ALTEC. the bass reflex enclosure

1 2 the bass reflex enclosure The loudspeaker enclosure is an important part of your home music system and should be given as much consideration as an...

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the bass reflex enclosure

The loudspeaker enclosure is an important part of your home music system and should be given as much consideration as any other part of your system. In the last few years many different types of enclosures have become available. Few of these represent anything new in the art of enclosure design. The majority are various forms of the folded horn type enclosure and have achieved considerable popularity because of their excellent bass response. However, this good bass response is usually accomplished at the expense of reproduction in the mid-range. Folded horns were used in theatrical speaker systems for many years but were obsoleted and discarded in favor of speaker systems using a combination of a straight horn and the bass reflex principle. S

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Altec Lansing has made detailed and exhaustive measurements in its acoustic laboratory on all types of enclosures, and these measurements disclose that no type can equal a carefully designed enclosure using the bass reflex principle for smoothness in frequency response and over-all listening fidelity. The reason for this is the freedom from phasing difficulties in the bass reflex enclosure as compared to other types.

\ \ 1 II I All Altec Lansing loudspeaker enclosures are designed around the bass reflex principle and have been carefully engineered to take the fullest advantage of the potentials of your Altec Lansing loudspeaker.






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A - 3 AO A power amplifier

A-440A control preamplifier

The A-MOA is designed for your home. Willi the door shut it is simple and will blend perfectly with your furnishings. Open there are controls to satisfy the most particular. 25 crossover selections make it possible to choose the correct recording characteristic for every record. Five inputs are provided, three high level for ceramic or crystal phonos, tape machines, tuner or television and two low level inputs for micro­ phones or equalized for magnetic phono cartridges. A special circuit permits monitoring from the tape playback head while recording. Full range tone controls and selection ol either loudness or volume complete the facility.

An audio engineer's dream, the A-340A uses premium power tubes of 100 watt capacity rated at a conservative 35 watts in a simple class A l circuit for long-lived performance stability.


input sensitivity:'

1.3 volts RMS lor 35 watts output.

input impedance:'

200.000 ohms.

inputs: outputs'. gain at 1 he lone controls flat low level, equalized (phono): low level, Hat ( m i c ) : high level (tv, tapo, radio): frequency response: noise level: controls:

power supply: lube complement: dimensions: finish: shipping weight: Hi Ice:

Thrt":.- Inqh level, Iwo low !• ."I t.-quahzfij or Two—one main arnplificr. out; recorder.

specifications output power and distortion:*

35 watts, loss than 0.5% tola! harmonic distortion.


66.5 db.

Irequency response:*

Within I db. 5 c.p.s. to 100.000 c.p.s.

noise level:*

95 db below full output.

GO db 63.5 db

load impedance:

8. 16 Ohms.

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output impedance:

Adjustable from —4 to + 4 . 5 ohms on 8 ohm tap. Less than .52 ohms on 16 ohm tap.

damping factor:

Greater than 35 on 16 ohm lap. +1.8 through inlinity to - 2 . 0 on 8 ohm tap.


Gain Adjustment. RQ Adjustment.

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High level inputs—volume max.. belter than 95 db, iI , l . • ii.ri.i.l. i ' l ' i ' i : I'liut. • ln-',;>-i It,in llt>. S ' " ' n ; Switch lot choice o l inputs and low Irequency crossover. H.f. equalization switch. Total combinations. 25. Phono selector switch. Volume—loudness conlrol with power switch. Volume— loudness-tape monitor switch. Bass and Ireble controls. Five independent level controls on bach. Seif-conlamed. Three AC receptacles conlrolip* by On-OH switch. 117V.. 60 cycles. Two-l2AY7, One-l2AU7. -

4-3/4" H. x 6-7 A3 D. x 14-3/8" W . M-il Q.] II V •:( 1' .jrnl, 15 pounds.

power supply:

117V.. 60 cycles.


O n o - 1 2 A Y 7 . O n e - 1 2 A U 7 . Two-6550. O n e - 5 U 4 G B . One-OA3/VR75.

shipping weight:

30 pounds.



$139.00 {Available without furniture cabinet lor custom installation. $126.00)

•Normal setting of R<; control.

