![](images/hifiadvice/johnrogers1.jpg) |
Trouble with your sound system?
If playback from your LPs or CDs sounds far from ideal,
there is a lot you can do to improve it. Here, John
Rogers of QR Design, the product development arm of
Ringmat Developments, helps you to identify the causes
and improve the sound from your hi-fi system.
How much time and effort have you spent on building up
your collection of personal, all-time greatest sounds?
Saving up hard-earned pennies, browsing around fairs up
and down the country, until - at last - your CD/LP
cabinet resembles your idea of music heaven. That is,
until you pick your favourite, play it on your hi-fi
system and... it just doesn’t sound right.
Blame it on gremlins, if you must, but there is a number
of reasons why sound reproduction goes awry.
For a start, the sound from any hi-fi system will only
be as good as the weakest link in the signal chain. That
is why many people opt for ‘separates’, rather than a
packaged system from one manufacturer: it is so much
easier to change the weakest component for something
better. In any case, separates will sound better for a
little extra outlay and, in some cases, even pound for
pound. If you are in any doubt, always ask your dealer
for a comparative demonstration. |
Speakers and Signal
Radiation
Choice of loudspeaker usually makes the
biggest difference in the balance and
‘tonality’ of the sound you hear, so
make sure it gives the sound you want to
live with in the future. Also, be
prepared to allow the speakers to
breathe. Some have been designed to go
up against a wall but, even so, and
generally speaking, they perform best a
little way away from walls, not only
from behind but also from the side.
The best results in a well-tuned system
are obtained with the speakers about
five or six feet apart in a
well-proportioned room and toed inwards
45°. In this way, on a line directly out
from each of the speakers, they are
aimed to cross and meet in front of the
speakers. However, few systems are ready
for that until major improvements have
been carried out to maintain accurate
signal phase. Therefore, initially start
by toeing-in the speakers so they are
aimed to cross and meet in front of the
speakers by about one-and-a-half times
the distance they are apart. As
improvements are made to the phase of
the signal the sound stage will open out
and widen, so that you will find you
need to gradually increase the degree by
which the speakers are toed-in to get
rid of congestion in the centre.
Now this may seem strange to some
readers, and this is because too much
emphasis has been given in the past to
the sound coming out directly from the
front of the speakers. In practice, the
speaker drive units should radiate a
sound into the whole listening area,
which can be more accurately understood
if you imagine the sound and the sound
sources in an arc behind each speaker
from a point source in the middle of the
drive units. Looked at another way, the
speakers are reflecting the sound as a
mirror image of a crossed pair of
microphones capturing the sound.
To fine tune, listen to the sound from
one speaker only. Very gradually move it
away from, and back towards, a rear wall
and tilt the speaker so as to adjust the
degree by which the speaker is toed-in.
Listen to how the timing and
transparency of the music changes. There
is a point where not only the timing
seems right, but it also sounds cleanest
and most dynamic (i.e. the emotion of
the music is at its height). Be sure you
choose an appropriate disc for whatever
source you are playing and, if one
doesn't seem to work for you, choose
another. Then set the other speaker, in
a two-speaker system, in the same
relative position and angle from the
rear wall. If there are more than two
speakers, such as in a home cinema
surround sound system, the foregoing
applies to the two main front speakers.
After finding the best positioning for
them, the same process should be
followed with the other speakers. If
they are in fixed positions on a wall,
the best that can be achieved is to
angle them out into their most effective
position.
All speakers are compromises in design
and have some degree of distortion. Some
are more successful than others in
finding the right balance, but
performance is difficult to assess
without removing as much distortion as
possible from the start or source of the
signal.
The Source
The greatest distortion comes from the
two ends of the signal chain - the
source, be it turntable, digital player
or some other signal generator, and the
speakers. We have already discussed
speakers, so let us have a closer look
at ‘the source’.
‘Source signal distortion’ is a result
of electrical and mechanical vibration
within the turntable, CD player or other
source component itself and, to a lesser
extent, further along the signal chain.
