INSTALLATION AND OPERATION of the BOSE 901 STEREO SPEAKER SYSTEM
I. Introduction The BOSE 901 represents a fundamental advance in realistic home music reproduction. The unique acoustic design of the speakers provides sound distribution in accurate simulation of live sound. The BOSE 901 Active Equalizer provides unprecedented accuracy and control of frequency response characteristics. Because the BOSE 901 system differs fundamentally from other speaker systems, IT IS IMPORTANT THAT THESE INSTRUCTIONS BE CAREFULLY FOLLOWED.
2. Note in Figure 1 that the front of the speaker is the flat surface and the rear is the ’'vee'* surface with the angled panels. This orientation of the speaker is important to obtain the proper distribution and reflection of sound radiated from the speaker. So, point the **vee*‘ toward the wall. 3. The distance of the speakers from the wail is very important.
ungrounded terminal^n^our amplifier. Connect the other speaker terminal to the "common" or gound terminal on the amplifier. If stranded wire is used be sure that loose strands do not short the speaker or amplifier terminals. Be sure the terminals are securely tightened. V. Connecting the 901 Active Equalizer THIS PART OF THE INSTALLJ^TION DIFFERS FROM THAT OF OTHER SPEAKER SYSTEMS. FOLLOW THESE INSTRUC TIONS STEP BY STEP.
4^ I Figure 2
the Equalizer to the RIGHT or B channel TAPE INPUT terminal on your preamplifier or receiver. (This pre amplifier termineil may alternatively be labeled TAPE Pl-AYBACK or TAPE MONITOR,) 4. Similarly, using a second cable connect the LEFT channel EQUALIZER OUTPUT terminal to the LEFT or A channel TAPE INPUT terminal on your preamplifier. 5. Using a third cable, connect the RIGHT channel EQUALIZER INPUT terminal on the Equalizer to the RIGHT or B channel TAPE OUTPUT terminal on your preamplifier.
operating properly. This tests the rest of your system since the Equalizer has not yet been switched into the system. If you cannot obtain any sound from the speakers, then there is an error elsewhere in your system. Any such errors must be corrected before proceeding further. 12, With the system still playing, move the TAPE MONI TOR or TAPE FUNCTION switch on your preamplifier to the MONITOR or IN position. (The Equalizer power switch should still be in the OFF position,) The sound should stop.
Equalizer to the RIGHT or B channel OUTPUT terinmal on the tape recorder. 3. Similarly, connect the UEFT channel TAPE IN terminal on the Equalizer to the liEFT or A channel OUTPUT on the tape recorder. 4. Connect the RIGHT channel TAPE OUT terminal on the Equalizer to the RIGHT or B channel INPUT terminal on the recorder. 5. Similarly, connect the LEFT channel TAPE OUT on the Equalizer to the LEFT or A channel INPUT on the recorder. These connections are illustrated in Figure 2.
the RIGHT channel EQUALIZER OUTPUT terminal on the Equalizer to the RIGHT or B channel INPUT terminal on your power amplifier. 4. Similarly, use a second cable and connect the LEFT channel EQUALIZER OUTPUT to the 1-EFT or A channel INPUT terminal on the power amplifier, 5, Using a third cable, connect the RIGHT channel EQUALIZER INPUT terminal on the Equalizer to the RIGHT or B channel OUTPUT terminal on your nreamp (the preamp terminal may adternatively be labeled PREAMP OUT or OUTPUT TO AMPLIFIER). 6.
I£ it doesn't, check the power connection to the Equalizer. With the Equalizer on, your system should operate normally. If it doesn't, recheck steps 1 through 8. 10. With the system operating, turn the Equalizer POWER switch off. The system should cease to operate. If it still plays, recheck steps 1 through 6. The 901 system is now completely installed and ready for use. The functions of the various controls are described in the next section. VII.
position, it reduces turntable rumble and other low frequency distur bances in a manner that has much less effect upon music than that caused by conventional rumble filters. This is achieved, as shown in Figure 4, by a unique filter design which provides a uniform attenuation below 40 Hz while causing no audible amplitude or phase deviations above 50 Hz.
db ro I Figure 4. Contours available with the TREBLE LEVEL switch in the normal or dotted position. db Figure 5. Contours available with the TREBLE LEVEL switch in the DEC REAS E position.
SPECIFICATIONS SPEAKER {EACH UNIT) Percentages Power of Reflected radiated and by Direct Sound, reflection 89% 11% Power radiated directly (Design ments.) percentages based upon concert hall measure Speaker Complement. Each unit contains nine high compliance, full range speakers with high energy magnets to allow large excursions without audible distortion on any program material. The speakers are acoustically coupled to eliminate audible resonances. Power Handling Capacity.
ACTIVE EQUALIZER (TWO CHANNELS) Program Contour Controls, The normally flat radiated power spectrum can be adjusted, by means of three front panel switches, to yield twenty different frequency contours designed for compensation of recording tech niques and room acoustics. Installation. The Active Equalizer is easily connected to any preamplifier, amplifier or receiver using the audio cables supplied. Construction.
