What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Marantz PM 350 amplifier

Marantz PM 350 Integrated amplifier
Features:
Bass, mid and treble tone controls
Left and right LED power meters
Low filter 6 dB/oct
Loudness compensation
Tape monitor
Tape 2 to tape 1 copy
41 step detented volume control
Connections:  Tuner; Phono MM; Tape 2/Aux; Tape 1 monitor; 2 speaker systems
Specifications:
Power Output Rating per Channel:
51 W at 4 Ω DIN
48 W at 4 Ω RMS
40 W at 8 Ω DIN
38 W at 8 Ω RMS
Total Harmonic Distortion (at RMS 8 Ω):  0,05%
Intermodulation Distortion:  0,04%
Damping Factor:  60 (8 Ω , 1 kHz)
M.M. cartridge Input
Frequency Response (RIAA):  ±1 dB
Signal-to-Noise Ratio:  77 dB
Input Impedance:  47 k Ω
Input Capacity:  250 pF
Input Sensitivity:  2,8 mV
Equivalent Noise at Input:  0,5 µV
Dynamic Range:  100 dB
AUX input
Input Impedance:  25 k Ω
Input Sensitivity:  150mV
Frequency Response:  10 Hz - 60 kHz
Signal-to-Noise Ratio:  96 dB
Output Voltage
Tape Out:  415 mV
Output Impedance
Tape Out:  220 Ω
Dimensions (W x H x D):  416 x 73 x 302 mm
Weight (net):  6,5 kg 

Marantz PM 310 amplifier

Marantz PM 310 Integrated amplifier
Features:
Bass and treble tone control
Left and right LED power meters
Low filter 6 dB/oct
Loudness compensation
Tape monitor
Tape 2 to tape 1 copy
41 step detented volume control
Connections:  Tuner; Phono MM; Tape 2/Aux; Tape 1 monitor; 1 speaker systems
Specifications:
Power Output Rating per Channel:
33 W at 4 Ω DIN
30 W at 4 Ω RMS
28 W at 8 Ω DIN
25 W at 8 Ω RMS
Total Harmonic Distortion (at RMS 8 Ω):  0,3%
Intermodulation Distortion:  0,3%
Damping Factor:  50 (8 Ω , 1 kHz)
M.M. cartridge Input
Frequency Response (RIAA):  ±1 dB
Signal-to-Noise Ratio:  74 dB
Input Impedance:  47 k Ω
Input Capacity:  250 pF
Input Sensitivity:  2,8 mV
Equivalent Noise at Input:  0,5 µV
Dynamic Range:  93 dB
AUX input
Input Impedance:  25 k Ω
Input Sensitivity:  150mV
Frequency Response:  15 Hz - 50 kHz
Signal-to-Noise Ratio:  96 dB
Output Voltage
Tape Out:  415 mV
Output Impedance
Tape Out:  220 Ω
Dimensions (W x H x D):  416 x 73 x 302 mm
Weight (net):  4,8 kg 

SAE Mark VIB tuner

SAE Mark VIB FM Digital Tuner
The SAE Mark VIB is the ulmost in versatility, reliability and the faithful reproduction of FM signals. Many new developments are unique to the Mark VIB. Foolproof tuning accuracy is achieved through the use of these exclusive SEA features. Digital Readout Frequency Display, the display of tuning and audio signals on a 3" rectangular oscilloscope, and the automatic selection of this oscilloscope display by a touch
sensitive tuning knob.
The Mark VIB is the industry's first FM tuner which features a direct numerical readout of the assigned frequency in MHz of the FM station tuned, SAE's Digital readout measures directly the tuner's own oscillator frequency with an accuracy equal to that required by the FCC for FM broadcast stations. In addition, the Mark VIB incorporates ultra-low distortion, outstanding separation and exceptional quieting and selectivity. It exhibits its superiority in weak signal areas of congested urban locations where critical tuning is necessary.

