When Grammy award-winning singer-songwriter Imogen Heap began her performance at Hard Rock Cafe,Saket,on Tuesday,the unassuming songstress brought the house down with her sticky notes,breathy vocals,interesting falsetto and songs that were intricately woven. The venue was packed and buzzing. While Heap performed a range of numbers that complemented her dishevelled hair,the one person who caught the audiences eye among her set of musicians was Indian flautist Ashwin Srinivasan,who was on the stage with a cellist and a drummer. Thirty-two-year-old Srinivasan collaborated with Heap on four tracks last night and he received much attention from the fans,and of course Heap,who kept appreciating him at regular intervals. There is something very scientist-like about Imogen. You see a hundred gadgets with and around her,those wrist mikes and tinkling bells,that eureka moment and then a child-like heart that just wants to be happy in the given moment and make interesting music, says Srinivasan,who met Heap almost four years back,during a concert at the prestigious Albert Hall,where Srinivasan was a part of percussionist Nitin Sawhneys ensemble. After this performance,Srinivasan was featured in Heaps last album,London Under,and has been a fixture in her concerts ever since. Imogen has always had a fascination for Indian sounds. But more than the flute,she likes me to sing with her and add that male voice to the whole concert, says Srinivasan,who has also played flute for Mira Nairs The Namesake and Amelia in the past. Heap began with a set of hi-tech songs,with a slew of gizmos,and Srinivasan collaborated on the tracks Let Go,Tidal,Goodnight and Go and Mind Without Fear. The flautist was also a part of her collaboration with Vishal-Shekhar on Star Worlds new show,The Dewarists. Heap had the audience singing harmonies by dividing them into three groups,as she sang a capella (a fast rendition of a song without any instruments). She concluded the performance with Hide and Seek,the hit number from her debut album Speak.