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

Quad ESL-63

 "The Quad ESL-63 sets new standards in three important areas of loudspeaker technology, low distortion, low colouration and controlled directivity, resulting in a a level of performance limited solely by the quality of programme source.
With Quad Esl-63's and  a CD player less than 0,1% THD intrudes between the listener and the studio master tape, reproducing exactly what was recorded, nothing added, nothing taken away and bringing the listener that much closer to the original sound."
From Quad Advert
 An electrostatic loudspeaker consists of light thin membrane on which is placed a charge, suspended between two acoustically transparent, (i.e. with holes), electrodes. When asignal is fed to the electrodes a field is generated between them and the charged diaphragm complled to move by an electrostatic force. Reversing the polarity of the signal on the electrodes causes the diaphragm to move in the opposite direction and thus sound pressure is generated.
The electrostatic loudspeaker has several inherent advantages. Since the diaphragm is driven over its whole surface it does not ned to be stiff and can be made extremely light and thus have negligible stored energy. Because of the good impedance match with the air it is not necessary to load the loudspeaker into a box and the problems associated with cabinet resonance disappear. Designing and manufacturing electrostatic loudspeakers is by no means easy but the potential is there for a higher degree of performance than with conventional loudspeakers.

An ideal loudspeaker would consist of a single point source reproducing all frequencies. The Quad ESL-63 uses the electrostatic principle to achieve just this. 
 Imagine a theoretically ideal point source loudspeaker radiating sound pressure waves and a plane in the air a short distance from the source at right angles to the direction of propagation. Were we able to make the air at the plane visible we should see concentric waves radiating out from the centre, as if we had just thrown a stone into a still pool.
If we replace the plane with a very light membrane, induce it to reproduce the air particle motion already observed and suppress the original source, the results to a listener on the far side are absolutely indistinguishable from those of the ideal source.
The Quad ESL-63 does exactly this.
It consist of a diaphragm suspended between two sets of concentric annular electrodes. Signal is fed to the electrodes via sequential delay lines and the diaphragm motion produces a sound pressure pattern which is an exact replica of that from an ideal source placed some 30 cms behind the plane of the diaphragm. The ESL-63 is a totally homogeneous sound source, phase true and very aperiodic with a frequency response both on and off axis quiete free from the irregularities which are inevitable with any multiway loudspeaker system.
The designer has complete control over the directivity of the loudspeaker and by increasing the directivity index smoothly with increasing frequency, optimum stereo performance is achieved.
The Quad ESL-63 is a dipole which has significant benefits in terms of room placement and stereo perception. With a sound dispersion pattern which resembles a figure of eight, a dipole radiates no energy in the plane of its diaphragm and does not excite room modes whose axes lie in this plane.
The nett result is a loudspeaker of unsurpassed accuracy which given the right programme material will produce a more realistic and satisfactory illusion of a live musical performance than has previously been possible.

Development of the Quad ESL-63 has taken many years. Much of the time has been spent in investgating and experimenting with new materials and production techniques, the result of which has been that variations due to manufacturing tolerances have been virtually eliminated, sample variation being to within less than ±½ dB and stability of the materials used is such that the performance will be maintained for the loudspeaker's useful life without the need for regular maintenance.
The impedance characteristic of the lodspeaker is nominally 8Ω and largely resistive, presenting no problems at all to the amplifier, but amplifiers which are not short circuit protrcted must not be used with this loudspeaker.  The amplifier should have an output capabilty of 40 V peak (100 watts into 8Ω). Amplifiers with output capability of up to 55V peak (190 watts into 8Ω) can be used, but to no advantage.
The loudspeaker is fitted with two protection circuits, one which limits the maximum input voltage fed to the loudspeaker and the other which detects fault conditions and instantaneously shorts the signal being fed to the loudspeaker. It is impossible to damage the loudspeaker elements, but the input voltage limiter has limited thermal capacity and persistent overdrive will overhear it.