Digital readout Frequency Display
Four long-life Nixie readout tubes identify the precise station frequency for any of the 100 channels available across the FM band. The readout count is updated 60 times per second to permit fast tuning across the band. Anti-hunt circuity is incorporated to prevent inter digital flickering.

Oscilloscope
A high-intensity 3" rectangular oscilloscope accurately displays the presence of multi-path distortion, center-of-channel tuning, relative signal strength and Lissajous displays of all stereo and mono signals with provisions for external inputs. Should a signal be absent, the oscilloscope trace intensity is automatically diminished.
Specifications:
IHF Sensitivity:  1,6 µV
Total Harmonic Distortion (1 kHz): 
Stereo :  0,15%
Mono :  0,1%
Noise:  better than 75 below 100% modulation
Capture Ratio:  1,5 dB
AM Suppression: better than 100 dB
Spurious Response Rejection:  better than 100 dB
Image Rejection:  better than 100 dB
Alternate Channel Selectivity:  140 dB
Stereo Separation:  50 dB at 1 kHz ;  38 dB at 10 kHz;  35 dB at 15 kHz
Frequency Response:  ±0,5 dB (20 Hz to 15 kHz)
RF Drift:  less than 15 kHz (±0,15%)
Rated Output/Load Impedance:  1,0 V (rms)/1500 Ω min.
Muting:  60 dB minimum with adjustable threshold control
Antenna Inputs:  300 Ω Balanced; 75 Ω unbalanced
Tuning Aids:  Nixie Digital Readout, 3" Rectangular Oscilloscope Stereo and Mono indicator lights
Power Requirement/Consumptions:  110 - 125 V; 50 to 60 hz / 20 watts
Dimensions: 
Front Panel (W x H):  432 x 146 mm (17" x 5,75")
Chassis (D):  267 mm (10,5")
weight:  11,4 kg (25 pounds)
Walnut Cabinet:  WC-1 optional

Onkyo CP-1030F turntable

An incredible sound experience awaits you. An experience that technology alone finds hard to explain. You'll hear music of such stunning purity and sensual richness, that you'll wonder how any turntable could make that much of a difference.
That's the secret of Onkyo. The unique ability to take you several steps beyond pure technology, to a world of more exciting sound. And we provide it in all our components, including all five of our turntables.
The Onkyo CP-1030F Full Automatic Turntable is an outstanding example. Its unique design lets you take much fuller advantage of today's most sensitive high-compliance cartridges, providing more perfect record groove tracking and more perfect damping of the vibrations that destroy perfect sound quality.
The Onkyo CP-1030F utilizes a uniquely designed low mass, straight-line carbon fiber tonearm and headshell. Its construction assures purer sound even with warped records. Infrared sensors replace the usual mechanical devices that detect the end of record play - returning the tonearm more silently to the Off or Repeat position. Manual cueing is also smoother and more precise, with far less lateral drift during stylus descent.
A Quartz-locked DC direct-driver motor, with an LED illuminated strobe, assures rotational speed accuracy. And a separate motor controls automatic tonearm movement functions.
The entire turntable rests on a highly stable triple-insulated suspension system to isolate it from room vibrations and sound vibrations from your speakers.
Styling is superb.
Silver-grey with black, low lustre metal and a crystal dust cover. Feather-touch control buttons are front-panel mounted, with a full array of LEDs indicating all function setting.
The CP-1030F is just one of five remarkable turntables from Onkyo.
Specifications
Type:  2-speed fully-automatic turntable with cueing lever
Turntable Platter:  310 mm (12-3/16") aluminum die-cast
Motor:  Brushless, coreless, slotless, DC Quartz Direct Drive
Speeds:  33-1/3 rpm, 45 rpm
Wow and Flutter:  0,03% WRMS
Signal-to-Noise Ratio:  75 dB (DIN B)
Tonearm:  Static balanced straight pipe
Effective Arm Length:  224 mm (8-13/16")
Overhang:  13 mm (1/2")
Maximum Tracking Error:  +3 degrees, -1 degree
Usable Cartridge Weight:  Min. 5,0 g; Max. 8,5 g
Power Supply Rating:  AC 110-120, 220-240 V, 50/60 Hz (or 240 V at 50 Hz. 120 V at 60 Hz, only)
Power Consumption:  6 watts
Dimensions (W x H x D):  453 x 370 x 133 mm (17-7/8" x 14-1/2" x 5-1/4")
Weight:  6,5 kg (14,3 lbs)
Cabinet Composition
Turntable Board:  Polystyrene
Bottom Board:  Fiber Reinforced Polyethylene
Dust Cover:  Polystyrene

