Tempo ramp up - applying it to audio


I have Cubase LE AI Elements 9.

I’ve recorded some audio (a few friends singing a backing vocal in harmony spread over several tracks). I would like to ramp up the speed of that audio gradually. Ive adjusted the tempo track to gradually ramp up from 80bpm to 160 bpm over about 16 bars and the drums (A midi drum kit) are speeding up beautifully in sync with the tempo track.

However, can’t figure out how to do the same with the audio files.

I have attempted selecting the audio file, then: Audio>>Advanced>>Set Definition from Tempo.

It a small sine wave icon appears on the file, but it does not ramp up the tempo of the audio… so ultimately the drums and the vocals go out of sync when you play them back.

Can anyone advise? Is it possible please? My backing singers have left the country and I think that ramping up the tempo will really inject some passion into the song!

Kind regards