Surround Monitor Unit
A Surround Monitor Control Module with Headphone Amplifier and PFL Control Section for 4U Frames
The Surround monitor control module I62 fits into slot 9 of the 4U high INTEGRATOR mounting frame. This surround monitor control module offers a simple solution when used with the select module I65 in connection with a 5.1 INTEGRATOR mixing system.
This surround monitor control module offers a mute circuit, the selection of a second set of monitors, the ability to monitor in mono as well as the phase exchange in the right channel. A stereo down mix matrix produces a stereo-signal from the 5.1 signal source. There are also separate cut switches for the 6 channels. An adjustable DIM circuit and a separate PFL input with remote control make possible the comfortable accessibility to the mixing unities INTEGRATOR as well as to other mixers. The inserted headphone amplifier is fed by the Stereo down mix matrix and completes the equipment of the device.
The inputs of the surround monitor unit are electronically balanced and have medium impedance and a level of +6dBu. The inputs are usually connected with the output of the one of the 5.1 select units. Naturally the connection with every arbitrary surround source is possible.
The selection of the PFL signal, (which can be supplied on a separate input), takes place either via the PFL switch or via a control signal, which is separated by an opto coupler, in this case the PFL switch indicates the combination. The control signal comes directly from the INTEGRATOR mixer. A potentiometer controls the volume of the PFL signal. In the case of using the module as a source select, automatic controller, a command signal can be applied in place of a PFL signal. A Jumper makes it possible to combine the PFL signal on certain channels; in this configuration the original signal is damped 20dB. The DIM circuit is adjustable by a potentiometer between 0 and 24dB. Also here the release can take place either the DIM key or by a control signal. An opto coupler also electrically isolates this signal; both control signals operate within the range of between 9 volts to approx. 30 volts.
The surround monitor unit has several integrated downmix matrix stages to allow the user to check the 5.1 input signal 's stereo and mono compatibility without affecting the source signal. The stereo downmix matrix adds the surround channels to their corresponding front channels. The level of the surround channels is reduced by 0, 3 or 6 dB by the stepper switch S->F. The off position of this switch disables this matrix function. The center channel is mixed into both the left and right front channels. The level is determined by the setting of the stepper switch C->LR. The calibrated values 0, 3, 4.5 and 6 dB are possible. The LFE channels are low pass filtered with an edge frequency of 80 Hz and added to all the front channels L, C and R. Its level is determined by an internal trim pot and normally adjusted to -6 dB. The mono signal is created by the addition of the left and right output of the downmix matrix. The level of the mono matrix is 3 or 6 dB depending on an internal jumper. If the stereo mode is selected, the right channel can be phase reversed by a switch. Besides the main cut switch, that mutes all the outputs there are separate mute switches for each channel. The main cut switch does not affect the headphone output as the separate cut switches do. The additional speaker output ALT is always in stereo mode and activates the stereo matrix.
The outputs of the I62 are electronically balanced. The maximum level is more than + 30 dBu. In the 94 dB position of the rotary volume control the total gain of the module is 0 dB. The headphone amplifier is well suited for all available headphones.