Heco Superior 840 speakers

"Superior" by Heco is the loudspeaker range for audiophiles who cherish excellent sound and intelligent design for small as well as for larger rooms. "Superior" means sophisticated technology down to the smallest detail. And the bigger the speaker, the more power handling and growing deep bass reproduction. Dynamics and sound intensity increase. Allow your amplifier to shine; with a punchy bass, tight midrange and brilliant highs. Heco "Superior"; that stands for undistorted reproduction of sound, perfectly musical - for all those who love the extraordinary.

Woofer Chassis
The woofer is constructed on an extremely stiff chassis made of pressure-cast light metals. The cone diaphragm is made of a quality multilayer cellulose material, coated with a special synthetic layer for damping. The small, lightweight coils, made of best copper wire and which are therefore extremely low in resonance, feature a high constant power handling. In the case of floor standing speakers, the double woofers are pneumatically isolated from one another by means of separate chambers.
Cone Mid-Range Speaker
The range of fundamental tones between 300 and 3000 Hz, to which the human ear is particularly susceptible, have to be transmitted with the ulmost phase linearity. That is why this range is being reproduced by a sole driver a newly developed phaselinear basic speaker with an absolutely neutral sound Polypropylene diaphragm. With the interior 230 S the supronyl-dome-diaphragm has proved successful.

Tweeter Dome
For the high-ranges a special metal dome made of aluminium-mahganese is being used. The light, single-layer voice coils, the highly flexible supronyl suspension and its diffusor with pressure chamber effect allow the enormous range of 2 to 20 kHz. From the musical point of view this means high brilliance, impulse fidelity and great resistance without any sharpness in the reproduction of high frequencies.

Frequency Cross-over
The frequency crossover design shows an intelligent and ingenious construction in order to achieve minimum loss without any additional distortion during signal transmission. In practice this means.
An ingenious combination of air - core and ferrite-core coils, polyester capacitors and high-quality electrolytic capacitors with tight tolerances. The precision mounting of the components onto the circuit board with its engraved conductors ensure optimum decoupling of the components from each other.
Specifications
Type:  3-way floor standing
Drivers:
1 x KHC 19 M
1 x TMC 120
2 x TC 190
Music Power Handling:  200 watt
Nominal Power Handling:  140 watt
Nominal Impedance:  4 Ω
Frequency Response:  24 - 35,000 Hz
Efficiency (1W/1m):  88 dB
Crossover Frequency:  250/2500 Hz
Suitable for Amplifier Terminal Resistance:  2 - 8 Ω (60 - 150 watt sinus/channel)
Suitable for Rooms u to:  70 m²
Cabinet Finish:  Walnut , oak, Mahagany veneer. Ash-tree back or white; varnish black or white
Special Finish:  Piano black, Mahagany high
Dimensions (H x W x D):  950 x 240 x 275 mm