A440A preamplifier— range at base and treble tone controls

The A-440A preamplifier and A-340A amplifier represent the highest development of the electronic engineer's art. They are exceptional in performance, operation and their amazing flexibility of control. Through the use of the most expensive professional components it has been possible t o provide simple circuitry that will continue to meet Altec's stringent specifications for years. Only Altec home music systems have this hidden value of professional quality.

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A440A preamplifier—phono equalizer curves


A340A ampliliei

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relative frequency — '.ponsc


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harmonic distortion vs. frequency


Here is a 10 watt amplifier and control preamplifier in one compact furniture unit for smaller systems, apartments and dormitories. Its circuitry and performance fully represent the professional audio quality that is the criterion of all Altec products. The use of the finest components is your assurance of years of perfect listening pleasure. Its controls are simple yet sufficiently comprehensive to assure proper listening quality from all types of records. There is a choice of four recording curves, facilities for microphone, and two inputs for tape or radio tuner. Fully variable tone controls provide a wide range of selection for individual taste.

loudness control characteristics

frequency -in cycles per second

range of bass and treble controls

frequency—in cycles per second

record crossovers

specifications dimensions: finish: frequency range: power output: output impedance: system gain: power requirements: inputs: equalization: tone control: volume control: loudness control:

facilities: shipping weight: price:

13" wide, 4-7/8" high, 9-3/4" deep. Mahogany or blond. 20-22,000 cycles. 10 watts. Less than 2% total harmonic distortion under critical measurement. 4, 8 or 16 ohms. 132 db maximum. 75 watts, 110V. 60 cycles. 1 low level for magnetic phono pickup or microphone. 2 high level for ceramic or crystal phone pickup, tape reproducer, radio tuner or tv audio. 4 compensation curves: European, LP, new AES (NARTB, RIAA, RCA, orthophonic), old RCA. Treble, 15 db boost, or droop at 10,000 cycles. Bass, 13 db boost or droop at 50 cycles. Individual volume adjustments for all three inputs. Compensated loudness control, flat at maximum posi­ tion, approaches Fletcher-Munson curves at lower settings. 2 110V, 60 cycle outlets controlled by amplifier power switch. 17 pounds. $129.00

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frequency — in cycles per second

For inexpensive high fidelity with the utmost simplicity this beautiful reproducer matched with any of the Altec speaker systems is truly a dream come true. The 901A contains a world renowned Collaro three speed record changer, a G.E. variable reluctance cartridge with separate sapphire needles for 78 and 33-1 /3 or 45 rpm records, and the superb quality of the Altec A-339A Melodist amplifier and control preamplifier. You'll enjoy the quality and simplicity of this system, either for yourself or as the perfect gift.




2 0 - 3 / 8 ' W ; 15-3/4'D: 11-1JT H.


Mahogany or blond.

frequency range:

20-22.000 cycles.

power output:

10 wails. Less than 2% lota! harmonic distor­ tion under critical measurement.

output impedance:

4. 8 or 16 ohms.

system gain:

132 db maximum.

power requirements:

75 watts. 110V. 60 cycles.


1 low level tor magnetic phono pic*up cr microphone. 2 high level for ceramic or crystal phone pickup, tape reproducer, radio tuner or tv audio.


4 compensation curves: European. LP, new AES (NARTB. RIAA. RCA. orthophonies Old RCA.

tone control:

Treble. 15 Ob boost or droop at 10.000 cycles. Bass. 13 db boost or droop at 50 cycles.

volume control:

Individual volume adjustments for all Three inpuls.

loudness control:

Compensated loudness control, Mat at maxi­ mum position, approaches Fletcher-Munson curves at lower settings.


2 110V, 60 cycle outlets controlled by amplifier power switch.

shipping wolght:

55 pounds.


