The MA-7A Reference Speakers are the ideal solution for musicians and computer users who must have the best audio quality possible in a very confined space. They are extraordinarily small reference speakers, yet are capable of producing incredible sound.   The MA-7A has a built-in bass enhancer that operates on psychoacoustic principles. It converts low frequencies into a series of overtones that the human ear cannot distinguish from the original low frequencies. Thus you don't overdrive the speaker yet hear bass frequencies that are outside its normal range. If you need more low end, the MA-7A offers a sub-out jack for connection to a subwoofer. The MA-7A offers conveniently placed volume and tone controls on the speaker's front panel. You can also connect 2 different sources directly into the MA-7A, such as your computer and your stereo, so can hear either source without switching cables. You can also plug headphones directly into the MA-7A. Plugging in headphones automatically defeats the speakers, allowing you to monitor without disturbing anyone. The MA-7As are magnetically shielded for close proximity to your computer monitor.