Voices on the Verge are Erin McKeown, Jess Klein, Beth Amsel, and Rose Polanzani, four young folk-pop singer/songwriters who work collaboratively while maintaining their solo careers.

Live in Philadelphia, their first collaborative album, was recorded live in front of a small audience in a recording studio.

The simple instrumentation is a combination of acoustic and electric guitars, with occasional piano (by Polenzani), clarinet (by Klein), and djembe (a small African percussion instrument, played by McKeown) adding texture.

Each singer does three of her own songs.

And therein lies the problem.

All four are very good singers, but they're a mixed bag as songwriters.

McKeown, whose solo debut, Distillation, was one of 2000's great under-heard gems, is a terrific songwriter, and her three songs are by far the best on the disc.

The sly Delta blues "Blackbirds," the jazzy "Didn't They" (which features some terrific clarinet by Klein), and the haunting "Softly Moses" (which, unlike the other two, is not on Distillation) are all great, and the Virginia-born McKeown has the most soulful and distinctive vocal style of the four.

The other end of the spectrum belongs to Polanzani, whose songs are unfortunately dull, except for "Thom II," which is eyeball-rollingly bad.

Klein and Amsel are in the middle, and their styles are so similar that it can be hard to tell who wrote which song without looking at the credits.

Both are quite nice in a Dar Williams sort of way, but they lack McKeown's individuality.