Impedance:  8 ohms nominal
Sensitivity:  1.5 µbars per volt referred to 1m. (i.e. 86dB/2.83V rms) 
Maximum Input: 
Continuous input voltage : 10 V rms;
Programme peak for undistorted output : 40 V;
Permitted peak input : 55 V
Maximum Output:  2 N/m² at 2m on Axis
Directivity Index:
125 Hz : 5.0 dB
500 Hz : 6.4 dB
2 kHz : 7.2 dB
8 kHz : 10.6 dB
Axis Band limits:  -6 dB at 3 Hz 3rd order
(Low Level) :  -6dB > 20kHz
Power Supply:  AC 240/200V 120/100V, 50/60Hz, 5 VA
Height : 925 mm
Width : 660 mm
Depth : 270 mm including 150 mm base
Weight Net:  18.7 kgs
Gross:  23 kgs

B&W DM-70

B&W DM 70 /Continental

Product Summary
The DM70 is new thinking on acoustical distribution pattern especially within the vitally important mid-frequency region of 400Hz to 5kHz, aiming towards exploring the advantage of an approximately spherical distribution pattern.
All units are designed and built within our factory to ensure maximum quality control and retention of the exclusive original design
The styling and general appearance has been designed to be acceptable in the world market, resulting in the Standard and Continental versions each available in various finishes.

 Technical highlights
A mid-frequency unit capable of handling input powers in the region of 35Watts RMS with distortion factors to the order of 0.5% or lower.
The bass radiator is capable of truly complementing acoustical distribution and power handling without occupying an unduly large enclosure volume.

 Electrostatic mid and HF unit
This is an eleven module doublet electrostatic unit covering all frequencies above 400 Hz. It's unique polar distribution pattern both improves stereo stability and increases the ratio of reverberant to direct sound. The pattern is virtually circular in a vertical plane through mid-band frequencies, providing a very wide, uniform arc.
Bass Unit
Bass frequencies are handled by a unit with a nominal 12 in (305 mm) piston diameter, chosen as being reasonably consistent with the enclosure volume to build a system with a resonance below 40 Hz , and a free air resonance in the region of 18 - 22 Hz.
The cone assembly consists of a laminated structure providing the stiffnes requiered to avoid break-up, and is additionallly braced and mass adjusted by small rectangular sections of synthetic rubber fixed at critical positions on the front face of the cone.
The massive magnet assembly ensures excellent damping and handling of transiants without hangover.

Bass Chamber
This is an infinite baffle type, with complex internalabsorbents making it almost aperiodic. Considerable attention has been paid to both finish and construction, the enclosure is acoustically inert, being built of 24 mm of 650 density chipboard and heavily braced.

B&W DM 70 Standard

Type:  Stand-mount loudspeaker system
Acoustic Load: 
Bass unit : Infinite
Electrostatic unit : Free standing with removable pad to control rear radiation pattern
Drive Units:
Electrostatic mid & HF unit covering all frequencies above 400Hz
305mm piston diameter bass/midrange unit
Axial response:  90° arc horizontal within ±2 dB an axis response at all frequencies up to 15 kHz
Frequency Response:   50 Hz to 15 kHz, ±4 dB
Crossover Frequency:  Nominally 400 Hz
Total harmonic Distortion:  1,1% at 1 kHz
Sensitivity:  95 dB at 1 metre
Nominal Impedance:  8 ohms
Power Handling:  25 W
System Resonance:  40 Hz ±1% (System Q below unity in the order of 0,9)
Standard Model
Height : 808 mm (including stand)
Width : 815 mm
Depth : 382 mm
Finish : Walnut or Teak
Weight:  50,8 kg (112 lbs)
Continental Model
Height : 820 mm
Width : 680 mm
Depth : 390 mm
Finish : Walnut and white
Weight:  36,3 kg (80 lbs)

B&W DM-6

 Bowers & Wilkins DM6 (1975 - 1979)
Floor-standing loudspeaker system
Product Summary
Early in 1972 it was decided to fill the gap in the existing range of B&W loudspeakers between the already successful DM2A and the DM70. Initially this was a fairly straightforward commercial requirement but as the development programme progressed its scope widened into the development of new measuring techniques and the use of new materials.
It culminated in the production of what is probably the first British Loudspeaker System to take account of relative phase between the drive units and offering a transducer that has a substantially minimum phase characteristic throughout the audio spectrum, with the resultant improvement in the reproduction of all transient information.

 Technical highlights
The DM6 Bass unit operated in an enclosure volume between 51-60 litres providing a system resonance below 50 Hz.
The Midrange Unit crosses over from the Bass unit at 500 Hz and operates up to the point of crossover by the HF unit which was estimated around 6 kHz. In view of the crossover frequencies chosen it was necessary for this unit to have a substantially linear response from well below 100 kHz to some 10 kHz.
To compliment the other two units and carry the frequency response well above 20 kHz. It was also felt desirable that unit should have really wide dispersion and that its diameter should be as small as possible consistent with the power handling required.

