Dorrough 40-A User Manual

DORROUGH ELECTRONICS
5221 Collier Place
Woodland Hills, CA 91364
(818) 999-1132
DORROUGH
LOUDNESS MONITOR
Model 40-A
DORROUGH
RELATIVE LOUDNESS
TO PEAK MODULATION
Model 40-B
Technical Instruction Manual
RELATIVE LOUDNESS TO PEAK MODULATION
MODEL 40-B
LOUDNESS MONITOR
MODEL 40-A
-25
-22
-20
-18
-16
-14
-12
-10
- 8
- 6
- 4
- 2
0
+ 2
+ 4
+ 6
+ 8
+10
+12
+14
NORMAL
PEAK
RANGE
NORMAL
RANGE
PERSIS
TENCE
dB
dB
dB
dB -36
1.6
-34
-32
-30
-28
-26
-24
-22
-20
-18
-16
-14
-12
-10
- 8
- 6
- 4
- 2
0
+1
+2
+3
2
2.5
3.2
4
5
6.3
8
10
12
16
20
25
32
40
50
63
80
100
125
% MODU
LATION
% MODU
LATION
Also covers Models 10-A(B), 12-A(B), 20-A(B), and 21-A(B)

Dorrough 40-A Specifications

General

Brand	Dorrough
Model	40-A
Category	Measuring Instruments
Language	English

Summary

Understanding Loudness Monitoring

Weston (VU) Meter Technology

Standard for level monitoring since 1939, quasi-average reading, ignores peaks.

Program Peak Meter (PPM) Technology

Program Peak Meter, displays and holds peak level, ignores integration time.

DORROUGH Loudness Monitor Features

Loudness Monitor Installation Procedures

Meter Unpacking and Damage Check

Procedure for checking the unit for shipping damage upon receipt.

Initial Meter Setup and Calibration

Steps to align the meter to match operating level requirements.

Mounting Options and Specifications

Loudness Monitor Operation and Use Cases

Using the Loudness Monitor

How to feed signals to the meter and adjust input controls.

Applications of DORROUGH Loudness Meters

Lists various uses of DORROUGH Loudness Monitors in broadcast/audio.

DORROUGH Loudness Monitor Circuitry Explained

Field Calibration of Loudness Monitors

Calibrating the 'A' Type Monitor

Step-by-step instructions for calibrating the "A" Type monitor.

Calibrating the 'B' Type Monitor

Step-by-step instructions for calibrating the "B" Type monitor.

Manual Notes and Reminders