Audio - Actuated Camera Flash Easy Car Tuneup with a Digital Meter

114 Pages·2014·10.33 MB·English

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WORLDS LARGEST SELLING ELECTRONICS MAGAZINE MAY 1982/$1
THE ELECTRONIC WORLD
Microcomputers: Which One Is Right for You?
Experimenting with Fiber Optics
Audio -Actuated Camera
Flash
Easy Car Tuneup with a Digital Meter
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w..:
Tested in this Issue:
Radio Shack TRS-80 Model III Computer
o
Acoustic Research AR48s Speaker
14024 1427b Sylvania 13" Color TV Receiver
4
Make waves with an Apple.
If you'd like to spend more of your research budget on
research and less on computer costs, consider the discoveries
of Dr. John Lilly and the Human/Dolphin Foundation.
Dolphins vocalize at 2,000-40,000 Hz (compared with
300-3,000 Hz for humans) and `converse" 10-15 times faster
than their bipedal brethren.
In 1968, Dr. Lilly's interspecies communication experi-
ments stalled for lack of affordable computer power to bridge
this gap. But today, with the help of Apple Personal Computers
and a DEC® PDP/11, things are going swimmingly.
A new program called JANUS (Joint Analog Numeric
Understanding System) uses a 48K Apple II Plus to generate
dolphin -comprehensible wave forms matched to dolphin-
. Fr
r
--
viewable symbols on an underwater
screen. Dolphin responses are analyzed :
..---- C>
through a PDP/11. A second Apple
-
monitors and eanxalypzese dratiam frome anll t.-
phases of the
The objective is to create an
artificial language that is mutually (
intelligible to both species, with
a beginning vocabu ary of 48 sound/symbol morphemes
associated with objects, locations and actions.
But, with all the micros available, why pick Apples?
Because they're inexpensive enough to allow the use
of a stand-alone computing system for dedicated functions.
Because they're portable and rugged enough for
field use in a wide range of environments.
And because they can be configured for many scientific
applications with no special I/O
APPLE!! APPLE III
Maximum RAM 64K 256K devices. (Apple's IEEE -488 inter-
VO 8 expansion slots 4 expansion slots +
built-in interfaces for face card will program and
disks and printer.
Disk Drives Up to 6 140K Built-in 140K + up to operate virtually any test, meas-
floppies. 3 additional floppies.
Available with ProFile"
urement or control instrument.)
5MB hard disk.
Languages BASIC, Pascal` Enhanced BASIC,
PILOT COBOL, UCSD Pascal" There's more software
Assembly. Assembly.
Keyboard Fixed 96 -character Fully programmable available for Apples than for
ASCII. 128 -character, includes
numeric keypad. any other microcomputer on
the market. And more full service dealers worldwide.
Communicate with one and find out how an Apple
can make waves for you, whatever your, ah ... porpoise.
apple
The personal computer.
The Human/Dolphin Foundation is a non-profit research organization. For more information, write Dr. John Lilly, P.O. Box 4172, Malibu, CA 90265.
For the authorized Apple dealer nearest you, call 18001538-9696. In California, call [phone]. Or write: Apple Computer Inc., 10260 Bandley Dr., Cupertino, CA 95014.
CIRCLE NO. 6 ON FREE INFORMATION CARD
MAY 1982 VOLUME 20, NUMBER 5
n you Popular Electronics
bed
WORLD'S LARGEST -SELLING ELECTRONICS MAGAZINE
RecordingEnglneer The Electronic World
COMPUTERS-WHICH ONE IS FOR YOU?/ Joe Desposito 45
A guide to making a wise computer buying decision.
Feature Articles
CURRENT -LIMITING TECHNIQUES/Mark Pitteikau 62
LEARNING QUIZ FOR ELECTRONICS/Fredrick W. Hughes 86
Construction Article.--,
DIGITAL AUTOMOTIVE TUNE-UP METER/C.R. Ball 37
Measures dwell angle, engine rpm and voltage.
EXPERIMENTING WITH FIBER OPTICS/ TJ Byers 63
SOUND -ACTIVATED PHOTO FLASH/Niel Ulevich 69
Simple circuit freezes the action in milliseconds.
HOW TO SWEETEN THE SOUND OF YOUR PHONO CARTRIDGE/Martin Nagel 70
Provides switching capability, precision performance and extremely low noise.
TEACH YOUR DIGITAL CLOCK TO CONTROL APPLIANCES/Robert Colwell 73
Turn a standard clock module into a versatile control center.
