Eventide BD500, Руководство оператора

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BD500 Broadcast Profanity Delay Chapter 2 Operation Page 11
©Eventide Inc. 1995-1999
doc release 10
Operation as a Precision Fixed Delay
The BD500 may be used as a fixed stereo delay line, adjustable from 0.000 seconds to 8.000 seconds. Opera-
tion is straightforward with several front panel buttons serving secondary duty as fixed delay controls.
There are two ways to enter precision fixed delay mode. The easiest is to shut down the unit, then turn it
back on holding down the REBUILD button. After the TST mode completes you will be prompted to select PFD
or BD . The 2nd method is from configuration mode. Go into bypass mode. In bypass mode the display shows
---
. Press the CONFIGURE button. This puts the unit into configuration mode. Now press the RAMP TO
ZERO button. You are now at the "on-line" configuration level. Now press the WAIT AND EXIT button twice.
This moves across the on-line level to the run parameter. The display should now show
RUN
. Now press the
WAIT AND EXIT button repetitively (stepping through run modes) until the display shows
PFD
. Press the
BYPASS button to exit configuration mode. The display should show
---
. Now press BYPASS to put the unit
in-line. The unit will be in fixed delay mode.
To return to profanity delay operation, press BYPASS, then CONFIGURE, then RAMP TO ZERO, then WAIT
AND EXIT twice. The display now shows
RUN
. Now press SNEEZE to return to the factory default setting of
the run parameter. Now press BYPASS to get out of configuration mode.
Controlling the Fixed Delay
In precision fixed delay mode the only operable buttons are titled BYPASS, REBUILD, RAMP TO ZERO,
and SNEEZE. The buttons behave as follows:
• BYPASS takes the unit off-line Always valid.
• REBUILD decrements selected delay digit. Valid if lit.
• RAMP TO ZERO increments selected delay digit. Valid if lit.
• SNEEZE selects one of 5-sets of digits to be adjusted. Always valid.
The bar graph below the three digit display indicates which of seven digits (five sets) is selected for adjust-
ment. The presence of the decimal point indicates that the three digits shown are the ones, tenths and
hundredths digits. Press the SNEEZE button several times to step through the selected digits. The following
illustration shows a 7.001625-second delay as the SNEEZE button is pressed five times.
editing the
first digit
1s of seconds
editing the
second digit
1/10 of seconds
editing the
third digit
1/100 of
seconds
editing the
fourth digit
milliseconds
Usage Notes
The BD500 provides precision down to 4 samples in length. Thus at 48ksamples/sec you will see 4/48000 of
a second adjustment precision, or 83.3microseconds. Thus if you move the last 3 digits up and down you will
see changes that are around 83 per jump. At 32ksamples/sec you will see 125uS adjustment precision.
The minimum delay the BD500 will allow is also dependant on the sample rate used by the BD500. The
minimum will be less than 5 milliseconds.
The fixed delay writes data continuously into the 8-second buffer. Changes in delay changes the position of
the play head, not the record head. That means that, if the delay length is adjusted by ear, the user doesn't
have to wait for new input audio to check the adjustment. While listening to an audio source, try adjusting
the seconds digit upward. It is easy to play the same 1-second piece of input audio eight times.
Note: When entering precision fixed delay mode from bypass the delay buffer is set to the previous value
used in the fixed delay. The delay line is erased, so the outputs will be silent for a brief time.
&00 &00 &00 001 625 &00
editing the 5th,
6th, and 7th digits
microseconds
back to 1st
digit, seconds