Warm-up:
1. How many types of loudspeakers can you
name depending on a) where they are placed and
b) their technology?
2. What do you know about the history of the
loudspeaker?
A long time ago, in 1874, before music was electrified, E.W. Siemens
was the first to present his patent (U.S. No149,797), describing a magnetoelectric
apparatus for “obtaining electric currents from the mechanical
movement of an electrical coil or for obtaining the mechanical movement
of an electrical coil from electrical currents transmitted through it” (the
so-called ‘dynamic’ driver), although he didn’t use this apparatus for
audible transmission as Graham Bell did. Later, in 1898, Oliver Lodge
developed a different system of a moving-coil driver with non-magnetic
spacers that could maintain the air gap between its inner and outer poles.
In the early 1920s, C.W. Rice and E.W. Kellogg improved the moving coil
cone loudspeaker, after they realized that a loudspeaker could produce a
flat frequency response, but only above its fundamental resonance
frequency. Their new improvement was really important at the time,
because prior to 1925, the maximum output which was available from a
radio set was in the order of milliwatts, for listening via earphones.
Consequently, the earliest forms of ‘speakers’ had to handle just a limited frequency range at low power levels. However, Rice & Kellogg’s device was powerful enough to produce a ‘loud’ sound that could be heard in a room full of people. That’s why this kind of devices were later called ‘loudspeakers.’
Rice & Kellogg’s innovative design led to the production of the first commercial loudspeaker ‘Radiola Loudspeaker 104 (RCA)’ in 1926, which had a built-in power amplifier and to date, this driving mechanism remains the most popular in the
market.
Today, loudspeakers are designed based on the same principles as the first loudspeakers including, however, a more sophisticated construction, especially regarding hi-end sound systems. Generally speaking, all speakers consist of a transducer, a radiator, a crossover and an enclosure (in the case of non-panel speakers). Furthermore, they all meet specifications according to which they can be characterized as higher or lower quality products. These specifications are the size
and type of the driver, the power, the impedance, the enclosure type, the number of drivers, the crossover frequency, the sensitivity and the maximum sound pressure level.
Moreover, loudspeakers are often used for specific purposes (home studio, professional studio, live recording, measurements, etc), and that’s the reason why they are available in various types (bookshelf, floor standing, satellite, in-wall). Additionally, loudspeakers are available in a wide range of technologies, so that
they satisfy different needs, that is, from a simple beeper in a watch to a sonar system or a complicated multi-device audio system. These technologies include horn loudspeakers, ribbon loudspeakers, bending wave transducers, flat panels, piezoelectric, electrostatic, plasma arc and digital speakers.
A. Reading comprehension
1. E.W. Siemens constructed a magneto-electric apparatus that
a) could be used for music listening
b) could transmit electro-magnetic signals through mechanical movement
c) had an electrical coil, which produced electrical currents through mechanical
movement
2. C.W. Rice and E.W. Kellogg
a) presented a new version of the moving coil cone speaker
b) were the first to construct the moving coil cone loudspeaker
c) produced the first magneto-electric apparatus
3. Regardless of the loudspeaker type, all loudspeakers share
a) the same technology
b) the same specifications
c) non of the above
B. Terminology: Match the words with their definitions in Greek
a. moving-coil driver ___ 1. συχνοτικό εύρος
b. frequency response ___ 2. εκπομπή
c. fundamental resonance ___ 3. συχνότητα διαχωρισμού
d. frequency range ___ 4. θεμελιώδης συντονισμός
e. transducer ___ 5. σύνθετη αντίσταση
f. impedance ___ 6. οδηγός κινητού πηνίου
g. transmission ___ 7. συχνοτική απόκριση
h. crossover frequency ___ 8. μετατροπέας, μορφοτροπέας
i. ribbon loudspeakers ___ 9. ηχείο ταινίας (μαγνητοστατικό)
j. loudspeaker enclosure ___ 10. καμπίνα ηχείου
k. sound pressure level ___ 11. προδιαγραφές
l. satellite ___ 12. επίπεδο ηχητικής πίεσης
m. complicated ___ 13. ηλεκτρικό ρεύμα
n. electrical current ___ 14. δορυφόρος
o. specifications ___ 15. πολύπλοκος
C. General vocabulary: Choose the correct word to fill in the blanks.
device, audible, innovative, purpose, prior to, components, consist of, maintain,
sophisticated, remain, invest
1. A loudspeaker is an electric _______.
2. The transducer is one of the _______ that a loudspeaker has.
3. Loudspeakers manufacturers _______ millions of dollars every year on
_______ technologies for hi-end speakers.
4. Dynamic loudspeakers still _______ one of the most popular types of
loudspeakers.
