Sennheiser has expanded its line of full-sized HD headphones with the release of the HD 428, HD 438 and HD 448. The latter of the new releases offers the highest-quality sound of the group, while the HD 438 features a more natural sound. The HD 428 provides better lower frequency quality and is intended for bass response. Each model utilizes a gold-plated quarter-inch stereo adapter and a closed-back, around-the-ear design to insulate the sound.

The entire HD headphone line is available from the J&R online store and will soon be added to the Best Buy headphone catalog. The HD 448, HD 438, and HD 428 can be purchased for $130, $120 and $100, respectively.