User manual ELECTRO-VOICE FORCE SUB DATASHEET

[. . . ] Most popular music is inherently bass-heavy, with most of that energy concentrated in the kick drum "thump" region between 60 and 80Hz. Force Sub has been designed for maximum output efficiency in exactly that range. [. . . ] Note that the sinewave test signals sometimes used have a much less demanding peak value relative to their average level. In actual use, long-term average levels exist from several seconds on up, but we apply the long-term average for several hours, adding another extra measure of reliability. Specifically, the Force TM Sub is designed to withstand the power test described in the ANSI/EIA RS-426-A 1980. The EIA test spectrum is applied for eight hours. To obtain the spectrum, the output of a whitenoise generator (white noise is a particular type of random noise with equal energy per bandwidth in Hz) is fed to a shaping filter with 6-dB-per-octave slopes below 40 Hz and above 318 Hz. When measured with the usual constant-percentage bandwidth analyzer (one-third-octave), this shaping filter produces a spectrum whose 3-dBdown points are at 100 Hz and 1, 200 Hz with a 3-dB-per-octave slope above 1, 200 Hz. The power-handling capacity of the Force Sub is 300 watts EIA (350 watts AES). For biamp operation choose an amplifier of approximately 300 watts RMS per channel, full 20-20, 000 Hz bandwidth at 8 ohms. For passive operation (Force Sub and Force fullrange connected in parallel) the power capacity of the full-range system must be taken into consideration. Remember that the Force full-range has a lower power-handling capacity than the Force Sub, so above the Force Sub's 125 Hz low-pass filter frequency all of the amplifier power is directed to the fullrange system. Only below 125 Hz is the power shared between the two systems, with the Force Sub getting the majority only on the very lowest notes. Therefore, for passive operation select an amplifier whose continuous 8 ohm rating, full 20-20, 000 Hz bandwidth, is appropriately sized to the fullrange system (a nice size for the Force is approximately 200 to 300 watts RMS @ 8 ohms continuous power per channel) and whose 4 ohm rating per channel is near the total for both systems. This class of amplifier, especially if it also incorporates good on-board limiters, provides plenty of power where you need it down in the bass region where both systems are drawing power in short duration pulses, but not so much as to seriously endanger the more delicate highfrequency components. An amplifier that matches this description very well is the Electro-Voice Q44, which is ideally suited to powering a Force or a passively crossed (parallel connected) Force and Force Sub system in stereo. [. . . ] The Limited Warranty does not apply to burned voice coils or malfunctions such as cone and/or coil damage resulting from improperly designed enclosures. Electro-Voice active electronics associated with the speaker systems are guaranteed for three (3) years from the date of original purchase. [. . . ]