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hobbyists's
views for hobbyists |
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DO YOU NEED NEW SPEAKERS? Every time people talk to me about their intention to buy new components, I always ask them what gave them the idea that made them want to buy a new amplifier, a new set of cables or - in this case - a different pair of loudspeakers. Almost in every case there is a good reason to question their motives.
Do
their motives justify the expenditure of new components? |
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CHECK THE FRONT END FIRST It goes without
saying that it is always right to ask about the equipment. It is important
to know how the signal is managed and also how the components and loudspeakers
are placed in the room. |
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The
advice on this page is there to give you some insight and to stress that
a less than optimum sound reproduction is not always the speaker's fault.
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WHAT ABOUT THE POWER AMPLIFIER? In order
to achieve maximum sound quality it is not sufficient to look at the
front end. Also the design of the power amplifier should be considered.
In that case we have to look at Watts, current and stability. And we
should consider the phase pattern if two amplifiers are being used in
a bi-amping configuration. Power amplifiers should have identical phase
patterns/characteristics. And a preamplifier should well match the phase
of the power amplifier. If not it is possible that a slight phase shift
will limit the fidelity in the top of the frequency band and thus will
inhibit the slam and the clean detailing of complex sound structures.
You all know from experience that the same preamplifier functions better
if connected to power amplifier X and does perform less well with power
amp Y. There are a few things to consider: |
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AND CABLES? Did you pay enough attention to the interconnects between components? And what about the loudspeaker cables? Do they transmit a well balanced, well extended frequency band? If not, get better cables first. ROOM: SHAPE, SIZE AND FURNITURE Then there
is the room you have positioned the speakers in. First
of all we have to take the size of the room into account. It should be
large enough to enable low frequency information to unfold. Then the shape
is important. Is the room long and narrow? Is it a square? Is it a large
room? And how is it damped by furniture, carpets, wallpaper, paintings,
shelves with books and records. And what are the actual positions of the
speaker systems? |
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What
do you get when the loudspeakers are well positioned:
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SPACE VERSUS HARMONICS Although
there must be only one right position for your loudspeakers in your
specific listening room, providing maximum stage, with good transients,
it is not always easy to obtain these qualities. CARE Once again:
Quite a few music lovers do not give the loudspeakers the attention and
care they really deserve - although they think they do! MIRROR IMAGE Not all loudspeaker
systems have the units placed in line, but only high price cabinets are
configured to mirror each other. Take care that the tweeters are always
on the inside. Not doing this will prevent the high frequencies to connect.
The delicate frequencies will be blurred by the longer waves of the mid
range units and or low mid transducers. The sound will become dull and
it is difficult to realize a perfect stereo image. Even at the CES of
2006 in Las Vegas there was at least one manufacturer who had placed his
expensive high end cabinets in such a way that the row with mid range
units was obstructing the sound of the tweeters which were positioned
at the outside. |
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POSITION OF THE TWEETERS When seen
from the front it does not seems to be important to place a-symmetrical
enclosures with the tweeters positioned in the inside. But when looked
at the radiation pattern of the enclosures positioned with the tweeters
to the outside, it is clear that the lobe of the low-mid frequency unit
is obstructing the radiation coming from the tweeters, though it might
seem not too severe. Nevertheless the better connection between left and
right gives the best sound stage. The enclosures with the tweeter in the
middle are symmetrical. There the radiation in both the vertical and horizontal
planes are optimal. Although these drawings may seem just looking at the
best placement in a theoretical way, you will see by experimenting that
you will find the best sound stage when the tweeters are positioned inwards.
What counts for the tweeters, also goes for mid range units if they are
placed towards the edge of the baffle. |
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If the loudspeaker system has one or two woofers in one side panel, be sure to place the cabinets in such a way that the woofers are at the outside of the sound stage. If you do not, the waves of the woofers will deteriorate the sound of mid range units and tweeters. |
ATTACK So initially all things depend on the designer of the loudspeaker system. Did he in his concept give bloom to violoncelli and violins, and enough weight to tubas and trombones? What about the possibility to provide a sharp and fast drum? And what are the dynamic capabilities of the lower mid section? After all the most important part is the region of 200 to 400 Hz. where the entire weight and the most power of the whole orchestra or jazz band comes into action. No designer in his right mind would neglect this fact. LOW FREQUENCIES And what
about the rendition of the lower frequencies under 100 Hz. In that region
most designs for the average consumer do badly connect with the room.