$225.00 (without legs. The t6' modern iron logs arc available as an accessory for $4.05

820C speaker system


826A iconic speaker system

Ask any audio engineer, he will confirm that the 820C is the finest speaker system in existence, for the home, regardless of price. Its smooth frequency response is guaranteed from 30 to 22,000 cycles, is without false bass or other misleading frequency accentuations. Internally the 820C consists of two 15" 803A low frequency speakers in an exclusive direct radiating exponential horn using a modified bass reflex principle with the additional advantages of a corner en­ closure. From 800 cycles to 22,000 cycles tones are repro­ duced by the 802C driver speaker mounted on the H-811B horn. Individual specifications on these units will be found elsewhere in this book. Truly the 820C is the finest speaker system for your Altec home music system.

This wonderful new speaker system in­ corporates one 15" 803A low frequency speaker, an N-800D dividing network and an 802C high frequency driver mounted on the H-811B horn. These professional components combined with the acous­ tically engineered bass reflex enclosure provide exceptional performance. The low chairside cabinet is an outstanding exampleof the cabinetmaker's art, reflect­ ing the finest taste in furniture design. Guaranteed frequency range, 35 to 22,000 cycles.

p r i c e : $525.00

p r i c e : $324.00

Altec "Voice of the Theatre" loudspeaker systems are used in more than 12,000 motion picture theatres throughout the world. Because of their superior quality they are used by all major motion picture studios as a performance standard for reproduction. This same engineering excellence is reflected in the design and construction of these Altec speaker systems for the home. They represent the finest product of years of development and research in one of the world's finest acoustical laboratories. From the massive 820C to the compact 700 each of these systems is the finest available.



700A melodist speaker syster

824A iconic speaker system

v o i c e of t h e t h e a t r e

The A-7 which uses one 15" 803A, an N-800D network and an 802C on the H-811B horn is the smallest of Altec's famous theatrical sound systems, The industrial finish en­ c l o s u r e uses A l t e c ' s exclusive direct radiating exponential horn combined with a modified bass rellex principle for smooth realistic bass. This system is of particular interest to those who wish to achieve the perfection of an Altec engi­ neered system in a custom installa­ tion. Guaranteed frequency range, 35 to 22,000 cycles. p r i c e : $260.00

This little iconic system utilizing the Altec developed phase com­ puted reflex enclosure provides e x c e p t i o n a l p e r f o r m a n c e for smaller installations. Using the n e w 412A 12" s p e a k e r , t h e N-3000A network and the famous 3000A high frequency speaker, this amazing system is guaran­ teed to have a range from 50 to 22,000 cycles.

The smallest of Altec's engineered speaker systems, the 700A uses a special 10" speaker coupled with the N-3000B network and the 3000A high frequency speaker to obtain amazing performance. With i t s phase computed reflex enclosure it has a guaranteed range from 70 to 22,000 cycles and is ideal for use in apartments, as a second speaker system in large installations or as an exceptional part of an econom­ ical Altec home music system.

p r i c e : $180.00

p r i c e : $99.00



Dimensions D

Power Rating




30 watts

16 ohms

Mahogany Blond




230 pounds


25 watts

16 ohms

Mahogany Blond




164 pounds


25 watts

16 ohms





180 pounds

824 A

20 watts

8 ohms

Mahogany Blond




55 pounds


20 watts

8 ohms

Mahogany Blond




30 pounds




" bif lex " speakers T h e s e A l t e c B I F L E X s p e a k e r s are t h e latest d e v e l o p m e n t f r o m A l t e c ' s f a m o u s a c o u s t i c l a b o r a t o r i e s . T h e y a r e c o m p l e t e l y n e w in d e s i g n c o n c e p t a n d e f f i c i e n t l y r e p r o d u c e a s m o o t h f r e q u e n c y r a n g e t h a t has never b e f o r e b e e n a c h i e v e d in a n y s i n g l e c o n e l o u d s p e a k e r . T h e d e v e l o p m e n t a n d use of m u l t i p l e c o n c e n t r i c c o m p l i a n c e s in t h e s e ' s p e a k e r s i s but a n o t h e r e x a m p l e of A l t e c ' s e n g i n e e r i n g l e a d e r s h i p . Like all A l t e c s p e a k e r s the n e w B I F L E X u n i t s have f r e q u e n c y r a n g e s g u a r a n t e e d by A l t e c L a n s i n g C o r p o r a t i o n .

