I don't have the best voice in the world - but I got by singing traditional unaccompanied Scottish / English / Irish songs. I found that funny songs that got the audience laughing covered up the creaks in my voice.

So I started to write my own funny songs set to traditional tunes.

It works for me and I find that, as an unaccompanied singer, I can hold the attention of an audience for a much longer period with my own brand of humour and singing, than by sticking to the traditional material.