Meridian DSP420 User manual

Meridian DSP420 In-Wall Loudspeaker
user guide

i
Preface
Meridian DSP420
In-Wall Loudspeaker
System User Guide

Preface
ii
Sales and service in the UK
Meridian Audio Ltd
Stonehill
Stukeley Meadows
Cambs
PE29 6EX
England
Tel [phone]
Fax [phone]
World Wide Web
http://www.meridian-audio.com
Part no: DSP420
Sales and service in the USA
Meridian America Inc
3800 Camp Creek Parkway
Building 2400
Suite 122
Atlanta
GA 30331
Tel [phone]
Fax [phone]
Designed and
manufactured in the UK by
Meridian Audio Ltd
Stonehill
Stukeley Meadows
Cambs
PE29 6EX
England
Copyright © 2003 Meridian Audio Ltd.
Boothroyd|Stuart Meridian, Meridian,
Meridian Digital Theatre, Meridian
Lossless Packing, MHR, and MLP are
registered trademarks of Meridian
Audio Ltd.
MHR: This product incorporates copyright
protection technology covered by certain
patent applications and intellectual
property of Meridian Audio Ltd. This
technology is provided for the express
purpose of securely containing copyright
audio within the Meridian System only.
Reverse engineering or circumvention of
this protection is strictly prohibited.
This guide was produced by
Human-Computer Interface Ltd,
http://www.interface.co.uk

iii
Preface
Important safety instructions
To avoid overheating
Do not position the speakers:
❍In direct sunlight.
❍Near heat sources, such as a radiator.
❍Directly above heat producing equipment, such as a power
amplifier.
The DSP420 front plate acts as a heatsink and requires
adequate ventilation. Ensure that air can flow around it.
To avoid interference
Do not position the speakers:
❍Near strong magnetic radiation, such as near a power
amplifier.
❍Refer to installation sheet for wiring and other important safety
instructions.
❍Heed all warnings.
❍Read the instructions.
❍Keep these instructions.
❍Follow all instructions.
❍Do not use this apparatus near water.
❍Clean only with a dry cloth.
❍Install only in accordance with the manufacturer’s
instructions.
❍Only use with a Meridian Audio DSP420 wall box.
❍Refer all servicing to approved service personnel.
❍Connection to the mains should be carried out by a skilled
and suitable qualified person.
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR
MOISTURE.

Preface
iv
Radio interference
FCC Warning: This equipment generates and can radiate radio
frequency energy and if not installed and used correctly in
accordance with our instructions may cause interference to
radio communications or radio and television reception. It has
been type-tested and complies with the limits set out in Subpart
J, Part 15 of FCC rules for a Class B computing device. These
limits are intended to provide reasonable protection against
such interference in home installations.
EEC: This product has been designed and type-tested to
comply with the limits set out in EN55013 and EN55020.

v
Preface
Contents
Introduction 1
Introduces the DSP420 In-Wall
Loudspeaker System, and gives guidelines
and suggested layouts to help you plan
your surround system.
The DSP420 In-Wall Loudspeaker
System ..................................................... 2
Sample configurations ............................. 5
Specification and accessories ................. 8
Unpacking the DSP420
loudspeakers 11
Gives details of the components supplied
with the digital loudspeakers, and explains
how to reset their configuration.
Unpacking .............................................. 12
Resetting the loudspeakers ................... 13
Using the DSP420
loudspeakers 15
Provides step-by-step instructions for
operating the digital loudspeakers in
compact systems with no other
preamplifier or control unit.
Selecting a source ................................. 16
Adjusting the volume ............................. 17
Adjusting the balance or phase ............. 18

Preface
vi
Configuring the DSP420
loudspeakers using a
computer 19
Describes how to configure the digital
loudspeakers using the Meridian
Configuration program.
The Meridian Configuration program ..... 20
Running the Meridian Configuration
program ................................................. 21
Creating a new settings file .................... 23
Changing the setup options ................... 25
Setting up sources ................................. 27
Completing the configuration ................ 29
Troubleshooting 31
Provides suggested solutions to typical
problems.
Troubleshooting ..................................... 32
Service and guarantee ........................... 34
Index ...................................................... 35

Introduction
1
Introduction
The DSP420 In-Wall Loudspeaker System uses high technology digital
signal processing to remove the compromises previously associated with
in-wall speakers, allowing them to achieve the same clear open sound and
wide frequency response as traditional free-standing speakers. DSP420
loudspeakers are ideal as part of a home theatre system, or as the basis
for a compact stereo system.
For instructions on installing and connecting up the loudspeakers please
refer to the separate sheet DSP420 Installation Instructions.
For instructions on setting up the loudspeakers turn to the next chapter,
Unpacking the DSP420 loudspeakers. Once they have been set up refer to
Using the DSP loudspeakers, page 15, for information about getting the
best results from all your music and film recordings.

