Model 737 Soundtrack Loudness Meter - Leq(m)
3-1
Chapter 3Cat. No. 448B Input Adapter Board

3.1 Introduction

The Cat. No. 448B is an input adapter board that mounts to the rear of a CP65. The card
will suitably switch and adapt signals from a two- or six-track source following logic con-
trol from the CP65, CP55, or DS4-E (UK). Format calibration and routing requirements
are therefore met automatically.
The Cat. No. 448B passes six balanced channels on to the Model 737 with a 3-dB L
and R channel attenuation. The Model 737 is then calibrated to compensate for this
attenuation with 3 dB more gain on the L and R input trim pots. When Format 05
(Dolby SR) is selected, the attenuation is switched out giving the required 3 dB gain on
Lt/Rt for this format. In addition, when either matrix formats are selected (Format 04
or 05), the C, Ls, Rs, and Sw channels are muted. This concept is appropriate for most
studio applications assuming that Lt /Rt exist on monitor buses 2/3 or 1/3. Input jumpers
are available to switch between the two.
The Cat. No. 448B can switch an auxiliary two-track input (i.e., Optical from Cat. No.
150) to the Model 737 and pass this auxiliary signal to the DS4-E (UK) auxiliary meter
input, normalized for Dolby Level. This increases the versatility of the board to cope
with varying installation requirements from the studio through preview and optical
transfer facilities.
Note: Refer to Figure 3-4 Cat. No. 448B Interface Adapter schematic on page 3-7.

3.2 Logic map

Table 3-1 shows the logic map of the Cat. No. 448B. X = switch closed; O = switch open.
Table 3-1 Logic map of Cat. No. 448B
MAT OPT SR Sw1 Sw2 Sw3ab Sw3cd
Sw4cd
-3 dB
(6-trk in) 6/2 Aux
in
-3 dB
(DS4-E
meter)
Format
0 0 0 O X O X No 2 Yes Yes Dolby SR (Aux in)
0 0 1 X X O X Yes 2 Yes No Dolby A (Aux in)
0 1 0 O X X O No 2 No Yes Dolby SR (6-trk in)
0 1 1 X X X O Yes 2 No No Dolby A (6-trk in)
1 1 1 X O X O Yes 6 No No Dolby Digital
1 1 0 O O X O No 6 No Yes Dolby Digital (0 dB)
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