[Ardour-Dev] Development Summary (5.8..ba24f287ca)

David Kastrup dak at gnu.org
Thu May 4 15:06:40 PDT 2017

Fons Adriaensen <fons at linuxaudio.org> writes:

> On Thu, May 04, 2017 at 10:04:59PM +0200, David Kastrup wrote:
>> The settling time for a filter with a bandwidth of 0.1 Hz is in the
>> order of 10s.  The existing filter state only represents about 1 second
>> of information.
> The 0.1 here is a relative bandwidth, so something around 100 Hz.
>> > should be. In other words, instead of say 0.1 W, your amplifier will
>> > produce 1 kW, assuming it has that power. Mine will clip at 400 W,
>> > still more than enough to fry the speakers.
>> >
>> > If this is representative of the quality of the a-*** plugins (by 'the
>> > Ardour Team') then I wonder what to expect next.
>> The mathematical problem as such is ill-posed when changing filter
>> parameters
> Only if you use the wrong filter topology to start with.

"wrong filter topology" is sort of hand-waving.  Robust behavior in the
light of parameter change is part mathematics, parts skillful tinkering.
Like actual analog EQ design.  I've had third-party filters (like
reverb) blow up on me when changing parameters as well.  It's not
exactly easy to get this kind of thing robust.

>> I suspect that you'd be qualified enough to fix this yourself
> No need to, I do have EQs that can be used safely.
>> in return for some care on Aeolus (like applying patches and
>> answering mail).
> I *do* normally answer mail. What do you refer to ?

I'll reply in private.  If you don't see anything within an hour, maybe
try whitelisting me and/or searching the SPAM folder if any.  I'm not
exactly renowned for pleasant mails but they are usually relevant.

>>  Is the a-EQ the only filter you would want to see sanitized?
> It's by no means the only one apparently written by naively 
> implementing some textbook equation without understanding it.
> This is also the sort of problem that will show up immediately.
> In other words there's no excuse for such crap.

For every task done by somebody there is someone who knows how it should
have been done better.  Sometimes somebody needs to drop the ball for
someone else to pick it up in the first place.

I've been picking a whole lot of balls up for LilyPond in the last few
years.  And I dropped a number of them, too.

David Kastrup

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