Type:  3-way floorstanding loudspeaker with stand
Drive Units:
1 x TW 20 high frequency unit voice coil diameter 19 mm
1 x 131 mm midrange unit MW 150 voice coil diameter 37 mm
1 x 224 mm low frequency woofer
Frequency Response:   50 Hz to 20 kHz, ±3 dB, 3 metres on axis
Crossover Frequency:  500 Hz, 5,000 Hz
Sensitivity:  95 dB at 1 metre
Nominal Impedance:  8 ohms
Power Handling:  25 W – 350 W
Height : 931mm (including stand)
Width : 410mm
Depth : 380mm
Weight:  36,1 kg

Luxman G-11

Laboratory Standard Series
Solid State Graphic Frequency Equalizer

Unlike conventional graphic equalizers using LC resonant circuits, the entire control circuitry of the G-11 features semi-conductors and capacitors, which makes it possible to offer not only an unrivalled 0,005% THD and ID even at 2V output but a superb S/N ratio exceeding 110dB (IHF A-curve)

The audio frequency ramge for both right and left channels is divided into 10 bands in 1 octave increments based upon the "A" tone, (440Hz) which is the standard tone of musical instruments.
10 center-frequency points are provided for each channel, which permit adjustment of the peak and dip at each point, enabling you to create whatever frequency response curve you want.
Overall selection of the maximum variable amount of peak and dip can be made by 2 steps (±6dB and ±12dB), which allows such operations as manual tone control for large tonal variations or as in the case of our Linear Equalizer for small variations, Therefore, you can enjoy wide range compensation of frequency response, such as frequency compensation of loudspeakers or phono cartridges, optimum control of room acoustic, compensation of RIAA curve, or frequency compensation of tapedecks, etc.
A bypass switch is also provided to check the effect of this equalizer and to compare equalized and unequalized response.

Output Voltage:  Typically 1V, max 6V (at flat position)
Output Impedance:  500 ohms
Total Harmonic Distortion:  no more than 0,005% (output 1V, 20 - 20,000 Hz, flat)
Intermodulation Distortion:  no more than 0,005% (output 1V, 60 Hz:7kHz = 4:1, flat)
Input Sensitivity:  1V
Input Impedance:  100 kohms
Frequency Response:  10 Hz - 100,000 Hz (within -1dB, at flat position)
Gain:  0dB (within ±0,5 dB, at flat position)
S/N Ratio: 
better than 115 dB (at flat position, IHF A weighted, input short-circuited)
Better than 95 dB 9at flat position, RMS input short-circuited)
Equalizer Centre Frequency:  28, 55, 110, 220, 440, 880, 1,8k, 3,5k, 7k, 14k Hz
Maximum Variable Amount:  ±12 dB and ±6 dB (selectable)
Bandwidth:  Q = 2.3
Channel Separation:  better than -80 dB (1 kHz)
Residual Noise:  below 0,018 mV (at flat position)
Additional Features:  Range Selector Switch, Bypass Switch, Extra AC Outlet (unswitched 300 W)
Power Consumption:  23 W
Dimensions (W x H x D):  438 x 314 x 126 mm (17-1/4" x 12-3/8" x 4-15/16")
Weight:  5,9 kg (12,9 lbs) Net

Pioneer SG-90

 Pioneer SG-90 
17-band Graphic Equalizer

-octave 17-band equalizer for true versatility -
Provides 17 controls per channel covering a range from 16 Hz to 25 kHz
Low distortion -
(0,001%, from 20 to 20,000 Hz, all controls flat), and a high signal-to-noise ratio (120 dB)
Auto fader -
Helps you create your own tapes with smooth fade-ins and fade-outs between songs
Adjustable control level -
± 12 dB for normal use, ± 6 dB for delicate critical adjustments
EQ switches -
Let you equalize a program source while recording unequalized "Reverse response" lets you perform tape noise reduction automatically.
2-deck connection -
Lets you apply equalization as you dub tapes.

Specifications SG-90
Equalizer Range:  ±12 dB / ±6 dB (switchable)
Center Frequencies:  16, 25, 40, 63, 100, 160, 250, 400, 630, 1k, 1,6k, 2,5k, 4k, 6,3k, 10k, 16k, 25k Hz
Total Harmonic Distortion:  0,001% (20 - 20,000 Hz, all controls flat, output  1V)
Gain:  0 dB (controls flat)
Frequency Response:  10 - 100,000 Hz,  0 dB, -2 dB
Signal-to-Noise Ratio (IHF, A network):
120 dB (output 2V)
114 dB (output 1 V)
Input Impedance:  47 k ohms
Output Impedance:  200 ohms
Power Requirements:  110/120/220/240 V,  50/60 Hz
Power Consumption:  34 watts
Dimensions (W x H x D):  420 x 131 x 351 mm (16-9/16" x 5-3/16" x 13-13/16")
Weight:  7,2 kg (15 lbs, 14 oz)