Equipment Reviews
ACOUSTIC RESEARCH AR48s THREE-WAY SPEAKER SYSTEM 20
SYLVANIA 13" COLOR TV RECEIVER 23
RADIO SHACK TRS-80 MODEL III DESKTOP COMPUTER 31
KROHN-HITE MODEL 4400 ULTRA -LOW DISTORTION OSCILLATOR 81
learn via
Columns
-
Audio Fundamentals 'Labs ENTERTAINMENT ELECTRONICS/Len Feldman 16
Listening Locations Equalized Digitally.
Control Room & Console Labs
COMPUTER BITS/Carl Warren 34
Studio -Synthesizer Lab Latest Micros Offer Power and Graphics.
° -
Digital Logic Lab COMPUTER SOURCES/Leslie Solomon 83
HOBBY SCENE/Joe Desposito 88
Disc Cutting Lab
SOLID-STATE DEVELOPMENTS/Forrest M. Mims 89
Obtain your Diploma in The Rainbow LED.
Multi -track Recording Technology DX LISTENING/Glenn Hauser 92
in one year, or Taiwan Gets American Relay Station.
B.S. Degreein Music Technology EXPERIMENTER'S CORNER/Forrest M. Mims 98
in four years Experimenting with Low -Power Integrated Circuits.
via the Institute of Audio Research- PROJECT OF THE MONTH/Forrest M. Mims 108
Dual- Polarity Five -Volt Power Supply.
New York University joint program,
Departments
Summer '82 Quarter starts
Tuesday, July 6th. .° EDITORIAL/Art Salsberg 6
=
The Two -Way Editorial Street.
Fall '82 Quarter starts
Thursddy; September BOth..' LETTERS 8
NEW PRODUCTS 10
Co(I or writélor 24-pg. illustrated brochure OPERATION ASSIST 101
-212/677-7580
, or NEW LITERATURE 103
1-800/847-4187 ADVERTISER'S INDEX 104
, (Toll -free outside of N.Y. State) ELECTRONICS LIBRARY 107
PERSONAL ELECTRONICS NEWS 1 22
nstitute
COVER PHOTO BY AARON KILEY
of Audio, GRAPHICS BY JACK WARD COLOR SERVICES, INC
r ° COPYRIGHT 1982 BY ZIFF-DAVIS PUBLISHING COMPANY. All rights reserved. Popular Electronics (ISSN 0032-4485) May
Research
1982, Volume 20, Number 5. Published monthly by Zit -Davie Publishing Co., at One Perk Ave., New York, NY 10018. Richard P.
64 University Place' Friese, President; Selwyn Teubmen, Treasurer. Bertram A. Abrams. Secretary. One year subscription rete lot U.S. end Posses-
Greenwich Village sions, 515.00; Canada, 520.00; all other countries. 523.00 (cash orders only, payable in U.S. currency). Second Class Postage
- ' Efla1o9li6s9h ed N(2e1w2 )Y o6r7k,7 -N7.Y5.8 100 003 PCInaadindea xadetad N, iena nwtdh Yefoo rrR kp,e aaNyd.meYre.' sn1 t0 Go0uf1 i8dp eoa stnotda gaPete arIindo ddciiatcisoahnl .a LPli tmOerPaaiUltiunLrgAe R.o ZfEfiiLctEe -DCs,Ta vRAiOsu tNhaIolCsroSiz eipnduc balulsids ihsneegcs o EnBLdoE aCctlTianRsgsO, NCmIaCardS a bnWyd O thRDeLr iDPve,o rTs. rtC aOdyecffl iecM.e aFDrlkye iRpntge..,g OiPsttoteaprwueldaa..r
Photography, Skiing, Stereo Review. Electronic Experimenter's Handbook, and Tape Recording 8 Buying Guide. Forms 3570 and
Licensed by N.Y. State Dept. ot'Edúcation all Subscription Correspondence: POPULAR ELECTRONICS. Circulation Dept. P.O. Box 2774, Boulder, CO 80302. Please allow
Approved for Veterans Training at least eight weeks for change of address, enclosing, it possible, an address label tom a recent issue. Permissions. Material in
this publication may not be reproduced m any form without permission. Requests for permission should be directed to John
CIRCLE NO. 23 ON FREE INFORMATION CARD Babcock. Rights and Permissions, Ziff -Davis Publishing Co., One Park Ave., New York, NY 10018.
2
POPULAR ELECTRONICS
'897 N.V. Grant Ave. Corvallis, OrEgon 97330 503/758-0521
DAWN.
