is a term that is applied mostly to jazz improvisation
. Technically, it can be applied to any style in which there is improvisation
, but it is most commonly used in a jazz
Trading fours usually means that two soloists 'trade' four bars each. So one of them improvises for four bars and then the other improvises for four bars, and so on, until the latter ends the 'duet'. Any instruments can trade fours, but it is commonly done either between two lead instruments (saxophone, trumpet, etc.) or between a lead instrument and drums.
The concept of trading fours, like many elements of jazz, comes from the work songs of African slaves. Often, these songs incorporated a 'call and response', when the leader would sing a phrase and the rest would chorus it back. This 'question and answer' is the founding structure of the blues, and is also the main idea behind trading fours. Good jazz players will turn their trading fours into a conversation. It shouldn't sound like two seperate entities, but rather two players responding to each other. Sometimes it sounds like one solo played on two instruments (listen to Sonny Rollins and Sonny Stitt trade eights and then fours on The Eternal Triangle - see if you can even tell when one stops and the other starts). Sometimes (more often) it sounds more like a question and answer (Sonny Rollins Quartet in Blue Seven).
You do not have to trade fours. It is possible to trade any number of bars. The most common after fours is eights, which I already briefly mentioned. This means that the soloists play eight bars each. This is usually done on up tempo tunes (Dave Weckl, Softly, as in a morning sunrise). Also, it is possible to change the amount of bars you are trading. This almost always comprises of shortening the amount of bars that are traded, as this builds up intensity. The first time I heard this was on Charlie Mingus' No Private Income Blues from Mingus in Wonderland, where Booker Ervin and John Handy trade fours, then twos, then play one bar each, and then just two measures each. Wow!
Often, a lead instrument will trade fours with a drummer to allow the drummer a solo without the drummer going into a whole chorus, which can be a bit long. It is sometime difficult for the audience to listen to a long drum solo, so this is a good way for the drummer to express himself.
Usually, the solos are played in the regular fashion, i.e. if a saxophone plays a solo, the whole rhythm section accompanies him/her, and if the drummer plays a solo, s/he is left alone. Sometimes, though, both players can be left alone, with the rhythm section staying silent, or the rhythm section plays a vamp, over which the soloists trade. It is also possible for more than two players to trade fours, playing four bars each in succession (for example - piano, drums, bass, piano, drums, bass... - Bill Evans, Twelve Tone Tune, from Blue In Green - Bill, Eddie Gomex and Marty Morell trade 12 bars each this way). The possibilities are endless!
Things to pay attention to when trading fours:
- When trading fours on songs whose length isn't divisible by 8 (i.e. four bars each), be careful, as the cycle doesn't complete in one chorus. Trading fours almost always ends after the second player's solo, so however many choruses you trade, you have to make sure that the second player ends it. For example, on a twelve bar blues, if a trumpet trades fours with the drums, the trumpet plays four bars, then the drums, then the trumpet. We have now completed one chorus. But this would be a bad time to play the head, as it doesn't feel complete. They must trade another chorus (drums, trumpet, drums), and then the trades end on the drummer.
- When trading fours with a drummer, it is nice to play rhythmic phrases, to let him respond to.
- Listen to the other player! You are having a conversation, not each one speaking separately. If you don't listen, that's exactly what it will sound like.
* trading fours is referred to in many languages other than English as four / four.