20/20 AD Quick Reference Guide
Using the Compressor
PUSH
DO
WORD CLOCK
IN
DO
3 + 4
1 + 2
OUT
AES
SYNC
IN
V ~
PUSH
4
IN
3
UNBAL
BAL
PUSH
PUSH
2
IN
1
UNBAL
BAL
PUSH
3 Oak Park • Bedford, MA 01730 USA • Tel 781-280-0300 • Fax 781-280-0499
Dynamic Range Compression
0dB
-3dB
-6dB
-8dB
-10dB
-12dB
-14dB
-16dB
-18dB
-20dB
-22dB
-24dB
-26dB
-30dB
-36dB
1
1.50:1
1.20:1
1.14:1
1.11:1
1.09:1
1.07:1
1.06:1
1.06:1
1.05:1
1.05:1
1.04:1
1.04:1
1.03:1
1.02:1
2
3.00:1
1.50:1
1.33:1
1.25:1
1.20:1
1.16:1
1.14:1
1.12:1
1.11:1
1.10:1
1.09:1
1.08:1
1.07:1
1.06:1
3
4
4.00:1
3.00:1
2.00:1
1.66:1
1.50:1
1.40:1
1.33:1
1.28:1
1.25:1
1.22:1
1.20:1
1.18:1
1.15:1
1.12:1
5
4.00:1
4.00:1
2.66:1
2.00:1
1.71:1
1.55:1
1.45:1
1.38:1
1.33:1
1.29:1
1.26:1
1.23:1
1.20:1
1.16:1
6
4.00:1
4.00:1
4.00:1
2.50:1
2.00:1
1.75:1
1.60:1
1.50:1
1.42:1
1.37:1
1.33:1
1.30:1
1.25:1
1.20:1
7
4.00:1
4.00:1
4.00:1
3.33:1
2.40:1
2.00:1
1.77:1
1.63:1
1.53:1
1.46:1
1.41:1
1.36:1
1.30:1
1.24:1
8
4.00:1
4.00:1
4.00:1
4.00:1
3.00:1
2.33:1
2.00:1
1.80:1
1.66:1
1.57:1
1.50:1
1.44:1
1.36:1
1.28:1
9
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
2.81:1
2.28:1
2.00:1
1.81:1
1.69:1
1.60:1
1.52:1
1.42:1
1.33:1
10
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
3.50:1
2.66:1
2.25:1
2.00:1
1.83:1
1.71:1
1.62:1
1.50:1
1.38:1
11
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
3.20:1
2.57:1
2.22:1
2.00:1
1.84:1
1.73:1
1.57:1
1.44:1
12
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
4.00:1
3.00:1
2.50:1
2.20:1
2.00:1
1.85:1
1.66:1
1.50:1
4.00:1
2.00:1
1.66:1
1.42:1
1.33:1
1.27:1
1.23:1
1.20:1
1.17:1
1.16:1
1.14:1
1.13:1
1.11:1
1.09:1
GAIN
THRESHOLD
To minimize the audibility of compression artifacts, use ratios from the unshaded portion of the table.
Set THRESHOLD to 0dB.
Start with RELEASE set to
100mS and adjust it for the
program material
Set compressor GAIN to 4dB.
Press PK HOLD and 1dB
SCALE. Set input so that peaks
read approximately -4dB.
Overload Protection
Recognizing Machine States
Flashing
Machine State
Comment
1dB SCALE and ATTEN
Outputs muted.
To unmute, press and hold 1dB SCALE and press ATTEN.
1dB SCALE and 4-CHAN
Sinewave generator mode
To exit, press and hold 1dB SCALE and press 4-CHAN.
1dB SCALE and EMPH
Diagnostics mode
To exit, turn 20/20 AD POWER off, then on again.
1dB SCALE and DISPLAY
Front panel lockout
To exit, press and hold 1dB SCALE and press DISPLAY.
WC or AES
External sync source selected
Connect the appropriate sync source or use EXT SYNC to
but not present
select Internal Sync (neither WC nor AES lighted).
48 and 44.1
AES sync source not present
AES sync source must be within 41-51 kHz range.
or out of range
Set THRESHOLD between
-18 and -36dB.
Shorten the time constant for
percussive program material
and lengthen it for voice.
Set RELEASE to 100 mS.
Start with compressor GAIN
set between 4 and 6dB.
Continuously Lit
WIDE, HF and 20BIT
Psychoacoustically optimized
4-CHAN, DISPLAY, LINK, compressor ON and ALT-MUTE
noise shaping activated
are disabled. To exit, press DITHER.