Pioneer SG-540 (1985)

 Pioneer SG-540 
Seven-band Graphic Equalizer
7 equalizer controls per channel -
The Sg-540 is versatile enough to compensate for room acoustics, speaker response and so on Center frequencies, individually adjustable for each channel, are 60, 150, 400, 1k, 2,4k, 6k, 16k Hz, control range is ±10 dB for each.
LED-lit slide controls -
Graphically show the overall shape of the equaliation curve in effect
Equalizer recording -
Equalized sound may be recorded on a connected tape deck. In this way, scratch and hiss noise can be eliminated as you dub records and tapes.
Tape monitor switch -
Lets you hear a connected tape deck
Low-noise, low-distortion circuitry -
You can add an SG-540 to your hi-fi system with assurance that it improves, not degrades, overall sound quality.
Low silhouette -
Lets you conveniently and easily squeeze the unit into your audio rack or shelf.

Specifications SG-540
Equalizer Range:  ±10 dB
Center Frequencies:  60, 150, 400, 1k, 2,4k, 6k,  15k Hz
Total Harmonic Distortion:  0,005% (1 kHz, all controls flat, output  1V)
Gain:  0 dB (controls flat)
Maximum Output Voltage:  6 V (1 kHz, THD 0,01%)
Frequency Response:  5 - 70,000 Hz,  0 dB, -1 dB
Signal-to-Noise Ratio (IHF, A network):  100 dB (output 1 V)
Input Impedance:  50 k ohms
Output Impedance:  600 ohms
Power Requirements:  110/120/220/240 V,  50/60 Hz
Power Consumption:  10 watts
Dimensions (W x H x D):  420 x 96 x 251 mm (16-9/16" x 3-7/8" x 9-1/2")
Weight:  3 kg (6 lbs, 10 oz)

KEF Uni-Q Driver

 A New Direction In Sound
The "Q" Factor  - or why speakers sound different in different rooms.
The Uni-Q principle, developed by KEF engineers, realises the long-held ambition of loudspeaker designerd to create the drive unit where all the sound radiates from a single source.
"Q" is the measure of a loudspeaker's directivity - how it bearns its sound towards the listener. It is this factor which very largely determines how a loudspeaker will sound in any given room.
When we listen to live music we hear each instrument, a trumpet, say, from one discrete point in space, together with a proportion of the sound reflected from around the hall or room.
With reproduced sound however, a single drive unit does not exist which peroduce the entire audible spectrum. Most loudspeakers employ two or more drive units, separated from each other. So now different parts of the trumpet come from two different locations - and at slightly different times.

 Because the directivities of the two units do not match at crossover, the sound is different at different listening positions. The tonal balance shifts as the listener moves. Sit off-centre and the trumpet becomes muted, the singer catches a cold.  Listeners in different posiitions, or indifferent roomscan heara coloure and out-of-focus soundstage.

Using Neodymium-Iron-Born, a newly developed magnetic alloy which has ten times the energy product of conventional ferrite, KEF designers have engineered a tweeter assembly small enough to be located in the neck of the bass unit's cone, precisely  at the point where the sound sources, the acoustic centres, of the two units coincide.
The direct and refflected path-lengths from both units to the listener's ear are now the same. Correct phase relationships ensure that high and low frequencies add up correctly to produce the desired response.

With Uni-Q, not only has KEF placed the woofer and tweeter on the same axis, their acoustic centres are also in the same plane. The directivity of both units is identical. The trumpet is back in one piece, unmuted and the singer's centrestage, in perfect health.
The unification of woofer and tweeter "Q" lies behind the revolutionary unit's name _the KEF Uni-Q Driver. More accurate sound in more locations, and from more listening positions is the keynote of Uni-Q.

KEF Q90 (1990-1994)

 KEF Q90
For those wanting the additional headroom and freedom provided by a full three-way system, the Q90 is the speaker of choice. This reflex-loaded floorstanding speaker is a no-compromise design, with a bold, dynamic and truthful performance. The 200 mm (8') unit, loaded by its own 11,7 litre sealed enclosure, gives wide open soundstanding, with outstandingly natural reproduction of voices and strings - the "difficult" areas of sound reproduction.
The reflex-loaded polymer-cone bass unit delivers powerful, extended but quick-sounding bass, with high output and power handling capability.
Twin gold-plated terminals allow bi-wired or bi-amplified operation. Adjustable, lockable feet give high stablility on any surface, and ensure that the Q90's exceptional dynamic qualities and midrange transparency are not compromised.
With all this, the Q90 has a small "footprint" - less than room square foot of floorspace - is elegantlt proportioned and easy to integrate into any listening room or hifi system.
Compatibility,flexibility, and high performance are the keynote features of the KEF Q90.