This ‘source signal distortion’ may
arise from use of the equipment’s own
‘feet’, the nature and polarity of the
surfaces under those feet, the casework
and structure of the equipment, the
fixed and moving components (which you
can often do little about) and the type
of support the LPs or CDs rest on (e.g.
the platter) whilst they are played. |
Special Vinyl Needs
In the past, records have usually been
supported by a rubber or felt mat. More
recently, bare platter surfaces have
been popular through the development of
special textures or the use of acrylic
and glass. Some designs have been based
around the use of clamps. All these
methods have failed to address the
fundamental issue: the enormous energy
generated when a stylus tracks the
groove wall of a record. This energy has
to go somewhere. With all the above
methods, to varying degrees, this energy
is reflected off the material under the
record surface and not only deflects the
stylus from properly tracking the record
groove but works its way up the
cantilever into the cartridge as
distortion. From there, it is amplified
and generated as massive distortion
through the speakers, along with a
severely damaged primary signal and the
loss of a great deal of information
RINGMAT, developed by Ringmat
Developments, eliminates this problem by
absorbing the unwanted stylus energy. It
replaces any supplied mat and rests upon
the bare platter, supporting the record
above. RINGMAT effectively ‘decouples’
the record from the platter by
supporting it with a narrow cork ring
placed under the centre of the mass of
the record. This cork ring moves between
two other cork rings on a special
substrate. This construction allows the
energy generated by the stylus to be
dumped into the air between the record
and the RINGMAT and into the air between
the RINGMAT and the platter below.
RINGMAT is now recognised as the leading
record support around the world and can
be used with nearly all turntables.
In the autumn of 1998, a more
sophisticated method of supporting
records on a platter was introduced by
adding three
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more components to work with RINGMAT, forming a
modular system called the RINGMAT Support
System. Among other benefits, the Support System
enables you to match the angle at which the
stylus tracks the record groove (‘stylus rake
angle’) with the angle at which the master disc
was cut by the cutting stylus, dramatically
reducing the amount of distortion feeding into
the signal chain.
Static Charges
Another significant factor in vinyl
replay is static and other unwanted
electromagnetic fields that affect
tracking and the delicate signals
handled by the stylus and workings of
the cartridge. Again, these problems are
largely removed by the introduction of
another Ringmat product, the LP STATMAT,
especially the LP BLUE and STATCAP,
which is available either separately or
as part of the RINGMAT Support System.
CDs are a similar story. The main
problem here is that static builds up in
the CD player while the disc is being
played, spinning at great speed in a
warm, dry environment. This static
build-up has a dramatic effect on both
the CD itself and the way in which the
signal is extracted and processed.
Moreover, as the CD revolves at high
speed, resonance in the CD and vibration
movement compounds the distortion in the
signal from the player. The same
problems arise with other digital
formats and players such as those for
DVD and SACD.
To deal with both these problems,
Ringmat Developments have created a
product called STATMAT. It is a thin,
featherweight film which you place on
the label side of the CD and which
remains there while the CD is played.
STATMAT is a powerful, though passive,
electrical device which prevents static
by way of evening out electromagnetic
fields. Simultaneously, its unique
design also minimises the effects of
resonance and vibration that occur as
the CD revolves. The latest version is
the CDi BLUE, which employs two STATMATs,
one each side of a BLUE substrate (hence
the “Blue” in the name). The top STATMAT
is a mirror image of the one below and
working together the two STATMATs create
a very powerful anti-static device. The
CDi BLUE and the LP BLUE are essentially
the same but they are of different
dimensions and require a different size
central hole.
SIGNAL DISTORTION
Whilst it may be true that the most
important part of a hi-fi system is its
source - usually the turntable and/or CD
player – it is so for two reasons.
Firstly, the old maxim ‘rubbish in,
rubbish out’. Secondly, there is another
factor at work here, in that distortion
inevitably accumulates a little along
the signal chain. This makes it all the
more important that you achieve as good
a signal as possible from your source
player. Otherwise, by the time the
signal reaches the speaker, there is as
much distortion as there is original
signal - perhaps even more.
