SoundCraft Spirit Monitor User Manual

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© Soundcraft Electronics Ltd. 1991
All rights reserved

Issue 1
Part No. ZZ2727

Information in this manual is subject to change without notice and does not represent a
commitment on the part of the vendor. Soundcraft Electronics Ltd. shall not be liable for
any loss or damage whatsoever arising from the use of information or any error contained
in this manual.

No part of this manual may be reproduced, stored in a retrieval system, or transmitted, in
any form or by any means, electronic, electrical, mechanical, optical, chemical, including
photocopying and recording, for any purpose without the express written permission of
Soundcraft Electronics Ltd.

It is recommended that all maintenance and service on the product should be carried out
by Soundcraft Electronics Ltd. or its authorised agents. Soundcraft Electronics Ltd. cannot
accept any liability whatsoever for any loss or damage caused by service, maintenance or
repair by unauthorised personnel.

Soundcraft Electronics Ltd.
Unit 2
Borehamwood Ind Park
Rowley Lane
Borehamwood
Herts.
WD6 5PZ
England

Tel: [phone]
Fax: [phone]

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User Guide

Contents

Introducti on . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Basic Princip les o f Monit or Mixing . . . . . . . . . . . . . 5

Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . 8

Connections and Connectors . . . . . . . . . . . . . . . 8

Fault Finding Guide . . . . . . . . . . . . . . . . . . . 10

Getting to know your console . . . . . . . . . . . . . . . . 12

Facilities . . . . . . . . . . . . . . . . . . . . . . . . . 12

Input Channel . . . . . . . . . . . . . . . . . . . . . . 12

Output Section . . . . . . . . . . . . . . . . . . . . . . 16

Master Section . . . . . . . . . . . . . . . . . . . . . . 18

Using your SPIRI T Monitor Consol e . . . . . . . . . . . . 20

Initial Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Application s . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Care of your mixer . . . . . . . . . . . . . . . . . . . . . . 23

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Selectable Options . . . . . . . . . . . . . . . . . . . . . . 25

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 26

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 28

Front Panel Layo ut . . . . . . . . . . . . . fold out rear page

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INTRODUCTION

Congratula tion s o n yo u r purc has e of a SPIRIT Monitor mixer.
Owning a Soundcraft console brings you the expertise and
support of one of the industry’s leading manufacturers and
the results o f over 17 yea rs exp erienc e suppo rting some of t he
biggest names in the business.

Designed by engine ers who understand the individua l needs
of musicians, SPIRIT Monitor has been built to the highest
standards using quality components and employing auto­mated assembly techniques beyond the reach of most
manufacturers of compact mixers.

A rugged steel chassis is combined with moulded side trims
to give protection and distinctive appearance. Custom­moulded controls, designed for the best ‘feel’ and visual
clarity complement the styling, resulting in a truly profes­sional stage monitor mixer which is ideal for both touring and
fixed installations.

SPIRIT Monitor is available in 16 an d 24 channel frame s izes,
and is designed to complement the SPIRIT Live range of
front- of-house consoles.

SPIRIT Monitor incorporates circuit technology identical to
that used on some of the most sophisticated Soundcraft co n­soles. The input channe ls are able to accept a wide range of
Microphone and Line level signals from separate input sock­ets. Every channel features wide range gain control, phase
reverse switch, 3-band Equalisation with swept Mid and LF
range, plus a Hi-Pass Filter, 8 Monitor Sends, PFL(Pre Fade
Listen), Peak LED and a high-quality linear fader.

Each of the eight Monitor Outp ut sections is provided with a
variable high-pass filter, insert point, LED bargraph meter,
Talkback and Dim s witches, a variable s end to the enginee r’s
wedge and a high quality linear fader.

The master section comprises contro ls for PFL monitoring, en­gineer’s wedge, LED bargraph meter for Wedge/PFL and
master Talkback and Dim switches. The wedge output is pro­vided with an insert point and high quality linear fader.

