Description: Completely restored: A sound experience like in a concert hall: BOSE 901 SERIES IV STEREO SPEAKERS, 1978, 2x 9 speakers!
(1 front speaker each with 11% direct power, 8 reflection speakers with 89% indirect power), impedance 8 Ohm, restored walnut cabinets, original tulip feet in black, new audio cables (2x over 5m) Including BOSE 901 Series IV ACTIVE EQUALIZER for the perfect sound adjustment according to personal taste, with filter & frequency settings in the high & low sound ranges, walnut cabinet All details about BOSE 901 in the original BOSE brochure below (download)

Note: The principle of the BOSE 901 SERIES III STEREO SPEAKERS is unique: nine identical full-range loudspeakers per speaker emit the sound evenly, directly and reflected in a concert hall-like 11:89 percent ratio.
The infamous stereo triangle has been resolved.
Every seat in the room is filled with lifelike sound!

In a concert hall, a large proportion of the sound is reflected by the walls, floor, ceiling and objects before it reaches the listener’s ears.
Dr. Amar G. Bose was already investigating this fact in the 1950s as part of his psychoacoustic research.
His team carried out measurements with the Boston Symphony Orchestra.
The data was later analyzed at M.I.T. – which led to the development of the BOSE 901 loudspeaker and the founding of the BOSE Corporation in 1964.

BOSE 901 speakers should be at least 30 cm away from the rear wall or suspended 30-50 cm below the ceiling. PS: Quote from an enthusiastic BOSE 901 owner: “The musical sound impression of the BOSE 901 speakers, whether for vocals, light music, large symphony orchestras, heavy organ music, jazz, solo drums etc. etc. was already stunning in the 1960s.
And it still is today.
With a normal hi-fi record by Karajan, the Piano Concerto No. 1 in B minor by Tchaikovsky, you could locate every soloist to the exact meter and then make a (symbolic) cross on the wall (in my case at the time about 4m) with a pencil.”