"What sort of distortion?" you may
think. "My turntable/CD player sounds
all right to me!" Sadly, this is, in
part, a case of not missing what you’ve
never had - in this instance, a
phase-linear, distortion-free signal. It
is a clarity and cohesiveness of the
sound and a realism that most people
associate with very expensive sound
systems, but which, in fact, comes
simply from preventing distortion
arising at source and accumulating along
the signal chain. Much of this
distortion arises as a result of
vibration, which is of two sorts.
One is mechanical, and stems from either
physical movement, even of a low order
and which cannot be felt, and from
resonance in the materials used. In
large measure, hard objects simply
touching one another cause this
vibration, and this is commonly found
where metal and, to a lesser degree,
wood and other hard substances, are used
against each other in a variety of
support roles under equipment, including
numerous attempts at isolation. It
certainly arises where spikes are in
use. And glass produces its own
distinct, hard sound.
The other type of vibration is
electrical. It is endemic in electronic
components, and for most users there is
not a great deal that can be done about
this. But another principal source of
electrical vibration is static and other
undesirable electromagnetic fields, such
as are found in and around equipment
used in hi-fi and home cinema systems.
To a large degree, this latter form of
electrical vibration can now be
eliminated with the utilisation of the
variety of anti-static products that are
now on the market.
Vibration occurs also within components.
The more straightforward designs, with
few buttons and options to change the
sound usually perform best as there are
fewer paths through which to accumulate
distortion, provided attention to detail
has been given in the design stage and
during assembly.
Good Vibrations
Support surfaces under equipment and
speakers are crucial in achieving the
sound you want. The vibration problems
they can cause are easily sorted with a
little help from certain products now on
the market. Ringmat Developments have
developed their own offerings to deal
with all these problems in the form of
RINGMAT FEET, RINGMAT DOMES and STATFEET
and further products will be released
during 2005. As mentioned above, there
are enormous problems also with the use
of spikes, however much they are
tightened, though many of these problems
can be ameliorated by the use of RINGMAT
SPIKE STOPPERS. These are placed
underneath the spikes, and when they are
used on top of STATFEET and, better
still, on top of RINGMAT FEET, there is
a noticeable improvement in sound
reproduction.
Amplifier Dynamics
So what about the amplifier? The most
important thing is that, when combined
with the speaker cable, the amplifier
can comfortably handle the load
presented by the speakers. More than
that, it can drive the speakers so well
that their full dynamic potential is
exploited. We’re not talking about
loudness - although this is obviously a
factor - but the dynamics associated
with accurately reproducing exactly how
much force, sustained pressure or
delicacy is used for each note when, for
instance, a keyboard is being played,
allowing you to recognise one musician
from another. After all, what interest
is there in music if it all sounds the
same?
If you play LP records using moving coil
cartridges, another aspect to bear in
mind with amplifiers is to ensure that
the output loading of the cartridge,
which usually falls into one of three
categories (100 Ohms, 40-47 Ohms and
10-20 Ohms), matches the impedance of
the amplifier's moving coil input. Some
amplifier manufacturers say their single
moving coil input impedance will handle
any moving coil cartridge - don't
believe it. There is the further
complication that some manufacturers use
loading specifications that do not seem
to relate to the real world when trying
to match them with those of the
cartridge. Otherwise, your choice of
amps is down to things like transparency
and control and how well images, the
sound stage and overall clarity are
retained when the volume is increased.
Besides cost, of course.
Budgeting
When you buy or upgrade a system, have
in mind a budget and allocate at least a
third of the cost for good equipment
supports and cable links, such as
interconnect, speaker and mains cables.
Yes, quality mains cables do make a
difference. If, however, you’re on a
really tight budget, leave supports and
cables until you have the money to
upgrade the system. In the past, I would
have suggested allocating 40 to 50 per
cent for the front end - turntable or CD
player, using the balance of the budget
towards the amplifier and speakers,
including support stands if the speakers
are not floor standing.