SPIRIT Monitor is des igned to be as user-friendly as possible,
but a few minutes spent reading through this manual will
help you become familiar with the product away from the
pressure of a live session, and allow you to gain full benefit
from the superb performance offered by your new mixer.

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Above all, remember that your SPIRIT mixer is designed to
extend your creativity. The more you explore the controls
and the effect they have on the sound output, the more you
will apprec iate the flexibility offered by your SPIRIT Monitor
mixer.

BASIC PRINCIPLES OF MONITOR MIXING

There was a time when the P.A. system and the operator ex­isted only to increa se t he ove rall volu me of the performers , s o
that they could be heard in a large room or abov e high ambi­ent noise levels. This just isn’t true any more. The sound
system and the sound engineer have bec ome an integral part
of the performance, an d the artists are heavily dependent on
the operator’s skill and the quality of the equipment. While
the quality of the front-of-house PA mix is of prime impor­tance, the ability of the artists to deliver the best performance
may be directly influenced by the quality of the stage m onitor
mix. Indeed, the monitor engineer may be required to pro­vide a number of quite different individual monitor mixes,
often under the most adverse conditions.

The following introduction to the basics of mixing are in­cluded for the benefit of those users who may not have any
significant familiarity with sound equipment, and who are
baffled by the endless jargon used by engineers and artists
alike.

The Mixer As one would expect, the main purpose of the mixer is to

combine sounds, but under precise and smooth control. The
faders provide you with total control of the final sound at
your finger tips and like an artist play ing an instrument you
should listen to your fader movements, not look at your
hands.

Your SPIRIT Monitor mixer accepts a wide range of input sig-
nals via a microphone input, for very low level signa ls, or a
line input, for higher level s ignals from , for inst anc e, ta pe ma­chines, effects processors, etc.

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The mixer is split into two se ctions . The Inputs receive, match
and process individual source signals, and dist ributes them at
precise mix levels to a choic e of Monitor Outputs. The Mas-
ter section provides monitoring of the audio signal at many
points in the mixer, either o n headphones or meters and pro ­vides additional master control of talkback functions.

The Equaliser controls are the most flexible and potentially
destructive feature of th e mixer. They have a similar effect on
the frequenc y response o f the input ch annel as the tone con­trols on a hi-fi syst em, but with much greater pre cision, and
allow particular characteristics of the input signal to be em­phasised or reduced. It is very important that you become
familiar with the effect each control has on the sound and this
is best achieved by spending time listening to the effect of each
control on a well-known track played through the mixer.

Phase Rever sal e nables the opera tor to revers e the polarity of
the signal entering the mixer, as a convenient way o f checking
for incorrect wiring or problems with microphone placement.

The Monitor Sends provide a way of routing the input sig-
nals to a number of outputs, to create individual mixes for
artists foldback or additional speake r outputs.

Pre-Fade-Listen(PFL) allows you to monitor the signal at
many points in the mixer. Pre ssing any P FL switc h places t he
signal at that particular point onto the headphones and the
PFL meter, to check the quality of the signal or to pin-point
problems. Using PFL will not affect the signals on the moni­tor outputs.

Each input channel and all outputs have an Insert ‘A’ gauge
jack socket, which is a break point in the signal pa th. It allows
the signal to be taken out of the mixer, through an external
piece of equ ipmen t an d then bac k into the mixer direct ly after
its original exit point. The Insert point is normally bypassed
by the ‘A’ gauge jack contacts, and is only brought into opera­tion when a plug is inserted. Typical uses would include
Effects Processors, Limiters, additional Equalisers or Delay
units.

The terms PR E and POST are often used in the context of In­serts, Equalisers and Channel Sends, and describe whether
that facility is placed before (Pre) or after (Post) another par­ticular section. This is explained further in the detailed
description of facilities.

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The Wedge output refers to the engineer’s own monitoring
output, which will typically feed a floor-mounted ‘wedge­shaped’ speaker via a suitable power amplifier.

The Talkback system allows the m onitor engineer to talk back
to artists, either individually via selected monitor outputs, or
together using a switch on the master se ction.

