On Mon, Jun 25, 2018 at 6:31 PM, Tim <termtech(a)rogers.com> wrote: ​but can it handle negative harmony?​ ​

Den 2018-06-26 kl. 00:31, skrev Tim: <snip> From the abstract of the patent [1] [2] "An audio matching method, use of the method in a game system, an audio matching system and a data carrier are provided, where the audio matching method is for comparing an input audio fragment with reference audio fragment variants, the method being an incremental search method, including repeating the steps of: obtaining a number of reference audio fragments variants on the basis of one or more stored audio fragments from a reference storage; and comparing the input audio fragment against the number of reference audio fragment variants to determine a comparison result; whereby repetition of the steps is carried out a predetermined number of times or as long as the comparison result improves." SOS had a review of it 4 years ago [3] ref. [1] https://patentimages.storage.googleapis.com/93/f6/7b/30b78e5067b5e5/US20120… [2] https://patents.google.com/patent/US20120132057A1/en [3] https://www.soundonsound.com/reviews/jam-origin-midi-guitar Cheers, -- /bengan

Le Mon, 25 Jun 2018 18:31:12 -0400, Tim &lt;termtech(a)rogers.com&gt; a écrit : <snip> To go fast and get a low enough latency, you can use can what time is between 2 consecutive peaks of the signal. Be aware than you would have to smooth the signal because when playing loud and the strings are touching the frets, the harmonic content become so weird you can get false maximums (as seen by a signal analysis of my electrical guitar with a memory oscilloscope), which will give you a much higher fundamental frequency than expected. Normal signal: * * * * * * * * * * * * * * * * * * * * * * *=========*=========*=========*==== * * * * * * * * * * * * * * * * * * Fretted signal: * * * * * ** * * ** * * * * * * * * * * * * * * * * * * * *=========*=========*=========*==== * * * * * * * * * * * * * * * * * * These double peaks can be very huge as an electrical guitar have a huge dynamic during the attack of the notes. Doing a repetitive arithmetic average calculation when the sampling are coming in must be enough to smooth them in real time, and to get ride of other high order harmonics at the same time. The latency will be dependant of the fundamental frequency, something like one period + trigger delay. Cheers, Dom -- If you have a problem and you are not doing anything to fix it, you are at the heart of the problem.

On Mon, Jun 25, 2018 at 4:31 PM, Tim &lt;termtech(a)rogers.com&gt; wrote: Had I sufficient time I'd like to investigate using hidden markov models and turbo coding the way some speech recognition algorithms do. This could give you estimates of the key you are playing in and use that data to calculate the likelihood of various pitches etc etc. I suspect you could get some interesting results. I don't know of anyone really working on polyphonic pitch recognition in the open source world. I think Bayesian filtering of some kind though would be compelling. Perhaps some of the work from ISSE ( http://isse.sourceforge.net/) could be used and made realtime. _Spencer