As soon as you can afford to, upgrade
with products directly linked to the
performance of the front end like
RINGMAT and STATMAT. Then improve the
mains cables and introduce
anti-vibration, anti-resonance and
anti-static products. Then seek to
improve the speaker and interconnect
cables.
A Tip with an Eye for
Future Developments
However, in view of recent research we
have carried out, I would add the
following rider. If you are really
interested in getting the very best
sound, and you are thinking of buying a
new amplifier, I personally would
recommend that you wait until later this
year, when the report on our research
work is published and more can be
revealed. Or, if funds can stretch that
far, a pre-power combination be sought.
More importantly, that instead of a
stereo power amp, a pair of mono power
amps is acquired instead of a single
stereo one. However you eventually view
the report, a pre-power combination will
stand you in good stead in the future.
Choosing Your Hi-fi
System
This subject is complicated because
there are so many variables and it
requires a good ear and experience to
get it right. At the end of the day, it
is down to you, with the help of a
competent dealer, to listen and judge
for yourself. Trust your own ears and
you should not be disappointed.
If you’re not sure where to start and
you do not have your mind fixed on a
particular make or model of this or that
(a fairly healthy approach, so as not to
be too disappointed when it comes to
judging with your own ears!), start by
choosing your speakers. Then find the
best amp and speaker cables to drive the
speakers and, finally, decide on the
front end - turntable and/or CD player.
Any turntable can be fitted into any
system, provided you match the loading
of the cartridge and the tonearm cables
with the rest of the system. You will
find that some CD and other digital
players have a better loading match than
others with the chosen amp and speakers,
quite apart from their own intrinsic
values. This helps to determine the
right synergy, as well as making life a
great deal easier for those who are
otherwise bewildered by the choice.
Wired Up
When you buy a system, or are making
changes, bear in mind that the system
has to work together as a whole. Find
out whether the components work best
with solid core or multi-strand cable -
keep to one or the other and don't mix
them, even down to the mains cable.
There are further aspects to this.
Amps can be fussy about which cables to
drive. So, when matching amps to
speakers, use this opportunity to decide
which cables to get – having already
decided between solid core and
multi-strand, you then need to decide on
particular cables. Thicker or relatively
thinner speaker cables each provide
different loading factors for the amp to
drive and have a major impact on the
sound.
There is a wide choice of cables on the
market. Despite this, Ringmat
Developments have started to market
their own simply because they could find
no others that met the exacting
requirements demanded for their own
sound reproduction test bed.
The Complicated Bit
If complex situations are not your
scene, pass on to the next section.
Amplifiers are designed to provide the
best dynamics with a given ‘load’ from
the front end on input and from the
loudspeakers and the speaker cable on
output. As a buyer, your aim should be
to match front-end, speakers and cables
to the loading requirements of the
amplifier, both in and out. At the same
time, loudspeakers are designed to
provide the best frequency response and
greatest clarity when provided with a
certain loading along with the signal.
Eventually, therefore, what one needs to
find is a ‘loading’ that is similar to
that which was used for the loudspeaker
design and in its fine tuning, where the
cables used in that design process are
always an important factor. This is not
easy, because speaker manufacturers are
unable to measure this ‘loading’ and so
it is down to the black art of the
dealer, or yourself, to find three sorts
of unspecified ‘loading’:
One for matching the input loading
requirements of the amplifier;
One to achieve the best dynamics from
the power output of the amplifier (an
extension of the usual need for 8 Ohm, 4
Ohm, 2 Ohm etc., matching); and
A third as representing a replica of the
loading used by the loudspeaker
manufacturer in testing and evaluating
the design and choice of components.
With luck, this may all fall into place
first time, especially if the dealer is
using components known to work well
together.
In other situations, at least you are
aware of the pitfalls.
This is where different cables come in,
because you can, to an extent, ‘tweak’
the loading of the system by the use of
different cables, though this is also
where hands-on experience in the past is
so helpful.
