January 1968 Popular Electronics
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
from
Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
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It is doubtful that
as many people today build their own stereo speaker enclosures as was the case
back in the 1950s through about the 1970s. During those decades stereo equipment
was a really big deal, as evidenced by the large number of articles in technical
and hobby magazines. I have posted a couple dozen articles on the subject here
on RF Cafe. Topics included equipment reviews and feature comparisons,
troubleshooting and alignment, modifications to commercial units,
build-it-yourself projects, optimized room layout and construction, and even
advice on how to best enjoy your stereo system. Lots of comics appeared in the
magazines as well poking fun at how a stereo enthusiast's family members and
neighbor might not appreciate the ear drum-busting power capability of your
system. There were also quizzes like this one on speaker enclosure baffle design
to challenge the stereo buff's technical knowledge (search the list below).
A Baffling Quiz
By Robert P. Balin
Speaker enclosure designs differ mainly in the
way they employ baffles, ports, tubes, columns, ducts, and horns to control the
sound radiated from the front and back of the speaker. To see how much you are baffled
by enclosures, try matching the cross-section drawings (A-J) of commonly used enclosures
with the names by which they are known (1-10).
1 Acoustic labyrinth ___
2 Air coupler ___
3 Baffle ___
4 Ducted-port phase inverter ___
5 Folded horn ___
6 Helmholtz resonator ___
7 Horn-loaded reflex ___
8 Infinite baffle ___
9 Klipschorn ___
10 Resonant column ___
<see answers below>
Quizzes from vintage electronics magazines such as Popular
Electronics, Electronics-World, QST,
Radio-Electronics, and Radio News
were published over the years - some really simple and others not so simple. Robert P. Balin
created most of the quizzes for Popular Electronics. This is a listing
of all I have posted thus far.
- RF Cafe Quiz #71:
Tech Headlines for Week of 3/13/2023
- RF Cafe Quiz #70:
Analog &
RF Filter Basics
- RF Cafe Quiz #69:
RF
Electronics Basics
- RF Cafe Quiz #68:
RF & Analog Company Mergers & Acquisitions in 2017
- RF Cafe Quiz #67:
RF & Microwave Company Name Change History
- RF Cafe Quiz #66:
Spectrum and Network Measurements
- RF Cafe Quiz #65:
Troubleshooting & Repairing Commercial Electrical Equipment
- RF Cafe Quiz #64:
Space-Time Adaptive Processing for Radar
- RF Cafe Quiz #63:
Envelope Tracking Power Amplifiers
- RF Cafe Quiz #62:
Stimson's Introduction to Airborne Radar
- RF Cafe Quiz #61:
Practical Microwave Circuits
- RF Cafe Quiz #60:
Ten Essential Skills for Electrical Engineers
- RF Cafe Quiz #59:
Microwave Circulator Design
- RF Cafe Quiz #58:
Microwave and Millimeter-Wave Electronic Packaging
- RF Cafe Quiz #57:
Frequency-Agile Antennas for Wireless Communications
- RF Cafe Quiz #56:
Tube Testers
and Electron Tube Equipment
- RF Cafe Quiz #55:
Conquer
Radio Frequency
- RF Cafe Quiz #54:
Microwave Mixer Technology and Applications
- RF Cafe Quiz #53:
Chipless RFID Reader Architecture
- RF Cafe Quiz #52:
RF and Microwave Power Amplifiers
- RF Cafe Quiz #51:
Antennas and Site Engineering for Mobile Radio Networks
- RF Cafe Quiz #50:
Microstrip Lines and Slotlines
- RF Cafe Quiz #49:
High-Frequency Integrated Circuits
- RF Cafe Quiz #48:
Introduction to Infrared and Electro-Optical Systems
- RF Cafe Quiz #47:
LCP for Microwave Packages and Modules
