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

B&W DM-550

 Following on from B&W's highly acclaimed and successful 100 Series, the DM550 digital monitor takes full advantage of a whole new generation of design technology to produce improved performance with a higher frequency range and lower colouration.  With its aesthetically pleasing styling, your DM550 is designed to anticipate individual preferences and match all types of environment.
System parameters for the B&W 500 Series have been optimised by the extensive use of computer aided design to ensure efficient and extended low frequency performance. To achieve the goal of flatter response curves and lower colouration, totally new drive unis have been designed - benefiting from the use of finite element predictions of cone behaviour and laser interferometer assessment of prototypes. Quite deliberately, the B&W 500 Series of loudspeakers are described as digital monitors. They have been designed for the age of the compact disc, with all the additional requirements that this material places on the loudspeaker system - such as increased dynamic range, increased transient information, lower noise floor, etc. B&W DM550 is however, just as much at home with good analogue material and essentially will faithfully reproduce whaatever signals are fed to it.
 Stand-mount/Bookshelf loudspeaker system
The tailored two-way closed box design incorporates a 6" bass/midrange driver with a large magnet assembly thrusting high pressure sound reproduced to precise limits dictated by the dimensions of small enclosure.
A one piece moulding has been used to strengthen the cabinet rigidity between drivers and front baffle. The metal-domed high frequency unit dictated by CAD allows the simplest of crossovers to be used. All of which increases cost-effectiveness without impairing linearity.
 Technical highlights
B&W's Tweeter technology ensures that the sound remains focused and time sensitive and that the stereo image is presented with unparalleled three dimensional accuracy.
The cabinets feature a specially designed high density front baffle which achieves almost Matrix-like stability in strengthening overall enclosure construction. The bevel edges of the front moulding reduce diffraction and improve dispersion.
The crossover components use heavy gauge wire throughout and new drivers guarantee not only high reliability but ensure that top specifications are met
 The design brief for DM550 called for a small and cost-effective loudspeaker that could be incorporated unobtrusively into the home, while still possessing the linearity and bass extension of true monitor system.

The drive units
The two-unit closed box alignment chosen for DM550 employs a specially designed 160 mm (6") bass driver, with 26 mm (1") high temperature voice coil. This enables a simple crossover to be employed which not only increases cost effectiveness but retains system linearity.
The new metal-domed tweeter uses the same diaphragm as the highly acclaimed Matrix 801 Series 2, and gives true piston behaviour up to frequencies in excess of 20 kHz. And like all B&W components, it's B&W made.
The enclosure
The expertise B&W have gained with cabinet technolgy following the invention of the B&W Matrixx Series has enabled us to reduce unwanted cabinet vibration. In the case of the 500 Series  our attention has been focused on the front baffle construction, and we make full use of modern structural plastics, to both strengthen and enhance the appearance.
 The crossover
Sophisticated computer technology has enabled B&W  to optimise each component in the crossover network at the design stage. Every production sample is also computer-tested to close tolerance, ensuring that each loudspeaker faithfully reproduces the original design specifications.

Overload protection
A 2-amp quick-blow fuse protects the system against excessive input of normal musical signals. However, certain abnormal signals, particularly those containing only high frequencies, could damage the tweeter. The usual precautions, such as turning off the amplifier before connections are made, should be observed. The fuse is located in the rear of the cabinet.
Frequency Range:  56 Hz to 30 kHz (-6 dB points)
Bass Loading:  Second-order closed box alignment
Frequency Response:  75 Hz 20 kHz, ±2,5 dB on reference axis
Dispersion:  20 Hz to 15 kHz
Vertical :  ±2 dB over 10° arc
Horizontal :  ±2 dB over 40° arc
Sensitivity:  87 dB (2,83 V/ 1 m)
Distortion (For 90 dB at 1 m)
Second Harmonic :
Less than 3% at 20 Hz to 200 Hz
Less than 1% at 200 Hz to 20 kHz
Third Harmonic:
Less than 2% at 20 Hz to 200 Hz
Less than 1% at 200 Hz to 20 kHz
Impedance: Nominal 8 Ω (not faling below 4 Ω)
Crossover:  third-order acoustic response low-pass and high-pass
Drive Units:
1 x 26mm high-frequency with aluminium dome, One 26mm coil on aluminium former, wound with polymide resin and heat cured
1 x 160mm bass/midrange with composite short fibre, 26mm coil on high temperature former, wound with polymide resin and heat cured
Power Handling:  Suitable for amplifiers with 10 W to 75 W output
Dimensions (H x W x D):  352 x 204 x 243 mm (13-7/8" x 8" x 9-1/2")
Weight:  5,5 kg  (12 lbs)

Cabinet Finish:  Simulated veneers of walnut or black ash

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