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In the Forum: Horn-Loaded Speakers
In the Thread: Horn Enclosures & "Non-standard" Drivers. Some Experience.
Post Subject: Horn Enclosures & "Non-standard" Drivers. Some Experience.Posted by Teodor on: 7/22/2011
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This project started in 2007 as an attempt to demonstrate that drivers different from the widely accepted low-Qts ones could be used in a back-loaded horn enclosures.
Visaton BG13P, a cheap and easy-to-get (at least in Europe) driver was chosen, basic T/S data as follows: Qts 1.04, Qes 1.58, SPL 92 dB/W/m, Fs 168 Hz. [paper voice coil former, not stated on manufacturer's site]
Nothing special for the back-loaded horn design, I think, throat area 27 cm2 (4.18 sq.in), mouth area 1438 cm2 (230 sq.in), horn contour length 215 cm (84.6"), hyperbolic-exponential type of contour [М(Т)=0.55], cut-off frequency set to 57 Hz, horn enclosure internal width 200 mm (7.9"). The volume of chamber behind the driver is less than 1 l (61 cu.in), maybe around 0.5 l (30 cu.in). Lowest audible frequency expected to be 10-12 Hz below the cut-off frequency, i.e. 45-47 Hz. Corner placement.
During the first listening tests, when placed at room's corners (a room with a relatively low /and sloped/ ceiling, though) these horns with these drivers indeed demonstrated lowest audible frequencies around 43..44..47 Hz, of course - with lower sound level than at 55..60..80 Hz, although this unevenness is not so embarrassing. No measurements have been ever taken. For me, surprisingly to some extent was the extremely small diaphragm displacement at sound levels such that the conversation between the listening tests participants was hardly possible. The overall impression of these horns is of not a quite bad sound reproducing devices 
OK, let me here now your comments. Any kind of opinion would be much appreciated. Thank you.
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