Ceilidh Bands and Barn Dance Bands always use a PA system of some kind. It is not possible to move once set up. If you are considering a performance that is outdoors if the weather is good, or indoor if it turns bad, then set the band up on the day in a marquee but facing out of an open sided marquee if the weather is good and facing in if not. If the weather changes, expect half an hour without music as the band turns their equipment around.
If you want music for a drinks reception before the Ceilidh, some bands can play acoustically for a 'music to listen to' situation, then plug in and use the PA for the Ceilidh. You must make us aware of this requirement before booking, as not all bands can do this and not all situations are suitable.
It is never realistic to do a Ceilidh without a PA system, although some people believe (to their cost) that it is.
This applies to our bands: