Meridian DSP420 User manual

DSP420
In-Wall Loudspeaker System
User Guide

ii
Preface Important safety instructions
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 RF420 rough-in box.
Only use attachments/accessories specified by the
manufacturer.
Use only with the cart, stand, tripod, bracket, or table
specified by the manufacturer or sold with the apparatus.
When a cart is used, use caution when moving the cart/
apparatus combination to avoid injury from tip-over.
Refer all servicing to approved service personnel.
Servicing is required when the apparatus has been
damaged in any way, such as power-supply cord or plug is
damaged, liquid has been spilled or objects have fallen into
the apparatus, the apparatus has been exposed to rain or
moisture, does not operate normally, or has been dropped.
Do not disassemble – no user-servicable parts inside.
Unplug the apparatus during lightning storms or when
unused for long periods of time.
This apparatus has been designed with Class 1 construction
and must be connected to a mains socket outlet with a
protective earthing connection (the third grounding pin).
The apparatus may be isolated from mains power by
unplugging the connector at the opposing end of the power
cord or cable from its supply outlet. As a result, this connector
should remain accessible.
Do not defeat the safety purpose of the polarized or
grounding plug. A polarized plug has two blades with one
wider than the other. A grounding type plug has two blades
and a third grounding prong. The wide blade, or the third
prong are provided for your safety. If the provided plug does
not fit your outlet, consult an electrician for replacement of
the obsolete outlet.
Protect the power cord from being walked on or pinched
particularly at plugs, convenience receptacles, and at the point
they exit the apparatus.
•
•
•
•
•
•
•
•
•
•
•
•
•
Safety warnings
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR
MOISTURE.
Do not expose the unit to dripping or splashing.
Do not place any object filled with liquid, such as a vase, on
the unit.
Do not place naked flame sources, such as lighted candles,
on the unit.
Do not install near any heat sources such as radiators, heat
registers, stoves, or other apparatus (including amplifiers)
that produce heat.
To avoid overheating
Leave at least 10cm around the equipment to ensure
sufficient ventilation.
Do not position the unit:
In direct sunlight.
Near heat sources, such as a radiator.
Directly on top of heat producing equipment.
The DSP420 front plate acts as a heatsink and requires
adequate ventilation. Ensure that air can flow around it. Do
not block any ventilation openings.
To avoid interference
Do not position the unit:
Near strong electrical or magnetic radiation, such as near a
power amplifier.
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.
•
•
•
•
•
•
•
•
•

iii
Contents
Contents
Introduction 1
The DSP420 In-Wall Loudspeaker System 2
Sample configurations 4
Specifications 6
Unpacking the DSP420 loudspeakers 7
Unpacking 8
Resetting the loudspeakers 9
Using the DSP420 loudspeakers 11
Selecting a source 12
Adjusting the volume 13
Adjusting the balance or phase 14
Troubleshooting 15
Troubleshooting 16
Service and guarantee 18
Index 19

iv
Preface Copyright and acknowledgements
Sales and service in the UK
Meridian Audio Ltd
Latham Road
Huntingdon
Cambridgeshire
PE29 6YE
England
Tel [phone]
Fax [phone]
Sales and service in the USA
Meridian America Inc
8055 Troon Circle
Suite C
Austell
GA 30168-7849
USA
Tel [phone]
Fax [phone]
http://www.meridian-audio.com
Designed and manufactured in the UK
Meridian Audio Ltd
Latham Road
Huntingdon
Cambridgeshire
PE29 6YE
England
Copyright © 2003-2009 Meridian Audio Ltd.
Part no: DSP420/2 (P80300)
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

1
Introduction
Introduction
The DSP420 In-Wall Loudspeaker System uses high technology digital
signal processing to remove the compromises previously associated
with in-wall loudspeakers, allowing them to achieve the same clear
open sound and wide frequency response as traditional free-standing
loudspeakers. 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 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 , page 7. Once they have been set
up refer to Using the DSP420 loudspeakers , page 11, for information
about getting the best results from all your music and video recordings.

2
Introduction The DSP420 In-Wall Loudspeaker System
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 and in turn
•
•
•
•
•
•
•

3
Introduction
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 loudspeaker
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 loudspeakers 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 toroidal
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 which incorporate a cast alloy
chassis and carbon fibre cone. They 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
loudspeakers 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.
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. 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.

4
Introduction Sample configurations
Meridian Digital Theatre™
DSP7200HC
DSP420 DSP420
DSP7200 DSP7200
G68 Digital Surround Controller
G96 DVD Player
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 DSP7200 loudspeakers, in conjunction with
a DSP7200HC centre loudspeaker, would provide
excellent choices for the front channels, giving a
complete system without compromise.

