18
Ampersand
MayJune, 1980
U
& mi i
by Martin Clifford
n hifi, a speaker yields the moment of
truth. Unfortunately, the speaker is
still the weakest link in the system,
though it doesn't bear the entire responsi
bility. What is heard depends not only on
the speaker, but on the size of the listening
room, its shape, acoustics, speaker posi
tioning, on the physical condition of the
ears, musical training, age and sex.
This means that the sound from speak
ers is subjective, tempered by a collection
of variables. It just isn't possible to plunk a
pair of speakers anywhere and expect
superior results. Luck plays a very small
part in speaker positioning.
The first step is to separate the speakers
until the stereo leftright sound is satisfy
ing. This can be done by playing a familiar
stereo record while trying the speakers in
different locations along the floor or on a
bookshelf. The sound should have a dis
tinct leftright characteristic and should
not seem to come from a single speaker, an
imaginary unit between the two.
Once the stereo balance is satisfying, the
speakers can be placed at various distances
above the floor, if possible, with the help of
speaker stands. This changes the response
in the bass, midrange or treble. Generally,
speakers near floor level will be "boomier."
Also, treble tones come cleanest when
aimed at ear level. Tilting the speakers
leftright or updown is also helpful. This
doesn't mean both will be placed identi
cally. One may be. higher or more at an
angle. The final criterion is that the sound
should be pleasing. ,
Speakers and power amps have a sym
biotic relationship. If a speaker requires a
minimum input of 10 watts and has a
maximum rating of 60, then the amplifier
can be somewhere between these two ex
tremes. While that's the safest way, it isn't the
best. An amp rated at 100 watts won't al
ways use this amount of power. A transient
or momentary peak can reach 100 watts
with minimum distortion and, since this
power demand is short lived, can be safely
handled by a 30-watt speaker. Most hi
fi'ers use amps with power ratings in excess
of speaker ratings.
Most in-home hifi speakers are 8 ohms,
the impedance of the voice coil. Speakers
should be connected to the 8-ohm taps on
the amp, even if it has 4 and 16 ohm taps.
Matching amps to speaker impedance
supplies the greatest possible transfer of
sound energy. Most auto speakers are
made with a 4-ohm impedance.
The efficiency of a speaker is the ratio of
sound output vs. audio power input. If an
amp drives a speaker with 10 watts and it
delivers 1 watt of sound pressure, that is
110 or 10 per cent efficiency, rather high.
A low efficiency speaker would be one
rated at about 0.5 to 2 per cent. The higher
the efficiency the smaller the possible
power requirement of the amp. High effi
ciency or low is a matter of personal pref-
fact:
this small
record
collection
represents a
$1,000
investment
It's true the largest invest
ment in almost any hi-fi sys
tem is frequently the cost of
the records played on it. . .and
it is equally true that a badly
worn phono stylus tip may ruin a
valuable (or irreplaceable) record in a
single playing!
With the rising cost of new phonograph records and the
difficulty in replacing treasured, older favorites it's the worst kind of
false economy to risk damaging them with a worn stylus.
Check your stylus (needle)
at least once a year
Always insist on a Genuine Shure replacement stylus. Substitutes will
not restore the Shure cartridge to its original performance standards.
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Shure Brothers Inc., 222 Hartrey Ave., Evanston, tL 60204, In Canada: A. C. Simmonds & Sons Limited
Outside the U.S. or Canada, write to Shure Brother Inc..
Attn: Dept. J6 tor information on your local Shure distributor.
Manufacturers ot high fidelity components, microphones, sound systems and related circuitry.
erence. Both types can give good results.
use 18 gauge wire, or even slightly I
thicKer, tor connecting speakers to amps.
The smaller the gauge number; the thicker
the wire. Speakers should not be con
nected to amps with the power turned on.
When records are played it is best to keep
the volume turned down until the sound
comes on and then advance the volume
control.
Turning up the bass tone control and
the loudness and volume controls simulta
neously may be asking for trouble. With
these advanced the bass speaker is being
asued to work hard and it may not be able
to do so, or at least not for very long.
Speaker fuse ratings are coarse, unreli
able, and don't work fast enough. They are
better than no Fuses, but not by much. It is
better to rely on good operating practice,
for this will help speakers from going
prematurely to their electronic Valhalla.
Speaker grilles are not only decorative
but protective. It's easy to damage speaker
cones so don't remove grilles unless its
necessary. Grilles are made to be acousti
cally transparent, so sound is not
improved with the grilles off.
Good hifi specs are important, but
refer only to new equipment. As a system
gets older, rumble, wow, flutter, high fre
quency oscillation and hum may become
evident. These produce sounds that make
speakers work more, so amps and turnta
bles should be checked periodically. Some
audio dealers do this without charge.
by Byron Laursen
f music be the food of love, how can we
improve the flavor? Santa Monicans
Wayne Umbertis and George Carlsen
have something that seems to turn the
trick, a between-amp-and-speakers, sub-
$200 add-on they call Dynamic Com
pliance Fidelity Enhancement System.