Type:  3-way floor standing
System:  SP3138
Drive units:
Bass unit (SP1285) : 200 mm (8") with 38 mm (1,5") coil (B200)
Midrange unit (SP1280) : 200 mm (8") with 38 mm (1,5") coil (B200)
B200 : midrange unit (SP1280),
Tweeter (SP1353) : Polymer dome with 25 mm (1") coil Fluid cooled, High Energy magnet Ne-Fe-B (NT25)
Crossover network:  SP2183
Frequency Range (±3 dB measured at 2m on reference axis):  40 - 20,000 Hz (-6dB 35 Hz)
Maximum Output (measured spl on programme peaks under typical listening conditions):  112 dB
Characteristic Sensitivity level:  89 dB (measured at 1m on reference axis for pink noise input of 2,83V rms[anechoic conditions] Q60 corrected for wall mounting)
Amplifier Requirements (into 8 ohms):  10 - 150 W
Nominal Impedance:  8 ohms
Enclosure Type:  Reflex
Internal Volume: 
MF: 11,7 litres (0.4 cu.ft.)
LF:  33,4 liter (1,18 cu.ft.)
Net Weight:  18,7 kg (41,1 lb)
Dimensions (H x W x D):  890 x 246 x 319 mm (35,0 x 9,7 x 12,5 inch)


 For thirty years KEF has proved to be a worthy holder of the title "The Speaker Engineers". Taime and again, highly advanced and innovative engineering techniques coupled with the most exacting attention to detail at every level and stage of production has ensured that KEF has led the world with a succession of major advances in loudspeaker design and technology. The KEF "Q" Series is no exception.

 KEF Q80
The Q80 is a floorstandig speaker of relatively compact dimensions. It is designed for the listener who needs big speaker performance without big speaker dimensions.
In addition to the 200 mm (8') Uni-Q unit, a passive rediator of the same diameter smooths, extends, and increasses bass output.Adjustable.lockable, spiked or capped feet allow the Q80 to be located firmly on the floor, with optimum stability on any surface, enabling the Uni-Q unit's outstanding imaging capability to be fully exploited.
All three Q Series models are fitted with heavy-duty twin gold-plated terminals suitable for bi-wired or bi-amplified use.
An easy 8-ohm load offers the amplifier no driving problems, and the Q80's high sensitivity allows lifelike levels of up to 110 dB, an outstanding figure for a speaker of Q80's size.

Type:  2-way floor standing
System:  SP3137
Drive units: 
Bass/midrange unit (SP1280) : 200 mm (8") with 38 mm (1,5") coil (B200)
Passive radiator (SP1288) : 200 mm (8") (BD200)
Tweeter (SP1353) : Polymer dome with 25 mm (1") coil Fluid cooled, High Energy magnet Ne-Fe-B (NT25)
Crossover network:  SP2189
Frequency Range (±3 dB measured at 2m on reference axis):  57 - 20,000 Hz (-6dB 40 Hz)
Maximum Output (measured spl on programme peaks under typical listening conditions):  110 dB
Characteristic Sensitivity level:  89 dB (measured at 1m on reference axis for pink noise input of 2,83V rms[anechoic conditions])
Amplifier Requirements (into 8 ohms):  10 - 125 W
Nominal Impedance:  8 ohms
Enclosure Type:  Passive Radiator
Internal Volume:  33,8 litres (1,9 cu.ft.)
Net Weight:  14,5 kg (32 lb)
Dimensions (H x W x D):  855 x 246 x 274 mm (33,6 x 9,72 x 10,8 inch)


 Why "Q"
KEF's Uni-Q two-way coincident-source drive unit is incorporated into all three "Q" series models. This unique drive unit combines both tweeter and bass/midrange units into one single chasis. This radical KEF development allows the sound from both units to reach the listener's ears at the same time, bringing readily audible benefits in terms of transparency, image stability and more natural sound reproduction.Uni-Q speakers are highly versatile in use. Being less affected by differing room acoustics, they will operate well in a wide range of placements and listening positions. Furthermore, an advanced and innovative design feature, unique to KEF ensures that all three Q-Series models share quite exceptionally low levels of cabinet colouration, even at high volumes.

