We sometimes get asked to have a ceilidh or barn dance without amplification. Forget it. It won't work and most bands won't even attempt it. Being in a small room doesn't help either, it is probably even worse as people's bodies absorb the sound and the noise of their feet thumping, laughter and shouting drowns everything out.
In the olden days, before amplification, Ceilidh bands were small orchestras, 10 or 15 strong. Remember, amplified music doesn't have to be loud, just enough to be heard comfortably and for the sound quality to be good rather than weak and strained. If the band is too loud, ask them to turn it down a bit.
This applies to our bands: