in this series of videos i'll be explaining what time signatures are and how they work in this video part one i'll be explaining the more common types of time signatures such as those listed here and i'll be demonstrating how to calculate missing time signatures from a passage of music it's really important that you understand note names and their values before looking at this video if you're not sure of the names of notes have a look at my video note names and their values firstly it's important to understand the meaning of a time signature so here's a time signature which most people have seen before 4 4 what does it tell us well the top number tells us how many beats are in a bar in this case there are four beats in a bar if the top number was 12 that would be 12 beats in a bar if there was a three there'd be three beats in a bar and so on technically you can have any number you like at the top as long as it's a whole number and not a fraction like two and a half but we'll start with smaller numbers first it's the bottom number that seems to cause most confusion the bottom number tells us the type of beat by this i mean do we count in crotchets minims quavers or something else in this example the bottom number is four this effectively means which note and here are a few can fit into a semi-breathe four times four times because there's a four at the bottom of the time signature the answer is a crotchet this one as it has a value of one and can fit into a semi brief four times so we can say that the full meaning of four four is four crotchet beats per bar the four being the number of beats the crotchet being the type of beat let's look at another example as there is an eight at the bottom you need to work out which of these notes can fit into a semi-breathe eight times here's our semi-brief at the bottom of the screen a minim only fits twice a semi-quaver fits 16 times whereas a quaver which is worth half fits eight times into a semi-brief so we've worked out that eight represents a quaver so the full explanation of this time signature is that there are three quaver beats in each bar the three being the number of beats the quaver being the type of beat this time signature which has a two at the bottom well that represents a minim as two minims each worth two fit into a semi-brief which has a value of four so the full explanation of this time signature is three minion beats per bar hopefully by now you're getting the hang of what time signatures represent so let's look at some fairly common time signatures four four this is a very common time signature so much so it is often abbreviated to this symbol the c is short for common time now i've already said that this time signature means that there are four crotchet beats in a bar this is true but it clearly doesn't mean that we can only write four crotchets in each bar of course not we can write anything we wish in the bar as long as the total value of the beats is exactly for no more and no less so this is acceptable so is this the four semiquavers equal beat one this crotchet is beat two the two quavers equal one beat and the final crotchet equals one beat so there are four beats in this bar this bar is also acceptable the four quavers equal two the final minim also equals two two plus two equals four beats we are allowed in this bar the same is true for every other time signature no matter what the time signature is displayed every bar must equal the number of beats in the bar so here's three eight remember this means three quaver beats in each bar it doesn't mean you can only have three quavers in each bar you could have six semi quavers if you wanted or indeed almost any type of beat as long as it doesn't exceed three quavers i mentioned a few moments ago that this symbol means 4 4 here's a time signature that looks very similar but means something else notice that there is a line through the middle as if the c has been cut in two well this is often called cut common time and it represents two two so firstly remember this is common time and equals four four this is cut time or cut common time and represents two 2. now a lot of students ask me why have 2 2 when you can just have 4 4 as they both have 4 crotchet beats in them my answer is simply no although 4 4 has 4 crotchet beats 2 2 does not it has two minion beats okay two minions can be split into two crotchet beats each so you may ask why have two two at all well there are quite a few reasons for this but the most common reason is to do the tempo or the pulse of the music for example 2 2 is quite commonly used for faster music 4 4 is generally used for slower not slow but slower music in 4. just don't worry too much about this if you're writing a piece of music it doesn't really matter whether you were to use 2 2 or 4 4. what's important is that you understand that 4 4 has 4 crotchet beats per bar and 2 2 has two minion beats per bar this does cause a problem if you're sitting a music theory exam and asked what time signature could be for this piece of music without really knowing how fast the music is to be played it's pretty impossible to know for certain therefore the answer could be four four or two two you'd get a mark for either the same dilemma appears in many other time signatures such as three four or three eight perhaps you want to compose a piece of music in three but you're not sure whether to use three four or three eight they both have three beats three four is in crotchet beats whereas three eight is in quaver beats generally three eight is used for faster rhythms but there's no real hard and fast rule so don't worry too much about this i will have a look a little more about this in my videos about composition now before we tackle some exam type questions there's something very important i need to point out here here's a full bar of quavers in 2 4 and 3 8. notice how in 2 4 the quavers are in groups of 2 whereas in 3 8 they are in a group of 3. i talk about the grouping of notes in my video about beaming but as a rule of thumb for the moment quavers in a time signature with