2011/3/5 Graham Percival <gra...@percival-music.ca>: > On Sat, Mar 05, 2011 at 12:54:31AM +0100, Janek Warchoł wrote: >> 2011/3/4 Graham Percival <gra...@percival-music.ca> >> > Well, playing on a $1000 (or even $1,000,000) violin is just a >> > matter of getting a recording of somebody tapping on such an >> > instrument. Such recordings (I only need 12 milliseconds of a tap >> > noise!) _are_ available online, but I haven't yet found a >> > recording which stated that it was available under the GPL. And >> > since sound recordings are covered by copyright, I can't just take >> > an existing one. :( >> >> Does this mean that Artifastring is already able to simulate violing >> sounds so perfectly that everything is a matter of "teaching" it how >> to do so? > > Artifastring is a very imperfect simulation of a violin. You can > think about this as having two stages: 1. the actions of the four > strings, and 2. the actions of the body (the "big empty part" of > the instrument). The way that it simulates the effect of a violin > body (or cello body) is by using a mathematical operation called > "convolution". This convolution is done by multiplying the sum of > the output samples of the strings with literally an audio > recording of tapping a violin. In engineering terms, this is an > approximation of the "impulse response". > > Because of this, switching to a different violin sound is purely a > matter of switching the "tap" recording. > >> I don't have much experience with violin, but judging by the audio >> samples i thought that it could use some improvement (independently of >> Vivi's playing skill improvement). > > Yes and no. The actions of the strings are imperfect, but the > violin used for the impulse response really is a bad instrument. > The "£100 pounds" figure actually included the bow, case, and > shipping. > > Also, generating an impulse response by tapping the instrument is > not a perfect impulse response. It's a decent approximation, but > serious acoustics researchers would use a frequency sweep or > something like that instead.
Ah, now i understand. Thanks for explanation. > But I'm not a serious acoustics researcher -- my goal is to > advance the art of automatic music performance. There's enough > work that I can do on performing chords, vibrato, and the like, > such that I'm not hugely concerned with the instrument quality at > the moment. And the methods for training Vivi are completely > general; if/when the violin sounds change (or even changes to a > cello or viola), all I need to do is spend 2-3 hours teaching her > how to play that instrument, by classifying audio! In other > words, there's no programming involved in this training; I'm just > acting like a parent of a music student. Yes, thats probably the best part :) > Of course, I'm hoping that when I present this at a conference, > somebody from the audience will say "wow, that's nice work, but > it's a pity that your physical model only approximates XYZ. I > have code that does this; could we work together? I don't mind > putting that code under the GPLv3." :) That's roughly what i meant by $1000 violin :) > So far, the only other open-source bowed-string simulation that I > know of is the 1986 Smith algorithm, implemented in the Synthesis > Toolkit in C++. Most of the algorithms in Artifastring have been > improved in the 2000s, but it's still much better than the version > in STK. > (the big open-source audio programs like Csound, Chuck, and > supercollider, all use STK for physical modeling, which means the > 25-year-old string algorithm) Whoah! That's suprising. cheers, Janek _______________________________________________ lilypond-user mailing list lilypond-user@gnu.org http://lists.gnu.org/mailman/listinfo/lilypond-user
