In each article in this series, we will be
looking at a different aspect of the hi-fi
signal chain – from source to speaker. In
view of its importance in the overall
reproduction of the sound, we are first
going to consider what happens at the
end of the line – the amplification system and the loudspeakers themselves,
for it is here that Meridian has very
much charted its own course among
consumer audio manufacturers, coming
up with a solution that is both elegant,
efficient and capable of extremely high
audio quality.
The traditional approach
The traditional method of designing a
hi-fi system has been with us for a long
time, and has hardly changed over the
years. Signal from a source – such as a
CD player – is fed into a preamplifier or
controller, and from there at line level to
an amplifier.
From this central cluster of equipment,
the now high-level signal is fed via
extensive cables to the loudspeakers
themselves.
The Meridian Papers - 1
Meridian Audio has taken an almost
unique course in the design of its hi-fi
systems, and particularly in its
loudspeaker design, where the signal
remains in the digital domain until the
very last moment, and the loudspeakers
include digital crossovers and signal
processing.
In the first of a series of articles on
Meridian audio products and technology,
Richard Elen looks at the company’s DSP
loudspeaker philosophy.
Meridian’s top-of-the-line DSP8000 speakers,
the essence of high performance
Fig. 1: The conventional arrangement of a sin-
gle power amplifier driving a two-way loud-
speaker system with a passive crossover.
Meridian Loudspeakers: The DSP Path
CABLES
PASSIVE CROSSOVER
HF DRIVER
EXTERNAL
POWER AMPLIFIER
LOUDSPEAKER
ENCLOSURE
LF DRIVER
If you examine the vast majority of current – and past – hi-fi amplifiers and
speakers, you will find the
same story: a single channel of amplification handles the full audible frequency
range of the system. A single pair of
cables carries this signal to the loudspeaker cabinet, and inside the enclosure the high-level audio is split into
multiple bands and fed to appropriate
drivers. The circuit that handles this
splitting is the crossover, and it consists
of a number of filters that separate out
the different bands to suit the requirements of the different drivers.
The simplest example of this traditional
approach is the two-way speaker shown
diagrammatically in Fig. 1, where the
full-bandwidth output from the amplifier is fed into a passive crossover that
derives signals to drive the tweeter and
woofer.
This, it turns out, is one of the worst
things you can do, as processing highlevel analogue signals requires components to be chosen primarily for their
power-handling capability and not for
their audio quality. The filters require
inductance, capacitance and resistance,
and to operate at high levels and low
impedances – in the order of a few
ohms – without losing efficiency, these
components are often far from perfect.
Inductors are iron or ferrite cored and
capacitors are non-polar electrolytics,
introducing distortion. In fact, everything is more difficult to manage at high
power levels. Suddenly the cables that
connect the amplifier outputs to the
loudspeakers can impact the sound of
the system, for example – something
that benefits only the makers of expensive cables.
Even if it is practical, at great expense,
to use air-cored inductors and film
capacitors, it is still difficult for the
designer to avoid making compromises
in the frequency characteristic of the
crossover without presenting unpleasant
loads to the power amplifier in terms of
impedance or phase angle. In addition,
the relative efficiencies of the drivers
have to be well matched to avoid wasting power and damping – this limits the
designer’s choices of which units to use.
Look at it another way: In a passive system, the only power available to drive
the crossover components is the signal
itself.
A solution, long known in the professional field, is to operate the crossover
at line level, ie before amplification
takes place. The amplification then follows the crossover instead of preceding
it. In modern professional live sound
installations it is extremely common to
pass the line-level signal to an active,
electronic crossover, then on to the
amplification and finally to the actual
drivers of the loudspeakers.
page 2Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
Hotrod or Hi-Fi?
Consider your car for a moment. Did you
buy the engine from one manufacturer,
the suspension from another and the
transmission from someone else?
Probably not. Yet this is the way that
high-priced hi-fi systems are often assembled. It is generally not known – and
impossible to know – how such a composite system will perform.
Components are chosen independently of
one another and out of context with the
sound of the system as a whole, often on
the basis of irrelevant, anecdotal or simply erroneous information.
Hardly surprising, then, that the elusive
Grail of audio – ‘musicality’ – is difficult,
if not impossible, to find in the traditional
audiophile arena. At best, hi-fis like this
are not integrated systems but hot-rods:
they do one thing well. This is why expensive systems often only sound their best
playing back one type of music.
Meridian believes in the complete, integrated system, and that a system should
be judged on how well the entire package
performs in the real world. This is why all
our components explicitly speak the same
electric and acoustic language. While their
performance with other manufacturers’
equipment is exemplary, they positively
sing when placed in chorus with equipment of their own pedigree.
In almost thirty years of existence,
Meridian has learned not only the parameters upon which a superb-quality total
system is based: we have also refined our
capability to design the individual components that comprise such a system.
Don’t forget, a Meridian system can be as
simple as a CD player and a pair of DSP
speakers. Because the amps and control
are in the speakers, that’s all you need.
Fig. 2: An alternative arrangement to that
shown in Figure 1, in which an electronic, line-
level crossover drives a pair of amplifiers feed-
ing woofer and tweeter.
ELECTRONIC
CROSSOVER
LINE LEVEL IN LOUDSPEAKER
ENCLOSURE
AMPLIFIER
LF POWER
AMPLIFIER
HF DRIVERHF POWER
LF DRIVER
However, such an approach – “bi-amping” or “tri-amping” the system – is far
too complex and prone to error to be a
very practical approach in the consumer
field.
The Active Loudspeaker
Back in the mid-1970s, multi-amping
was almost unknown. Even more
unconventional was Meridian’s first
product, the M1 Active Speaker, which
placed both active crossover and amplification, plus the associated power unit,
in the same enclosure as the loudspeaker drive units. The principle is illustrated
in simple form in Fig. 2.
This method delivers a number of
important benefits. First, there is a simple line-level connection between the
preamplifier and the loudspeakers: a
large, heavy box and associated cabling
disappears at a stroke.
Second, the crossover is operating at
line level, so the considerations as far as
components are concerned are the
same as with, say, a preamplifier, and
the quality delivered by such a crossover
should be equivalent. The highest quality components can be employed, such
as metal-film resistors and plastic capacitors, for example.
But there are not simply benefits on the
component side. The designer of an
active crossover can design each element of the crossover – including independent adjustment of phase and
amplitude, and filter curves as complex
as are required by the acoustic system –
without having to be concerned with
issues such as matching driver efficiencies or the impedance of the configuration.
In addition, there is another major benefit in that the amplifiers are connected
directly to the drivers: there is one
power amplifier per crossover band. The
directness of the connection means that
the amplifier can control the driver over
its entire range. DC coupling between
amplifier and driver results in a high
damping factor.
In simple terms, this means that if the
speaker cone makes a movement other
than because of an input signal – as a
result of a resonance, for example, the
electrical energy generated by this
movement is fed back to the amplifier
and restrains the motion of the cone –
allowing the amplifier to control the
driver.
This electromagnetic damping reduces
resonance, cone effects and spurious
responses. Not only that: the direct connection between amplifier and driver
means that the amp can control cone
movement beyond the range of the
crossover band assigned to it – important, because a tweeter’s resonant frequency, for example, can often be outside the frequency band supplied to it
by the crossover. In an active system, the
amplifier can deal with this; in a passive
system, it can’t.
This tight control also allows a Meridian
to sound excellent at any level, from a
whisper to a surprisingly loud shout.
It’s also important to consider the loudspeaker as a complete system. For the
designer, this gives a great deal more
possibilities than simply multi-amping an
existing passive design.
Less power, more sound
On the face of it, there is a downside to
this approach: the system requires a
power amplifier per crossover band,
rather than just one.
The truth is, however, that the active
loudspeaker is much more efficient.
When a single amplifier is used in a passive system, apart from the power wasted producing heat in the crossover,
there also have to be allowances in the
power amplifier for all manner of
extraordinary unknowns: strange impedances at certain frequencies, a wide
page 3Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
Digital Audio:
Music to the Ears
Digital audio technology is now widely
regarded by industry experts as the best
means to hear music in the home.
Because music recorded digitally can be
transmitted, even over long distances,
and played back with no change from the
original, like Morse code over a telegraph
line.
Why is this important? Traditional analogue systems behave much like the childhood game in which each player repeats a
whispered message into the next player’s
ear, and so on down a chain. Each analogue link – turntable, amplifier, cable,
speaker – whispers an analogy of what it
hears to the next, but something is
always lost or added. What emerges at
the end, while charming, may not resemble the original message.