5
Introduction
DSP420 Digital Stereo System
DSP420 DSP420
G96 DVD Player
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. With
Meridian sources this operates seamlessly via the
Meridian Comms system.
Alternatively, the volume can be controlled with the
Meridian System Remote using the optional G12
Remote Eye.
Other applications
Other applications include:
Main loudspeaker in a Digital Music System with a
Meridian CD Player (G12 required).
Main loudspeakers with another source of digital
audio; eg satellite (G12 and MSR+ required).
Second zone loudspeaker in a Meridian two-room
plus system (long M5 lead, G12, and MSR+
required).
These applications may require additional accessories;
for more information see Available accessories , page 6.
•
•
•

6
Introduction Specifications
Connections
Digital input: 1 x balanced digital (AES/EBU) input
on RJ45. 32kHz – 96kHz sampling rates.
Digital output: 1 x RJ45 with balanced digital audio
and control for a second loudspeaker.
9-pin D connector for RS232 PC setup and control,
null modem, 9600 baud, 2N1, no handshake.
Digital formats
44.1–96kHz. FIFO locks at 44.1, 48, 88.2, or
96kHz ±150ppm.
PCM using SPDIF/IEC60958, or MHR connection
support with auto-detection.
Signal processing
1 x Motorola 56364 running at 100MHz.
1 x 24-bit Multi-bit delta-sigma DAC with 128x
oversampling.
Crossover linear-phase ±30º at 2.3kHz.
Output stages
Power amplifiers: Low feedback complementary
bipolar design, with output-stage error correction and
twin loop design.
Bass: 85W RMS.
Treble: 65W RMS.
Acoustic
Bass drive units: 2 x 127mm (5") carbon fibre
custom drivers, cast alloy chassis.
Treble drive unit: 1 x 25mm (1") aluminium dome
neodymium magnet, with protective grille.
•
•
•
•
•
•
•
•
•
•
•
•
•
Characteristics
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.
Frequency response: 55Hz-20kHz ± 3dB
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
Power: 100-125; 200-250V AC 50-60Hz.
6VA idle; 200VA max.
Meridian Audio reserves the right to amend product
specifications at any time.
Available accessories
The DSP420 is shipped ready to be used as a
loudspeaker in a small Meridian Digital Theatre with a
Meridian DVD Player (such as the 800 or G96) or a
Meridian Digital Surround Controller (such as the 861,
G68, or G61R).
Other applications, and some advanced features, may
require one or more of the following accessories,
which can be purchased from your Meridian retailer:
Meridian System Remote Plus (MSR+).
G12 Remote Eye for remote control reception.
Meridian SpeakerLink cables (available in various
lengths).
•
•
•
•
•
•
•
•
•
•
•
•
•

7
Unpacking
the DSP420
loudspeakers
Unpacking the DSP420
loudspeakers
This chapter explains what you should find when you unpack the
loudspeakers, prior to installing them. It also explains how to reset the
configuration from the front panel.
For information about installing and connecting up loudspeakers please
refer to the DSP420 Installation Instructions leaflet, supplied separately.
For information about configuring the loudspeakers, using the Meridian
Configuration Program, please refer to the Meridian Configuration
Program Guide .

8
Unpacking
the DSP420
loudspeakers Unpacking
The digital loudspeaker system is supplied in a box
containing the following components:
DSP420 loudspeaker module.
Grille assembly.
Spare grille scrim.
This user guide.
DSP420 Installation Instructions leaflet.
Screw pack (containing six screws) for loudspeaker
module.
Meridian Comms interconnect lead.
Configuration Program CD.
Grille removal tool.
If any of these items is missing, please contact your
retailer. We suggest that you retain the packaging
carefully, as it provides maximum protection in transit.
•
•
•
•
•
•
•
•
•

9
Unpacking
the DSP420
loudspeakers
Resetting the loudspeakers
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:
POWER LOCK
RESET
Lock indicator
Power indicator
Power
switch
Reset switch
Channel selector
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 swith.
•
•
•
•
Indicator lights
The following table explains the function of the
indicator lights on the front panel:
Indicator State What it means
Red On Power supplied to
loudspeaker.
Flashing Loudspeaker is being
reset, or loudspeaker has
overheated and has shut
down.
Green On Loudspeaker is locked to a
digital input.
Off Loudspeaker is in standby.
Note: The indicator lights are blanked if the displays on
the Meridian system have been blanked.