Phase Out
Even with the speakers, amps and cables
sorted out, why do some recordings still
sound better than others? In the case of
LPs, this is partly due to differences
in thickness of the vinyl and the angle
at which the records were cut, which can
be easily sorted out using the Ringmat
Spacers marketed by Ringmat
Developments. Apart from this, the main
reason is the incorrect absolute phase
of the signal on playback in relation to
that embedded in the software, but this
in itself is only part of a much larger
and more complex problem. Whatever the
source - records, CDs, tapes, even radio
and TV broadcasts – there are
significant endemic phase and corruption
problems that affect the sound you hear.
QR Design has carried out extensive
research into these matters and most of
the important issues are now understood
and most problems are capable of being
addressed and corrected. A report is
planned for publication later in 2005.
Roll Out
So now you’re ready to roll! With a few
simple tests and tweaks, aided by one or
two distortion- or vibration-busting
components, it doesn’t take much to get
the best out of your beloved collection.
Get rid of all those ‘gremlins’ in your
hi-fi system using the handy hints
below. Do make sure you follow them
step-by-step though! |
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It's
those Gremlins again... |
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Sound from turntable not
as detailed as from CD |
|
Static and mechanical
vibrations are affecting
stylus tracking
Alignment of cartridge
and tonearm needs
adjustment |
|
Use RINGMAT or, better
still, the RINGMAT
Support System & RINGMAT
FEET
Follow the instructions
in the Ringmat Booklet
“How to set up and fine
tune a turntable” |
|
Sound from CD player
lacks the warmth and
involvement of vinyl |
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Static and mechanical
vibrations of CD
transport are affecting
phase of the signal |
|
Use CD STATMAT & RINGMAT
Feet |
|
Music sounds flat;
doesn’t hold your
attention. Imaging not
precise |
|
With vinyl, stylus rake
angle is incorrect with
that LP
Phase of the signal
corrupted & time delay
problems. Absolute phase
of your system may be
inverted to that of the
recording. At best, the
odds are that it is
right only 50% of the
time |
|
Adjust height of tonearm
or the LP via spacers
under the record
Invert absolute phase.
But this is only part of
the problem. The rest
will be explained when
this whole issue is
covered in the
forthcoming report
mentioned above |
|
Absolute phase keeps
changing between tracks
and at edits |
|
You haven’t complained
enough in the past |
|
Everyone complains to
the record companies |
|
Sound from speakers not
crisp and clean. Bass
not right. Insufficient
emotion present in sound |
|
Time delay problems
caused by static,
vibration under
equipment and incorrect
speaker positioning |
|
Use better anti-static
and isolation products
Adjust position of
speakers in relation to
rear wall
More will be revealed in
forthcoming report |
|
Imaging from speakers is
poor |
|
Speakers incorrectly
aligned |
|
Adjust distance between
speakers and toe
inwards. There is likely
to be an alignment
problem with the drive
units in the speakers –
await forthcoming report |
|
Sound unbalanced:
Treble and bass too
prominent; mid-range
recessed
OR
Mid-range too prominent,
lacking extension in
treble and bass |
|
First, have problems
above been solved? |
|
Try suggested solutions
above |
|
Loading of a moving coil
cartridge not matching
impedance of amplifier
input |
|
Change impedance of m/c
input on amp or step-up
device or phono stage or
change to better
matching cartridge |
|
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Ensure that type of
cable used is consistent
(solid core or
multi-strand) try
thicker/thinner speaker
cable. Try
interconnecting cables
with a lower capacitance |
|
Output loading of CD
player not suitable to
rest of system |
|
Try other makes of CD
player |
|
Loading of speakers and
cable not matching load
sought by amplifier
OR
Loading of system not
matching that of speaker
design |
|
Some amps have an
optional output loading
(8 Ohms, 4 Ohms, 2
Ohms). Try different
settings. As a last
resort, try different
amps or speakers |
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