an eight at the bottom are grouped together in threes do remember this rule okay if you're going to be sitting a music theory exam you often come across questions whereby you'll be given a melody or a rhythm and you have to write down what the time signature is let's try a few examples now the first thing to notice is that the quavers are grouped in twos this immediately means we can ignore any time signature with an 8 at the bottom if there were a two at the bottom of our time signature we'd be counting in minims as the two represents minimum beats now if we add all the note values together half plus half plus one equals two one minim equals two therefore as there is one minim in this bar the top number in our time signature would be one making the full time signature one two this is a very rare time signature and if i think about it i don't think i've actually ever played a piece of music in one two so let's try again let's try counting in crotchets so a four at the bottom the two quavers each worth half equal one crotchet and there's another crotchet here so there are two crotchets in this bar as there are two we add a two to the top of our time signature so two four which is a much more common time signature is the answer how about this one there's no quavers in this one so we can't dismiss time signatures with an eight at the bottom just yet so let's look at the options if there was an eight at the bottom meaning quaver beats we have to count up all of the quavers in the bar so in this minim there are four quavers remember that each quaver equals half the second minim therefore has another four quavers this crotchet is made up of two quavers as is this one and here's another minim so another four quavers if we count up all of the quavers there is a total of 16. so our time signature could be 16 8. i'll pop this at the bottom of the screen as a possible answer for the moment okay so how about if we count in crotchets a four at the bottom of the time signature two crotchets here two here one one and another two we count up all the crotchets there are eight of them so the time signature could be eight four i'll pop this at the bottom of the screen as well finally how about counting in minims a two at the bottom of the time signature one minim here one minim here these two crotchets equal one minimum and one final minimum so four minims in total this could be four two so which of these options to choose well the answer is four two now there are lots of reasons for this some of which are quite complex and i'll discuss this further in part three but the main feel or pulse of the beat is clearly in two due to the abundance of minims it's also easy to count to four rather than having to count eight as in eight four in every bar besides why write eight four when like fractions it's easier to express as four two as for sixteen eight well this is actually another very rare time signature if you're studying music theory with the associated board you'll never get asked a question about 1680 it's what's called an irregular time signature and i'll be looking at irregular time signatures in part four of this series of videos in a nutshell irregular time signatures are when the beat cannot be split equally into twos or threes remember i said that when the time signature has an eight at the bottom the quavers are grouped into threes we can't group 16 quavers into equal groups of threes that have to be two groups of two this makes it an irregular time signature 4-2 however is a very common time signature and emphasizes the minim beats quite a tricky question this one in this example there are two bars and the second bar has a rest in it always make sure that you count any rests in a bar when calculating a time signature rests are just as important as the notes themselves to calculate the time signature let's start with counting in crotchets a four at the bottom of the time signature well this wouldn't work as we'd end up with one and a half in each bar remember you can only have whole numbers at the top of a time signature it can't be a minion beat as there isn't even one minim in each bar but we can count in quavers and eight at the bottom of our time signature two quavers in a crotchet and one here so there are three quavers in this bar let's just check the second bar as well there are three quavers don't forget to include that quaver rest we've already put the eight at the bottom of the time signature to represent the quaver beats we've calculated that there are three quaver beats per bar so we can add in three as the top number to our time signature so the answer is 3 8. one final example no quavers in this question but if we did count them there are eight so it could be eight eight if we counted crotchets there are four so the answer could be four four and if we counted in minims there are two so the answer could be two two the answer's not eight eight as why have eight eight when you can have four four a simpler way to express eight quavers in a bar remember with an eight at the bottom we're looking to group our quavers in groups of threes now in eight eight it's not possible to group all of your quavers equally into groups of threes that have to be groups of twos so it makes it an irregular time signature so is it two two or four four well it could be either you'd get a mark if you put four four or two two in fact you'd also get a mark if you chose to use the symbols for common time or cut common time there is simply no way we can tell whether the composer wrote this in four four or two two so just be aware that sometimes and only sometimes there may be a choice of answers now i could keep providing examples like those we've just tackled but as there is an unlimited amount of possibilities i will leave it there the key thing to do is to count and explore each time signature option in time you'll get quick at this and you'll be able to spot missing time signatures very quickly in the next video i'll be explaining the difference between simple and compound time signatures in the meantime thanks for watching