hello guys! if you have to sing accapella (without music) , what type of song should you choose? slow, fast....etc...????? one more question, why do the musicians want new singers to perform accapella? to listen to the singers' voice quality and vocal techniques? if so, should i choose a song that is slow with great vocal preformance?? this is so improtant, if you guys have experience regarding this topic, please give me advices and ideas. many thanks in advance.