Great, my pleasure. Here attached is also Zölzer's algorithm. I'll need to double-check and see if all is correct but it might be a good starting point.
Dario On Sat, 23 May 2020 at 23:31, Julius Smith <julius.sm...@gmail.com> wrote: > Cool, these are great to have for evaluation, learning, and variety of > choice, thanks! > > - Julius > > On Sat, May 23, 2020 at 2:24 PM Dario Sanfilippo < > sanfilippo.da...@gmail.com> wrote: > >> >> Thanks for testing, Julius. >> >> I'll see if I can get the limiter in Zölzers book in the next few days >> and I'll do another PR with that if I manage. >> >> I've also just added the stereo version of the other limiter: >> https://github.com/grame-cncm/faustlibraries/pull/37/commits/12763e053c7fb84371cfaa17bf89f2c9a1821418 >> . >> >> Dario >> >> >> On Sat, 23 May 2020 at 22:10, Julius Smith <julius.sm...@gmail.com> >> wrote: >> >>> Since the delay for the input path is our "lookahead delay", setting it >>> to the attack time sounds ideal to me. >>> >>> On Sat, May 23, 2020 at 12:54 PM Julius Smith <julius.sm...@gmail.com> >>> wrote: >>> >>>> I've been happy with limiter_1176_R4_mono, but I'll now compare it >>>> to limiter_basic_mono, by offering both with a checkbox to choose, and >>>> listen for the difference (see attached test program). >>>> My limiter needs are merely to turn hard-clipping into soft-clipping >>>> for voice and tonal instruments. >>>> >>>> I believe the "limiter slope" is the compression ratio to use above >>>> threshold (4 in the case of limiter_1176_R4_mono). >>>> >>>> >>>> >>>> On Sat, May 23, 2020 at 3:57 AM Dario Sanfilippo < >>>> sanfilippo.da...@gmail.com> wrote: >>>> >>>>> >>>>> Hi, Julius. I understand. >>>>> >>>>> See this: >>>>> https://github.com/grame-cncm/faustlibraries/pull/37/commits/8f1bd1ba78ff4919637a9bfd9ec635225cfb4ba5 >>>>> . >>>>> >>>>> That's a basic lookahead limiter based on this post: >>>>> http://iem.at/~zmoelnig/publications/limiter/. >>>>> >>>>> This algorithm is even simpler: it just calculates the amplitude >>>>> profile using a peak-holder and it smooths out attack and release using, >>>>> respectively, a one-pole lowpass and a peak envelope. Those filters are >>>>> based on the e^(-2pi) time constant (Chamberlin's design for 1pole >>>>> filters). This time constant works in this case as the input delay is set >>>>> by the attack of the system, so the amplitude profile to calculate the >>>>> scaling factor roughly reaches its maximum after the attack time. The >>>>> release time might be changed with some other constant, if more >>>>> appropriate. >>>>> >>>>> Personally, I'm satisfied with it but I also designed it for my >>>>> specific case, that is, stability in self-oscillating systems. I needed a >>>>> cheap solution with low distortion; I'm not sure if this works well for >>>>> most applications. People are invited to test and comment. >>>>> >>>>> I had a look at Zölzer's limiter, pp 231 and 232, but I don't quite >>>>> understand what "the slope of the limiter" is. What do you think? He >>>>> also doesn't mention a specific delay for the input path but I'd assume >>>>> that it is the same as the attack time. >>>>> >>>>> Dario >>>>> >>>>> >>>>> On Sat, 23 May 2020 at 01:38, Julius Smith <julius.sm...@gmail.com> >>>>> wrote: >>>>> >>>>>> Hi Dario, >>>>>> >>>>>> Yes the current limiter is simply a compressor, using the usual >>>>>> (causal) amplitude follower, that applies a ratio of 4 starting halfway >>>>>> up >>>>>> (-6 dB). Please feel free to make us a new one that is nicer! >>>>>> >>>>>> Julius >>>>>> >>>>>> On Fri, May 22, 2020 at 11:19 AM Dario Sanfilippo < >>>>>> sanfilippo.da...@gmail.com> wrote: >>>>>> >>>>>>> Hello, list. >>>>>>> >>>>>>> Am I missing something with co.limiter_1176_R4_mono? I see that >>>>>>> there is no lookahead mechanism inside and, if I test it with a song at >>>>>>> +60dB, the output of the limiter is rather consistently at about 25 dB. >>>>>>> >>>>>>> Best, >>>>>>> Dario >>>>>>> _______________________________________________ >>>>>>> Faudiostream-users mailing list >>>>>>> Faudiostream-users@lists.sourceforge.net >>>>>>> https://lists.sourceforge.net/lists/listinfo/faudiostream-users >>>>>>> >>>>>> -- >>>>>> "Anybody who knows all about nothing knows everything" -- Leonard >>>>>> Susskind >>>>>> >>>>> >>>> >>>> -- >>>> "Anybody who knows all about nothing knows everything" -- Leonard >>>> Susskind >>>> >>> >>> >>> -- >>> "Anybody who knows all about nothing knows everything" -- Leonard >>> Susskind >>> >> > > -- > "Anybody who knows all about nothing knows everything" -- Leonard Susskind >
limiter_Z.dsp
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