C2-2450A O
PERATION
M
ANUAL
78
The compensation is needed because most projectors cannot output pure black –
there’s always some light ‘leaking’ to the projection screen. Thus when you’re
trying to output black, there will be a ‘hot area’ where the two projectors are now
overlapping, of twice the projector’s ‘black level’ output.
The solution is to adjust the ‘Eb comp cent’ value (the first in the ‘Eb comp
cent/side’ menu) to compensate for this centre brightness error. By increasing this
value, it will increase the brightness of the non-overlap area.
To get this value right, you must first make sure that the units connected to the
projectors are outputting black – e.g. in the Adjust windows menu you can disable
the output. Then increase the ‘Eb comp cent’ value until the non-overlap area’s
brightness has increased to be the same as the overlap (centre) area.
The 2
nd
value (‘Eg comp side’) is for where horizontal and vertical edge blending is
being performed – e.g. a 2x2 arrangement. This value increases the brightness of
the overlapping areas, with the exception of the centre ‘square’ where all projectors
overlap.
12.12
Aspect ratio adjustment
Since your original video source is probably 16:9 (or a similar aspect ratio), it will
also be necessary to change your vertical zoom value differently to the horizontal
one. This is best done after projector alignment by performing the following:
1. Go to the ‘Adjust windows’ menu and change ‘Aspect adjust’ to ‘Advanced’.
This enables separate H & V zoom adjustments.
2. Go to ‘Adjust windows’ for Output 1 (1A) and you will now be able to adjust
the vertical zoom independently of the horizontal zoom. H zoom should be
left as it is, so adjust the V zoom until the correct aspect ratio of your output
is achieved.
3. Go to ‘Adjust windows’ for Output 2 (2B) and adjust the V zoom to the same
value as Output 1 (1A).
12.13
Locking both outputs together
If your video source contains live (moving) video then it is worthwhile locking one
channels’ output to the other’s – this will eliminate any line or frame drift, which may
cause frame-rate conversion problems. This is best done by locking Output 2 to
Output 1.
For dual-channel units such as the C2-7000 series, perform the following:
1. Go to ‘Adjust outputs’
2. Ensure that ‘2B’ is selected – press Toggle 1 / 2 (Shift-1) if not.
3. Where ‘Lock [Off] RGB1’ is seen (where RGB1 is the default Lock source),
change the Lock source to ‘OUT1’.
4. Then change the Lock method from ‘Off’ to ‘Genlock’.
