Pressure wave transducing
First Claim
1. A system for transmitting pressure wave energy with a medium that propagates pressure waves comprising,transducing means having a vibratile surface for converting energy in one of pressure wave and electrical forms to the other,at least one low loss pressure wave transmission line means for transmitting energy between said medium and said vibratile surface,said pressure wave transmission line means having one end adjacent to said vibratile surface and the other end adjacent to said medium and an effective length corresponding substantially to a quarter wavelength at the lowest frequency of pressure wave energy to be transmitted between said medium and said vibratile surface.
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Accused Products
Abstract
A loudspeaker driver has its front surface adjacent one end of a low loss acoustic waveguide and its rear surface adjacent to one end of a second acoustic waveguide that is one third the length of the first. The other openings of the waveguides face air and couple acoustical energy substantially uniformly over a relatively broad range of frequencies extenting into the bass frequency region. An equalizer includes a notch filter so that the frequency response of the equalizer below a bass cutoff frequency is sufficiently low to prevent audible distortion.
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Citations
41 Claims
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1. A system for transmitting pressure wave energy with a medium that propagates pressure waves comprising,
transducing means having a vibratile surface for converting energy in one of pressure wave and electrical forms to the other, at least one low loss pressure wave transmission line means for transmitting energy between said medium and said vibratile surface, said pressure wave transmission line means having one end adjacent to said vibratile surface and the other end adjacent to said medium and an effective length corresponding substantially to a quarter wavelength at the lowest frequency of pressure wave energy to be transmitted between said medium and said vibratile surface.
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35. In a loudspeaker system characterized by a low bass cutoff frequency below which low bass cutoff frequency said system does not produce appreciable output sound energy including a vibratile surface and equalization circuit means for sharply reducing system response below said low bass cutoff frequency while maintaining system response in a passband above said low bass cutoff frequency the improvement comprising,
notch filter means comprising said equalization circuit means and having a notch frequency that is closer to said low bass cutoff frequency than to zero frequency for helping sharply reduce the system response below said low bass cutoff frequency, said notch filter means comprising means for reducing audible distortion emanating from said vibratile surface and maintaining said system response from said notch frequency to zero frequency significantly below said system response in the passband.
Specification