By contrast, digital audio first encodes
music as digits – ones and zeros – in patterns describing specific sound waves.
This is the binary language of computers,
and it’s very difficult to mistake a one for
a zero. No matter how long the chain, at
its end digital equipment listens only for
patterns of those two digits, which it
reassembles into music, ignoring all other
whispered information as noise.… ➤
range of loads, and so on. The common
method of dealing with these possibilities is to give a power amplifier four
times the current delivery capacity it
needs; and give it and its power supply
the ability to handle the strange loads
likely to be encountered in use and
abuse.
Engineering for the unknown inevitably
means over-engineering. But in a properly integrated active system, however,
each part of the system, including the
amplifiers and power supply, can be
designed specifically to provide the
power required – no more, no less –
and into a known, carefully defined
load. This can obviously improve efficiency and reduce the need for overengineering. Thus such a design does
not have to be more expensive than a
conventional passive approach. It can
certainly be more efficient, and more
effective.
But there’s more. Imagine we are listening to a piece of music that includes a
bass part and cymbals, and that to
replay this accurately at a chosen level
on a two-way system we want to see a
not unrealistic voltage of 20v peak at
the terminals of both the tweeter and
the woofer. To do this with a passive
system, even ignoring losses in the
crossover, the driving amplifier needs to
develop 40v peak.
For a 8-ohm system, this requires an
average power of 100W (by Ohm’s Law,
the power is equal to the voltage
squared divided by the impedance). In
the equivalent active system, with a 1v
line level input, a pair of 25W amplifiers
will do the same job! (See Fig.3.)
Extend this thinking to a three-way system, and three 25W amplifiers in an
active configuration will do the same
job as a 250W amplifier driving a passive system.
page 4Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
Fig. 3: Considerably less power is needed to
deliver the same voltage – and thus the same
sound level – from an active system than a pas-
sive one.
Digital Audio:
Music to the Ears
➤ ...Hence the crystal clarity of good digital sound: no detail lost, no noise added.
Paramount among audiophile truths is
that music’s electronic journey to our ears
should be as short and unadorned as possible; this preserves the fragile nuances of
live performance. This is why, for example, audiophiles have long rejected analogue tone controls, correctly seeing them
as electrical mazes where musical subtleties are lost or rearranged.
Yet the typical purist hi-fi is hardly pure.
Rather, it’s a confusion of components
with varying reactive properties, tangled
together through a rat’s nest of electrically whimsical cables. Each piece lengthens
the path and damages delicate harmonic,
phase and other relationships that contour music.
The amusing irony is, these boxes and
cables are generally assembled for tone
control: each piece chosen for how its
voice changes the message.
Why not simply replace the whole corrupt
chain with one transparent digital link,
particularly if the music source is digital
already?
At Meridian, that’s exactly what we did.
In essence, we decided to convert the signal from a source into digital form as
early as possible and at the highest level
of quality (if it wasn’t already), then
maintain that signal in digital form as
long as possible before converting back to
analogue (although the part of our hearing system from middle ear to brain is
actually digital, analogue pressure waves
carry the sound from a loudspeaker,
through the air, to the ear). So in a complete Meridian system, the signal is only
converted from digital to analogue immediately before it enters the amplifier.
COMPOSITE INPUT 40V PEAK
PASSIVE CROSSOVER
HF DRIVER
20V PEAK
LF DRIVER
20V PEAK
ELECTRONIC
CROSSOVER
COMPOSITE INPUT, ˜1V PEAK
HF POWER
AMPLIFIER
LF POWER
AMPLIFIER
HF DRIVER
20V PEAK
LF DRIVER
20V PEAK
To give an
example from
Meridian’s
product line, the
DSP6000 includes
four channels of 70W
amplification.This is equiva-
lent to about 1kW driving a
conventional passive system.
It is evident from these comparisons
that an active system can produce surprisingly high levels from a significantly
smaller amplification system. There are
significant improvements in efficiency
that can be realised with an active system, even if it is more difficult to design
– or rather, we could say that it is possible to implement a more sophisticated
design, with many additional features,
to deliver these and other benefits.
Bass Extension
There is more to an active loudspeaker
than simply improving the efficiency and
overall performance of the system. An
active approach can deliver benefits that
are simply impossible for a passive system to realise. We can’t change the
laws of physics, but we can use them to
our advantage.
There is a known relationship between
the low –3dB cutoff frequency (f), the
physical volume of the enclosure (V) and
the efficiency (e). It is:
e = V/f
3
x K
where K is a constant relating to the
system’s design. In a nutshell, this
means that the cost of a smaller cabinet
is either less bass or lower efficiency.
The ability to consider an active loudspeaker as a total system – an active
crossover with filtering, amplifier, power
supply, driver and enclosure – allows the
overall response and performance of the
system to be modified, essentially altering that constant, K, in the equation
above.
For example, the original Meridian
“Interactive Bass” system used auxiliary
filtering, and the particular alignment
provides a sixth-order rolloff plus an
additional octave of bass compared to a
passive speaker of the same volume and
efficiency (see Fig. 4). Putting this more
impressively, a passive speaker with
equivalent bass response would need to
have eight times the volume, or twice
the linear dimensions.
In addition, this alignment minimises
cone movement of the bass driver for a
given output – indeed, cone deflection
for a ported system such as the
DSP7000, 5000 or 5500 is one third as
much as using the same drivers in a passive sealed box with equal broad-band
excitation.
page 5Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
DSP8000 – the inside story
The rigid enclosure, laminated from Russian
Birch plywood and aluminium alloy, has six
coats of hand-finished piano lacquer. The six
horizontally-opposed bass drive units neutralise
cabinet resonance. The rear-mounted sealed
DSP crossover and eight power amplifiers are
mounted on a precision machined heat sink.
page 6Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
The electronics inside Meridian’s
DSP8000 system
Power supply
8 x Power Amplifiers, one per driver
Crystal clocks
Microprocessor
Programmable Logic arrays
Digital to Analogue Converters
(four channels)
Digital Signal Processing chips
(Motorola DSP56362)
y
Fig. 4: The overall response of an active speak-
er can be tailored, the bass improved and the
maximum cone excursion limited by careful use
of electronic filters.
Electronics
Cabinet
Level
Net result (6th order)
Relative
cone deflection
Frequenc
Being able to deliver bass from an
enclosure an eighth of the size is a useful ability, because it enables us to make
loudspeakers that are physically the
right size: on a human scale (see later).
That means that they will fit into a room
more easily, and take up less space.
But it also means that stereo and surround imaging will be significantly
improved, because the nearer to a point
source your loudspeakers are, the more
they can be made to disappear when
recreating a soundfield in your listening
room, especially when using Meridian’s
advanced decoding technology such as
Ambisonics and Trifield.
The Digital Link
Once we began to see the introduction
of widespread digital music distribution
media, from the Compact Disc (1984)
to the Digital Versatile Disk (DVD) and
the latest DVD-Audio specification,
there was another step we could take:
we could keep signals in the digital
domain for as long as possible: from
source to speaker (see sidebar: Digital
Audio: Music to the Ears).
When it comes to active loudspeakers, a
digital design has a great deal to commend it. To begin with, there are no
long analogue cables carrying line level
signals to the loudspeakers, with the
possibility of induced hum and noise.
Instead, a slim cable carrying a single
channel of digital audio data is all that’s
required (actually, we add a second
cable to carry communications signals
between the different parts of the system, but it doesn’t carry audio).
Full level is supplied to the loudspeakers,
removing potential problems with noise
at low signal levels, and the loudspeaker
now has a user interface, if only to control and indicate the volume – in fact
Meridian loudspeakers have a display
that can indicate a number of system
parameters… or be turned off.
The DSP Dimension
Now we come to what is – for now –
the final step on the path, with the
addition of digital signal processing
(DSP) to the digital loudspeaker. In
Meridian DSP speaker designs, digital
signal processing is used to implement
the crossover.
This means that the digital to analogue
converter (DAC) can be placed even
later in the chain. In fact a separate
DAC is used for each band of the loudspeaker system, maximising the system’s
dynamic range – a current system can
deliver up to 120 dB – giving better
intermodulation performance, and
offering a level of background noise
below 10 dB SPL.
This, however, is only the beginning.
With digital signal processing on board,
you can do a great deal more. For
example, you can design “impossible”
crossovers, with linear phase, steep
slopes and time delay compensation.
