Dick Burwen’s 20,000 Watt Home Hi-Fi System with AUDIO SPLENDOR. Three of five speaker horns shown.
Dick started designing the equipment for his current sound system in 1962 and it is almost finished. His “preamplifier” occupies 3-1/2 racks 7 feet high at the back of his sound studio. In 2009 he disconnected some of the analog tone control units, still in excellent working condition, because they were obsoleted by his new computer digital signal processing system. The small discrete component operational amplifier cubes in the grey panels at the bottom became the basis of Analog Devices’ first products in 1966.
The first unit designed was an automatic lighting controller that responds to the music. Mounted in a half-rack outside the left edge of this photo, It delivers up to 20 A at 115 V AC on each of 4 channels. It has been in use 70 hours per week since 1966. Bass is red, middles are green, and highs are yellow. The control circuit boards were redesigned for improved performance in 1982, but the silicon controlled rectifier power stage is the same as it was in 1962.
Each speaker horn has a conical flare and is 13 feet deep. The mouth of each front horn is 8 feet x 8 feet. At the throat, a JBL mid-range exponential horn with a pair of 2440 compression drivers delivers sound between 400 Hz and 6 kHz. An array of 30 Cerwin-Vega tweeters reproduces sound from 6 kHz to 20 kHz. Behind the mid-range horn are two 16-inch Empire woofers covering 15 Hz to 400 Hz. The left front and right front horns each have two 24-inch Cerwin-Vega sub-woofers for frequencies below 50 Hz.
The active crossover network equalizes the speakers. Dick spent a year tweaking its frequency response so that a recording of his son, Russell, playing drums in the front center horn, became difficult to distinguish from the real drums. Below is the crossover frequency response.
