Meridian America DSP420 - Manual (Page 2)

high resolution. These amplifiers are coupled
directly to the drive units for the most efficient
delivery of power and the best possible control
over driver excursion. Both analogue and digital
variants exhibit extremely low levels of noise and
distortion, aided by careful star earthing, while
the power supply includes a substantial toroidal
transformer and audiophile-grade capacitors.
Meridian DSP
The DSP420 accepts digital input signals up to
96kHz/24bit, 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
specially-designed six-layer PCB using a powerful
100 MIPS Motorola DSP engine. Thanks to
this sophisticated audio computer, the DSP420
embodies identical high-technology features
to those found throughout the Meridian DSP
Loudspeaker family. These include:
• Position control to compensate for speaker
location
• FIFO memory buffer at the 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, delivering a
frequency response free from drive unit or
electronic colouration
• Transparent tone controls
• Absolute phase control
• Phase-corrected balance control
Active Bass Extension
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 produces a convincingly ‘big box’ sound
from an in-wall unit. At moderate volumes, a
psychoacoustically-correct filter significantly
extends the bass response, while at high volumes
dynamic DSP bass protection is used to prevent
the woofers from bottoming.
Analogue or Digital – Your Choice
Following the success of the original DSP420, the
loudspeaker is now also available in an analogue
active version, the M420. The M420 features a
balanced line-level audio input (which may be
unbalanced), with an XLR link from back-box
to speaker unit (the digital unit is connected
to the back-box via a 15-pin DSUB cable) and
analogue crossover. The amplifiers, bass drivers
and enclosure are identical in both variants. In
addition, a redesigned back-box is available,
common to both units, that features several
design improvements based on installer feedback
from the original design. Audio and power
interfacing are built into fire-retardant boxes.
The available redesigned back-box kit includes
both analogue and digital input boards, allowing
the correct board to be installed as appropriate.
While the original screw terminals are retained,
digital audio and Meridian Comms connections
also employ BNC connectors, while analogue
audio is on XLR. Power is hard-wired into the
back-box and supplied to the speaker assembly
via an IEC connector, thus helping to maximise
the speed and efficiency of installation.
Acoustics
The DSP420/M420 front baffle and acoustic
back box are made from aluminium. This offers
very low resonance at low frequencies and is
further damped by the incorporation of stiffening
into the back-box. Additional high frequency
damping means that the whole system suffers
exceptionally low cabinet colouration and delivers
excellent mid-range transparency. All damping
materials have been fully tested and in all cases
comfortably meet or exceed building regulations
for in-wall design.
The bass drive units are two parallel 5in woofers
with cast alloy chassis, carbon fibre cones and
very large shielded magnets that provide excellent
drive and control.
The tweeter (aluminium-domed in the DSP420,
silk-domed in the M420) has a Neodymium
magnet and a protective grille, while an
acoustically transparent grille protects the front
baffle and drive units from harm when installed.
Its powder finish means the grille can be easily
painted, helping the unit to blend in with its
surroundings.