Patent Publication Number: US-5894523-A

Title: Voice delay feedback apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a novelty apparatus having a microphone and earphones, and in which an audio signal input to the microphone is delayed and fed back to the earphones so as to make speech difficult, humorous, discombobulated, and often unintelligible. 
     2. Description of the Related Art 
     Audio feedback loops are well known in the audio field. Generally speaking, a feedback loop is an undesired consequence of having an amplified audio signal fed back through the amplification loop. In an audio system, a microphone is used to receive an audio input signal, which is then amplified by an audio amplifier and output through a speaker. The feedback loop is created when the output signal from the speaker is subsequently received by the microphone. The feedback can cause undesired consequences, typically a high-pitched squeal sound, when the input signal and the amplified signal are out of synch with each other, or distortion. In general, audio feedback is an undesired side effect in audio systems. 
     On the other hand, in order to speak properly humans typically require audio feedback between what they say and how they hear what they say. In other words, in order to speak properly the person speaking must hear what he or she is saying. In the absence of such feedback (such as when a person is deaf), speech becomes difficult. If a device can change such feedback, then it can interfere with normal speech. Such a system could be used as a novelty device in order to observe the reaction of the user&#39;s speech to the feedback. Such person speaks as if they were drunk or a stutterer. 
     SUMMARY OF THE INVENTION 
     The present invention is an audio delay and feedback apparatus which includes i) audio input means for receiving an input audio signal and for generating a first electrical signal corresponding to the input audio signal, ii) delay means for receiving the first electrical signal and for generating a second electrical signal corresponding to but delayed from the first electrical signal by a predetermined amount of time, and iii) audio output means for receiving the second audio signal and for generating an audio output signal corresponding thereto. 
     The audio input means is preferably a microphone and the audio output means is preferably earphones, with the microphone and earphones are mounted on a headset. The delay means is preferably also mounted on the headset, making the unit self-contained. 
     In a preferred embodiment, the first electrical signal is digital and the delay means comprises a digital memory. An A/D converter digitizes the first electrical signal and a D/A converter converts the second electrical signal to an analog signal. The system includes a memory for storing the first electrical signal and playback means for selectively playing back the memory to the audio output means. This enables the user to playback a previously recorded segment to enable the user to hear how he/she sounded while speaking and simultaneously receiving delayed feedback. The playback means is preferably a manually actuated switch on the headset. 
     In an alternative embodiment, the delay means includes i) a moving continuous magnetic tape, ii) a write head for writing the first electrical signal onto the magnetic tape, and iii) a read head spaced from the write head for reading the first electrical signal from the tape, the read head generating the second electrical signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram of the audio feedback system of the present invention. 
     FIG. 2 is a schematic diagram of a digital embodiment of the delay circuit of the invention. 
     FIG. 3 is a schematic diagram of an audio tape embodiment of the delay circuit of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, the present invention is a novelty audio feedback device that is generally self-contained in a headset 2. Headset 2 includes a microphone 4 positioned near the mouth of the user, and at least one, and preferably two, earphones 6. This type of headset is conventionally worn by telephone operators, singers and the like. Conventional wiring connects the microphone and earphones to a delay circuit 10. 
     The function of delay circuit 10 is to receive an audio input signal from microphone 4, to delay the audio signal by a predetermined amount of time, and to output the delayed audio signal to headset 2. In a preferred embodiment, the predetermined time delay is in the range of 1/2 second to 2 seconds. However, any appropriate time delay may be utilized as desired. Thus, in the system of the invention the sounds made by the person talking are delayed and played back to the ears through the earphones 6. This causes confusion to the speaker and renders the speaker unable to speak intelligibly. Typically, a user will not even be able to count to ten without repeating and/or skipping numbers. Saying simple nursery rhymes also becomes very difficult and the person comes across as being unintelligible, drunk, very humorous, as their speech is often incoherent. 
     Delay circuit 10 preferably includes batteries for powering the delay circuit, microphone 4 and earphones 6. Alternatively, delay circuit 10 may be powered by any appropriate A/C or D/C power source. 
     Delay circuit 10 may utilize any appropriate circuitry for introducing a time delay in an audio signal. In a preferred embodiment, as shown in FIG. 2, digital circuitry is used to implement the time delay. The input from microphone 4 is channeled through an analog-to-digital (A/D) converter 28 and input to a delay circuit 24. Delay circuit 24 is preferably a first-in/first-out memory that receives the digitized input signal and outputs the same digitized signal a predetermined time thereafter. The delayed digitized signal is then input to a digital-to-analog (D/A) converter 30 and output to headphones 6. A playback memory 26 is provided for storing the input from microphone 4 for a predetermined amount of time, preferably about 15 seconds. Memory 26 preferably records the sounds made by the user for later playback so that the user may hear how they sounded during use of the device. Delay circuit 10 preferably includes an on/off switch 20 and a playback switch 22. When playback switch 22 is actuated, the contents of memory 26, i.e., the previous 15 seconds of input from microphone 4, are output to headphones 6. 
     In an alternative embodiment, as shown in FIG. 3, a continuous loop of moving magnetic tape 32 may be utilized to delay the audio input from the microphone. The audio input from the microphone is input to a conventional record head 34 which records the analog audio signal onto moving magnetic tape 32. A predetermined time later, e.g., 1/2-2 seconds later, the recorded-upon portion of the magnetic tape passes read head 36 which reads the magnetic signal from moving tape 32 and outputs the signal to headphones 6. 
     It will be appreciated that any appropriate circuit for delaying the audio input signal, such as a fully analog circuit, fully integrated circuit or a microprocessor-based circuit, may be utilized as desired. Moreover, rather than being integrated within the headset, delay circuit 10 may be belt-worn, or a free-standing unit, e.g., a table-top mounted device. More generally, although the present invention has been described in detail with respect to certain embodiments and examples, variations exist that are within the scope of the invention as defined in the following claims.