- RF Cafe Quiz #46:
RF, Microwave, and Millimeter-Wave Components
- RF Cafe Quiz #45:
Dielectric and Thermal Properties of Materials at Microwave Frequencies
- RF Cafe Quiz #44:
Monopulse Principles and Techniques
- RF Cafe Quiz #43:
Plasma Antennas
- RF Cafe Quiz #42: The Micro-Doppler
Effect in Radar
- RF Cafe Quiz #41: Introduction
to RF Design Using EM Simulators
- RF Cafe Quiz #40: Introduction
to Antenna Analysis Using EM Simulation
- RF Cafe Quiz #39: Emerging
Wireless Technologies and the Future Mobile Internet
- RF Cafe Quiz #38: Klystrons,
Traveling Wave Tubes, Magnetrons, Crossed-Field Amplifiers, and Gyrotrons
- RF Cafe Quiz #37: Component
Reliability for Electronic Systems
- RF Cafe Quiz #36: Advanced
RF MEMS
- RF Cafe Quiz #35: Frequency
Synthesizers: Concept to Product
- RF Cafe Quiz #34: Multi-Gigabit
Microwave and Millimeter-Wave Wireless Communications
- RF Cafe Quiz #33: Battlespace
Technologies: Network-Enabled Information Dominance
- RF Cafe Quiz #32: Modern Communications
Receiver Design and Technology
- RF Cafe Quiz #31: Quantum
Mechanics of Nanostructures
- RF Cafe Quiz #30: OFDMA System
Analysis and Design
- RF Cafe Quiz #29: Cognitive
Radar
- RF Cafe Quiz #28: Human-Centered
Information Fusion
- RF Cafe Quiz #27: Remarkable
Engineers
- RF Cafe Quiz #26: Substrate
Noise Coupling in Analog/RF Circuits
- RF Cafe Quiz #25: Component
Reliability for Electronic Systems
- RF Cafe Quiz #24: Ultra Low
Power Bioelectronics
- RF Cafe Quiz #23: Digital
Communications Basics
- RF Cafe Quiz #22: Remember
the Basics?
- RF Cafe Quiz #21: Wireless
Standards Knowledge
- RF Cafe Quiz #20: Famous First
Names
- RF Cafe Quiz #19: Basic Circuit
Theory
- RF Cafe Quiz #18: Archaic
Scientific Words & Definitions
- RF Cafe Quiz #17: Inventors &
Their Inventions
- RF Cafe Quiz #16: Antennas
- RF Cafe Quiz #15: Numerical
Constants
- RF Cafe Quiz #14: Oscillators
- RF Cafe Quiz #13: General
Knowledge
- RF Cafe Quiz #12: Electronics
Corporations Headquarters
- RF Cafe Quiz #11: Famous Inventors &
Scientists
- RF Cafe Quiz #10: A Sampling
of RF & Wireless Topics
- RF Cafe Quiz #9: A Smorgasbord
of RF Topics
- RF Cafe Quiz #8: Hallmark Decades
in Electronics
- RF Cafe Quiz #7: Radar Fundamentals
- RF Cafe Quiz #6: Wireless Communications
Fundamentals
- RF Cafe Quiz #5: Company Logo
Recognition
- RF Cafe Quiz #4: General RF
Topics
- RF Cafe Quiz #3: General RF/Microwave
Topics
- RF Cafe Quiz #2: General RF
Topics
- RF Cafe Quiz #1: General RF
Knowledge
- Vacuum Tube Quiz,
February 1961 Popular Electronics
- Kool-Keeping Kwiz, June
1970 Popular Electronics
- Find the Brightest
Bulb Quiz, April 1960 Popular Electronics
-
Where Do the Scientists Belong? - Feb 19, 1949 Saturday Evening Post
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-
What's
Your EQ? - January 1962 Radio-Electronics
-
What's
Your EQ? - February 1962 Radio-Electronics
-
What's
Your EQ? - March 1962 Radio-Electronics
-
What's
Your EQ? - July 1961 Radio-Electronics
-
What's
Your EQ? - August 1961 Radio-Electronics
-
Can You
Name These Strange Electronic Effects? - August 1962 Radio-Electronics
-
What's
Your EQ? - September 1961 Radio-Electronics
-
What's
Your EQ? - September 1962 Radio-Electronics
-
What's Your EQ? - October 1961 Radio-Electronics
-
What's Your EQ? - November 1961 Radio-Electronics
-
What's Your EQ? - March 1964 Radio-Electronics
-
What's Your EQ? - April 1962 Radio-Electronics
-
What's Your EQ? - May 1962 Radio-Electronics
-
What's Your EQ? - June 1962 Radio-Electronics
-
What's Your EQ? - April 1967 Radio-Electronics
