5-1
DFP-3000
5. A-Chain alignment using DFP-D3000 front panel controls
The most direct means of A-Chain alignment is to use with external test equipment and the controls
available through the Decoder front panel. There are two approaches. The first, recommended for experi-
enced cinema engineers, is to align the projector’s optical playback system so as to produce nominal
settings (preset gain = 0.0 dB) in the DFP-D3000. This has the potential benefit of best sound quality as
preamplifiers, noise reduction, and matrix decoding circuits will be operating at optimal levels. The
second approach is to set the DFP-D3000 to match the existing alignments in the projector’s optical
playback system. This approach has the benefit of ease of setup, but requires that the optical system is
already correctly aligned. Gain trims should end up near 0.0 dB with a properly aligned projector. With
either approach, it is important to first ensure a high quality optical system alignment. For detailed
instructions on aligning a forward scan optical reader system, see Tech Note TN99111901; to align a
specific brand of reverse scan reader, follow its manufacturer’s documentation.
5.1 The following instructions require that the projector’s optical reader has been properly aligned, the
projector is mechanically sound, and its optical playback system is clean. See TN99111901 for instruc-
tions on aligning a forward scan optical reader.
The initial steps for A-Chain alignment are common to both alignment approaches.
5.2.1 Prepare a test cable.
This cable connects from a standard 1/4-inch stereo phone plug to the input connectors of your multichan-
nel Real Time Analyzer (RTA) and simultaneously to the inputs of your dual-channel X-Y oscilloscope.
The front panel phone jack on the Decoder has line-level output signals wired with Tip = Lt, Ring = Rt,
and Sleeve = audio common (ground). The Lt and Rt signals connect to each input of your RTA and to
the horizontal and vertical inputs of your oscilloscope. See available Tech Note TN99101201 for details
on making up this test cable.
5.2.2 Connect the test cable.
Set up your oscilloscope for X-Y display, i.e., to display phase relationships between two equal signals.
Connect the test cable to the X and Y oscilloscope inputs. Connect Lt or Rt to your RTA input. Insert the
phone plug end of the test cable into the headphones jack on the front panel of the DFP-D3000.
5.2.3 Set the MONITOR SELECT switch of the Decoder to position 1 (the LCD screen will briefly
display L+LC+C+SL/R+RC+SR). Set the adjacent HEADPHONES volume control to the 12:00
(straight up) position.
5.3 Enter the A-Chain access password in order to adjust preamplifier gains and set the slit loss equaliza-
tion frequency. You will need to play customary alignment films at times during this process. The default
A-Chain password is “SONY”.