Lectrosonics Venue 3.9 - Manual (Page 10)

Venue
Select Diversity Modes
Press MENU/SELECT and rotate the knob to SetUpRx
and press the knob. The SetUpRx screen provides
menu selections for various operating parameters.
Rotate the knob to DivMode and press the knob again.
Three diversity reception modes are available:
• Switched Diversity
• OptiBlendTM Ratio Diversity
• Frequency Diversity
Switched Diversity
In this mode the phase of one of the antennas is
switched when the RF signal level drops down to a
point where a dropout is about to occur. Each receiver
produces an audio output channel for a maximum of six
in each VRM assembly.
OptiBlend (Ratio Diversity)
Ratio diversity uses two adjacent receivers and pans
back and forth to blend their audio outputs to favor the
one with the strongest RF signal.
Most of the time both receivers have good signals, so
the audio is blended equally, which improves the signal
to noise ratio by 3 dB. The advantage to this mode is
that the comparator and panning take place at higher
RF levels, long before the receiver is close to a dropout.
The receiver will pan to the quieter receiver long before
the signal gets weak enough to cause a dropout. The
panning action is smooth and seamless to avoid any
audible artifacts that would occur with abrupt switching.
In this mode two paired receivers are used for a single
audio channel. The total number of audio channels will
vary according to how many modules are set to the
switching mode and how many to the ratio mode.
Frequency Diversity
Frequency Diversity differs from the other two diversity
modes in that it uses two receiver modules and two
transmitters operating on a different frequencies. The
purpose of frequency diversity is to have redundancy in
the system for critical productions such as live televi­
sion. The receiver will pan to system with the strongest
RF signal to maintain operation during dropouts, dead
transmitter batteries, etc.
Frequency Diversity has two modes of operation: nor­
mal mode and test mode. Test mode is automatically
activated when the DivMode Setup Screen is active and
Frequency Diversity is selected. In this mode, the audio
is always blended 50/50 to allow balancing of the trans­
mitters. The phase of one audio channel is inverted so
the two will cancel each other (null) when mixed at the
same level. On exiting the DivMode Screen, the normal
mode is activated and the blending ratio is controlled by
comparing the RF signal strengths at each receiver.
Note: In Frequency Diversity mode, both
transmitters must be the same type and model
and be operating in the same compatibility mode.
The microphones must also be placed very close
together to minimize comb filtering.
1. Verify that the frequency and compatibility modes of
the receiver modules match the associated trans­
mitters and that the transmitters the same model.
2. Set up the transmitters according to the manufac­
turer’s recommendations and adjust the input gain
for the voice levels expected during the production.
3. Navigate to the DivMode Setup Screen.
4. Plug a set of headphones into the front panel
PHONES jack to monitor the blended output. You
can also monitor the output from the rear panel
XLR jack on either receiver in the pair.
INVT shown in Off Position
5. While listening to the blended output, adjust the
gain control on one of the transmitters so that the
audio loudness drops way down (nulls). If the output
does not null, then reset the transmitter input gain
control back to where it was and press the Func­
tion button on the front panel next to INVT on the
LCD. This will invert the phase of the audio on the
second receiver so it will null properly.
6. Repeat Steps 1 through 5 for each receiver module
pair set to Frequency Diversity Mode.
LECTROSONICS, INC. 10