5. A high-quality loudspeaker is supposed to _______ its dynamic coherence
across the audio spectrum.
6. The frequency of 5 Hz isn’t _______ by human beings.
7. Except for the standard rectangular shape of loudspeakers, there are many
other _______ designs.
8. _______ the 20th century, musicians couldn’t record their songs and publish
their own music album.
9. The _______ of a loudspeaker user’s manual is to present the specifications
and related technical information about the product.
10. Most loudspeakers_______ drivers mounted in an enclosure.
D. Language tip: Words often confused
There is often too much confusion about words ending in -ic and -ical for nonnative
English speakers, often altering the meaning of a sentence. In particular,
Greek students of English tend to translate both -ic and -ical as -ικός in Greek, but
without understanding the difference between these two cases. Let’s see some
examples:
1. electric vs electronic vs electrical: electric refers to things using electricity
for power, e.g. a hair dryer is an electric device or we say electric car and not
electrical car. However, when we refer to things using more complicated
technologies in terms of handling electricity (such as Printed Circuit Boards), we use
the term electronic, e.g. a mobile phone is an electronic device. On the other hand,
electrical is used when we refer to things that are related to electricity, e.g. electrical
engineer. In this case, we couldn’t say electric engineer, because we would imply a
person (the engineer in the previous example) that runs on electricity!
2. mechanic vs mechanical: A mechanic is someone who repairs machines, like
a car mechanic. Mechanical is an adjective that can refer either to the field of
mechanics, e.g. mechanical engineer or to something that follows the laws of
motion, e.g. mechanical waves. Moreover, it is used to refer to the design and
construction of machines, e.g. mechanical leg.
3. economic vs economical: Economical refers to something relatively cheap or
something that is good value for money, e.g. an economical car. Moreover, it can be
used for a person to indicate that he/she is careful about spending money, e.g. she was always very economical; she never bought things she didn’t really need or that
something uses minimal resources, e.g. an economical heating system, an
economical method of waste disposal. However, economic is an adjective relating
to economics or the economy, e.g. economic policies, economic development,
economic crisis.
4. periodic vs periodical: We use periodic (adjective), when we talk about
something that happens at regular intervals, e.g. periodic wave or periodic signal.
On the other hand, periodical is a magazine, journal or newspaper that is published
regularly, e.g. legal periodicals.
Can you tell the difference between the words logic - logical and classic -
classical? Use a dictionary to confirm your answers.
E. Writing
Loudspeakers user’s manual offer valuable information about connectivity,
positioning, specifications and troubleshooting. Below, there are sample some
values and information about a loudspeaker. Some manuals contain more or
slightly different kind of information than others, e.g. not all manuals provide
information about dispersion or max continuous SPL. Match the following words
with the correct piece of information.
power handling, sensitivity (2.83V@1m), frequency range, nominal
impedance, crossover frequencies, positioning, amplifier compatibility, cabinet
dimensions, finish, weight, dispersion, max continuous SPL, drivers, grilles
1. _____________________ HF (1’’), MF (3’’), LF (9’’)
2. _____________________ 150 Watts unclipped program
3. _____________________ Not less than 15cm from rear wall
4. _____________________ Horizontal: ± 75° Coherent
Vertical: ± 15° Coherent
5. _____________________ 350 Hz and 3 kHz, 4th order
6. _____________________ 110 dB SPL @ 1m
7. _____________________ 86 dB SPL
8. _____________________ 55 Hz - 22 kHz
9. _____________________ 8 Ohm
10. ____________________ 100 - 1000 Watts
11. ____________________ 720 x 310 x 510mm
12. ____________________ 38 kg
13. ____________________ Cherry wood veneer finish
14. ____________________ Satin grey (removable)