[FFmpeg-user] asubboost and asupercut

[Michael Koch]

Am 27.11.2020 um 20:50 schrieb Paul B Mahol:
> On Fri, Nov 27, 2020 at 8:24 PM Michael Koch <astroelectronic at t-online.de>
> wrote:
>
>> Am 27.11.2020 um 19:25 schrieb Paul B Mahol:
>>> On Fri, Nov 27, 2020 at 7:09 PM Michael Koch <
>> astroelectronic at t-online.de>
>>> wrote:
>>>
>>>> Hello,
>>>>
>>>> I have a few questions about the asubboost and asupercut filters.
>>>>
>>>> -- In asubboost it's not yet clear how the block diagram of the filter
>>>> looks like. Especially the "decay" and "feedback" options are unclear.
>>>> What's the input of the the delay line? Before or after the low pass
>>>> filter? Where does the feedback go to? Before or after the lowpass
>>>> filter? I have attached a sketch of a possible block diagram, but it's
>>>> only a wild guess.
>>>>
>>> This filter just adds delayed sub frequencies set by cut off frequency
>> back
>>> to output. Decay sets decay of old sub echo in buffer and feedback sets
>> how
>>> much
>>> new sub frequencies are added to the delay buffer.

I did try to reverse engineer the asubboost filter from its output 
signal. Is the attached sketch correct?
It seems the "feedback" parameter is unnecessary because it does exactly 
the same thing as "wet".

Michael

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