 KEF Q60
Fast, well controlled bass performance with accurate, detailed, midrange and the capability to play at realistic levels with modest power requirements sums up the remarkable Q60. Designed for stand mounting 400-450 mm (15' - 18') high, a 200 mm (8') Uni-Q bass-midrange unit, with 25 mm (1') NIB magnet tweeter centrally placed, is loaded by a 20 litre reflex enclosure, 18 mm (3/4') thick. Careful bass alignment makes the Q60 tolerant of positioning, with the ability to recreate the life-like three-dimensional qualities of well recorded music in almost any environment.

Type:  2-way bookshelf
System:  SP3136
Drive units: 
Bass/midrange unit (SP1280) : 200 mm (8") with 38 mm (1,5") coil (B200)
Tweeter (SP1353) : Polymer dome with 25 mm (1") coil Fluid cooled, High Energy magnet Ne-Fe-B (NT25)
Crossover network:  SP2181
Frequency Range (±3 dB measured at 2m on reference axis):  60 - 20,000 Hz (-6dB 45 Hz)
Maximum Output (measured spl on programme peaks under typical listening conditions):  110 dB
Characteristic Sensitivity level:  90 dB (measured at 1m on reference axis for pink noise input of 2,83V rms[anechoic conditions] Q60 corrected for wall mounting)
Amplifier Requirements (into 8 ohms):  10 - 100 W
Nominal Impedance:  8 ohms
Enclosure Type:  Reflex
Internal Volume:  19,8 litres (0.7 cu.ft.)
Net Weight:  7,2 kg (15,8 lb)
Dimensions (H x W x D):  479 x 246 x 274 mm (18,9 x 9,72 x 10,8 inch)

Denon DCD-1800 -R

The DCD-1800 employs a Denon Super Linear Conventer to prevent degradation of sound quality in the PCM playback system, assuring accurate reproduction of recorded sound. The CD player is capable of reproducing the actual musical scene as it is in conjunction with carefully selected parts.

Audio Section
Number of Channels:  2, stereo
Frequency response:  5 - 20,000 Hz, ±0,5 dB
Dynamic range:  95 dB
Signal-to-Noise Ratio:  96 dB
Harmonic Distortion:  0,003% (at 1 kHz)
Channel Separation:  94 dB 9at 1 kHz)
Wow and Flutter:  less than measuring limit
Output Voltage:  2,0 V r.m.s.
Disc for use:  Compact Disc
Playing Time:  60 min/side (max. 79,8 min/side)
Diameter:  120 mm
Signal Format
Sampling Frequency:  44,1 kHz
Quantization:  16-bit linear/channel
Transmission Bit Rate:  4,3218 M bits/sec
Pickup Section
System:  Objective lens driving system laser pickup
Lens Drive System:  two-dimensional parallel driving
Light Source:  Semiconductor laser
Wavelength:  800 mm
General Characteristics
Power Supply:  Voltage is shown on rating label, 50/60 Hz
Power Consumption:  28 W
Dimensions (W x H x D):  434 x 110 x 372 mm (Width with decorative wood board 464 mm)
Weight:  8,9 kg (9,5 kg  with decor. Wood board)

Onkyo DX-7911 (1997)

Twin-Core AEI (Anti-Electromagnetic Interference) transformer provides clean and abundant power.
Modular chassis construction and optimized layout.
New Linear Motor Actuator for faster access and better pickup precision.
Fine Pulse Conversion System (FPCS) for remarkably natural, warm-sounding digital music.
Proprietary AccuPulse Quartz System, the most advanced single-bit digital-to-analog (D/A) conversion system available.
RI (Remote Intractive) remote control RC-308C

CD Player:  Model DX-7911
Signal Readout System:  Optical non-contact
Reading Rotation:  About 500 - 200 rpm (constant linear velocity)
Lineary Velocity:  1,2 - 1,4 m/s
Error Correction System:  Cross Interleave Reed-Solomon code
D/A Converter:  1 bit PWM Accupulse D/A Converter
Sampling Frequency:  352,8 kHz (Eight-times oversampling)
Number of Channels:  2 - stereo
Frequency Response:  2 Hz - 20 kHz
Total Harmonic Distortion:  0,0025%
Dynamic Range:  110dB
Signal-to-Noise Ratio:  110 dB
Channel Separation:  108 dB
Wow and Flutter:  below threshold of measurability
Output level:  2 volts rms
Headphone Jack: 1, optimum load impedance 8 to 200 ohms
Power Consumption:  26 watts
Power Supply:  120 V and 220 -230 V AC, 50/60 Hz
Dimensions (W x H x D):  435 x 131 x 365 mm (17-1/8 x 5-3/16 x 14-3/8 inch)
Weight:  10,5 kg (23,1 lbs)

