Intro
Contents
Yours truly was visiting a friend who was cleaning out his office; he asked me to check if there was anything interesting in music equipment. If not, the thrift store would pick it up. There was a lot to see, including a collection of historic 78 rpm records and an antique mechanical gramophone with horn. A fullsize 12″ laserdisc player. And a pair of Bowers & Wilkins speakers, type DM5. Surprisingly, the drivers still seem to be in good condition and were not cracked or dried out. Wonder how these would sound nowadays? Read on!
Bowers’ DM5 series dates back to 1976; at that time, the company was 10 years. The DM5 is the successor to the D5, also a small-sized speaker. In the 70s, home loudspeakers were often on the large side. Driver technology had not yet advanced to the point where room-filling sound could come from small speakers. In 1976 B&W began developing the 800 series, with the 801 being introduced in 1979. On the face plate we can read that the DM5 states is made in Worthing, the place where Bowers & Wilkins started and where the 800 series is still manufactured. DM is an abbreviation for Domestic Monitors and that is exactly what the series stands for; compact speakers intended for use in a medium-sized home. The DM1 was launched in 1968 and later evolved into the 600 Series.
70s
Reading the DM5 user manual is like a time travel to the 70s. The list of international distributors  mentions Dutch company Audioscript; nice to note that Audioscript was the very first importer of B&W products outside the UK. Currently, Audioscript is an importer of Luxman. B&W was on the cusp of great development in the mid-1970s, in company size and in products. The DM5 comes from the period when it was still a relatively artisanal brand with production facilities close to the company’s core.
Q
The DM5 is a two-way monitor in a closed cabinet. Crossover filtering is at 4.5 kHz. The manual also addresses the Q factor: the degree to which the speaker is able to absorb the energy of the driver. The higher the Q, the less there is energy dissipation. The lower the Q, the better the speaker’s enclosure can handle the energy and the less there is unwanted resonance. According to the manufacturer, the DM5 has a Q of 0.75 and the system resonance is at 53 Hz. These would be values appropriate for speakers many times larger than the DM5. B&W therefore promises “a big sound from a small enclosure.”