2
Introduction
The DSP420 In-Wall Loudspeaker System incorporates the
result of several years of research and development into
innovative technologies.
Meridian DSP
The DSP420 accepts digital input signals up to 96kHz/24-bit,
including Meridian High Resolution (MHR) streams from Meridian
surround controllers, processors, and DVD players.
Enclosed in a fully shielded housing, Meridian’s unique DSP
processing is performed on a specifically designed six-layer
PCB using a powerful 100 MIPS Motorola DSP engine. Through
this sophisticated audio computer the DSP420 receives all of the
same high technology features that can be found throughout the
Meridian DSP loudspeaker family. These include:
❍FIFO memory buffer input for the lowest possible jitter.
❍Linear-phase crossover for precision drive unit integration.
❍Tweeter delay for perfect driver alignment.
❍48-bit resolution volume control.
❍Minimal frequency equalisation to give a frequency response
free from drive unit or electronic coloration.
❍Transparent tone controls.
❍Absolute phase control and phase-corrected balance control.
A further DSP enabled enhancement to the audio performance
of the DSP420 is Meridian’s active bass extension. This deepens
the response of the system without excessive woofer excursion
The DSP420 In-Wall Loudspeaker System

Introduction
3
and in turn produces a convincingly ‘big box’sound from an
in-wall unit. At moderate volumes, a psychoacoustically correct
filter extends the bass response much further than can be
achieved with an analogue speaker of equal size while at high
volumes dynamic DSP bass protection is used to prevent the
woofers from bottoming. As a result only the very lowest
frequencies are reduced.
Power amplifiers
The speakers are driven by two high-power, low-feedback
power amplifiers using carefully selected bipolar output devices.
The amplifiers are direct coupled to the drive units for the most
efficient delivery of power and the best possible control over
driver excursion.
The power supply includes a substantial torroidal transformer
and audiophile-grade capacitors, and the system uses careful
star earthing, resulting in extremely low levels of noise and
distortion.
DSP420 drivers
Each DSP420 loudspeaker uses two parallel 127mm (5") bass
drive units. These incorporate a cast alloy chassis and a carbon
fibre cone, and have a very large magnet which provides
excellent drive and control. Combined with Meridian’s active
bass extension technology, they provide surprisingly rich, deep
bass, quite unprecedented for this size of cabinet.
The treble unit is a very high quality 25mm (1") aluminium dome
with a neodymium magnet and a protective grille. It is extremely
well matched to the woofer, and also tonally very compatible
with the other speakers in the Meridian range.
The DSP420 is enclosed in an acoustic back box and front baffle
constructed from aluminium, which has low resonance at low
frequencies and has been further dampened by incorporating
stiffening into the back box. Additional high-frequency damping
ensures that the whole system suffers exceptionally little cabinet
coloration and delivers excellent mid-range transparency. All
damping materials have been fully tested to ensure they comply
with building regulations for in-wall designs.

4
Introduction
Meridian High Resolution (MHR)
The DSP420 In-Wall Loudspeaker System supports Meridian
High Resolution (MHR), to allow you to connect to other MHR-
compliant Meridian products to take advantage of high-rate
audio sources, and provide the additional benefits of lower jitter
and improved sound quality on all sources.
MHR is a proprietary secure encoding format that uses
encryption and anti-copy methods to provide a secure copyright
protection environment, and allow the secure transfer of audio
streams within a Meridian-only system for playback only.
Meridian Comms
The DSP420 In-Wall Loudspeaker System is part of the Meridian
family of advanced digital, analogue, and video components,
and these incorporate a sophisticated communications link, to
allow you to control any combination of units using a single
remote, and ensure that they will work together as a fully
integrated system.
The communications system also allows you to extend your hi-fi
system into two or three rooms, with the ability to control the
sources in one room from the controller in another room.
The following pages show two recommended configurations
based on the DSP420 In-Wall Loudspeaker System to illustrate
the flexibility of Meridian components.

Introduction
5
Sample configurations
Meridian Digital Theatre™
Meridian DVD Playe r
DSP5500HC
DSP7000
DSP420 DSP7000 DSP420
504
Meridian Surround Processor
DSP420 loudspeakers can be used in conjunction with a
Meridian Surround Processor to provide the two rear channels,
and optionally two additional side channels, to create an
unobtrusive surround system with superb music and cinema
sound.
A pair of DSP7000 loudspeakers, in conjunction with a
DSP5500HC centre speaker, would provide excellent choices for
the front channels, giving a complete system without
compromise.