Heco Superior 740 loudspeakers

About The Aesthetics Of Sound
Just as serious listeners will strive for aural perfection, so Heco have added the dimension of visual perfection. This creates a harmonious product.
Heco is standing at the crossroads of science, technology and art.. The aim is demanding - to achieve the perfect, neutral reproduction of sound and to present it in a high-class design.
This has been a constant channenge; requiring knowledge, experience and creativity.
Heco has been building loudspeakers for many years and we have now come near to the ideal, both in aesthetics and in sound. A highly qualified staff along with advanced manufacturing procedures and innovative technology has been needed to achieve this. The result - a sound performance which equals the joy of art - today and tomorrow.
Integrated Subwoofer System ISS
Heco's new ISS technology skillfully blends and integrates an entire subwoofer system into each loudspeaker it incorporates a totally separte acoustic volume chamber within the cabinet and steep low-pass filtering for the subwoofer signal (18 dB/octave slope to 24 dB/octave slope according to model) with decoupling between 150 Hz and 250 Hz. All Superior models 9excepting the Superior 620) and the Interior models 330 S, 430 S, and 535 s can therefore be considered  as "cum basso continuo system" . The driver itself is suspended in a rigid casting of solid aluminium with a polypropylene cone.

Wide Bandwidth Midrange
When you listen to music the most critical area is the midrange, the frequencies between 300 and 3000 Hz. If this area is not correct, even the best woofers and tweeters can not save the sound.
Heco research has developed a new technology to reproduce this crucial region of music a new midrange driver which covers this entire range alone - without having to cross over to the woofer or tweeter
This design produces absolutely perfect phase coherency throughout the region. You can hear the result; smooth, clear natural voices and instruments.
Aluminium-manganese dome tweeter
Heco use their finest metal dome tweeters in the "Superior" and "Interior" models. Developed and manufactured by Heco, these drivers have exce[tional frequency response and power handling as well as a wide dispersion. They ensure smooth upper frequencies.
Specifications
Type:  3-way floor standing
Drivers:
1 x KHC 19 M
1 x TMC 170
1 x TC 170
Music Power Handling:  160 watt
Nominal Power Handling:  120 watt
Nominal Impedance:  4 Ω
Frequency Response:  28 - 35,000 Hz
Efficiency (1W/1m):  88 dB
Crossover Frequency:  150/3000 Hz
Suitable for Amplifier Terminal Resistance:  2 - 8 Ω (50 - 130 watt sinus/channel)
Suitable for Rooms u to:  60 m²
Cabinet Finish:  Walnut , oak, Mahagany veneer. Ash-tree back or white; varnish black or white
Special Finish:  Piano black, Mahagany high
Dimensions (H x W x D):  850 x 220 x 255 mm

Teac A-510 mkII cassette deck

Controls and Switches
Friction-locked belt driven L&R record level
Ganged output level
Timer control function
Bias and equalization selection
Dolby / MPX filter on-off
Input selection
Record level meter peak hold on-off
Record meter auto/manual peak reading reset
Record level meter brightness [hi/lo]
Counter memory on-off and reset

An outstanding feature of the Teac A-510 Mk II is a peak indicating bar-graph record level indicator with both instantaneous and peak-hold modes. The peak-hold can be programmed to automatically reset after a few seconds, or maintain its value until manually reset. A pre-wired socket allows full-feature remote control with a plug in remote controller. Unit can be timer started in either the record or play mode. It has bias and equalization selectors for normal, high-bias (chrome) and metal tapes and a Dolby noise reduction system. The Teac A-510 MkII also has some useful taping controls; a record mute that can be used while the tape is driving and a "flying start" record switch that allows you to switch to the record mode while the tape is in the play mode. There is also an end-of-tape-stop feature, memory reset counter and timer-controlled record/play to provide maximum operator convenience.