"Somebody described it," boasts Um
bertis, "as looking through a window with
the screen removed." Indeed, handed a
swtich box that cut the Dynamic Com
pliance feature in and out of two sets of
speakers, one of them cheap and the other
high-cost, I heard a sense-pleasing
improved fullness of sound over both sets.
with the greatest enhancement effect
noticeable on the cheap pair. It was like the
difference between hearing a great acous
tic guitar in one's own lap and a fair one
over a p. a. system. Frequencies that were
harsh, irritating and tinny without the de
vice became round and luxurious when
Dynamic Compliance was switched on.
The device's essential components are a
power booster, which allows the main amp
to operate at lower levels, hence farther
from distortion, and circuitry that pur
portedly refines the communication
between amplifier and speakers.
Dynamic Compliance, Inc. plans the
same strategy that made the Dolby Noise
Reduction System profitable for its in
ventor: they'll sell direct to consumers via
mail order, but the future rides on licens
ing agreements from established stereo
equipment manufacturers
Already, Concord Electronics has re
leased two Dynamic Compliance
amplifiers for car stereo, with a brochure
full of impressive claims about slewing
rate, intermodulation distortion and
amplitude linearity. By me, a thoroughly
non-technical type with an oversized ap
petite for music, no spec sheet could make
so dramatic an impression as did the
switch box that clarified everything the
speakers had to deliver.
See the ORIGINAL
PIASTER RECORDING
Dealer in your area
SOUTHWEST
UNIVERSITY OF NEW MEXICO
Hudson's Audio Ontcr. Albuquerque
Hi Fi House, Albuquerque
Sound IdeL., Albuquerque
Trans-America Audio. Albuquerque
UNIVERSITY OF TEXAS
Audio Consultants. El Paso
Casa Sonklo, El Paso
Howell Electronics. FJ Paso
Music Systems, El Paso
UNIVERSITY OF TEXAS
Audio Vision. Dallas
Fantasia Records Ic Tapes. Arlington
Melody Shop, Dallas
Phase Research. Dallas
Sound Climax, Dallas
Sound Ideas Inc., Arlington
Texas Hi Fi. At Stores
UNIVERSITY OF TEXAS
Audio Concepts, Austin
Audio-Video, Austin
TEXAS TECH UNIVERSITY
Hi Fi. Lubbock
SOUTHERN METHODIST UNIVERSITY
Thomson Sound. Dallas
UNIVERSITY OF OKLAHOMA
Thomson Sound, Norman
SOUTHEAST
UNIVERSITY OF TENNESSEE
Hi Fi House, Knoxville
Music Jungle, Knoxville
, Stereo Village, Knoxville
TULANE UNIVERSITY
Alterman Audio, New Orleans
Campo Appliance, New Orleans
Leisure Landing, New Orleans
Wilson's Audio. New Orleans
UNIVERSITY OF CEORCIA
Sonic Stereo, Athens
lape City, Athens
CEORCIA STATE UNIVERSITY
Back Door Stereo, Atlanta
Flat Julian's Audio, Atlanta
Hi Fi Buys, Atlanta
The Sound Haus. Atlanta
Stereo Designs, Atlanta
Turtles Records k Tapes, AH Stores
Writ side Audio, Atlanta
UNIVERSITY OF ALABAMA
Audition, Birmingham
The listening Room, Birmingham
Lawrence Stereo, Birmingham
Odyssey Records, Birmingham
UNIVERSITY OF FLORIDA
Audio Etc.. Gainesville
Audio Innovators. Gainesville
UNIVERSITY OF NORTH CAROLINA
Audio Works, Chapel HiD
Paradise Records Ic Tapes. Chapel Hill
Stereo Sound, Chapel Hill
Vkkers Audio. Chapel Hill
UNIVERSITY OF VIRGINIA
Back Alley Discs, Charlottesville
The Sound Machine, Charlottesville
EAST
UNIVERSITY OF PITTSBURG
Listening Post, Pittsburg
National Record Mart. Pittsburg
Opus One, Pittsburg
Ovation Audio, Pittsburg
COLUMBIA UNIVERSITY
Borgers Hi Fi. New York City
Sam Goody's, All Stores
King Karol Records, New York Cky
Harvey Sound, New York Gity
Audio Exchange, New York lily
PENN STATE
Watson F-quipment Sales. State OdleRe
UNIVERSITY OF PENNSYLVANIA tc TEMPLE
UNIVERSITY
David Mann Umited. Philadelphia
Ed Smith Audio, Philadelphia
listening Booth, Philadelphia
UNIVERSITY OF MARYLAND
Audio Krafters, College Paik
S.U.N.Y. BUFFALO
Stereo Emporium, Buffalo
Alltronk s, Buffalo
The Speaker Shop. Buffalo
UNIVERSITY OF CONNECTICUT
J. Robert Barry, Manchester
Hi Fi Stereo HViux, Newmgion
YALE UNIVERSITY
Take 5 Audm
HARVARD UNIVERSITY
Harvard Coop, Cambridge
MASSACHUSETTS
Sound ic Music, Northampton
BOSTON UNIVERSITY
Natural Sound, f t imington