Creating monitor m ixes on stage in close proximit y to micro­phones demands constant awareness of the problem of
acoustic feedback. The Dim buttons enable the engineer to in-
stantly lower the output level on any outputs to avoid this
problem while more precise level adjustments are made.

A mixer is often judged, amongst other factors, by the amount
of Headroom available. This is a measure of the reserve a vail-
able to cope with sudden peaks in the input signal, without
distortion caused by Clipping, when the signal becomes so
high that it would exceed the po wer supply rail voltages and
is as a res ult limited. This commonly occurs wh ere gain set­tings are incorrectly set or where sources are improperly
matched to the mixer input. If the source signal is too high,
clipping and distortion resu lts. If the signal is too low it be­comes masked by the background noise which is present to
some degree in all mixers. The diagram below illustrat es this
point.

Clipped

Signal

Noise

If the signal level is too high, clipping dis tortion
may occur.

Signal

If the signal level is too low it may be masked
by the noise.

Noise

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GETTING STARTED

CONNECTIONS AND
CONNECTORS

Although this may see m a simple subject, fa ul ty co nne ctors a nd
cabling are the source of most sound system problems. Correct ly-

made cables of the proper type, with the right connectors for
the job will ensure peak performance from your system with
minimum noise pick-up. The following section w ill help you
to connect SPIRIT Monitor correctly.

Two different types of audio c onnectors are u sed, 3-pin XLR
and 1⁄4" three pole (‘A’ gauge) jacks . These are used in severa l
configurations as shown in the diagrams below.

2. Hot(+ve)

3. Cold(-ve)

1. Screen

Balanced

Input

1. Screen
(ground)

3. Cold (ground sense)

2. Hot (In phase)

Ground Compensated

Output

3POLE(stereo)JACK

Send

Return

Screen

Tip

Ring

Insert Points Line Input Headphones

Tip

Ring

Sleeve

Sleeve

Hot(+ve)
Cold(-ve)
Screen

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Left Signal
Right Signal
Ground

Balanced and
Unbalanced

All channel inputs are balanced, i.e. there are separate
+ve(hot) and -ve (cold) wires for each signal plus a ground.
The design of the d ifferential input amplifiers is such that in­terference picked up on these wires is cancelled out. This is
because, sinc e both wires are in close p roximity, the same in­terference will be p icked up on each wire and balance d input
amplifiers will only amplify the difference between +ve(hot)
and -ve(cold). Any signal on both hot an d c old (i.e. noise) will
not be amplified - this is known as common mode rejection
(CMR). Balanced inpu ts should always have both +ve and ­ve connect ed or if the source is u nbalanced sourc e, the signa l
should connect to +ve and the -ve pin of the input should be
shorted to ground.

Note: many modern audio/musical instruments have elec­tronically balanced outputs which should not be unbalanced
by shorting one wire to ground. Always use yo ur inputs bal­anced where possible.

All of the outputs are ground compensated a technique which
provides a very effective way of optimising noise immunity,
without the cost and complexity of balanced outputs. These
outputs employ ground compensation to cancel out the effects
of variation in ground potential bet ween the mixer a nd other
equipment which would otherwise show up as hum. If the
output is driving a device or amplifier that has an unbalanced
input, connect the -ve(cold) signal to the ground.

Polarity You will probably be familiar with t he concept of polarity in

electrical signals and this is of particular importance to bal­anced audio signals. Just as a balanced signal is highly
effective at cancelling out unwanted int erference, so two mi­crophones picking up the s ame signal can c ancel out, or cau se
serious degradation of the signal if one of the cables has the
+ve and -ve wires re vers ed. This phas e reversal can be a rea l
problem when microphones are close together and you
should therefore take care always to connect pins correctly
when wiring audio cables.

Grounding and
Shielding

For optimum performan ce it is vital that all signals are refer­enced to a solid, noise-free earth ing point and that all signal
cables have their screens c onn ect ed to groun d. To avo id ea rth
‘loops’, use balanced connections where po ssible and ensure
that all cable screens and othe r signal earths are connec ted to
ground only at their source and not at both ends.

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