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 <[email protected]> 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 < > [email protected]> 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 <[email protected]> >> 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 < >>> [email protected]> 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 >>>> [email protected] >>>> 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
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