We report a new design for an acoustically resonant spectrophone well suited for intracavity operation with widely tunable lasers. Operation with Brewster angle windows or in a windowless mode is possible, and high quality factors (560 and 509, respectively) are achieved. Windowless operation permits continuous monitoring of ambient air. We discuss factors limiting the sensitivity, ∼10−7 cm−1, and present a double chopping scheme capable of significantly reducing the acoustical background encountered in windowless operation. The sensitivity of the spectrophone's performance to misalignment is also examined.