{
  "patent_number": "US 8168877",
  "country": "US",
  "title": "How to Automatically Generate Musical Harmonies from Audio",
  "original_title": "Musical harmony generation from polyphonic audio signals",
  "summary": "This 2012 patent describes a system that listens to music and automatically generates harmony notes to accompany a melody, even detecting and ignoring accidental strums on stringed instruments.",
  "what_it_does": "This patent details an apparatus that can create musical harmonies. It takes a melody signal and an accompaniment signal, analyzes their sound content, and then figures out what harmony notes would sound good. Specifically, it identifies the current melody note and looks at the 'spectral content' (basically, the mix of frequencies) of the accompaniment music. Using this information, it generates at least one harmony note. A clever part is its ability to detect and ignore 'unintentional strums' from stringed instruments, like when a guitarist accidentally brushes strings during a chord change, so it doesn't mess up the generated harmony. It can even output these harmonies as MIDI data or mix them with the original sounds for real-time performance.",
  "what_it_does_not_cover": [
    "Generating harmonies without analyzing the spectral content of an accompaniment signal",
    "Generating harmonies without identifying a current melody note",
    "Harmony generation that does not suppress determination based on an unintentional strum",
    "Methods that do not involve receiving at least one polyphonic electrical signal from a multi-stringed instrument",
    "Detecting unintentional strums without comparing received notes to templates based on open string tuning"
  ],
  "filed": "2007-10-02",
  "granted": "2012-05-01",
  "expires": "2027-10-02",
  "status": "active",
  "holder": "Harman International Industries Canada Ltd",
  "holder_url": "https://patentbrief.org/company/harman-international-industries-canada-ltd",
  "inventors": [
    {
      "name": "William Norman Campbell",
      "url": "https://patentbrief.org/inventor/william-norman-campbell"
    },
    {
      "name": "Peter R. Lupini",
      "url": "https://patentbrief.org/inventor/peter-r-lupini"
    },
    {
      "name": "Glen a. Rutledge",
      "url": "https://patentbrief.org/inventor/glen-a-rutledge"
    }
  ],
  "times_cited": 24,
  "tags": [
    "consumer_electronics",
    "software",
    "telecommunications"
  ],
  "abstract": "Melody and accompaniment audio signals are received and processed to identify one or more harmony notes and a harmony signal is produced based on the one or more harmony notes. Typically the melody note is identified and a spectrum of the accompaniment audio signal and is obtained, and one or more harmony notes are identified based on the melody note and the accompaniment spectrum. The melody, and accompaniment signals can be processed in real-time for combination with the harmony signal in an audio performance. In some examples, audio signals are processed and harmonies generated for subsequent performance based on, for example, MIDI files generated from the audio signals.",
  "url": "https://patentbrief.org/patent/us/8168877/musical-harmony-generation-from-polyphonic-audio-signals",
  "markdown_url": "https://patentbrief.org/patent/us/8168877/musical-harmony-generation-from-polyphonic-audio-signals/md",
  "google_patents_url": "https://patents.google.com/patent/US8168877",
  "relatedPatents": [
    {
      "patentNumber": "5973252",
      "countryCode": "US",
      "title": "How Real-Time Pitch Correction and Auto-Tune Technology Works",
      "url": "https://patentbrief.org/patent/us/5973252/auto-tune-pitch-correction"
    },
    {
      "patentNumber": "12277178",
      "countryCode": "US",
      "title": "How Music Apps Learn What You Don't Want in Playlists",
      "url": "https://patentbrief.org/patent/us/12277178/media-content-item-recommendation-system"
    },
    {
      "patentNumber": "5579430",
      "countryCode": "US",
      "title": "How Digital Audio Compression Works",
      "url": "https://patentbrief.org/patent/us/5579430/digital-encoding-process"
    },
    {
      "patentNumber": "11361763",
      "countryCode": "US",
      "title": "How Smart Speakers Know You're Talking to Them After a Command",
      "url": "https://patentbrief.org/patent/us/11361763/detecting-system-directed-speech"
    },
    {
      "patentNumber": "6424946",
      "countryCode": "US",
      "title": "How Computers Automatically Label Different Speakers in Audio Recordings",
      "url": "https://patentbrief.org/patent/us/6424946/amazon-personalized-recommendations"
    }
  ]
}