Marantz CD-10 (1993)

Specifications Marantz CD-10
Audio Characteristics
Channels:  2, stereo
D/A conversion:  1-bit linear/channel
Transports Type:  CDM4/D36
DAC Type:  TDA 1547
Frequency Characteristics
Line Output Jack:  20 to 20.000 Hz, ±0,2 dB
Dynamic Range:  96 dB
Signal-to-Noise Ratio:  108 dB
Channel Separation:  100 dB or more (at 1kHz)
Total Harmonic Distortion:  0,0015% (at 1kHz)
Wow & Flutter:  Precision of quartz
Analog Output Jacks:
Line Output Jacks:  Output level 2 V RMS
Output Impedance:  100 Ohms
Matching Load Impedance:  10 k Ohms or more
Digital Output:  Pin jack, 0.5 Vp-p/75 Ohms (rectangular optical connector), optical output -19 dBm
Optical Readout System
Laser:  AlGsAs semiconductor
Wavelength:  780 nm
Signal System
Sampling Frequency:  44.1 kHz
Quantization:  16-bit linear/channel
Error Correction:  Cross-interleave read solomon code (CIRC) class A D/A conversion
Power supply
Voltage:  230 V
Line Frequency:  50 Hz or 60 Hz
Power Consumption:  18 W
Cabinet, etc.
Dimensions (W x H x D):  457 x 136 x 358 mm
Weight:  approx: 16.5kg

JBL L26 Decade

 The L26 was developed through the technology that made JBL the leading manufacturer of loudspeaker system for professional use. It meets the same stringent requirements as JBL studio monitors, providing clear, crisp reproduction, freedom from distortion and lack of coloration - all reasons most major recording groups insist on JBL professional loudspeakers for live performances as well as studio recording.
The L26 achieves the open, effortless performance that is characteristic of JBL loudspeaker systems. It even approaches, within just a few decibels, the thunderous volume levels required of JBL monitors in the recording studio. Each component of the L26 - low frequency loudspeaker, high frequency direct radiator frequency dividing network and enclosure - has been designed to function as part of the complete system, optimizing performance and efficiency without sacrificing definition orthe ability to accurately reproduce the fleeting bursts of sonic energy, known as transients, so essential to realism.
Like all JBL loudspeaker system, the L26 utilizes a ported enclosure to increase efficiency and dynamic range rather than a sealed "acoustic suspension" enclosure which achieves bass response at the expense of efficiency, dynamic range and transient reproduction. Efficiency is important for two reasons; it permits use of a relatively low power, moderately priced amplifier, and it allows the amplifier to operate at a lower power level, providing the reserve necessary to achieve full dynamic range and excellent transient reproduction. Efficiency and outstanding reproduction make the L26 ideal for the music listener wanting to combine superb performance with compact size.

 Technical Information
Each component of every JBL loudspeaker system is designed and produced by JBL personnel to the most rigorous standards in the industry. JBL loudspeaker frames are massive cast structures, produced to exacting tolerances. Magnetic assemblies are precisely manufactured of low-reluctance iron, energized by large, high grade megnets. Voice coils are held to within one turn of design specifications. Stamped frames and mass-produced voice coils would be less expensive; however, the resultant loss of structural integrity, magnetic force and acoustic efficiency would tend to degrade low-distortion performance and transient response - qualities that have become JBL hallmarks.

 The L26 Enclosure
The enclosure, embodyying every concept of fine furniture design and construction that has made JBL leader of the industry, complements the  acoustic characteristics of the loudspeaker system. It utilizes a ducted port extending through the baffle panel to provide the proper resistive load on the loudspeaker cone for improved efficiency and dynamic range. To achieve maximum strength and resistance to vibration, all panels are constructed of 3/4-inch stock, side and back panels are lined with acoustic padding, and all joints are hand-fitted, lock-mitered and wood-welded.
The search for refreshing visual approach to loudspeaker enclosures led JBL to explore the use of new finishes, in this case natural oak. The beauty of its grain structure is brought out by a hand-rubbed oiled finish. The contrast of the contemporary grille and natural finish reflects the most recent decorator trends, permitting use of the L26 as an active design element in the listening room.

