B&W Bowers & Wilkins DM2, 1973, made in England

Link: hifiengine | audio-heritage

Book shelf type monitor speaker system. 
DW 200 which is a 20 cm cone type Woofer using a BX (Bextrene Cone) cone is carried in low-pass. 

This unit was designed focusing on the frequency characteristics and distortion characteristics of a particularly important midrange, and in addition to the effective diameter 150 mm BX cone with a center dome of 54 mm diameter, aluminum bobbin that can withstand large inputs and special resin processing 38mm voice coil, high compliance rubber edge is used. As a result, the linearity and resistance to input characteristics of the mid range are improved. 

HF 1300 which is 3.5 cm dome type tweeter which is also used for BBC monitor speaker is carried in high region. 

The 1.8 cm dome type super tweeter is carried in the super high region. 

The network section has adopted a blocking characteristic of 18 dB / oct which applied phase correction and impedance correction to the high pass part of the high frequency range.

B & W's proprietary ALL system (Acoustic Line Load System) is adopted as an enclosure, lowering the low-pass characteristics and lowering the total harmonic distortion and Doppler distortion as compared with the conventional load method. 
ALL method is a kind of backload type, but unlike conventional backload type and maze type, it is very short reverse horn type. In addition, three different types of sound absorbing materials are packed in the interior of the horn. This horn length is designed to 1/8 of the wavelength, suppressing corn excursion (cone fluxing phenomenon) of 30 Hz to 60 Hz, and using the frequency characteristic of this band. In addition, unnecessary mid-range energy on the back of the DW 200 is attenuated by three kinds of sound absorbing materials, which together with an enclosure using a high-density chip board minimizes coloring and unnecessary sound in the mid-low range I will.

method 3 way · 3 speaker · ALL method · book shelf type
  • For low-pass: 20 cm cone type (DW 200) 
  • For high regions: 3.5 cm cone type (HF 1300) 
  • For super high region: 1.8 cm dome shape

Frequency characteristic 35 Hz to 25 kHz
Maximum input 60 W
Impedance 8 Ω
Output sound pressure level 90 dB (SPL)
Crossover frequency 2.5 kHz, 12 kHz
Network attenuation 18 dB / oct.
External dimensions Width 352 × height 644 × depth 345 mm
weight 23 kg
Optional Pedestal (leg) STA / 2 (price unknown)

Unit                                DW 200               HF 1300             Super Twitter
Model                        BX cone type       Plastic cone     Plastic dome
Nominal diameter        200 mm               35 mm             18 mm
Cone diameter        150 mm               -                              -
Edge                        Rubber / Roll       -                              -
Voice coil diameter.      38 mm              21 mm             18 mm
VC Impedance        8 Ω                      16 Ω                     8 Ω

самый первый выпуск, модель DM2 без других индексов типа "мк2" и "a"