Specifications
Track System: 4-track, 2-channel stereo
Heads: 2 heads, Erase and Record/Playback
Tape Type:  Compact Cassette C-60 and C-90
Tape Speed:  1,7/8 ips (4,76 cm/s)
Motor:  FG servo controlled DC motor
Wow and Flutter:  0,05%
Frequency Response:
Metal Tape :  30 - 18,000 Hz
CrO₂ Tape:  30 - 18,000 Hz
Normal Tape:  30 - 15,000 Hz
Signal-to-Noise Ratio:  56 dB (3%T.H.D.)
Rewind/Fast Forward Time:  approx. 90 sec. C-60
Inputs:
Line 60 mV/50 k Ω
Microphones:  0,25 mV/-72 dB (200 Ω or more)
Outputs
Line:  0,3 V (load impedance of 50 k Ω or more)
Headphones Jack:  8 Ω
Power Requirement:  100/117/220/240 V AC 50/60 Hz
Power Consumption:  29 W
Dimension (W x H x D):  440 x 147 x 345 mm (17-5/16" x 5-13/16" x 13-9/16")
Weight:  9,5 kg (20-15/16 lbs)

Kenwood KX-500 cassette deck

Kenwood's KX-500 cassette deck offers metal tape capability along with flourescent peak meter convenience. This "popular-priced" deck was designed for operating ease through use of a new, exclusive "soft touch" mechanism which actually feels like the more expensive solenoid switches. Also featured is Kenwood's dual-belt design drive system which is claimed to provide wow and flutter below 0,05% WRMS. A stabilized tape path ensures accurate and smooth tape flow during the life of the deck, and sendust-coated tape heads minimize wer. The tape selector in the KX-500 is combined with a variable bias-adjust control to optimize the performance of each individual tape. With metal tape and Dolby, Frequency Response is 30 to 16,000 Hz, and Signal-to-Noise ratio is 62 dB.
Adittional features include:
Two microphone jacks with built-in preamps to record in stereo from wide-band dynamic microphones; a single record button instead of a conventional-often awkward to use-two-lever system.

Specifications
Type:  Single compact cassette deck
Track System:  4-track, 2-channel stereo
Tape Speed:  4,76 cm/s
Heads: 
1 for record/playback head
1 for erase head
Motor:  Electronically controlled DC motor
Tape Type:  Normal, FeCr, CrO2, Metal
Noise Reduction:  Dolby B
Frequency Response:
Metal tape :  30 Hz to 16,000 Hz
Signal to Noise Ratio:
With Dolby B :  64 db
Wow and Flutter:  0.05%
Total Harmonic Distortion:  1,3%
Input:
Line :  77,5 mV
Mic :  0,19 mV
Output Level:
Line :  0,39 V
Dimensions (W x H x D):  400 x 139 x 281 mm
Weight:  4,3 kg

Onkyo TA-2058 cassette deck

The Integra Series
Onkyo's Integra sound is one that comes as close as possible to duplicating the abundance of energy and the richness of detail of a live performance. Whether you're seking to capture all the tonal colors that a symphony orchestra is capable of creating, or the synthesized, electronically amplified sounds of modern music, the cassette decks introduced here are designed to bring them to you with astonishing realism. They represent Onkyo's high technology achievements constantly refined through listening tests by experts. You'll have to operate and listen to one of these superb tape decks to understand Onkyo's dedication to excellence in the audio field; the live sound of the Integra Series.

Full Automatic Accubias with 5 Response Positions
Both the TA-2058 and TA-2048 Cassette Deck are equipped with Onkyo's unique Accubias system for fine tuning the recording bias to achieve the widest, flattest frequency response possible. On the TA-2058 , Accubias is completely automatic; the optimum amount of bias is applied for each tape type. There are aso 5 preset frequency rsponse positions so that the user can manually set the bias to obtain the desired sonic characteristics. Proper biasing is essential for high quality recording, and Onkyo has made great strides in bias accuray, automation and the elimination of guesswork.

4-Digit Real Time Tape Counter
A 4-digit LED displays the minutes and seconds elapsed since tape fransport was started or the time remaining. Instead of just a tape counter, the real time counter gives you the actual program time of the tape you're listening to. This means no more guesswork, for instance, about how much actual time is left on a cassette when recording. Locating a particular song or editing becomes much easier. There are a series of tape length selector buttons below the time display compatible with all standard cassette formats.

