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FAQ:
rec.audio.* Systems 2/99 (part 2 of 13)
9.0 High
Fidelity Systems
People
frequently use the term "Stereo" to refer to a sound
reproduction system. To be more accurate, we will use the term High
Fidelity System to refer to a pile of equipment including at least one
source, at least one amplifier, and at least one speaker. Common sources
are turntables, CD players, tape players, tuners, and receivers.
9.1 What is
a receiver?
A receiver is
a tuner, power amplifier, and preamp combined. A common receiver has
inputs for a turntable, a CD player, a tape deck, and perhaps one or two
other sources. It probably also has selector switch(s), tone controls, and
a volume control. A receiver may have outputs for two speakers, or for
more. Some receivers do |not have phono preamps, a trend that may become
more common as vinyl loses popularity. Many receivers contain surround
sound processors.
9.2 What is
a tuner?
A tuner is a
radio reception device which can not drive speakers. Sometimes, the radio
in a tuner is higher quality than the radio in a receiver. A tuner may or
may not receive the AM broadcast band, but 99.999% will receive the FM
broadcast band. Some also receive short wave bands, frequencies used for
long-distance rather than for local commercial broadcasts.
9.3 How
should I go about selecting a system?
If you're
looking to buy something, the first step is to figure out what you can
spend. If you're looking for a whole system, this gets tricky, because you
have to allocate amounts for the different components. The most popular
current rule-of-thumb for a single source system (speakers, amp, 1
something-player) is to divide the money about equally among the three
parts. If you want several players, you'll have to decide whether they are
all equally important, and so deserve the same amount of money; or whether
some are less important, in which case you can spend less on them and put
the savings elsewhere.
This rule
isn't hard-and-fast. It's just meant as a starting point so you don't have
to listen to every possible combination of equipment. If you are building
around a CD player, you might spend a bit less on the player and a bit
more on the speakers. If you are buying turntable (or something else which
plays by physical contact) on the other hand, it might be good idea to put
a bit extra into the player. The reason for this is that if you skimp on
the turntable, then when you come to buy a better one you may find that
your records have been worn out by the cheap player. If you skimp on the
speakers, on the other hand, then when you can afford better speakers the
music will still be there on your records.
Another
perspective says that you should spend the most you can on your source, as
the sound can never be better than what you get off of the record/CD.
See also 12.1,
12.2, and 10.1 for information on what to listen to and what to listen for
when evaluating speakers, turntables, CD players, tape recorders, and
systems in general.
9.4 How can
I improve the sound of my stereo?
The cheapest
improvement you can make, and perhaps the most effective, is to position
your speakers carefully and correctly. See 13.1, below. This will improve
the frequency response flatness, making it easier to hear every instrument
and voice. Setting speaker position correctly can also improve the
three-dimensional recreation of a stereo image.
9.5 Do I
want a combo system or separate components?
Combo systems
used to be cheap jokes; that's not always true now. Some sound very nice;
there are even some made by "audiophile" companies, and they
sound even nicer. They've got lots of advantages. They take up less space.
The controls tend to be well-integrated, especially if they are
remote-controlled. Therefore, they are easy to operate; this can be a
major plus if some of the people who'll use it are afraid of, or not very
good at, technology. Also easy to set up, and don't leave millions of
wires dangling all over everywhere.
If you do go
for a combo, get a brand name; either an audiophile company, or a good
"consumer electronics" company. Brand-X combos are generally
overpriced and unpleasant. If possible, buy it where you can listen to it
first, such as a "real" hi-fi shop. Mid-range hi-fi shops sell
combos, as a way of introducing beginners to quality sound.
In most good
combos, the speakers are the weak link. If you do go for a combo, you can
almost always improve the sound drastically by buying a set of better
speakers. Better speakers start in the $100-$200 price range. Some of the
best combos come without speakers, forcing you to do this. A good combo
with replacement speakers will give you very pleasant music.