6
Introduction
The DSP420 can be connected directly to almost any source
that provides a PCM SPDIF output, including CD or DVD
players, some PC soundcards, and digital satellite decoders.
The DSP420 includes a DSP volume control, and with Meridian
sources this operates seamlessly via the 500 comms system.
Meridian DVD Player
DSP420 DSP420
DSP420 Digital Stereo System
Alternatively, the volume can be controlled with the Meridian
System Remote using the optional 512 Remote Eye.

Introduction
7
Other applications
Other applications include:
❍Main speaker in a Digital Music System with a Meridian CD
Player (512 required).
❍Main speakers with another source of digital audio; eg satellite
(512 and MSR required).
❍Second zone speaker in a Meridian two-room plus system
(long M5 lead, 512, and MSR required).
These applications may require additional accessories; for more
information see Available accessories, page 9.

8
Introduction
Specification and accessories
Frequency response 55Hz-20kHz ±3dB
Crossover Linear-phase ±30º at 2.3kHz.
Drive units Woofers: 2 x 127mm (5") carbon fibre
custom drivers, cast alloy chassis.
Tweeter: 1 x 25mm (1") aluminium dome
neodymium magnet, with protective
grille.
Control 2 x Meridian Comms.
9-pin D connector for RS232 PC setup
and control, null modem, 9600 baud,
2N1, no handshake.
Cabinet Aluminium front baffle with sealed,
mechanically dampened and insulated
acoustic enclosure.
Dimensions Frame 457mm (18") square x 89mm
(3.5").
Hole cutout 420mm (16.54") square.
Power 100-125; 200-250V AC 50-60Hz.
6VA idle; 200VA max.
Meridian Audio reserves the right to amend product
specifications at any time.
Specification
Digital inputs 1 x cable, 75Ω, IEC958, 44.1kHz-96kHz.
FIFO locks at 44.1, 48, 88.2, or 96kHz ±
150ppm, PCM and MHR.
1 x digital output cable, 75Ω, IEC958,
providing a copy of the selected input.
Processing 1 x Motorola 56364 running at 100MHz.
Power amplifiers Low feedback complementary bipolar
design, with output-stage error
correction and twin loop design.
Treble: 65W RMS.
Bass: 85W RMS.
Digital to analogue 96kHz/24-bit.
conversion
Distortion Typically <0.01%, or <0.05% up
to full power at all frequencies.
Noise and hum <-95dBr at all volume settings.
Acoustic output Typically >104dB spl @ 1m.
Acoustic noise <15dB spl @ 1m.

Introduction
9
Available accessories
The DSP420 is shipped ready to be used as a speaker in a small
Meridian Digital Theatre with a Meridian DVD Player (such as the
800 or 598) or a Meridian Digital Surround Controller (such as
the 861, 568.2, or 561).
Other applications, and some advanced features, may require
one or more of the following accessories, which can be
purchased from your Meridian dealer:
❍Meridian System Remote.
❍512 Remote Eye for remote control reception.

10
Introduction

Unpacking the DSP420 loudspeakers
11
Unpacking the DSP420
loudspeakers
This chapter explains what you should find when you unpack the
speakers, prior to installing them. It also explains how to reset the
configuration from the front panel.
For information about installing and connecting up speakers please refer
to the DSP420 Installation Instructions leaflet, supplied separately.

12
Unpacking the DSP420 loudspeakers
Unpacking
The digital loudspeaker system is supplied in a box containing
the following components:
❍DSP420 speaker module.
❍Grille assembly.
❍Spare grille scrim.
❍This user guide.
❍DSP420InstallationInstructions leaflet.
❍Six screw packs for speaker module.
❍Meridian Comms interconnect lead.
❍Configuration program.
❍Grille removal tool.
If any of these items is missing, please contact your dealer. We
suggest that you retain the packaging carefully, as it provides
maximum protection in transit.

Unpacking the DSP420 loudspeakers
13
Resetting the loudspeakers
POWER LOCK
RESET
Lock indicator
Power indicator
Power
switch
Reset switch
Channel selector
To reset the configuration of the
digital loudspeaker
The following procedure can be used to reset the configuration
of the DSP420 loudspeaker to the default settings, without
needing a computer, using the reset switch accessible below the
front panel.
●Turn off the power at the front panel.
●Press and hold in the reset switch, using a suitable object
such as a bent paperclip or the grille removal tool.
●Turn on the power.
The red power indicator on the front panel will flash. When the
indicator stops flashing:
●Release the reset switch.