjmusicnotes Apr 17 '15 at 22:52

Time signatures are not needed. Gregorian chant was written without time signatures. As much as they are not needed, they are extremely helpful in so many ways I struggle to think of all of them. Time signatures and measures work together, and measures are very helpful in keeping track of where one is in the music. Also, time signatures provide rhythmic information that would be tedious to communicate in any other way.

Breaking even a short piece into measures and providing a repeated rhythm for those measures is just one aspect of the immense benefit of using time signatures.

Another way to look at it is as an analog to key signatures. You don't need to use a key signature - you could just put accidentals wherever you want them to be played. But using key signatures is extremely helpful, even when there are a lot of accidentals, since it gives you a home base for the tonality of the music.

• I heartily disagree with your ideas. Time signatures are dependent on the music. Next time you play Stravinky's Firebird with an orchestra, let me know how it goes without measure numbers. Some forms of music don't need time signatures, like the ones you mentioned, however, it is important to know how best to organize your music. Your comments on key signatures are equally silly and misguided. – jjmusicnotes Apr 17 '15 at 22:50
• I think we actually agree and I worded my answer in a way that confused you. Also your comment comes off a little ad hominem, which seems unnecessary if intentional. – Todd Wilcox Apr 17 '15 at 23:06
• Imagine if your ruler was only marked with millimetre lines, and had no centimetre markings (or maybe even numbers on). Measuring would be pretty tough! It's often helpful to have a big unit, and a small unit. Bars can be the big unit here - it enables a conductor holding a practice session to say "let's go to bar 86" without the performers having to count forward hundreds of individual notes, adding their durations. One thing the time signature does is define how many beats (small unit) are in your bar (big unit).

• Time signatures are understood to imply a feel. with 4/4, the first beat will be strong, the second weak, the third quite strong, and the last quite weak (but perhaps having a little extra oomph in anticipation of the next strong beat. 6/8 is Strong - weak - weak - quite strong - weak - weak, and so on. So the time signature implies a feel within each bar, as well as just giving you a bigger unit of counting.

No-one plays notes for a pre-determined amount of actual milliseconds - it's almost impossible to do, and certainly would not sound musical. How on earth would one re-set the stop watch to time the next note?

The PULSE of a piece is stated in bpm, but this is a guide rather than a target, and makes sure that one performer or many, as in a band, keep together. In LEGATO playing, one note follows another without a perceivable break. If it's STACCATO, the attack of each note is at the same instant as the legato, but there's a gap between that note and the next.

In 4/4 for example, at 60 bpm, four crotchets would be played in turn, consecutively, in time with a metronome set to 60bpm. 8 quavers would be played in the same time as that, so would be twice as quick, and half as long each.

You seem to be confused with the whole concept of music notation and its translation.

EDIT -Or - does the lack of a time signature include the lack of bar lines to match it? If the bar lines are still present, there maybe is no real need for a stated time signature, as a count of the first full bar quickly tells the player. A different can of worms.

Clarification:

• time signature is something like 4/4 or 6/8 showing how many notes a bar comprises of. It says something about the characteristic of a piece, because the first note of a bar is always slightly accented

• a metronome specification like a quarter = 60 determines the simple speed to start with, which might be modified later using accelerando, ritardando or simple a new specification.

You seem to talk about the second topic under the title of the first. From both issues there is no connection to how many notes your instrument is able to play. In your example with the given metronome indication the second quarter has to play at 1s, the 3rd quarter at 2s etc.

Note, that many composers do not bother with metronome indications but stay with an italian term like "Andante", which has quite a range even when using the table from a metronome which even may widen with additional knowledge of the piece. The metronome numbers may then added later by the editor of the sheet music.

• "Quarter note equals 60" means that if you see a quarter note in the score, it hast to be played for one second. If you see two quarter notes with different pitch, how do you know when to play the second note? You just play the first note for one second, you stop playing this first note and immediately start playing the second note for another one second? or you play the first note, you keep playing this first note for 0.2 seconds, and without stop playing this first note, you start playing the second note. – Carlitos_30 Apr 17 '15 at 19:57
• @Carlitos_30 - your premise is false. If a quarter note =60, then it gets played for one second. Longer or shorter, and it's not a quarter note! If notes overlap, then it's shown in the dots. And the two notes which start at different times, but finish together, will have different shapes (a crotchet and a quaver, maybe). But in a 4/4 bar, there needs to be enough notes and/or rests to fill it with 4 beats, and at 60bpm that bar will last just 4 secs. – Tim Apr 18 '15 at 12:31