Sounds good,
you say, so why do people bother with components? Well, you can get better
sound with a component system -- but usually at the expense of convenience
and size. A good component system will normally require a mixture of boxes
from different makers to get the best results, so you've got to spend more
time listening to things. However, if you listen to your music seriously,
then the performance of a component system is the reward for that extra
work.
Components are
harder to set up and operate. However, as noted, you can get better sound.
You also get more flexibility. If, for example, you decide you want a
better CD player, you just replace the CD player. With a combo system,
you've got to replace the whole system. If your component tape deck
breaks, you can remove it from the system and take it in for repair or
replacement. With a combo, the whole system has to go in for repair or be
replaced.
When you want
to add some new recording medium to your system (laserdisc, VCR, DAT, DCC,
MD, ...), if you've got components you just go buy the appropriate box.
Many combo systems do not have places (or many places) to attach extra
bits, so again you could be looking at replacing the whole thing. With a
component system, you can add a turntable; most modern combos can't cope
with turntables any more. Do you have a record collection?
If you're
really not sure, components are the safer bet; if you're going to make a
mistake, that's probably the better way to be wrong. But, if you're sure
that a combo would be best for your needs, it can be a totally reasonable
choice.
Now, some
people may be tempted by one-maker 'component sets', particularly the
modern, miniature ones. They tend to be equivalent to combos. Most use
non-standard connections, rather than the normal twin phono plug, so that
it's likely you can't swap or add components anyway. Even where they use
standard interconnects, they may rely on non-standard interconnections for
control purposes. In a few cases, they also rely on sharing power, with a
power supply in only one of the boxes and the rest taking low-voltage
connections from that. And, no one maker makes the best everything. By
default, assume that they will have the same disadvantages (and most of
the same advantages) as combos. If it's important for it to work with
"standard" components from other makers, be sure to ask before
you buy.
One-maker
'component sets' are also often of lower quality than true individual
components. Component sets are designed for convenience and appearance,
rather than sound quality.
And, if you're
in doubt, go for separate components.
9.6 How can
I get better FM radio reception?
-
Use a
(better) antenna. (See 9.7 and 9.8 below)
-
Use a
(more) directional antenna. (See 9.7 and 9.8 below)
-
Aim your
directional antenna. Rhombics are ungainly to move, but Yagis and
dipoles are small enough to point right at the station. With the
dipole, to tune in a station to the East, run the antenna North-South.
With a Yagi, point the individual elements North-South with the
smallest element on the East end.
9.7 How
good are these compact FM antennas?
For receiving,
small is ugly. The bigger the antenna (all else equal) the better. Of
course, all else is never equal, but these fancy, expensive mini antennas
tend to be awful. Some compensate for their small receiving structure with
a small antenna signal amplifier. However, the quality of that amplifier
is often no better than the quality of the amplifier in your tuner or
receiver, so the antenna just gives you a stronger signal, complete with
stronger noise.
All of that
said, some compact FM antennas can work better than a simple dipole in
some situations. Some have an internal amplifier, which helps with weak
signals if the input stage in your receiver is poor. Some are directional.
Some aren't. If possible, be sure that whatever you buy can be returned
for a refund if it doesn't work out well for you.
9.8 What
makes the best FM radio antenna?
Although there
is no "best" antenna for everyone, one of the most directional
is the "rhombic". Being very directional, this antenna can
select one weak station out of many strong ones, or one group of stations
originating from a general direction. In addition, very directional
antennas are good at reducing multipath interference, a problem which is
more severe in cities with tall buildings.
This antenna
is very long, and made up of four pieces of wire with feedline at one end
for antenna connections and a resistor at the other for termination.
Rhombics for FM broadcast band use are at least 15 feet (4.5 meters) long,
but can be made fairly narrow, less than 3 feet (1 meter) wide. A more
narrow antenna will be more directional. A longer antenna will give a
stronger signal.
