The Bose 901 Series 1 speaker system is a classic audiophile system that U.S. premium hi-fi manufacturer Bose introduced in 1968. It is discontinued as of May 2011, but vintage hi-fi fans still use and appreciate the speaker because of its quality and features. The reflected and direct sound technology of these speakers dates back to 1968, and Bose has updated the series several times since the introduction of the Series 1, most recently in 2007 with the Series VI.
Each speaker measures 20 9/16 inches wide, 12 3/4 inches high and 12 7/8 inches deep. The equalizer measures 2 13/16 inches high, 9 1/4 inches wide and 6 3/4 inches deep.
Speaker Power and Performance
The Bose 901 Series 1 speakers have a maximum power output of 270 watts per channel RMS at 8 ohms. They can handle a power surge of 400 watts for less than five seconds. The minimum amplifier output necessary to operate the speakers is 25 watts per channel, and the speakers produce a continuous sine wave of 50 watts per channel. Eighty-nine percent of the power is radiated by reflection, and 11 per cent is radiated directly.
Size of Speaker Components
Each Bose 901 series 1 speaker is made up of eight small speakers, called drivers, positioned four on each side of its trapezoidal housing. The diameter of each speaker is 4 1/2 inches, with a maximum driver excursion, or size discrepancy, of plus or minus 1/4 inch. The nominal driver impedance is 8 ohms, making the speakers compatible with any amplifier that has an 8-ohm speaker output. Each ceramic magnet of each driver weighs 9.6 oz.
Equalizer Technical Specifications
The Bose 901 Series 1 equalizer is an active equalizer that contains 10 transistors. It sits between the amplifier and the speakers. Its input impedance is 150 kilo-ohms, and its output impedance is less than 100 ohms. The equalizer requires an impedance of 5,000 ohms to operate, and its maximum output voltage is 4 volts. It produces a maximum gain, or sound boost, of 18 decibels at 35 hertz.
Features of the Equalizer
The Bose 901 Series 1 equalizer allows the user to adjust bass and treble according to individual taste. It includes 19 preset sound patterns and a special Below 40 switch that filters out low-frequency sounds, such as turntable rumble, without disturbing bass or other desired sounds.
Bose 901 Compatible Receivers
What's needed to run Bose 901s power image by Guy Pracros from Fotolia.com