-
What's Your EQ? - March 1967 Radio-Electronics
-
What's Your EQ? - December 1964 Radio-Electronics
-
What's Your EQ? - January 1967 Radio-Electronics
-
Wanted: 50,000 Engineers - January 1953 Popular Mechanics
-
What's Your EQ? - August 1964 Radio-Electronics
- Voltage Quiz
- December 1961 Popular Electronics
-
What is It? - June 1941 Popular Science
- What Do You Know
About Resistors? - April 1974 Popular Electronics
-
What's Your EQ? - September 1963 Radio-Electronics
- Potentiometer Quiz - September
1962 Popular Electronics
-
Mathematical Bafflers - March 1965 Mechanix Illustrated
- Op Amp Quiz -
October 1968 Popular Electronics
- Electronic "A"
Quiz - April 1968 Popular Electronics
-
What's Your EQ? - May 1961 Radio-Electronics
-
Popular Science Question Bee - February 1939 Popular Science
-
What is It? - A Question Bee in Photographs - June 1941 Popular Science
-
What's Your EQ? - June 1961 Radio-Electronics
-
What's Your EQ? - June 1964 Radio-Electronics
-
What's Your EQ? - May 1964 Radio-Electronics
-
What's Your EQ? - August 1963 Radio-Electronics
-
What's Your EQ? - May 1963 Radio-Electronics
- Bridge
Function Quiz - September 1969 Radio-Electronics
-
What's Your EQ? - March 1963 Radio-Electronics
-
What's Your EQ? - February 1967 Radio-Electronics
-
Circuit Quiz - June 1966 Radio-Electronics
-
What's Your EQ? - June 1966 Radio-Electronics
- Electronics
Mathematics Quiz - June 1969 Popular Electronics
- Brightest
Light Quiz - April 1964 Popular Electronics
-
What's Your EQ? - April 1963 Radio-Electronics
- Electronics "B" Quiz
- July 1969 Popular Electronics
- Ohm's Law Quiz
- March 1969 Popular Electronics
-
Antenna Quiz - November 1962 Electronics World
- Color Code Quiz
- November 1967 Popular Electronics
- CapaciQuiz
- August 1961 Popular Electronics
- Transformer
Winding Quiz - December 1964 Popular Electronics
-
Audiophile Quiz - November 1957 Radio-electronics
- Capacitor
Function Quiz - March 1962 Popular Electronics
- Greek Alphabet
Quiz - December 1963 Popular Electronics
- Circuit
Designer's Name Quiz - July 1968 Popular Electronics
-
Sawtooth Sticklers Quiz - November 1960 Radio-Electronics
-
Elementary
Radio Quiz - December 1947 Radio-Craft
- Hi-Fi
Quiz - October 1955 Radio & Television News
- Electronics Physics
Quiz - March 1974 Popular Electronics
- A Baffling Quiz
- January 1968 Popular Electronics
- Electronics IQ
Quiz - May 1967 Popular Electronics
- Plug and Jack
Quiz - December 1967 Popular Electronics
- Electronic
Switching Quiz - October 1967 Popular Electronics
- Electronic
Angle Quiz - September 1967 Popular Electronics
- International
Electronics Quiz - July 1967 Popular Electronics
- FM Radio
Quiz - April 1950 Radio & Television News
- Bridge Circuit
Quiz -December 1966 Popular Electronics
- Diode Function
Quiz - August 1965 Popular Electronics
- Diagram Quiz,
August 1966 Popular Electronics
- Quist Quiz - November
1953 QST
- TV Trouble Quiz,
July 1966 Popular Electronics
- Electronics History Quiz,
December 1965 Popular Electronics
- Scope-Trace Quiz,
March 1965 Popular Electronics
-
Electronic
Circuit Analogy Quiz, April 1973
-
Test Your Knowledge of Semiconductors, August 1972 Popular Electronics
- Ganged Switching
Quiz, April 1972 Popular Electronics
- Lamp Brightness
Quiz, January 1969 Popular Electronics
- Lissajous
Pattern Quiz, September 1963 Popular Electronics
- Electronic
Quizoo, October 1962 Popular Electronics
- Electronic
Photo Album Quiz, March 1963 Popular Electronics
- Electronic
Alphabet Quiz, May 1963 Popular Electronics
- Quiz: Resistive?