Another very
directional antenna is the "yagi", which looks just like a
common TV antenna. You can even use a common TV antenna as a very good FM
antenna. The FM and TV bands are very close together. It has the
advantages of being cheap, directional, and easy to rotate.
One of the
simplest and easiest to make antennas is the folded dipole, made from 300
ohm twin lead. It is approx. 58" long. This antenna is surprisingly
good for receiving signals in a moderately strong signal area. Folded
dipoles come with many tuners and receivers as a standard accessory. They
are also available for approximately $2 at audio and department stores.
Whatever
antenna you have, you can often get it to work better for specific
stations by moving it. In the case of the folded dipole, sometimes it
works better vertically, and other times it works best horizontally.
Sometimes, you can get that one elusive station to come in perfectly if
you bend the two ends of it at funny angles. Don't be afraid to
experiment. One warning. As atmospheric conditions change, the best
antenna placement may also change.
An excellent
reference book on antennas is printed by the American Radio Relay League (ARRL).
It is called The ARRL Antenna Book. Currently in its 17th edition, it is a
736 page large, illustrated paperback which includes a disk of MS-DOS
software. It costs $30 plus s/h. It has fairly complete antenna theory,
practical information such as charts, drawings, comparisons, and tips on
construction and adjustment. ISBN 0-87259-473-4. The ARRL is founded and
chartered as a non-profit organization to better amateur radio, and
antennas are a vital part of amateur radio.
American
Radio Relay League
225 Main Street
Newington CT 06111 USA
203-666-1541
Also useful:
Practical
Antenna Handbook by Joseph J. Carr
Tab Books #3270/McGraw Hill - ISBN 0-8306-3270-3
9.9 What
about power line conditioners?
Each home and
each outlet has slightly different power line impedance and power line
noise. Each amplifier is affected by power line impedance and power line
noise differently. Power line conditioners try to reduce this line noise.
Some also change the power line impedance in a way which is supposed to be
better. We will leave it to your ears to decide if these devices help the
sound of your system enough to justify their expense.
9.10 How
can I reduce vibration sensitivity?
Some complain
that heavy foot falls will cause skipping or more subtle sonic problems
with CD players or turntables. If you have these problems, there are a few
different things which you can try to reduce the problem. One is to add
weight to the rack which holds the equipment. Heavier things move slower.
If you can get the motion slow enough, it won't cause sonic or tracking
problems.
Another
solution is to add rubber or elastomer (Sorbothane) cushions under the CD
player or turntable. This might make it better, but might also make it
worse. Experiment.
A third
solution is to increase the coupling between the rack and the floor using
spikes, which concentrate the weight on a very small area.
Another way to
increase the coupling between the rack and the floor is to use a plastic
adhesive like HoldIt, sold under the UHU trade name in office supply
stores.
9.11 What
equipment can I buy that is 100% made in the USA?
There are many
lines of equipment that are carefully hand crafted in the USA.
Unfortunately, these systems are usually the high-end ones. Some US
companies also make gear in the far east. When in doubt, ask. Some US
audio manufacturers are:
9.11.1 Any
information on equipment made in other countries?
Thanks to
Stephane Tsacas, we know:
Australia:
Canada:
Czech
Republic:
Denmark:
France:
Germany:
Italy:
Korea:
Netherlands:
New
Zealand:
Norvegia/Norway:
Switzerland:
UK:
9.12 Should
I buy "xxx"? Which is better: "yyy" or "zzz"?
We can provide
facts and opinions (and you get to decide which is which :-), but we can't
recommend if, or which way, you should jump, because we don't know what
your priorities are. (That won't stop us from trying, though!) For
example, if you are considering a used item at a low price vs. a new one
at a higher price, one of us might say "go for the new one because of
the warranty", when another would say that you can fix it yourself if
it breaks. They're both right.
This also
applies to speakers. One may have very good, flat bass, but only go so
low, where the other may go lower, but have less flat frequency response.