THE
Introducing the Enhancer l[: a new
FA
Standard which is improving the NEW ERA
relationship between Humans and
Apples. The Enhancer ][ can help
your Apple ]['s keyboard become FOR APPLE H:
more sociable by remembering
words or phrases which can be
entered into the Apple by the mere THE
touch of a key. Life can become
even easier because the Enhancer ][
can remember what you typed ENHANCER H
while your Apple was busy talking
to your disc (or doing other things).
Naturally, it knows the difference w
.
between upper and lower case a`
I
letters and what shift keys are 4 N1,U!_!
0
supposed to do. It even knows to
auto repeat any key held down. The
Enhancer replaces the encoder
lE
board making installation simple.
Suggested retail price: $149.00.
r
VIDEOTERM SOFT VIDEO KEYBOARD AND ACCESSORIES:
SWITCH DISPLAY ENHANCER Videoterm Utilities Disc $37.00
The Soft (includes)
Font Editor
Video
Pascal Mid -Res Graphics
Switch is
Applesoft Read Screen Utility
an auto-
' matic ver- Top & Bottom Scrolling
Pascal Vidpatch.
sion of the
Graphics Template
popular
Tcohleu mtimn ec taersdt ed Videoterm 80 Splwatietc. hI -t The original Keyboard and Display CharHaacltfe rI nSteent sEitPyR OMs $29.00 ea
80 characters x 24 lines knows Enhancer is still available for Revi- Inverse
True decen7ers whether it should disp ay 40 or 80 sion 0-6 Apples (on which the new German
7 x 9 character resolution columns or Apple graphics. It does Enhancer II will not fit). These Katakana (Japanese)
LCoowm ppoawtibelre c woinths ummopsttio wno rd tohuet tseigdnioaulss s wo oyroku o df osnw'tt chhavneg t ov.i dTehoe - Aatp pchleips hloacvaet imonesm oDr1y , sEe1le c&t sFo1c. kTehtse L(Einxep aDnrdaewdi)n g Graphics
processors Soft Video Switch canoe controlled Keyboard and Display Enhancer Spanish
Softcard and CP/M compatible by software. Any Videotºrm with allows entry and display of upper & French
Modem compatible Firmware 2.0 or greater may be lower case letters with fully func- Math & Greek Symbols
Most popular character set of used with the Soft V deo Switch. tional shift keys. It does NOT have Super & Subscript
aAnltye r8n0a tceo lcuhmanra ccaterdr fonts available Tpohret esdin. gPlea cwkiareg es phriifcte m isc d$ 3it5 a.0ls0o. sup- ubsueffre rd.e fTinhaeb pler ikceey iss n$o1r2 a9 t.y0p0e. ahead D(Evnohraakn cEePr)R OM $29.00
Suggested retail price $345.00 Lower Case Chip $29.00
CIRCLE 64 Apple and Apple II are registered trademarks of Apple Computer Inc.
couter.
Th& personal
4995
Introducing
the Sinclair ZX81
If you're ever going to buy If you already own a ZX80
a personal computer, now is the The 8K Extended BASIC
time to do it. chip used in the ZX81 is available
The new Sinclair ZX81 is the as a plug-in replacement for your
most powerful, yet easy -to -use ZX80 for only $39.95, plus shipping
computer ever offered for anywhere and handling-complete with new key-
near the price: only $149.95' completely board overlay and the ZX81 manual.
assembled. So in just a few minutes, with no
Don't let the price fool you. The special skills or tools required, you can
ZcoXu81ld haassk jufosrAt ainbb raoe uaptke etrhsvroeonruyagtlh hcino gm pyuoute r. accMuarathtee mtoa t8ic dael cainmda ls pcileancetifsic functions uphapovgwerea erdfvueel yrfyeotauhtriun ZrgeX se8 x0oc f teotph het a cZvoXen8 t1ain.ll u (toYhueos u 'lld is-
the origTinhIaen l ZpSXei8nrs1co laisni raa lZ mcXoa8mjo0pr- tuahtdeevr aswn ocreld 'osv er IlSik eAU uPntRioqImNueTa ,t oiRcnU esN -yt noatunacdxh e LerISrnoTtrr y d oeft ekcetyio wn oarndds palnady , SbCuRt yOoLuL ccaonm smtilal nudsse tthoe g ePtA mUSoEv ing
graphics.)