10
Unpacking
the DSP420
loudspeakers

11
Using the DSP420
loudspeakers
Using the DSP420 loudspeakers
In systems with a Meridian preamplifier or control unit all of the functions
of the DSP420, including volume, tilt, and bass, are operated via
the controller. For more information refer to the user guide for the
preamplifier or control unit, and you can ignore this chapter.
However, the DSP420 In-Wall Loudspeaker System can also be
connected directly to a digital source to create a complete, minimum
system. This chapter provides step-by-step instructions for operating the
digital loudspeakers in a system with no Meridian preamplifier or control
unit.

12
Using the DSP420
loudspeakers Selecting a source
When not playing, the digital loudspeakers should
be left in the standby state. This ensures that the
components of the loudspeakers operate at maximum
efficiency from the moment you start.
To select a source
Press the appropriate source key on the remote; eg
DVD.
This will bring the digital loudspeakers out of standby. If
there is a signal to the loudspeakers the green indicator
on each loudspeaker will be illuminated.
To switch to standby
Press Off on the remote.
The loudspeakers will switch to standby and the green
indicator on each loudspeaker will go off.
•
•

13
Using the DSP420
loudspeakers
Adjusting the volume
The digital loudspeakers adjust the volume in precise
steps of 1dB, where 9dB is equivalent to doubling the
loudness, and can be varied in the range 1 to 99dB.
When you first connect power to the digital
loudspeakers the volume is set to 65, which is similar
to the midway position of the rotary volume control on a
conventional preamplifier.
To change the volume
Press the red Aor Vkeys on the remote.
To mute the sound
Press Mute on the remote.
To restore the sound
Press Mute again on the remote.
Alternatively, the sound will be restored if you adjust the
volume.
•
•
•

14
Using the DSP420
loudspeakers Adjusting the balance or phase
The balance control of the DSP420 In-Wall
Loudspeaker System uses digital signal processing
to compensate for an off-centre listening position by
delaying and diminishing the sound in one loudspeaker,
thus effectively shifting the loudspeaker’s image back.
To change the balance
Press <or >on the remote.
There are 20 settings in each direction.
To reset the balance to the centre
Press Von the remote.
Note: Because the use of the balance control
processes the digital signal, you may hear a slight
clicking as the balance is adjusted.
To change the phase
Press Aon the remote.
The phase function controls the absolute phase of
the digital conversion. It can be used to compensate
for signals that are out of phase, giving an unnatural-
sounding bass.
•
•
•
•

15
Troubleshooting
Troubleshooting
This chapter provides suggested solutions to typical problems that may
occur when setting up the digital loudspeaker(s).
If you are still not able to resolve a difficulty with the help of this guide
and the suggestions in the following pages, please contact your Meridian
retailer or Meridian Audio Ltd.

16
Troubleshooting Troubleshooting
Red power indicator on front panel not
lit
Check the following:
The power switch on the front panel of the DSP420
is turned on.
If the DSP420 will still not illuminate, check any fuses
in your power supply and the fuse on the front panel
of the DSP420. If these are all intact, contact your
retailer.
Red power indicator on front panel is
flashing
This normally indicates that the DSP420 has
overheated and that it has shut down to cool down. If
the DSP420 is cold, it may indicate a fault.
Allow the DSP420 to cool down. It should then
operate normally.
Green lock indicator will not light
The green indicator lights when the product is out of
standby and is locked to a digital source.
Check that the digital audio input is wired correctly
and that it is connected to an active source of SPDIF.
Check that the COMMS is wired correctly and that
the Meridian system is out of standby.
Note: The DSP420 boots to an out of standby state,
unlike other Meridian DSP loudspeakers, so repowering
the unit will ensure that it is out of standby.
Drive units move when the loudspeaker
is switched on or off
This is normal as the loudspeaker’s active electronics
settle.
•
•
•
•
Sound is odd or mono
Check the channel selector switches on both
loudspeakers are correctly set.
Only the master loudspeaker plays
Check the RJ45 cable is connected correctly.
Centre not working
Check that the channel switch is set to LEFT/
CENTRE.
There is radio interference
The DSP420 is a digital audio and computing device
which has been designed to very high standards of
electromagnetic compatibility.
If this equipment does cause or suffer from interference
to/from radio or television reception then the following
measures should be tried:
Reorient the receiving aerial (or antenna) or route the
antenna cable of the receiver as far as possible from
the DSP420 and its cabling.
Ensure that the receiver uses well-screened antenna
cable.
Relocate the receiver with respect to the DSP420.
Connect the receiver and this product to different AC
outlets.
If the problem persists contact your retailer.
Configuring the DSP420 does not have
any effect
Make sure that you are configuring the DSP420 used
as the master digital loudspeaker in the system. This
determines the configuration of all digital loudspeakers
in the system.
•
•
•
•
•
•
•
•