Which is better? Depends on the buyer. Good speakers are carefully
designed to achieve a balance of performance that matches the priorities
of the designer. Some designers put much of their budget into appearance.
Some designers put their budget into very high efficiency. Others strive
for the smallest box which can deliver an acceptable low frequency
performance. Do you really want people on the network making that decision
for you?
9.13 What
is Surround Sound? Pro Logic?
In an effort
to make movie soundtracks more dramatic and engaging, Dolby Labs created a
signal encoding which encodes more than just two channels of audio onto
the stereo signal. Many popular receivers and home-theater systems include
the required circuitry to decode these signals. These components are
referred to as Pro Logic, Dolby Pro Logic, or Surround Sound components.
Very few audio recordings contain this encoding, but it is very common
with movie soundtracks and some network TV programs.
Best Surround
Sound reproduction requires five separate speaker systems, but some
improvement is claimed from a surround sound receiver and three speakers
over two speakers. In its best implementation, surround sound will give a
fuller sense of being in the middle of the action. The quality of the
image is a function of the recording, the broadcast quality, and the
choice of reproduction components.
9.14 What
do they mean when they say "It sounds warm?"
There are many
subjective terms used to describe slight differences in frequency
response, distortion, noise, etc. Thanks to Bruce Bartlett and Pro Audio
Review, we present this Sound Quality Glossary. This glossary puts a
meaning behind many different, common terms. There is no guaranty that
people mean the same thing when they use these terms. However, these
definitions give insight into why a system sounds the way it does and may
also help bridge the communications gap.
Airy:
Spacious. Open. Instruments sound like they are surrounded by a large
reflective space full of air. Good reproduction of high-frequency
reflections. High-frequency response extends to 15 or 20 kHz.
Bassy:
Emphasized low frequencies below about 200 Hz.
Blanketed:
Weak highs, as if a blanket were put over the speakers.
Bloated:
Excessive mid-bass around 250 Hz. Poorly damped low frequencies,
low-frequency resonances. See tubby.
Blurred:
Poor transient response. Vague stereo imaging, not focused.
Boomy:
Excessive bass around 125 Hz. Poorly damped low frequencies or
low-frequency resonances.
Boxy:
Having resonances as if the music were enclosed in a box. Sometimes an
emphasis around 250 to 500 Hz.
Breathy:
Audible breath sounds in woodwinds and reeds such as flute or sax. Good
response in the upper-mids or highs.
Bright:
High-frequency emphasis. Harmonics are strong relative to fundamentals.
Chesty:
The vocalist sounds like their chest is too big. A bump in the
low-frequency response around 125 to 250 Hz.
Clear:
See Transparent.
Colored:
Having timbres that are not true to life. Non-flat response, peaks or
dips.
Crisp:
Extended high-frequency response, especially with cymbals.
Dark:
Opposite of bright. Weak high frequencies.
Delicate:
High frequencies extending to 15 or 20 kHz without peaks.
Depth:
A sense of distance (near to far) of different instruments.
Detailed:
Easy to hear tiny details in the music; articulate. Adequate
high-frequency response, sharp transient response.
Dull:
See dark.
Edgy:
Too much high frequencies.
Trebly.
Harmonics are too strong relative to the fundamentals. Distorted, having
unwanted harmonics that add an edge or raspiness.
Fat:
See Full and Warm. Or, spatially diffuse - a sound is panned to one
channel, delayed, and then the delayed sound is panned to the other
channel. Or, slightly distorted with analog tape distortion or tube
distortion.
Full:
Strong fundamentals relative to harmonics. Good low-frequency response,
not necessarily extended, but with adequate level around 100 to 300 Hz.
Male voices are full around 125 Hz; female voices and violins are full
around 250 Hz; sax is full around 250 to 400 Hz. Opposite of thin.
Gentle:
Opposite of edgy. The harmonics - highs and upper mids - are not
exaggerated, or may even be weak.