TOO MUCH Bass reflex
systems have the advantage of being fast (and do not need powerful magnets),
but the bigger designs often have a bass that is not easily controlled
in every listening room. Fortunately nowadays many small 2-way bassreflex
systems have an early roll-off and are at the same time quite dynamic.
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In certain cases it can be beneficial to add panels to the baffle if the distance to the back wall is too long. This improves the midband and makes the instruments more tangible. |
If you are not happy with your speakers I won't keep you from going to the shop and inquiring about the model that you read about in the review. But if the reason for the change is that you cannot get the sound right with the speakers you actually own, then you should read on before you go shopping. Bear in mind that there is a chance that you will not easily get the full benefit from a new pair of speakers if you have not exercised and tried your old speaker's potential to the full. It therefore is advised that you give your current speakers the attention they deserve.
CONDITIONS My record
collection is growing and growing. Once in a while I have to put extra
shelves along one of the walls of my listening room. Of late the growth
factor has been rather high. The result is that I became more and more
unhappy with the sound that my speakers were producing. The
extra record storage had changed the position of my speakers without moving
them. |
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CLEAR THINKING Generally
speaking changes also can be brought about by a plant that is growing
out of control or by adding a large painting or two to your collection
on a wall. (Do never ever put plants in between the speakers or right
behind one or both if you want the maximum of stage.) A new piece of furniture
or a slight rearrangement of chairs also suffices to disrupt - although
slightly - the familiarity of the acoustics. Even a little table in front
of your listening chair does impair the stereo image and the correct flow
of the sound. |
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OPENNESS Keep the
space as open as possible. Finally an unfamiliar sounding could be brought
about by the fact that one or both speakers were slightly moved when the
room was cleaned. Even
worse is of course a smaller or larger table reflkecting and redirecting
the soundwaves. Or a plant distorting the image. And do not forget that
the components placed in between speakers also have their benificial and
most of the time detrimental effect. |
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(Supporters) |
SHOE BOX It is
of the utmost importance to take the shape of the room into account.
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SOUND BALANCE In smaller
rooms - like mine for instance which measures in centimeters the well
appreciated 360 (W) x 610 (L) x 255 (H), a shoe box so to say -
small speakers can attain an extremely high performance not only as far
as the extension of the low end of the frequency band is concerned. By
trying to regulate the best position it is possible to create a realistic
sound balance. TWO VERSUS THREE SPEAKER CABINETS The Super
Audio Digital Disc and the new formats which are being developed to give
a more precise high resolution audio, make it possible to have a center
channel as was originally recorded by the |
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FOOLED? Because
of the physical properties of the cabinet (if it is a modern item),
complaints are often heard that they do not sound at all what the
reviewer was raving about or the manufacturer's brochure so eloquently
promised. Sometimes loudspeaker systems are demonstrated in a shop
while standing in a row with many other speakers. And of course the
sound is completely different from what it should be.
DESIGN I count
a few strongly high-end oriented audiophiles as my friends. They modified
a commercial model by shortening the vertical distance between the
tweeter and woofer by more or less eliminating the baffle and without
redesigning the filter. As an extra they placed the small enclosures
far away from walls and corners. |
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ACOUSTICS I often ask a prospective buyer who asks for advice to make a drawing of his listening room and let him indicate furniture, equipment, loudspeakers, etc. and I discuss with him the layout. It can be necessary to add some damping on the walls in the form of panels, a few square feet of carpet halfway the room and a piece on the back wall, and probably in one far corner as well. Nowadays the fashion is to put just a few pieces of furniture in the room as if it were a museum of modern art. Such a room will behave badly. DAMPING The drawings
that accompany this article show some solutions that can give
you an idea of how the frequency characteristics of the room and of
the speakers can be compensated for by adding damping panels (dp)
to the left and right of the loudspeakers and in the corner to the
left of the listening chair where the front end is located (record
player, CD player and pre amplifier). The power amplifier is placed
between the loudspeakers as is the custom nowadays. |
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It
is not what you have got, but what
you do
with it,
that counts. |
DEMONSTRATION Many years ago Farad Azima of Mission Electronics came to our country to introduce his Mission products for the first time. He set up a demonstration for an audience of over a hundred audio dealers. The Dutch importer had positioned the new Mission speakers on tables placed many feet apart so that the entire audience could see and hear the loudspeakers. Without hesitation Farad Azima took the two 770 speakers and put them right down on the floor, the distance between the speakers being not more than about six feet. The 770's sounded like music: harmonious, with remarkable transient response and extended frequency band. (I must add that the 770's had quite a remarkable and generous low end which was of great help of course.) Everyone was amazed. In order to let over one hundred audio dealers hear the music, most people had thought that it would be necessary to put the speakers on stands that were high enough to overlook the room and that they should be positioned at a great distance from each other in order to create a large stereo image. That proved to be a misconception. Many music lovers place their speakers much too far apart.
