Equalizer's is not my expertise so it is best to consult with a professional, but KICKER 03KQ5 5-Band Parametric Equalizer looks ok. Remember that is something you should really consult an expert with. Keep the volume down.
Legacy is a good brand also check this product out KICKER 03KQ30 30-Band Equalizer.
it depends on the song. play with the sliders until it sounds right to you. the sliders go from low frequencies to high frequencies. from the left to the right.
If your boyfriend is a serious car audio freak, the Pioneer DEQ-9200 3 Band Parametric Equalizer is a good gift if he is looking to trick out his stereo system.
The Equalizer - 1985 Shades of Darkness 2-5 was released on: USA: 5 November 1986 West Germany: 13 April 1988
The Equalizer - 1985 Encounter in a Closed Room 3-5 was released on: USA: 14 October 1987 West Germany: 21 October 1988
The Equalizer - 1985 Torn 1-17 was released on: USA: 5 February 1986 West Germany: 3 December 1987
The Equalizer - 1985 Desperately 1-11 was released on: USA: 4 December 1985 West Germany: 5 November 1987
The Equalizer - 1985 Heartstrings 2-11 was released on: USA: 17 December 1986 West Germany: 5 May 1988
The Equalizer - 1985 The Rehearsal 3-10 was released on: USA: 2 December 1987 West Germany: 5 January 1989
The Equalizer ended on 1989-08-24.
The Bose 901 speaker system includes an equalizer that is generally connected between the pre-amp and the power amp. In many cases, this will be a "tape out" connection and a "tape in" connection. To add an additional equalizer, connect the output of the Bose equalizer to the input of the additional equalizer. Then, the output of the new equalizer is connected to the amplifier input that the Bose equalizer was originally using.