Handel’s Messiah has long been a Christmas ritual, and Portland Baroque Orchestra plays it as the composer intended, on instruments of his time. The music becomes lighter and more intimate: from the triumphant Hallelujah to the solo arias, every line can be heard. The orchestra is led by Gary Thor Wedow, a specialist in historically informed performance, and the singing is by Portland Baroque Voices, PBO’s new professional vocal ensemble. For those who know Messiah from recordings and want to hear it without the gloss.