largest selling personal computer and easy editing
the first for under $200. Randomize function useful for both With the 8K BASIC chip, your
In fact, the ZX81's new 8K Extended games and serious applications ZZXX 8P0r inwtiell ra alsnod bSei necqlauiirp spoefdtw taor eu.s e the
BASIC offers features found only on com- Built-in interface for ZX Printer
puters costing two or three times as much. 1K of memory expandable to 16K Warranty and Service Program"
Just look at what you get: The ZX81 is also very convenient The Sinclair ZX81 is covered by a
Continuous display, including moving to use. It hooks up to any television set 10 -day money -back guarantee and a
graphics to produce a clear 32 -column by 24 -line limited 90 -day warranty that includes free
Multi -dimensional string and numerical display. And you can use a regular parts and labor through our national
arrays cassette recorder to store and recall service -by -mail facilities.
Plus shipping and handling. Price includes Connectors ipr ograms by name. "Does not apply to /X81 kits
for TV and cassette, AC adaptor, and FREE manual.
r
"= y;;`;tis.'.,.w
.
¡........
'
.4ó.i
I
NEW SOFTWARE:Sinclair has ZX PRINTER: The Sinclair ZX 16K MEMORY MODULE: ZX81 MANUAL: The ZX81
published pre-recorded pro- Printer will work with your ZX81, Like any powerful, full fledged comes with a comprehensive
grams on cassettes for your or ZX80 with 8K BASIC. It will computer, the ZX81 is expand- 164 -page programming guide
ZX81, or ZX80 with 8K BASIC. be available in the near future able. Sinclair's 16K memory and operating manual de-
We're constantly coming out and will cost less than S100. module plugs right onto the signed for both beginners and
with new programs, so we'll back of your ZX81 (or ZX80, experienced computer users.
send you our latest software with or without 8K BASIC). A $10.95 value, it's yours free
catalog with your computer. Cost is $99.95, plus shipping with the ZX81.
and handling.
T9995 comp
personal
ter.
Introducing
the ZX81 kit
If you really want to
save money, and you enjoy
building electronic kits, you
can order the ZX81 in kit form
for the incredible price of just
$99.95' It's the same, full -featured
computer, only you put it together ,
yourself. We'll send complete, easy -
to -follow instructions on how you can
assemble your ZX81 in just a few hours.
All you have to supply is the soldering iron.
How to order
Sinclair Research is the world's larg- Tf.
est manufacturer of personal computers.
The ZX81 represents the latest ,
technology in microelectronics, and it
picks up right where the ZX80 left off. /4'
Thousands are selling every week.
We urge you to place your order
for the new ZX81 today. The sooner you yM
order, the sooner you can start enjoying
.
your own computer.
To order, simply call our toll free ,
number, and use your MasterCard or VISA.
To order by mail, please use the
oupon. And send your check or money AD CODE \05PE PRICEf CITY. AMOUNT
order. We regret that we cannot accept
ZX81 $149.95
purchase orders or C.O.D's.
ZX81 Kit 99.95
CALL 800-543-3000. Ask for op-
erator #509. In Ohio call 800-582-1364. 8K BASIC chip (for ZX80) 39.95
In Canada call 513-729-4300. Ask for 16K Memory Module (for ZX81 or ZX80) 99.95
operator #509. Phones open 24 hours
Shipping and Handling 4.95 $4.95
a day, 7 days a week. Have your Master- +
Card or VISA ready. To ship outside USA add $10.00
These numbers are for orders TOTAL
only. For information, you must write to
Sinclair Research Ltd., One Sinclair Plaza, MAIL TO: Sinclair Research Ltd., One Sinclair Plaza, Nashua, NH 03061.
Nashua, NH 03061.
