STEREO SYNTHESIZER

• US 3,670,106 A
• Filed: 04/06/1970
• Issued: 06/13/1972
• Est. Priority Date: 04/06/1970
• Status: Expired due to Term

• Current Assignee: AKG Acoustics, Inc. (Samsung Electronics Co. Ltd.), Simmons Healthcare, Inc.
• Original Assignee: Robert A. Orban
• Inventors: Orban, Robert A.
• Primary Examiner(s): Cooper, William C.
• Assistant Examiner(s): Brauner, Horst F.
• Application Number:
  US05/025,775
• Time in Patent Office: 799 Days
• Field of Search: 179/6,6A,6P
• US Class Current: 381/17
• CPC Class Codes: H04S 5/00 Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation

Abstract

A stereo synthesizer for synthesizing a stereo output from a monophonic input, according to which a source of monophonic sound signals is connected to two sound channels, the signals being applied directly to the two sound channels and also in delayed fashion thereto by means of a network transfer function so as to reinforce the direct signals in one channel and oppose them in another channel as a function of frequency. The network transfer function is such that the amplitude of the frequency response is independent of frequency while the phase response varies as a function of frequency.

Claims

1. Stereo synthesizer apparatus for synthesizing a stereo output from a monophonic input comprising:

a source of monophonic sound signals, means directly connected to said monophonic source so as to form at least two separate sound channels for conveying said monophonic sound signals, electrical means connected in one of said channels providing a network transfer function for producing phase-delayed signals, according to which the degree of phase shift varies continuously and non-linearly with frequency, means, directly connected to said electrical means, for combining the input signals from said separate sound channels, including said phase-delayed signals, so as to produce at the output channels thereof, respectively, enhancement signals and opposition signals corresponding to the algebraic sum of the input signals and opposition signals corresponding to the algebraic difference between the input signals, and transducer means directly connected to said output channels of said means for combining so that the respective enhancement and opposition signals are reproduced by said transducer means.

2. Apparatus as defined in claim 1, further comprising electrical means for producing phase-delayed signals connected in another of said separate sound channels.

3. Apparatus as defined in claim 2, further including electrical means for adjusting the phase response of either or both of the means for producing phase-delayed signals.

4. Apparatus as defined in claim 2, further including means for controlling the ratio of the gains of the two means for producing phase-delayed signals, whereby control is established over the separation of the two output channels.