Genelec 7060A, 7070A, 7071A Subwoofer bypass control, Phase correction method with test equipment

Table 2. Recommended subwoofer/main monitor combinations.

consists of a LED in a compact case and a RJ11 cable to connect the case and the "REMOTE" RJ11 connector on the amplifier panel.

Subwoofer bypass control

A bypass control feature is included in the subwoofer circuits so that the effect of the subwoofer on the whole monitor system can be determined. With the bypass switch on, the high pass filters for the main monitors are overridden and the system behaves as if the subwoofer was not connected. The bypass function has no effect on the LFE input. Two different bypass remote controllers are avail- able as optional equipment: 1092-400 switch that can be connected to a 1/4" jack connec- tor on the amplifier panel and 7000-416 that connects to the "REMOTE" RJ11 connector. The 7000-416 option also includes remote control of the "LFE +10 dB" function and a link for the 7000-415 remote LED option.

necessary to temporarily connect either of the channels to this output.

Power up the system and set the DIP switches 3 (SUM IN MODE) and 4 (LFE +10 dB) on the first switch group to "ON" Now you should hear an 85 Hz test signal from the subwoofer and the main monitor connected to the center channel output.

Toggle the -180° phase switch (DIP 4 on the second switch group) on and off, and set

it to the position which gives the lowest sound level at the listening position.

Next toggle the -90° phase switch (DIP 3) on and off, and again set it to the position which gives the lowest sound level.

Finally, set the -180° phase switch (DIP 4) to the opposite setting and deactivate the test signal.

Phase correction method with

test equipment

The following procedure matches the phase between the subwoofer and the main moni- tors using a frequency analyser and a pink

noise generator. Connect a high grade meas- uring microphone to the analyser and feed pink noise into the "CENTER IN" input of the subwoofer. The subwoofer's bass man- agement system will direct the frequencies above 85 Hz to the center main monitor while the subwoofer reproduces the frequencies below 85 Hz.

Position the microphone at the listening position and adjust the input sensitivity of the subwoofer until frequencies below and above 85 Hz are reproduced at equal level. Then adjust the phase control switches for the maximum dip of at least -6 dB at the crossover frequency (85 Hz).

Change the -180° switch to the opposite setting. The phase should now be set correctly and the frequency analyser should show a smooth response around 85 Hz.

Overload indicators

The mode indicator LED on the amplifier panel will turn from green to yellow to indi- cate clipping and then to red to indicate that the protection circuit has activated. If this occurs frequently, reduce the input level to the subwoofer until the LED remains green.

If the LED on the amplifier panel is not easily visible, the optional Remote LED Kit can be used to bring it into view. The kit

Subwoofer in analogue matrix

surround sound systems.

When using Genelec 7060A, 7070A or 7171A subwoofers in a consumer analogue matrix surround sound system, such as Dolby Sur- round, Dolby Pro-Logic or Pro-Logic II or a professional matrix decoder such as a Dolby SDU-4, route the front channels through the subwoofer so that the output of the sub- woofer is matched to the rest of the system and select "Large" setting for the front speak- ers on the decoder. If there is a subwoofer channel output on the decoder it should NOT be connected to the subwoofer's "LFE IN" input since the processing within an ana- logue decoder will conflict with the filtering in the subwoofer. Connecting the rear channels to the subwoofer is optional since the rear channels from most matrix decoders are band limited down to 100 Hz.

Monitoring the LFE channel in digital discrete surround sound systems

Some digital surround sound systems use a discrete Low Frequency Effects channel which should be connected to the "LFE IN" input on the amplifier panel. This enables the subwoofer to correctly reproduce all the bass information in the mix.