 High Frequency -
The 1,4-inch direct radiator contributes to the dramatic  presence of the loudspeaker system and provides accurate reproduction of delicate overtones and harmonicas extending beyond the range of human audibility. Presence creates the feeling that a performance is taking place in front of the enclosure, rather than coming from within it.
As in the low frequency loudspeaker, the high frequency direct radiator combines a large voice coil interacting with a powerful magnetic potential for efficiency and transient reproduction with definition and accuracy. The small diameter of the cone and center dome provides a wide sound distribution pattern, assuring that each listener hears the same tonal balance and blend of direct and reflected sound, regardless of position withhin the listening area.
The entire dynamic assembly is surrounded by a ring of dense foam damping material to absorb unwanted radiation and reflections.

Low Frequency -
Solid, well-defined reproduction is provided by a 10-inch, long excursion loudspeaker. Its massive Alnico Vlow-loss magnetic assembly concentrates all the magnetic energy where it contributes most to loudspeaker performance - the voice coil gap.
A massive die cast aluminum frame maintains the precise alignment of the voice coil within the gap to a tolerance of ane thousandth of an inch. An ordinary stamped frame cannot insure the structural rigidity necessary for long term, low-distortion performance. The copper voice coil, two inches in diameter, drives an integrally stiffened cone. This large coil, interacting with the magnetic force, provides the physical drive necessary for instantaneous transient reproduction; the mass and stifness of the cone have been carefully researched to provide optimum low frequency performance and definition. The cone is suspended at its outer edge by a highly flexible ring to absorb extraneous sound waves within the cone material and allow the long excursion necessary to achieve dynamic range and extend bass response through the lowest registers of the audio spectrum.

 Dividing Network -
The function of a properly designed frequency dividing network is much more complex than simply directing low and high frequency information to the appropriate reproducer. Vitally important to the sound of a loudspeaker system is precise control of the drivers through the transition frequencies. To accomplish this, the tolerances of JBL network components are much more stringent than normal industry practices. The network,installed in the l26 has a continuously variable control permitting adjustment of the relative loudness of the high frequency direct rdiator to satisfy individual preferences and the acoustic properties of the listening room.

Power Capacity
The specified power capacity indicates the continuous program power level that can be accepted by a JBL loudspeaker  system without damage. Its peak power capacity is considerably greater than the continuous rated value, as indicated by the remarkable transient response of JBL loudspeaker system components. The L26 will reproduce clean sound at comfortable listening levels when driven by an amplifier having an output of as little as 10 Watts RMS per channel. However, for reproduction of the full dynamic range of contemporary recordings at high volume, a quality amplifier delivering up to 60 Watts RMS per channel will provide optimum performance. Such an amplifier has the reserve power necessary for accurate reproduction of transients, which can reach momentary peaks equivalent to ten times the average power level. In almost all cases, the volume level generated by a JBL loudspeaker will become noticeably discomforting to the ear before the loudspeaker can be damaged by excessive power from the amplifier.

JBL attributes major importance to the validity of published information.  Rather than repeat the ambiguity of most technical specifications, JBL has traditionally refrained from listing data  for which no widely-accepted test procedure has been established. In the absence of such standards any wellequipped laboratory can legitimately produce a variety of frequency response curves for a loudspeaker, depending on the conditions selected. At JBL the final analyses are comprised of extensive listening sessions. Although laboratory data are an integral part of the process, the trained ear is the ultimate criterion.  The success of this philosophy is reflected in the enthusiastic acceptance of JBL systems by recording studio engineers, producers and performers - professionals whose artistic achievements are closely related to the equipment they use. In every critical listening situation - wherever the sound of the loudspeaker must be depended upon - JBL is the overwhelming professional choice.

Power Capacity:  35 Watts continuous program
Nominal Impedance:  8 ohms
Dispersion:  90° horizontal and vertical
Crossover Frequency:  2000 Hz
Efficiency:  76 dB (1 Watt at a distance of 15 feet)
Low Frequency Loudspeaker
Nominal Diameter : 10 inches (250 mm)
Voice Coil : 2 inch (50 mm) copper
Magnetic Assembly Weight : 2,5 pounds (1,1 kg)
Flux Density : 8500 gauss
Sensitivity : 40 dB
High Frequency Direct Radiator
Nominal Diameter : 1,4 inches (36 mm)
Voice Coil : 5/8 inch (16 mm) copper
Magnetic Assembly Weight : 1,6 pounds (0,7 kg)
Flux Density : 15,000 gauss
Sensitivity : 47 dB
Finish: Natural Oak
Grille:  Stretch fabric
Grille Color Options:  orange, Blue, White or Brown
Dimensions:  12-3/4 x 24 x 13-1/4 inch (320 x 610 x 34 mm)
Weight:  41 lbs (19 kg) shipping