NAME
ADDRESS
CITY/STATE/ZIP
- U.S. Dollars
O"k
E7
The Two -Way Editorial Street
Editing is a two-way street. We try our best same time. It's best to send a letter with a in the dark. Should a word-processing sys-
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Popular Electronics Editorial and Executive Offices Ziff- Davis Publishing Company
ONenew PYaorkr k,A Nveenwu eY ork 10016 Richard P. Friese President
JOE MEsICS 212 725-3500 Albert S. Traína President, Consumer
Publisher
Magazine Division
ARTENdUitRo rPia.l Director Publisher Furman Hebb Executive Vice President
Joe E. Mesics Phillip T. Heffernan Senior Vice Presidents
212 725-3568
DONALD MENNIE Sidne'y Holtz
LTEEeSxcLehIcnEuic tSaivlO eD LEiOrdeMictotOorNr NAdewve Yrtoisrikn gO Mfficaen ager: EPdhwiliapr dS inDe. Muhlfeld
JOHN R. RIGGS Richard Govatski(725-7460) Robert Bavier Vice Presidents
Managing Editor Sales: Baird Davis
EDWAARrtD D I.t rUecXtoBr AUM TKoemn LBipakllao u( 7(72255-3-3558708) ) George Morrissey
Selwyn Taubman Treasurer
JOSTEePcHhn DicEaSl EPdOitSoIrT O SMuiidtew e1s4t0e0rn, O18f0fi cNe. Michigan Ave., Bertram A. Abrams Secretary
DAFVeaIDtu rNes. WEdEitBoEr R SCahleicsa: gToe, dI LW 6e0lc6h0 1 (312 346-2600) I PEadrkit oArviae.l , coNrerews pYoonrdke,n cNeY: P1O00P1U6.L AERdi toErLiaEl CcToRntOribNuICtioSn,s
ANDRE DUZANT must be accompanied by return postage and will be handled
Technical Illustrator Western Representative with reasonable care: however, publisher assumes no re-
Norman S. Schindler & Associates, Inc. sponsibility for return or safety of manuscripts, art work, or
ProductionR OEBdiLtoErS 7050 Owensmouth Ave., #209 models submitted.
Canoga Park, CA 91303 (213 999-1414)
EJdEiFtoFr iaNlE AWssMisAtaNn t Sales: Norm Schindler, Jo Ann O'l lara whTichhe wpuillb lbiseh veiro lhaatse dn ob ky ntohwe lemdagkei nogf aonr y upsrinogp roief taarnyy riitgemhtss
Contributing Editors: Representation In Japan disclosed in this issue.
Waiter Buchsbaum, J. S. Yagi
Lan Feldman, Glenn H , Julian Hirsch, Iwai Trading Co., Ltd. MPA
Forrest Mime, Stan Prenttas, Oari Warren 603 Ginza Sky Heights Bldg. 4i1tf
MARIE MAESTRI 18-13, Ginza 7-Chome Member Audit Bureau
Executive Assistant Tokyo, Japan 104 or Cvcutat,o e
6 POPULAR ELECTRONICS
TEK2200 SERIES THE PERFORMANCE/
DUAL TRACE OSCILLOSCOPES PRICE STANDARD
1PJ(tronix 22 13 e°w,°auacve
8 8
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maw
e r i
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IS MI la
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Thictronix 2213
Introducing a direct line
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built for your bench!
From the world's most lesser -name scopes. 2 mV div to 10 mV/div). ance, positive attachment,
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loscopes: a new scope, sign includes 65% fewer from 0.5 s to 50 ns (to 5 probe tip.
plus a new direct order mechanical parts, fewer ns/div with X10 mag). The price: Just $1100
number, that finally circuit boards, electrical Sensitivity: Scale factors complete*. Order direct
makes it practical to put connectors and cabling. from 100 V div (10X probe) from Tektronix National
Tektronix quality on your Result: a lower price for you to 2 mV/div (1X probe). Ac- Marketing Center. Phones
bench ... at work or home. plus far greater reliability. curate to ± 3%. Ac or dc are staffed by technical
Among professional en- Yet performance is pure coupling. people to answer your
gineers and technicians Tektronix: there's 60 MHz Delayed sweep meas- questions about the 2213.
there is no substitute for the bandwidth for digital and urements: Standard Your direct order includes a
performance and reliability high-speed analog circuits. sweep, intensified after 15 -day return policy and full
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of Tektronix oscilloscopes. The sensitivity for low signal delay, and delayed.
Now, for the first time, measurements. The sweep (Need dual time- base Now it's easier than
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vanced scope at an un- A complete trigger system accuracy to ± 1.5%? Ask a Tek scopel
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The scope: the 2213. 2213 PERFORMANCE normal, vertical mode, and (In Oregon, Alaska and
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(x)MA1R TEO TO Ex(ZLLENCE
Copyright©1982 Tektronix, Inc All rights reserved 121
WHY K40
BECAME THE
LARG EST
SELLING
CB ANTENNA
LETTERS
IN JUST
ONE YEAR!
Wrong Wow and Flutter when bass keys aren't struck, their
Soetade In the review of the Realistic SCT-32 strings resonate, adding to richness of
cassette deck, the figure given for wow sound.)
and flutter should have been 0.06% not This is not to imply that my speakers
0.6%.-M. Winston, Radio Shack. Ft. now equal a pair three times as large
Worth, TX. with twice as many drivers, costing ten
times as much. But distortion becomes
noticeable only at sound levels far louder
OFFERS A
Bass Boost and Distortion than what I would care to listen to.