Grainy:
The music sounds like it is segmented into little grains, rather than
flowing in one continuous piece. Not liquid or fluid. Suffering from
harmonic or I.M. distortion. Some early A/D converters sounded grainy, as
do current ones of inferior design. Powdery is finer than grainy.
Grungy:
Lots of harmonic or I.M. distortion.
Hard:
Too much upper midrange, usually around 3 kHz. Or, good transient
response, as if the sound is hitting you hard.
Harsh:
Too much upper midrange. Peaks in the frequency response between 2 and 6
kHz. Or, excessive phase shift in a digital recorder's lowpass filter.
Honky:
Like cupping your hands around your mouth. A bump in the response around
500 to 700 Hz.
Mellow:
Reduced high frequencies, not edgy.
Muddy:
Not clear. Weak harmonics, smeared time response, I.M. distortion.
Muffled:
Sounds like it is covered with a blanket. Weak highs or weak upper mids.
Nasal:
Honky, a bump in the response around 600 Hz.
Piercing:
Strident, hard on the ears, screechy. Having sharp, narrow peaks in the
response around 3 to 10 kHz.
Presence:
A sense that the instrument in present in the listening room. Synonyms are
edge, punch, detail, closeness and clarity. Adequate or emphasized
response around 5 kHz for most instruments, or around 2 to 5 kHz for kick
drum and bass.
Puffy:
A bump in the response around 500 Hz.
Punchy:
Good reproduction of dynamics. Good transient response, with strong
impact. Sometimes a bump around 5 kHz or 200 Hz.
Rich:
See Full. Also, having euphonic distortion made of even-order harmonics.
Round:
High-frequency rolloff or dip. Not edgy.
Sibilant.
"Essy" Exaggerated "s" and "sh" sounds in
singing, caused by a rise in the response around 6 to 10 kHz.
Sizzly:
See Sibilant. Also, too much highs on cymbals.
Smeared:
Lacking detail. Poor transient response, too much leakage between
microphones. Poorly focused images.
Smooth:
Easy on the ears, not harsh. Flat frequency response, especially in the
midrange. Lack of peaks and dips in the response.
Spacious:
Conveying a sense of space, ambiance, or room around the instruments.
Stereo reverb. Early reflections.
Steely:
Emphasized upper mids around 3 to 6 kHz. Peaky, nonflat high-frequency
response. See Harsh, Edgy.
Strident:
See Harsh, Edgy. Sweet: Not strident or piercing.
Delicate.
Flat high-frequency response, low distortion. Lack of peaks in the
response. Highs are extended to 15 or 20 kHz, but they are not bumped up.
Often used when referring to cymbals, percussion, strings, and sibilant
sounds.
Thin:
Fundamentals are weak relative to harmonics.
Tight:
Good low-frequency transient response and detail. Tinny, Telephone-like:
Narrowband, weak lows, peaky mids. The music sounds like it is coming
through a telephone or tin can.
Transparent:
Easy to hear into the music, detailed, clear, not muddy. Wide flat
frequency response, sharp time response, very low distortion and noise.
Tubby:
Having low-frequency resonances as if you're singing in a bathtub. See
bloated. Veiled: Like a silk veil is over the speakers. Slight noise or
distortion or slightly weak high frequencies. Not transparent.
Warm:
Good bass, adequate low frequencies, adequate fundamentals relative to
harmonics. Not thin. Also excessive bass or midbass. Also, pleasantly
spacious, with adequate reverberation at low frequencies. Also see Rich,
Round. Warm highs means sweet highs.
Weighty:
Good low-frequency response below about 50 Hz. Suggesting an object of
great weight or power, like a diesel locomotive.
COPYRIGHT
NOTICE The information contained here is collectively copyrighted by the
authors. The right to reproduce this is hereby given, provided it is
copied intact, with the text of sections 1 through 8, inclusive. However,
the authors explicitly prohibit selling this document, any of its parts,
or any document which contains parts of this document. |
