Syncopation: This is one of the things that starts to add additional interest to rhythm. This is where we hold a note across a beat in such a way that we almost start to feel that the offbeat is the beat temporarily. This will often be in a context with a straight groove such that you can clearly feel the tension between the two. If everyone starts playing on the offbeats for a lengthy stretch then you might just want to rewrite it so those become the actual beats. You need something to compare against for syncopation to make sense. It’s often very short - sometimes just a beat or two, but it can also go on for several measures. Jazz uses syncopation a lot - notes either come in half a beat before you think they should (anticipation) or half a beat later than you think they should (delayed attack).

In classical music, syncopation hasn’t historically been used all that much for melody, but it is used all the time for background lines to give some movement to otherwise static lines. As a violist, I play syncopated background lines all day long - it’s kind of our bread and butter! You can find examples of violas (and 2nd violins) doing that in almost any orchestral or chamber piece you look at, but one example that jumps out to me immediately is a particularly tense section in the exposition of Brahms’ 2nd symphony, where several instruments including the violas play a pulsing figure offset from the beat by one 16th note (so we are tied across the beat the whole time). The violins and cellos have a melody on the beat we are playing against. Even with that melody, it can be quite challenging to hold this syncopation accurately for that long and come out at the right spot at the end, particularly since there are several points where we have to change pitch together in the middle of that!

Swing: In a lot of the music I play (mostly classical and various offshoots of Celtic folk), the subdivisions of a beat are played more or less straight, which is to say that they are roughly evenly spaced over the course of the beat. In a lot of other music, there is an overt swing, where the offbeat is pushed to be closer to the next beat note rather than the beat note before it. Swing can have all sorts of subtlety and nuance. Some people would smack me for saying that Celtic folk music is straight, as it really isn’t completely even. Reels are generally more or less even, but you will still feel a subtle distinction between the onbeat and offbeat notes - the offbeat notes will be delayed ever so slightly, and also played at a lower volume than the onbeat notes, which gives a very light swing to those tunes. Jigs are much more noticeably swung - Jan Tappan, the leader of the Scottish Fiddlers of Los Angeles, says that if you say “hippity hoppity” that will get you close to the right feel of a Scottish jig, which is somewhat more uneven than an Irish jig. Even Irish jigs are not really straight though. Irish hornpipes, however, are much more overtly swung, and actually begin to approach a dotted feel. I need to be careful again here though, as traditionally they are not really dotted (or even triplet swing). You need to listen to recordings of good players for hornpipes, because the real feel of a hornpipe cannot be accurately notated with our notation system. Because they are often written with triplet swing today as the closest you can get, many newer players play them more like that, but that isn’t traditionally how they were played.

Jazz and other styles growing out of it uses swing much more overtly than that though, and the default setting for jazz is to swing things. The faster a tune is, the straighter it will become, but songs at a moderate pace are almost universally played swung unless marked otherwise.