TRADING IN her trademark samba for more conventional sounds, Pink Martini diva China Forbes steers straight for the middle of the road on ’78, her first solo album in more than a dozen years (Heinz Records). In the interests of stylistic comparison, give a listen to her new, streamlined version of “Hey Eugene,” last heard as the title track from Pink Martini’s most recent record. What was once a soulful strut with a punchy horn chart is now a playful, radio-ready admonishment to a former fling, something along the lines of Liz Phair or Fiona Apple. Forbes definitely succeeds in proving that she’s no one-tango pony, though her breathless reminiscing about lost love on “You Were/I Was,” and “’78” is far more evocative than such middling, Sheryl Crow-like tracks such as “Lovely Day” and “Everybody Needs Somebody Now.” This collection is certainly catchy enough, aided by the able hands of local producer Gregg Williams, who finesses out all of the rough edges: Fans of polished, feather-light rock should be duly enthusiastic. But longtime Forbes followers who are accustomed to her more fiery performances with Pink Martini might find this entry just a wee bit tepid. (Forbes will celebrate her CD release Feb 21 at Doug Fir Lounge.)