The singer, who is recording her second album with the group, said their new material would be written by themselves and more "vocally driven" than their last LP Sweet 7.
"We're currently in the studio recording at the minute. This album is more vocally driven and organic," she told Dean Piper.
"We really want to be all about the voices so are just getting round an acoustic guitar to write the songs at the minute. Speaking as a fan, I loved The Sugababes round the 'Freak Like Me' days where it was all about the vocals.'
Ewen also added that they aren't working with famous producers on the record in a bid to stand out in the charts.
She continued: "We've recorded about 15 tracks so far. There are no big-name producers we're working with as then we'll end up sounding like them and everything that's out there at the minute.
"I'm counting this as my first album as I've been there from the beginning and have had just as much input. It will definitely sound a lot different to Sweet 7 as that was current and fitted into what was around in the charts when it was released."
Ewen recently confirmed that the band will not release a new single this year.