Speaker design is very much a series
MONEY BACK Re "Electronic Bass Boost for Woof- of compromises, of trade-offs between
ers" (November 1981), distortion is pro- different parameters. Bass equalization
portional to how far the diaphragm is certainly worthy of consideration for
WOUBLE GUARANTEL moves. Including greater motion by high-fidelity applications where healthy
"equalizing" or whatever other means bass response is desired from reason-
TRANSMITS must inevitably create an increase in able -size speakers-even though the
modulation distortion.
FARTHER Harmonic distortion in loudspeakers, pisr icneo t isn eac egsrseaartye rt op oawcceer prt eqhiugihre mleveenlst. oItf
RECEIVES even up to several percent, may be distortion as a trade-off.-Richard
ignored because the frequencies gener- Kaufman, New York, NY.
CLEARER ated are harmonically related to the
input frequencies. But modulation dis-
tortion, even in amounts of a fraction of CP/M Users Address
...THAN ANY ANTENNA a percent, causes objectionable effects.
IT REPLACES! anCd eertvaeinn trheev ieewxiss tednecney othf em aoduudliabtiiloitny addInre stsh e fJoar nuthaer y C1P98/M2 issUusee r(sp 3G0r)o uthpe,
dmisotdourtliaotnio,n adltishtoourtgiohn baonthd afrmeqpulietundcye -- fCroPm/M w uhsiec ha reC aovmapiluatbeler , Lshaonugluda gbee s1 6f5o1r
modulation distortion have been mea- Third Ave., New York, NY 10028.-
sured and demonstrated to be audibly Stan Veit, New York, NY.
perceived. For those who are deaf to dis-
tortion, bass boost is the way to go.-
Paul W. Klipsch, Klipsch and Asso- Tax Tips
ciates, Hope, AK.
Your editorial "The IRS Cometh"
Author's reply: Distortion is only in-
directly related to diaphragm excursion. (December 1981) is well -taken. I hope
A driver's range of linear (undistorted) your readers will see it and heed its
bmyo tviooinc em caoyi l beo vleimrhiatendg , bay nidts bsyu stpheen snioonn ,- amdvoincee yb.e- cWa.u sRe. iHt acman, Jsra.,v eM tihlteomn , sWomVe.
linearity of air under compression in the
speaker enclosure. Larger drivers do not
automatically guarantee lower distor- Making PC Boards
tion. Small drivers will often exhibit less In building projects from your maga-
transient, harmonic, and intermodula- zine, I have developed a process for
tion distortion than larger drivers that making pc boards that, I think, is simple
have less cone motion due to imperfect and does not require any special photo-
piston motion of larger diaphragms. In- graphic equipment. First, make a copy
termodulation is normally present in of the foil pattern on a photo -copying
music, but can be aggravated by cone machine. Use a machine that produces
breakup in larger diaphragms. clean white areas and a solid black
S 1 Equalization does not necessarily in- trace. Second, make a negative on high -
crease cone motion at a given cutoff fre- contrast film by direct -contact printing.
quency (for drivers of the same size) The exposure is made with the photoco-
AN AMERICAN MADE PRODUCT where one driver is equalized and the py face down against the emulsion on
FROM AN AMERICAN COMPANY. other is not. It can be demonstrated that the film. Experiment with exposure
Call your local CB Dealer equalization masks some forms of dis- times to get the best contrast. Finally,
tortion. Any modulation distortion pro- make the pc board from the negative,
duced by bass boost is present only dur- using negative photo -sensitive resist. To
ing the presence of deep bass in program improve this process even more, it would
For a FREE demo! material. My listening tests have shown be helpful if you printed the patterns
this condition to be preferable to a lack with nothing on the reverse side so the
AMER [CAN ANTENNA of bass reproduction. For example, the photocopy step could be omitted and the
© Copyright 1979 American Antenna Elgin, Illinois lyoowuers st penaoktee rso nc aan 'tp riaenporo disu c2e7 .t5h atH zn.o teI,f nthergoautgivhe mthaed e bpya gdeir.e-cKt e-cnorpicy k priCnthining,
pianos just won't sound real. (Even Hamilton, Ontario, Canada.
CIRCLE NO. 3 ON FREE INFORMATION CARD
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