Other Features:
3-Motor, 3-Head configurtation with Special Hard permalloy
Silent tape transport with Micro-Computer Control
Auto Space Function
Automatic-Music Control System
Dolby B, C and HX-PRO
Two repeat modes
Two 10 segment, 2-color LED level indicators
Separate left and right microphone jacks
Rec/Play timer switch
Memory Play and Stop switch
MPX filter with on/off switch
Compatible with RC-5T remote control unit
Optional wood grain side panels (CW-K58) can be attached for added elegance

Specifications
Track Format:  4-tracks, 2-channels
Erase System:  AC erase
FF and Rewind Time:  90 sec. (C-60)
Wow and Flutter:  0,045% (WRMS)
Frequency Response:
Metal Tape :  20 - 19,000 Hz (30 - 18,000 Hz ±3 dB)
High Position Tape :   20 - 18,000 Hz (30 - 17,000 Hz ±3 dB)
Normal Tape :  20 - 17,000 Hz (30 - 16,000 Hz ±3 dB)
Signal-to-Noise Ratio:  60 dB (Metal, Dolby Nr Out)
Inputs [Sensitivity/Impedance]:
Line In Jacks :  [2] 60 mV/50 k Ω
Microphone Jacks : [2] 0,6 mV(600 Ω) /5,6 k Ω
DIN in Jack :  [1 EU models] 0,1 mV(1 k Ω) /2,7 k Ω
Outputs [Level/Impedance]:
Line Out Jacks :  [2] 500 mV (0 dB)/more than 50 k Ω
Headphone Jack :  [1] -/8 - 200 Ω
DIN Out Jack :  [1 EU models] 500 mV (0 dB)/more than 50 k Ω
Motors:  3 motor system, DC servo Motor x 1 , DC motor x 2
Heads:  Rec/Pb Special hard permaloy  x 1; Erase, Ferrite x 1
Power Supply Rating (4 types):  AC 120/220 V Switchable 50/60 Hz
Dimensions (W x H x D):  435 x 112 x 360 mm (17-1/8" x 4-3/8" x 14-1/8")
Weight:  6,1 kg (13,4 lbs)

Onkyo TA-2048 cassette deck

Onkyo Integra 3-Motor, 3-Head Cassette Deck

Special Hard permalloy
The 3-head design has some distinct advantages over the conventional combined Pb/rec format. Since the playback and recording heads are separate, the playback head gap width can be made narrower than the recording head so it can capture with greater precision the higher frequency sounds. For durability and improved metal tape compatibility the rec and pb heads are fashioned out of Special Hard Permalloy. This format also lets you monitor (from tape) what you.ve just recorded so you can fine tune and optimize the recording level. The 3-motor system achieves superb stability and reliability in tape transport. A servo controlled capstan motor is the ultimate in self-correcting precision, and the rell table motor further contributes to eliminating wow and flutter. The head block is moved into place by its own independent motor for optimum functionality and precision.

Silent Tape Transport with Micro-Computer Control
When tape transport begins, the head block is silently and smoothly lifted into position. Besides eliminating annoying start-up noises, this micro-computer controlled system avoids mechanical shocks that could cause misalignments of head azimuth and transport parts. Also, much less power is needed, so there's no need for oversized transformers in the power supply which might be potential sources of hum and induction noise.
Auto Space Function
This very simple but useful feature automatically inserts a 5-second silent space in the tape when the Auto Space button is pressed. Later, in playback, the AMCS automatic search system will detect these pauses electronically and stop the tape at just the right spot.

Automatic-Music Control System (AMCS)
This function allows you to skip forward or reverse to the beginning of the adjacent section of recorded music. The first 10 seconds of that section are played and then scanning continues, playing the first seconds of each successive track until the play button is pressed. With AMCS you can quickly search for the section of a tape you're looking for , or quickly scan the entire contents of a tape.

