I feel like there's a lot of unrealized potential in open bands. A typical contra dance band has 2-4 musicians while an open band might have twenty. This could be a big opportunity for sounds and textures that aren't practical with a small band, but instead you tend to just get a fuller but less tight and less varying version of a regular band. When there is variation it's typically in the form of having some portion of the musicians drop out ("only winds!"), giving solos to people ("next time through just Julie!"), and dynamics ("slow build over the whole next time through!"). These are effective and easy to lead, so they're a good place to start, but with so many musicians what else can you do?

Before I get more into this, though, there are a lot of different goals organizations, band leaders, and musicians might have with open bands. I'm going to be approaching this from the perspective of trying to make music that modern urban contra dancers generally most want to dance to. I think this is the best approach for a standard evening-dance open band, though I do think it's also valuable to have other open bands that are more about giving people practice playing for dancers. For example, BIDA occasionally puts on a family dance before the evening dance, and for that we have a low-pressure all-acoustic open band that plays simple tunes with unison melody and minimal variation. In that situation I think this is completely the right choice!

Ok, but say this is a regular evening dance and you're leading an open band: what do you do with all these musicians? If you don't tell them otherwise they'll default to unison melody. This gives a more complex texture, but it doesn't add all that much: a single fiddle is already able to do a great job in this role, a second melody instrument helps some, and by the time you add a third the contribution is getting pretty small. I think a better direction to come at this is allocating your extra musicians to other roles: what would your piano player be doing if they had more hands, or more textures to draw on?

Another stereotypical open band thing is to have a "resting position" or "default arrangement" of everyone playing. This is like an organ player defaulting to pulling out all the stops! Instead, consider that as your most intense arrangement, and most of the time have many fewer people playing.

As a new band leader, one way to try this out is to pick a pair of strong players, rhythm and melody, and start the dance with just them. While the dance is running, think about what the music most needs and which of your musicians are best positioned to provide it; talk to them and have them come in. Repeat until you've built the texture you want. If you still have more time in the set, try dropping back to just those two initial musicians, and then bring the others back in but in a different order than you did initially. Try different combinations of the parts, and then close the set out with everyone back in.

Coming up with non-melody things for people who think of themselves as melody players to do can be a lot of work, and is worth thinking through before the dance, especially if you're not practiced at coming up with novel arrangements on the fly. Here are some ideas:

• Slow chords that reinterpret the tune. Progressions like "I vi IV V" or "IV I V vi". At least four beats per chord, but eight or sixteen can also work well. Melody players aren't generally used to thinking about numbers, so call the root note instead. Holding up signs with the chords in addition to calling them is also good. You can do it at different speeds, and even drop the melody entirely and have everyone on the chords for a time through the dance. The simplest version is long notes, though this works well with all sorts of patterns.

• Lead a simple rhythmic riff, just a few notes. People joining in as they pick it up gives you a natural build. Consider only running the riff over the A part or B part, to support the structure of the dance and to keep it interesting longer.

• If you have percussion players, start a set or tune with just one them and your lead melody. Suggest to the percussion player that they play an interesting accessible rhythm. Bring in other musicians gradually as they get into this groove. If you don't have anyone specifically on percussion, this also works with other instruments. Ask around whether anyone is interested in leading a rhythm. This general approach is good for dances in the middle of the energy continuum; anything except "smooth and pretty" or "high energy closing set" (though it could even work for the beginning of the latter).

• Along similar lines, if you don't have anyone playing percussion lead something very percussive. Think about the different things a drum kit would do and assign those to different people. This can include not playing tonally at all, for instruments that can thump, chuff, or scratch. If you do need something tonal, pick a super simple chord progression to combine this with, like I IV, at least at first, so your musicians can be focusing on the percussion aspect without needing to put a lot of thought into chord changes.

• Get inspiration from horns. While it's uncommon to have actual horns at an open band you tend to have a lot of instruments with similar constraints to horns, in that they only (or prefer to) play one note at a time: this means many of the things horns do can work well. One of the classic horn parts is short repeated rhythmic patterns at the end of the phrase, which supports contra dancing well. Another stereotypical bit is stacking a chord, most commonly a V7, where you bring in each of the notes in order For example, for E7 you'd start one or a few people on E, then after a few beats (4 or 8) bring in another person or people on G#, then B, then D. You can even double stack, continuing after the D with another round on higher instruments. Here's a video introducing writing horn parts: youtube. Standard horn parts can get pretty complex, but keep things simple: you want things people can easily pick up on the fly.

A lot of this can seem cheesy, but embrace the cheese. You're not a serious band, you're a one-off group trying to give people a good time. They're busy dancing, and will enjoy music they can feel.

One place to watch out with the advice above is keeping your musicians happy. As I wrote before I think your main goal is happy dancers, but an open band won't sound good the night of, and will collapse in the long term, if the musicians aren't having fun. Most of your musicians are most comfortable playing melody, want to play most of the time, and may find responding to calls a bit stressful, so you probably want to end up more towards the "everyone playing unison melody" end of the spectrum than if you were only going for the best sound for dancers.