Inductive? or Capacitive?, October 1960 Popular Electronics
- Vector-Circuit
Matching Quiz, June 1970 Popular Electronics
- Inductance
Quiz, September 1961 Popular Electronics
- RC Circuit Quiz,
June 1963 Popular Electronics
- Diode Quiz, July
1961 Popular Electronics
- Electronic
Curves Quiz, February 1963 Popular Electronics
- Electronic
Numbers Quiz, December 1962 Popular Electronics
- Energy Conversion
Quiz, April 1963 Popular Electronics
- Coil Function
Quiz, June 1962 Popular Electronics
-
Co-Inventors Quiz - January 1965 Electronics World
-
"-Tron" Teasers Quiz - October 1963 Electronics World
- Polarity Quiz
- March 1968 Popular Electronics
-
Television
I.Q. Quiz - October 1948 Radio & Television News
- Amplifier Quiz
Part I - February 1964 Popular Electronics
- Semiconductor
Quiz - February 1967 Popular Electronics
- Unknown
Frequency Quiz - September 1965 Popular Electronics
- Electronics
Metals Quiz - October 1964 Popular Electronics
- Electronics
Measurement Quiz - August 1967 Popular Electronics
- Meter-Reading
Quiz, June 1966 Popular Electronics
- Electronic
Geometry Quiz, January 1965 Popular Electronics
- Electronic
Factor Quiz, November 1966 Popular Electronics
- Electronics
Math Quiz, November 1965 Popular Electronics
- Series Circuit
Quiz, May 1966 Popular Electronics
- Electrochemistry
Quiz, March 1966 Popular Electronics
- Biz
Quiz: Test Your Sales Ability - April 1947 Radio News
- Electronic
Analogy Quiz, November 1961 Popular Electronics
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Baffling Quiz Answers
1 - D) An Acoustic Labyrinth is a form of bass-reflex enclosure which uses
a folded rear air column designed to be one-quarter wavelength at the low-frequency
resonant point of the speaker. The resonant column dampens the resonant peak of
the speaker and extends the low-frequency response.
2 - I) An Air Coupler is an air column designed to be one-quarter wavelength
at the speaker's low-frequency resonance point to minimize the resonant peak and
provide improved speaker-to-room (free air) acoustic impedance-matching.
3 - G) The Baffle, box baffle, or Hartley-Turner enclosure, uses a series
of vented, sound-absorbent baffles to absorb back radiation and minimize back loading.
4 - A) A Ducted-Port Phase Inverter is a form of bass-reflex enclosure
in which a duct provides additional acoustic inductance to resonate with the acoustic
capacitance provided by the volume of the enclosure. The reduced acoustic capacitance
requirement permits a more compact cabinet for the same speaker resonant frequency.
5 - F) A Folded Horn offers the advantages of speaker-to-room acoustical
impedance matching in a more compact cabinet than an otherwise impractically large
straight horn design.
6 - B) The Helmholtz Resonator, or R-J enclosure, is a form of bass-reflex
enclosure in which the port, in the form of a narrow, circular slit surrounding
the speaker, supplies additional acoustical resistance for improved low-frequency
damping of the speaker.
7 - E) The Horn-Loaded Reflex enclosure is a form of ducted-port phase
inverter having the increased radiation resistance and higher efficiency provided
by the horn-shaped duct.
8 - C) An Infinite Baffle enclosure is not really infinite in the sense
that all of the front radiation will go forward without refraction, but back-enclosed
cabinets do prevent the back radiation from interfering with the sound radiated
from the front of the speaker and, in that sense, are considered a practical form
of infinite baffle.
9 - H) A Klipschorn enclosure is a folded, exponential horn which uses
the corner of the room as the final flare of the horn mouth, and thereby, in effect,
places the listener within the horn.
10 - J) A Resonant Column is a cross between an infinite baffle and a tuned
pipe coupler that provides the large air volume of an infinite baffle in an enclosure
design which requires less floor space.
Posted September 5, 2019
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