4 0 8 A


The ideal speaker for smaller critical uses where the benefits of a larger unit are prohibited by space, weight or other factors. T h i s economical new unit is truly amazing. T h r o u g h the use of a large magnet and a carefully designed magnetic structure this speaker achieves an efficiency that is o u t s t a n d ­ ing for such a small unit. Using the newly developed BIFLEX principle this compact 408A speaker has a guaran­ teed frequency range from 60 to 13,000 cycles.

T h i s new 12" speaker, employing the multiple concentric c o m p l i ­ ances, is truly outstanding in effi­ ciency, quality ot reproduction, smoothness and breadth of fre­ quency response. It is guaran­ teed by Altec to have a range of at least 40 to 13,000 cycles when mounted In a proper enclosure. For d e s i g n , p e r f o r m a n c e and craftsmanship the 412A BIFLEX is a speaker that will please the most critical.

price: $24.00

p r i c e : $45.00

The quality of a loudspeaker is determined by its frequency response, its efficiency and its lack of distortion... by its ability to reproduce accurately in sounds 'he electrical energy presented to it by the amplifier Altec Lansing speakers are unsurpassed. Years of experience in the field and research in one of the most comprehensive private acoustical laboratories in the world combine with the highest standards of precision engineering and craftsmanship to make Altec Lansing speakers the very finest procurable.

"duplex"® s p e a k e r s A l t e c " D u p l e x " speakers are mechanically a n d electrically independent high a n d low frequency loudspeakers mounted within the physical size of a single f r a m e . T h e y are, without exception, the finest speakers in the w o r l d . Every " D u p l e x " speaker carries the unconditional quality guarantee that it will reproduce smoothly and efficiently t h e entire frequency range from 30 cycles to 22,000 cycles per second w h e n mounted in a proper cabinet. No other speaker or combination of speakers carries such a guarantee.

I 601A 12 This speaker combines in one superlative unit an efficient 12' low frequency speaker with the 3000A high frequency driver unit and horn and a 3000 cycle cross­ over network. Unconditionally guaranteed frequency response: 30 cycles —22,000 cycles.

A companion piece to the 601A and identical in every way with the exception that it is mounted on a 15" frame and uses a 15" cone with a larger low frequency magnet for more efficient repro­ duction of very low frequency bass.

price: $99.00 including network

price: $114.00 including network

e 604C is the newest model o l the us professional type A l t e c 604 " D u p l e x " ker which has long been the quality ndard of the audio industry. A n i m ed 15' cone and newly designed exnsntial multicellular horn and 1600 cycle ork make it possible for the 604C u p l e x " to n o w have a guaranteed freency response from 30 cycles to 22,000 les. Further d e s i g n improvements able this speaker t o handle 50 watts peak power without d i s t o r t i o n . T h i s peaker has no peer for high quality music and mc

specifications Power


Magnet Weight


15 watts

8 ohms

.65 lb.


20 watts

8 ohms


415 A

25 watts

8 ohms

Voice Coil Max. Cone Diam. Resonance




Dimensions Diam. Depth



75 cycles

8-1 /4"


6 lbs.



50 cycles

12-1 /4-


15 lbs.

2.4 lb.


45 cycles



25 lbs.

8 0 2 C driver and H - 3 1 1 ES horn power: range: impedance: distribution: dimensions: price:

N-800D network

803A speaker 30 watts. 16 ohms. 30-800 cycles. 2.4 lbs. 3" 45 cycles. Diam., 15-5/16"; Depth. 7" $60.00

In many homes the finest high fidelity installation can be made by building-in the components. For this reason Altec Lansing Corporation makes these professional quality components available so that you may have the finest in your custom home music system. Either of these speaker systems will provide perfect reproduction when mounted in a proper enclosure. To assist you in the construction of your cabinet Altec Lansing Corporation has prepared a special brochure describing the proper methods of design and construction and also provides a user assistance service to answer special questions and give advice so that you may be sure to realize the full potential of your Altec home music system.

Use the famous Altec 3000A high frequency speaker and N-3000A network with either the 412A or 415A to achieve full 22,000 cycle performance. Or if you already have a system, the two units can be used to modernize it and achieve true Altec quality. Only Altec speakers provide a full 22,000 cycles range. This high frequency unit is ideal to extend the frequency range of your present Altec 600B or 603B speaker or any other good single cone speaker.

