The 19” rackmount Mackie HM-400 4-Channel Headphone Amplifier offers an incredible amount of versatility and excellent sound quality in a single rack space. The HM-400 features a main L/R stereo input that feeds into four channels with separate EQ and Aux In plus three outputs each for a total of 12 headphone outputs. This rugged amplifier is perfect for professional applications such as studios, houses of worship, and practice spaces. For routing versatility and a high number of outputs, consider the Mackie HM-400 today.