Vocal processing with accompaniment music input
Systems, including methods and apparatus, for generating audio effects based on accompaniment audio produced by live or pre-recorded accompaniment instruments, in combination with melody audio produced by a singer. Audible broadcast of the accompaniment audio may be delayed by a predetermined time, such as the time required to determine chord information contained in the accompaniment signal. As a result, audio effects that require the chord information may be substantially synchronized with the audible broadcast of the accompaniment audio. The present teachings may be especially suitable for use in karaoke systems, to correct and add sound effects to a singer's voice that sings along with a pre-recorded accompaniment track.
1. A method of generating a time-aligned harmony signal, comprising:
receiving an accompaniment audio signal;
analyzing the accompaniment audio signal to determine chord information corresponding to a chord of the accompaniment audio signal;
receiving a melody note from a singer;
generating a harmony signal harmonized to the chord of the accompaniment audio signal and the melody note;
transmitting the harmony signal to an output mechanism to produce output harmony audio;
causing the accompaniment audio signal to be stored in digital memory for a predetermined delay time; and
streaming the accompaniment audio signal to the output mechanism after the predetermined delay time has elapsed to produce accompaniment audio;
wherein determining chord information requires a first duration of time, and wherein the predetermined delay time is at least equal to the first duration of time.
2. The method of claim 1 , wherein the accompaniment audio signal is pre-recorded, and the melody note is received in real time from a karaoke singer.
3. The method of claim 1 , wherein the harmony signal is produced substantially in real time with receiving the melody note.
4. The method of claim 1 , wherein the predetermined delay time approximates the first duration of time.
5. The method of claim 1 , further comprising transmitting the melody note to the output mechanism.
6. The method of claim 5 , wherein the output mechanism is a loudspeaker.
7. The method of claim 5 , wherein the output mechanism is an output jack.
8. The method of claim 1 , further comprising:
determining a musical key of the accompaniment audio signal;
creating a pitch-corrected melody note by shifting the melody note received from the singer into the musical key of the accompaniment audio signal; and
transmitting the pitch-corrected melody note to the output mechanism.
9. The method of claim 1 , wherein the predetermined delay time exceeds the first duration of time by a time required to generate the harmony signal after receiving the melody note.
10. A harmony generating method, comprising:
causing a digital signal processor to:
(i) receive an accompaniment audio signal;
(ii) analyze the accompaniment audio signal to determine chord information contained within the accompaniment audio signal;
(iii) store the accompaniment audio signal in memory for a predetermined delay time while the chord information is determined;
(iv) after the chord information is determined, transmit the accompaniment audio signal to an audio output mechanism;
(v) receive a melody audio signal produced by a singer's voice;
(vi) generate at least one harmony note based on the chord information and the melody audio signal; and
(vii) transmit the melody audio signal and the harmony note to the audio output mechanism.
11. The method of claim 10 , wherein the audio output mechanism is a loudspeaker.
12. The method of claim 10 , wherein the audio output mechanism is an output jack.
13. The method of claim 10 , wherein the accompaniment audio signal, the melody audio signal and the harmony note are transmitted to the audio output mechanism substantially simultaneously.
14. The method of claim 10 , wherein generating the harmony note is based on the chord information excluding chord changes of less than a predetermined duration and also excluding chords determined to have been produced by percussion instruments.
15. A method of generating harmonized audio signals with a digital signal processor, comprising:
with a digital signal processor, receiving an accompaniment audio signal, analyzing the accompaniment audio signal to determine a chord of the accompaniment audio signal, and producing chord information corresponding to the chord;
with the digital signal processor, receiving a melody note produced by a singer, and generating a synthesized harmony signal corresponding to the melody note and the chord of the accompaniment audio signal;
storing the accompaniment audio signal in memory at least until the chord information has been produced; and
transmitting the accompaniment audio signal, the melody note and the synthesized harmony signal to an output mechanism to produce synthesized harmony audio, wherein the accompaniment audio, the melody note and the corresponding synthesized harmony audio are substantially simultaneously produced by the output mechanism.
16. The method of claim 15 , wherein the chord information includes chord duration information, and wherein the digital signal processor is configured to ignore chord changes lasting less than a predetermined threshold duration.
17. The method of claim 15 , wherein the output mechanism is a speaker.
18. The method of claim 15 , wherein the output mechanism is an output jack.
19. The method of claim 15 , wherein the accompaniment audio signal is pre-recorded, and wherein analyzing the accompaniment audio signal includes identifying and ignoring portions of the accompaniment signal that represent sounds produced by percussion instruments.
20. The method of claim 15 , wherein the accompaniment audio signal is pre-recorded, and wherein analyzing the accompaniment audio signal includes identifying and ignoring portions of the accompaniment signal that represent chord changes of less than a predetermined duration.