N-3000A network

3000A high frequency speaker power: impedance: range: distribution: dimensions: price:

20 watts. 8 ohms. 3000—22,000 cycles. Hon, 90"; vert.. 40'. 2-5/8" H; 2-7/8" W; 3" D. $40.00

See your dealer or write Altec for information regarding the design and construction of enclosures that will realize the full potential of these wonderful speaker systems.

impedance: hf attenuation: crossover: dimensions: price:

8 ohms. 2—2 db steps. 3000 cycles. 3-1 IS" H: 2-5/8" Square. $18.00

The enclosure for your speaker is an important part of your system. A poorly engineered cabinet may create false resonances, cause distortion, create holes in the mid-frequency response, and even destroy tones; while a properly designed enclosure actually enhances the speaker's performance. These Altec enclosures have been designed and tested in A l t e c ' s acoustic laboratories to assure maximum performance from your Altec speaker. They, like all other parts of your Altec home music system, have been designed with but one thought: to give you matched components that will provide the finest quality.

a period cabinet in mahogany, 35" x 3 1 " x 17"

$160.00 607 a compact phase computed enclosure for 8" and 12" speakers, in mahogany or blond, 28" x 19-112" x 16" $81.00

a corner enclosure, always the best for extreme bass, in mahogany or blond, 36-112" x 36" x 23-112" $138.00

modern, can be used either vertically or horizontally, with or without legs; cabinet, 30" x 36" x 16-112"; legs, 5" high; in mahogany, matte walnut, or blond


For IS' speakers order 606A, 607A. or 608A. For 12* sneakers order 606B, 607B. 608B or 609B. For 8* speakers order 609C.

304A AM-FM broadcast tuner

305A AM broadcast tuner

The 304A belongs in the finest homes as part of a complete Altec home music system. It is without peer and will provide years of listening enjoyment of the finest broadcast quality. Requires a conlrol amplifier such as the A-440A or A-339.

For areas where FM broadcasting is not available and for more economical installations the 305A provides flawless reception, utilizing fully the quality potentials of A M broad­ casting. Requires a control amplifier such as the A-440A or A-339. |




Tuninn; on-off, AM. FM. FM-AFC.


Tuning. On-off.

broadcast range:

AM: 540—1720 kilocycles. FM: 88—108 megacycles.

broadcast range:

AM: 540—1720 kilocycles.

tm sensitivity:

Absolute—0.8 microvolt. Quieting—6.0 microvolts.


1 volt cathode follower matched for A-440A 4 A-339.


1 volt cathode follower matched for A-440A 4 A-339.


power supply:

117 volts; 60 cycles: 20 watts.



2-6BA6. 1 each 63E6. 6AL5, 6AB4.


14-1 IT W; 8-1 IT D; 6-1 IT H.


Mahogany or blond.

shipping weight:

12 pounds.



power supply:

117 volts; 60 cycles; 65 watts.


4-6BA6, 2-6AL5, 2-6AB4, 1 each 6BE6, 6U5/6G5, 6B07A. 6AU6, 12AT7.


14-1 IT W; 8-1 IT D; 6-1 IT H.


Mahogany or blond.

shipping weight:

14 pounds.





Outstanding engineering d e s i g n , t h e use of the finest available c o m p o n e n t s with large safety f a c t o r s , precision craftsmanship and intensive production testing make A l t e c tuners t h e choice of the professional broadcast industry. T h e y are exceptional for their sensitivity, selectivity and above all their stability and freedom from drift even after h u n d r e d s of hours of use. T h e y are housed in beautiful hardwood cabinets d esig n e r - m a t c he d to blend with your entire A l t e c h o m e music system a n d t o c o m p l e m e n t your finest furnishings.

m i c r o p h o n e s • a m p l i f i e r s • control c o n s o l e s • l o u d s p e a k e r s - horns • a m - f m t u n e r s • scientific i n s t r u m e n t s • t h e a t r e s y s t e m s • public address s y s t e m s • high f i d e l i t y s y s t e m s • t r a n s f o r m e r s


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