And thanks to highly accurate phasing
between the drivers, the “beam” of the
system can be steered for the best experience at the listening position: there is
even an axis control that allows the midrange frequencies to be precisely tailored to suit your height.
Volume control in a Meridian DSP loudspeaker is handled by a precision combination of analogue and digital techniques, combining to give the best of
both worlds.
In addition, “balance” is not simply a
matter of changing the relative levels of
the speakers. Instead, the balance control is a “Where am I sitting?” control. If
you are listening to a stereo system and
move to the left, you hear more level
from the left speaker because you are
nearer from it, and further away from
the right, from which you hear less. But
that’s only part of the story.
page 7Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
What is dither?
Why do we need it?
In the analogue world, as a signal dies
away, it does so smoothly. As the level
drops, the signal gets progressively quieter. At some point it reaches the same
level as the noise. But importantly, if the
signal level continues to drop, you can
still hear it, despite the fact that it is
below the noise floor.
In the raw digital environment, everything is different. What happens when a
bit changes between a one and a zero is
essentially inaudible at high levels,
because there’s so much going on. But if
you’re dealing with low-level signals, such
as reverberation dying away, or the fade
at the end of a track, the transition of bits
from zero to one and back again becomes
increasingly important.
As the level of a signal drops, it is represented by fewer and fewer binary digits,
and the changing of these bits becomes
increasingly noticeable – it’s called “quantization distortion”. Ultimately, you simply run out of bits, and when this happens, the signal just stops, and in a 16-bit
system such as Compact Disc, this happens at an audible level. This behaviour is
another of the several factors that gave
early digital recordings a bad name, and
led some pundits to claim, erroneously,
that digital audio was fundamentally inferior to analogue.
Quite early on in the history of digital
audio, it was discovered that a solution to
the problem was to add noise to the signal. At low levels, the effective result of
this procedure is to turn the last few bits
on and off at random, smoothing out the
sound and ensuring that everything will
not simply disappear as the level falls.
This noise is referred to as “dither noise”
or simply “dither”. Truly random (white)
noise, called “flat dither”, contains all frequencies and is clearly audible. More commonly, a noise spectrum where the energy in the highs and lows is modified
somewhat (“triangular dither”) is used to
make the dither noise smoother and more
benign… ➤
Because you are nearer to the left
speaker, the sound takes less time to
travel from the speaker to your ears –
and you are further from the right
speaker, so the sound takes longer to
arrive. Meridian’s approach to “balance”, using the power of DSP, automatically adjusts these subtle time
delays, so wherever you decide to sit,
signals will arrive at the right time, as
well as at the right level.
In addition, our processors can provide
decoding using Trifield and Ambisonic
technologies, which literally recreate a
solid image of the original environment
in your listening room – producing an
incredibly lifelike surround-sound experience, and even rotate the soundstage to
suit where you are sitting.
Meridian’s DSP loudspeakers utilise 48bit internal fixed-point resolution. This is
a long way beyond what anyone can
actually hear, but when you perform
DSP operations, additional bits are created and it is vital that these are preserved.
Furthermore, whenever digital signals
are processed, they have to be dithered
correctly.
Dither is a special form of noise that is
added to a digital signal whenever operations are performed on it. It smooths
out imperfections and significantly
improves the sound of a system. In fact,
a properly optimized dither signal can
make the resolution of a digital system
effectively infinite (See sidebar, “What is
Dither?”).
DSP technology is also used to provide
additional features, such as tone controls and, because the loudspeaker
knows the sound pressure level it is producing, loudness controls can be implemented more naturally than ever
before.
The same principles can provide dynamic bass extension in smaller speakers,
where low frequencies are boosted
more at low levels. The system computes cone movement, frequency and
level, and as a result can provide bass
protection, shutting down if there is a
risk of parameters being exceeded. The
voice coil temperature is also calculated,
permitting precision thermal protection.
And finally, allowance can be calculated
for different locations of the loudspeaker in a room, such as boundary compensation when it is placed near a wall.
Digital signal processing also comes into
play when you use a system at different
levels. Our ears are less sensitive to bass
and treble when we listen quietly: DSP
can compensate for this according to
carefully-research psychoacoustic principles.