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PERPENDICULAR Take
care that the fronts of the speakers are exactly on the same imaginary
line, a line which is perpendicular to the walls (refer to the drawing
at left). The distances to the walls on the left and the right should
be about the same. |
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COMPROMISE As said,
the ideal listening room has the shape of the best concert halls in
the world: the shoebox. ADJUSTMENTS Once
you have determined a basic position for the speakers, you can start
by slightly increasing the distance between the speakers and place
them also closer to the back wall. ART If you
are a newcomer to the art of adjustment you will learn that the ideal
position is not reached in a few minutes or half an hour. Even if
you think that it is right you may find the next day (ears relaxed)
that it does not sound right. So take your time. It may take several
days. |
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NATURAL SPACE Putting
the speakers farther from all walls gives a leaner bass. If you want
more support from the lower frequencies from the side walls and will
put the speakers closer to these walls, then you have to put them
also closer to the back wall at the same time. In practice this means
that there is a line at 45 degrees (refer to drawing) along which
the speaker can be moved to and fro. LP & CD Some
people think that CD is superior in establishing a real to life
sound stage with height and depth. Due to the troubled manufacturing
process of analogue Lp's with tape copies, matrix production and
great numbers of Lp's being pressed from one matrix, this is often
true. Many music lovers think that Lp's are not able to deliver
the same quality of stereo image and depth. But there are a lot
of Lp's that do and that is why they are so much in demand. |
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APERTURE If you still
do not get the sound picture in your living room right, then it is likely
that you have overlooked a very important aspect of how to bring the stereo
image to life. You may have overlooked the nature of the vertical aperture
of your loudspeaker systems. It all depends on the dispersion characteristics.
A 2 way system with a tweeter beneath the low midrange driver may have
a loop that is directed upward. Short loudspeaker stands can be used.
A d'Appolito-design has a loop that is pointing straight at you. In hat
case your ears should be at the tweeters' height. For big loudspeaker
systems the same is not always true. If you have placed the speakers and
your listening chair at the correct height, then you should take care
that the tops are perpendicular to the back wall. You can check this with
a spirit level. You will
never get the right image if the speakers are not facing you exactly in
the same way. Adjusting the spikes of the stands will help you in leveling
the cabinets. ANGLE In order
to see if the height is correct you can adjust the angle of the speaker
by putting a piece of wood underneath the cabinet at the back and listen
again to know if the sound stage is improving. You can determine if you
should change the height of the stands and to what extend. |
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PRACTICE MAKES PERFECT The general
rule is not to place the speakers too far from each other. Always
connect the mid band acoustically, no matter what size and shape of
room you have. That is the most important issue. From there you can
gradually adjust the distances, in very small increments. By adjusting
the positions, you will learn about the nature of the loudspeaker
system, about the positive and negative effects of you listening room.
After some time you will discover the best position. That is the position
which gives space, depth, which will improve focus. You will discover
the acoustics of the hall or studio where the recording was made.
You will also discover that mono recordings have a stage as well and
that the sound is positioned in the center. DIFFERENT
HEARING |
© Rudolf A. Bruil - Page first published on the www in August 2001, and updated since.
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& Music Bulletin |
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