User manual ELECTRO-VOICE 731 DATASHEET

[. . . ] Use of a mains separator transformer is mandatory during maintenance while the appliance is opened, needs to be operated and is connected to the mains 3. Switch off the power before retrofitting any extensions, changing the mains voltage or the output voltage. The minimum distance between parts carrying mains voltage and any accessible metal piece (metal enclosure), respectively between the mains poles has to be 3 mm and needs to be minded at all times. The minimum distance between parts carrying mains voltage and any switches or breakers that are not connected to the mains (secondary parts) has to be 6 mm and needs to be minded at all times. [. . . ] The 731 Controller has been designed to be used in high-performance installations that employ active 2-way systems plus sub woofers. Applications like these also mostly incorporate professional linear power amplifiers like the Electro-Voice P1200, P2000, P3000 or Q44, Q66. When using processor controlled power amplifiers like the Electro-Voice P1250, the processor section is simply switched off. Installing and operating the 731 Controllers is easy as can be since the user does not need to know any complex detail about crossover functions and equalization. All controls for matching the sound to different acoustic conditions and loudspeaker systems are located on the front panel. Difficult tasks - like electronic signal routing and settings for instance - are automatically carried out inside the appliance. The newly designed PowerMax12 crossover function (patents pending) optimally utilizes amplifier output power and loudspeaker transmission capacities. Compared to conventional crossovers or controllers, this results in an improved overall sound quality which is achieved with less effort. The 731 Controller is also most suitable for integration in active 2-way instrument reinforcement applications for keyboards, E-bass and drums. The PowerMax12 crossover function eliminates the often complained about "lack-of-punch-and-definition", like it is common for conventional active musical instrument reinforcement systems. Its excellent dynamic range of more than 116dB, the extremely low noise level and the outstanding price-performance ratio makes the 731 Controller an advantageous alternative to conventional crossover and controller solutions ­ even in the critical field of permanent installation. FRONT PANEL 1. This setting is often used when reproducing CDs or other pre-recorded audio programs. With the PowerMax12 x-over function, setting the crossover frequency is extremely uncritical. Often enough, when the system is operated at medium sound pressure levels, changes are not registered. Only when operating the reinforcement system at extremely high levels and depending on the actual setting of the crossover frequency, minor differences in the subjective peak dynamic of the low frequency range and in the coverage of mid frequency band can be heard. FRONT PANEL 7. Sub Out Mono control The control is normally set to its center (0dB) position. This control is used to adjust the loudness level of the summed low-frequency audio signal of the two channels "A" and "B", which serves to feed a connected monaural sub woofer power amplifier. The "Mute" switch attenuates the Sub Out Mono audio signal, which allows to easily check the entire sound reinforcement system. The green "Signal" LED indicates the presence of an audio signal while the red "Peak" LED lights when the audio signal is clipped inside the 731 which might result in distortion. In case the "Peak" LED lights continuously, lowering the input "A" and input "B" level controls is recommended to maintain the entire dynamic range. 8. Lo Out Stereo The control is normally set to its center (0dB) position. This control is used to adjust the loudness level of the low-frequency audio signals of the two channels "A" and "B", which serves to feed a connected sub woofer stereo power amplifier or two separate power amplifiers, respectively. The "Mute" switch attenuates the Sub Out Stereo audio signal, which allows to easily check the entire sound reinforcement system. [. . . ] The low-frequency audio signal feeding channel "A" of the sub woofer power amplifier is present at the LO-output. The mid-high-frequency audio signal feeding channel "A" of the mid-hi or full-range power amplifier is present at the HI-output. 13. SUB MONO output The 731 Controller's outputs are electronically balanced (pin2 = +, pin3 = -, pin1 = shield). This output is meant for the connection of an additional active center sub woofer or sub woofer power amplifier. [. . . ]