“Human-sized” speakers
Meridian’s speakers look, as well as
sound, distinctive, and of course both
these factors are related. It has been
shown that loudspeakers that are as
close to human-like as possible produce
the best imaging – mirroring, in a sense,
the position of human sense organs.
The “head” of a Meridian DSP loudspeaker (such as that of the DSP8000
shown above) produces the vast majority of sound from 200 Hz up, which is
where stereo and surround localization
takes place.
page 8Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
What is dither?
Why do we need it?
➤ …Dither is not only required when a
signal is converted between the analogue
and digital domains: it is also needed any
time a digital signal processing (DSP)
operation is carried out, such as decoding
a surround bitstream from a DVD, applying a DSP preset, or passing through a
digital tone control.
The more highly optimised the dither signal, the higher the resolution – the further
you can hear below the noise, and the
more detail you can hear.
In a properly dithered system, the resolution is effectively infinite.
If you remove, or disconnect, the
“head”, you can hear very little
definition. Psychoacoustically we are at
our best listening in small spaces, to
loudspeakers that have similar physical
characteristics to a speaking human
being.
Our loudspeakers are essentially
“human-sized” because psychoacoustic
research indicates that humans are most
highly developed to appreciate this size
of sound-producing system, and they
will thus sound the most natural.
As much effort goes into cabinet design
as into the electronics within, and the
keynote here is extremely high integrity.
Cabinets are heavy and rigid, allowing
no inadvertent movement. Typically,
they incorporate multiple layers of wood
and metal, bonded together for maximum damping.
The DSP6000 and DSP8000, for example, include side-firing woofers that are
horizontally opposed, so that the net
movement is zero. Advanced materials
ensure that the cabinet is so dead that
movement stops at once when excitation ceases, with no ringing.
Meridian DSP loudspeakers are perhaps
best thought of as musical instruments.
The most difficult sounds to reproduce
are those of individual instruments, such
as piano or flute, and small ensembles
that are on the same kind of scale as
the listening room.
If you were to record a live string quartet in your listening environment, the
most difficult test of a “high fidelity”
system would be to replay that experience in the same room. Meridian DSP
loudspeakers rise to that challenge.
page 9Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
page 10Meridian Loudspeakers: The DSP Path The Meridian Papers - 1
Meridian Audio Limited
Stonehill, Stukeley Meadows,
Huntingdon, Cambridge PE29 6EX
United Kingdom
Tel 44 (0)1480 445678
Fax 44 (0)1480 445686
Further technical details, images,
product reviews and company
history are available from Meridian
Audio or from our website,
www.meridian-audio.com
Meridian America Inc.
3800 Camp Creek Parkway
Building 2400, Suite 122
Atlanta GA 30331 USA
Tel (404) 344-7111
Fax (404) 346-7111
© 2003 Meridian Audio Limited.
Version DS4a 280403
Written by Richard Elen
Designed by Allen Boothroyd & Richard
Elen
Meridian Audio’s DSP8000 speakers are a
testament to both engineering and aesthetics… You can play extraordinary deep
bass tones and put a glass of water on
top of the cabinet, and the water won’t
move.
Popular Mechanics
The effortless sweep of the DSP8000s
presentation was aided by the extended
and well-defined low frequencies.
Stereophile
This system delivers a performance that’s
state-of-the-art, especially when it comes
to bass extension and control.…The
Meridian rules supreme when it comes to
scale, authority and sheer low-end
weight.
What Hi-Fi
At first you’d think it would be crazy to
control a system through a pair of speakers. But when the loudspeakers in question are Meridian’s DSP5000s it begins to
make perfect sense.
What Hi-Fi
Much more than just a speaker, the
DSP5000 is designated a ‘music system’.…This modestly sized speaker is
capable of a surprisingly high acoustic
volume or sound level.… Meridian’s ace in
the hole here is a dynamic, music-controlled correction for the overall bass
alignment which allows clean, remarkably
extended bass under normal conditions.…The DSP5000 has to be heard. For
its size it offers a remarkable combination
of bass power and extension, of maximum volume level, of user control and
adjustability, and of stereo image performance.
Hi-Fi News & Record Review
Speakers don’t get much smarter than
this!
Sound & Image
The Audio Press on Meridian
DSP Loudspeakers
The DSP7000 series takes the advanced
technology of the flagship DSP8000 series
and implements it in a more compact form.
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