Lexicon 20/20 AD manual Compressor Knob Values, Gain Threshold Release

Using the 20/20 AD Lexicon

THRESHOLD

GAIN

0dB

1

2

3

4

5

6

7

8

9

10

11

12

-3dB

1.50:1

3.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

-6dB

1.20:1

1.50:1

2.00:1

3.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

-8dB

1.14:1

1.33:1

1.66:1

2.00:1

2.66:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

-10dB

1.11:1

1.25:1

1.42:1

1.66:1

2.00:1

2.50:1

3.33:1

4.00:1

4.00:1

4.00:1

4.00:1

4.00:1

-12dB

1.09:1

1.20:1

1.33:1

1.50:1

1.71:1

2.00:1

2.40:1

3.00:1

4.00:1

4.00:1

4.00:1

4.00:1

-14dB

1.07:1

1.16:1

1.27:1

1.40:1

1.55:1

1.75:1

2.00:1

2.33:1

2.81:1

3.50:1

4.00:1

4.00:1

-16dB

1.06:1

1.14:1

1.23:1

1.33:1

1.45:1

1.60:1

1.77:1

2.00:1

2.28:1

2.66:1

3.20:1

4.00:1

-18dB

1.06:1

1.12:1

1.20:1

1.28:1

1.38:1

1.50:1

1.63:1

1.80:1

2.00:1

2.25:1

2.57:1

3.00:1

-20dB

1.05:1

1.11:1

1.17:1

1.25:1

1.33:1

1.42:1

1.53:1

1.66:1

1.81:1

2.00:1

2.22:1

2.50:1

-22dB

1.05:1

1.10:1

1.16:1

1.22:1

1.29:1

1.37:1

1.46:1

1.57:1

1.69:1

1.83:1

2.00:1

2.20:1

-24dB

1.04:1

1.09:1

1.14:1

1.20:1

1.26:1

1.33:1

1.41:1

1.50:1

1.60:1

1.71:1

1.84:1

2.00:1

-26dB

1.04:1

1.08:1

1.13:1

1.18:1

1.23:1

1.30:1

1.36:1

1.44:1

1.52:1

1.62:1

1.73:1

1.85:1

-30dB

1.03:1

1.07:1

1.11:1

1.15:1

1.20:1

1.25:1

1.30:1

1.36:1

1.42:1

1.50:1

1.57:1

1.66:1

-36dB

1.02:1

1.06:1

1.09:1

1.12:1

1.16:1

1.20:1

1.24:1

1.28:1

1.33:1

1.38:1

1.44:1

1.50:1

As both the formula and the table show, raising the threshold increases the ratio

—making the compression more audible above the THRESHOLD setting. However, because signals below the threshold are boosted linearly through the compressor, raising the threshold may decrease the amount of time the compressor is reducing gain. This may decrease the audible artifacts.

Conversely, if you lower the threshold all the way to -36dB, you will pretty much guarantee that all but the quietest signals will experience some amount of gain reduction, but the ratio will be so small (1.2:1) that the total effect may be less noticeable than a higher threshold setting.

Start with RELEASE time set to about 180 mS, then shorten the time for percussive program material and lengthen it for material such as voice.

RELEASE times of 0mS to ∞ are available. Attack time of the compression is automatically set as a function of the signal rise time.

Compressor Knob Values

5 6 7		-18 -16	-14	56	100 180
4	8	-20	-12	32	320
3	9	-22	-10	18			560
2	10	-24	-8	10			1S
1	11	-26	-6	5		∞	1.5
0	12	-30	-3	0
		-36	0
GAIN		THRESHOLD		RELEASE
(in dB)		(in dB)		(in mS and S)

Note that changing the settings of GAIN and THRESHOLD while recording may produce audible clicks. If, for artistic reasons, you wish to turn the compressor off during a recording, do so by increasing the release time to ∞ . (Using the compressor on/off switch may produce a click.)

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