It's difficult to tell if Roxy Music became so confident and full of musical bravado because they released so many fantastic records in the ‘70s or if their records were so fantastic because Roxy Music were simply confident and full of bravado to begin with. In either case, 1975's Siren is the last in the series of five near-perfect albums that Roxy Music released in just four years.
At least in Bryan Ferry's case, it appears the confidence was inborn. Ferry had always been a charismatic and appealing frontman, but on Siren, even more attention is given to him. Placed even further into the spotlight, Ferry responds to the pressure with an increased level of flair and theatricality. Though he's been given some room to try out different vocal styles, from the earnest (for Ferry at least) "Could It Happen To Me?" to the urgent "Both Ends Burning," in each track Ferry ends up sounding like no one but himself.
In consolidating its focus on Ferry, Roxy Music had to alter their approach to songwriting. With Brian Eno gone, the lengthy instrumental interludes found on their debut are almost entirely absent on Siren. While the band's newly found concision might dull the edges of their sound a little, the album's songs are still far from middle-of-the-road. In particular, the multi-segmented "She Sells" is a composition as complex as anything the band has ever written.
Arguably, Siren was the last truly great Roxy Music album (Avalon was good in its own, different way). It is a consistent, rewarding album, and all the more remarkable for satisfactorily following up such classics as Roxy Music, For Your Pleasure, Stranded, and Country Life. It may be that Ferry has even more great music left in him, and if he'd stop releasing live albums and recording other people's songs, maybe we'd find out.