Resonance is the characteristic of some systems to store and release energy at particular frequencies. It's not limited to filters, mechanical systems like springs or pendulums have resonance (get on a swing at the park and try to change your frequency and you'll feel the effects of resonance).
In an electrical system, a minimal passive resonant circuit would be one with 2 capacitors and 2 resistors. Selecting the values of the components determines the frequency, but what happens is that at a certain frequency the energy gets stored and passed back and forth between the capacitors, like the swing going back and forth. This storage and energy swapping emphasizes that frequency. Depending on the "Quality factor" or amount of resonance that frequency can become much more apparent than the other frequencies in the signal even if the input is wide-band. When you are talking about delay and feedback, you are creating a digital filter, but I think it is worthwhile to spend some time understanding the theoretical concept and think in terms of energy and frequency. Your feedback delay becomes the storage and certain frequencies will resonate with that system. > But it is having the resonance in parralel to a dry sound that bothers me; but may be that's the only way to do ? I'm not sure what you mean but I think you need some study in filter design, because a single feedback delay causes comb filtering but its not a classical lowpass. Is that what you are trying to achieve? Digital filters are almost universally combinations of short delays (typically 1 sample) placed in different patterns and fed back in different amounts (e.g. https://en.wikipedia.org/wiki/Digital_filter#Filter_realization). Here are some resources that may help you: http://www.dspguide.com/ch14.htm https://www.native-instruments.com/fileadmin/ni_media/downloads/pdf/VAFilterDesign_2.0.0a.pdf That first one is a book that can help you more with the fundamentals in the early chapters as well. I hope this is somewhat helpful, if not perhaps I need to understand better specifically what you are trying to achieve. _Spencer On Fri, Jul 20, 2018 at 10:13 AM, Mehdi Touzani <mehdi.touz...@gmail.com> wrote: > Hi all, > I follow the llist for a while, but I am not a DSP programmer, I do DSP > audio apps for about 20 years now, for sonic core plateform "Scope" and > Xite". I begin with other things like juce or flowstone, but so far, > scope is still far superior in terms of sound results. Too bad there is no > scripting tool for it (well there is but it is not available to me). > > My question is probably weird for you - like super noob - , because i am > NOT looking for math or codes, but hints about a general > design/architecture. > > So... how do you do a resonance in a lowpass circuit? :-) not the > math, not the code, just the architecture. > > Personnally, i came to the conslusion that some kind of very short delay > with feedback, mixed in parallel with the non resonance low pass sound, > could do the trick. . The more feedback, the more resonance, and with > feedback over -6dB, it would begin to self resonate. > > But it is having the resonance in parralel to a dry sound that bothers me; > but may be that's the only way to do ? > > I have read about hardware filters and ok, there is math, but there is > also the effect of the hardware components. Some articles even suggest that > a bandpass in parralel could do the trick : or more exactly, a bandpass > fonction is created after the resonance, to remove frequencies that would > overlap with the cutoff. > > > So, any hints that could help me improve the process etc would be very > welcome. > > Thanks > > Mehdi > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp >
_______________________________________________ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