Dolby B, C and HX-pro
Conventional Dolby B reduces noise in the higher frequency ranges while the newer Dolby C does the same for the high and middle ranges where tape hiss and modulation noise, though less audible, can still degrade fidelity. The TA-2058 is additionally equipped with HX-Pro which constantly monitors the high frequencies in the audo signal and adjust the bias current for optimum flat frequency response. When recording music with a lot of high frequency peaks, HX-pro will automatically lower the bias to allow for the additional high range "headroom" required to capture these sounds without running into tape saturation and distortion problems.

Two repeat Modes
The single and full repeat modes allow you to repeat a single song if you like or to listen to a whole cassette side a second time.
Specifications
Track Format:  4-tracks, 2-channels
Erase System:  AC erase
FF and Rewind Time:  90 sec. (C-60)
Wow and Flutter:  0,045% (WRMS)
Frequency Response:
Metal Tape :  20 - 19,000 Hz (30 - 18,000 Hz ±3 dB)
High Position Tape :   20 - 18,000 Hz (30 - 17,000 Hz ±3 dB)
Normal Tape :  20 - 17,000 Hz (30 - 16,000 Hz ±3 dB)
Signal-to-Noise Ratio:  60 dB (Metal, Dolby Nr Out)
Inputs [Sensitivity/Impedance]:
Line In Jacks :  [2] 60 mV/50 k Ω
Microphone Jacks : [2] 0,6 mV(600 Ω) /5,6 k Ω
DIN in Jack :  [1 EU models] 0,1 mV(1 k Ω) /2,7 k Ω
Outputs [Level/Impedance]:
Line Out Jacks :  [2] 500 mV (0 dB)/more than 50 k Ω
Headphone Jack :  [1] -/8 - 200 Ω
DIN Out Jack :  [1 EU models] 500 mV (0 dB)/more than 50 k Ω
Motors:  3 motor system, DC servo Motor x 1 , DC motor x 2
Heads:  Rec/Pb Special hard permaloy  x 1; Erase, Ferrite x 1
Power Supply Rating (4 types):  AC 120/220 V Switchable 50/60 Hz
Dimensions (W x H x D):  435 x 112 x 360 mm (17-1/8" x 4-3/8" x 14-1/8")
Weight:  5,8 kg (12,7 lbs)

Heco Precision 400 loudspeaker


Heco precision Series loudspeakers feature a patented woofer duet claimed to ensure accurae bass response. For prcise midrange and high frequency sound, both soft dome midrange drivers and tweeters utilize a special polymer material made exclusively for Heco.
To prevent the effects of spurious vibrations, the acoustic suspension cabinets are built of particle board that is "five times more dense than usually used for speaker cabinets".
All models have two environmental contour controls, a nominal DC impedance of 8 ohms, and an efficiency control rated at 91 dB/SPL at 1 m/1W.

Specifications
Type:  3-way acoustic suspension
Power Handling:  120 - 200 watts
Frequency Response:  25 - 25,000 Hz
Impedance Nominal :  4 ohms
Crossover:  600 Hz / 3,000 Hz
Drivers:
LF :  300 mm(12 inch) Woofer
MF :  50 mm (2 inch) Midrange
HF :  19 mm (3/4 inch) Tweeter
Volume:  66,0 litre
Dimensions (H x W x D):  650 x 375 x 270 mm

Weight:  19,0 kg

Heco Precision 300 loudspeakers


Heco Precision Series Model 300 

Specifications
Type:  3-way acoustic suspension
Power Handling:  100 - 170 watts
Frequency Response:  25 - 25,000 Hz
Efficiency Control Rated:  91 dB/SPL at 1 m/1W.
Impedance Nominal :  4 ohms
Crossover:  700 Hz / 3,000 Hz
Drivers:
LF : 245 mm (10 inch) Woofer
MF :  50 mm  (2 inch) Midrange
HF :  19 mm (3/4 inch) Tweeter
Volume:  41,8 litre
Dimensions (H x W x D):  500 x 310 x 270 mm
Weight:  16,5 kg