At vocal quintet Mezzotono's concerts this weekend, the audience will hear mandolins, drums and guitars, but they will not see a single instrument on stage.
The Italian ensemble is one of the highlights of this year's lnternational A Cappella Festival Singapore and will perform at the festival's opening free concert on Saturday.
The evening features more than 100 Singapore and international singers at the Singapore Botanic Gardens' Shaw Foundation Symphony Stage.
The festival has been organised annually by charity group The A Cappella Society since 2008 and this year has seven international acts from Asia and Europe, plus Singapore groups including TAS Voices, Acappuccino, Tropicappella and new kids on the block, Asia Pacific Youth Choir For Peace.
The 10 concerts lined up mostly at the Aliwal Arts Centre range from funk to swing and body percussion, while Kuala Lumpur-based quartet Shades are showcasing the music of P. Ramlee in their performance on Oct 26.
The International A Cappella Festival has grown in size and influence since it began in 2008 with a few performances at The Arts House. There are now a dozen-odd concerts every year and last year's event attracted at least 1,500 concertgoers.
The buzz appears to be attracting performers as well.
The A Cappella Society's founder Angelina Choo, 38, says: "We have always relied on teams travelling to the Taiwan A Cappella Festival or the Korean Festival to make a stopover here. This year, we have had to work with teams coming direct to Singapore."
Among them is Mezzotono, a five-member touring group based in Bari, Italy, which have performed in Taiwan and Malaysia but are coming here for the first time. Their visit is sponsored by the Italian Cultural Institute in Singapore.