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PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

thesis project: in-ceiling loudspeaker: survey
thesis project: in-ceiling loudspeaker: survey
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Old 3rd September 2013, 12:50 AM   #11
mickeymoose is offline mickeymoose  Canada
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Join Date: Nov 2008
Active paging systems were promoted about 30+ years ago. Analog of course, not D-amps. As I recall they used a 3-wire system and had a 1 or 2 transistor circuit at the speaker location. The name Davis (not Don or Chip) is in my mind. Heavily hyped, low sales.
There is no reason with todays technology to have D-amps at each speaker location, phantom powered, with additional control signals in sub-audio, all on a single pair of wires.
I'd jump right in, where I but younger! E
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Old 3rd September 2013, 10:24 PM   #12
Robbie42 is offline Robbie42  United States
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Join Date: Mar 2009
Location: South Florida

The system you are speaking of was designed by Dr. Richard Heyser, and was manufactured and sold by J.W. Davis in Dallas, Texas. It was called the D.S.A. (distributed signal amplification), or something close to it, and actually sounded nice for smaller background music installations, and the like, although it could be problematic at times (it was sensitive to cable capacitance, and thus was prone to violent oscillation when it didn't "like" the cable provided, or the length of said cable.
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Old 4th September 2013, 11:53 AM   #13
phase_accurate is offline phase_accurate
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Join Date: May 2002
Location: Switzerland
For the lowering of structural sound I'd go for a design with two drivers in opposite positions and thereby canceling inertial forces. One is radiating downwards and the other one upwards having its radiation "bent" down via some kind of reflector. One of the drivers has to be behind a lowpass filter. The whole arrangement can be made looking flat when mounted into a hollow ceiling.


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