29 Jul
2007
29 Jul
'07
9:59 a.m.
Hallo Steve, list !
I just noticed, that the "triple band parametric with shelves" LADSPA
plugin generates a DC offset (tried version 0.4.15 and 0.4.14).
The offset is not always the same: first when I create the plugin, there
is no offset. Then I pressed play/stop (in ardour) and the DC offset was
here - also the amount of the offset is somehow changing when I play
with different parameters (but I did not find out a real correspondens).
However, when I use the "Single band parametric" and the shelves alone I
don't get an offest (which should be the same code ?).
I also made some other small additions to your plugin collection:
- single low and high shelving filters (see attached files): they are
the same code as in "triple band parametric with shelves", because I
often need only a single shelving filter
- in the "single band parametric" the slider to change the frequency was
linear, I changed this to logarithmic (file attached)
Maybe you could include those plugins/changes in your collection, at
least for me they are quite usefull.
LG
Georg
29 Jul
29 Jul
1:43 p.m.
Georg Holzmann wrote:
- in the "single band parametric" the slider
to change the frequency was
linear, I changed this to logarithmic (file attached)
Thanks for that, it is now much easier to use the plugin in Ardour,
which clamps the minimum frequency setting to about 3Hz (which I think
is also a good thing; dragging the slider accidentally down to zero
before had some nasty effects).
Unfortunately jack-rack doesn't clamp the minimum frequency, so it goes
right down to zero, and 0-20Hz takes up three-quarters of the slider's
adjustable range (which is rather tedious).
According to the XML file the minimum frequency is set as 0.0 * sample
rate. Why does Ardour clamp at about 3Hz, is this an added 'feature' of
Ardour? (it is certainly useful to me)
Regards,
--
Steven Chamberlain
steven(a)pyro.eu.org
1:57 p.m.
[Steven Chamberlain]
Unfortunately jack-rack doesn't clamp the minimum
frequency, so it goes
right down to zero, and 0-20Hz takes up three-quarters of the slider's
adjustable range (which is rather tedious).
According to the XML file the minimum frequency is set as 0.0 * sample
rate. Why does Ardour clamp at about 3Hz, is this an added 'feature' of
Ardour? (it is certainly useful to me)
It's quite sensible for a host to clamp a port value hinted
'logarithmic' this way. After all, log(0) doesn't compute.
About the 'sample rate' hint: I've removed all references to it from
my own plugins. It just doesn't work as expected in all hosts, and
that's no surprise to anyone who has examined ladspa.h's attempts at
describing its operation. Just do 'logarithmic' instead and clamp in
the plugin code -- not as nice but good enough, and consistent.
Tim
3:11 p.m.
On 29 Jul 2007, at 16:46, Tim Goetze wrote:
[Steven Chamberlain]
My preferred solution would be if host authors fixed their sample-
rate-hint implementations, but it's not perfect even when it does work.
In general I want to be able to say something like minimum 10Hz,
maximum 0.45 x samplerate.
- Steve
Unfortunately jack-rack doesn't clamp the
minimum frequency, so it
goes
right down to zero, and 0-20Hz takes up three-quarters of the
slider's
adjustable range (which is rather tedious).
According to the XML file the minimum frequency is set as 0.0 *
sample
rate. Why does Ardour clamp at about 3Hz, is this an added
'feature' of
Ardour? (it is certainly useful to me)
It's quite sensible for a host to clamp a port value hinted
'logarithmic' this way. After all, log(0) doesn't compute.
About the 'sample rate' hint: I've removed all references to it from
my own plugins. It just doesn't work as expected in all hosts, and
that's no surprise to anyone who has examined ladspa.h's attempts at
describing its operation. Just do 'logarithmic' instead and clamp in
the plugin code -- not as nice but good enough, and consistent.
4:44 p.m.
[Steve Harris]
My preferred solution would be if host authors fixed their sample-rate-hint
implementations, but it's not perfect even when it does work.
In general I want to be able to say something like minimum 10Hz, maximum 0.45 x
samplerate.
True, that would be nice. In the meantime, for most purposes I find a
range like 10 Hz to 20 kHz to be generously sufficient. That's easily
achievable with a simple 'log'-hinted control. Nyquist-dependent
clamping is usually not a real problem since sample rates are almost
universally in excess of 44 kHz.
Tim
2:17 p.m.
Hallo!
Thanks for that, it is now much easier to use the
plugin in Ardour,
which clamps the minimum frequency setting to about 3Hz (which I think
yes, here ardour clamps it at 1.76 Hz ...
Unfortunately jack-rack doesn't clamp the minimum
frequency, so it goes
right down to zero, and 0-20Hz takes up three-quarters of the slider's
adjustable range (which is rather tedious).
Maybe it is better if the minimum is fixed to 20 Hz ? Or does someone
need parametric EQs below 20 Hz ?
LG
Georg
3:09 p.m.
On 29 Jul 2007, at 17:17, Georg Holzmann wrote:
Hallo!
It should have a minimum set, yes, I must have just overlooked it.
- Steve
Thanks for that, it is now much easier to use the
plugin in Ardour,
which clamps the minimum frequency setting to about 3Hz (which I
think
yes, here ardour clamps it at 1.76 Hz ...
Unfortunately jack-rack doesn't clamp the
minimum frequency, so it
goes
right down to zero, and 0-20Hz takes up three-quarters of the
slider's
adjustable range (which is rather tedious).
Maybe it is better if the minimum is fixed to 20 Hz ? Or does
someone need parametric EQs below 20 Hz ?
3:21 p.m.
On 29 Jul 2007, at 12:58, Georg Holzmann wrote:
Hallo Steve, list !
I just noticed, that the "triple band parametric with shelves"
LADSPA plugin generates a DC offset (tried version 0.4.15 and 0.4.14).
The offset is not always the same: first when I create the plugin,
there is no offset. Then I pressed play/stop (in ardour) and the DC
offset was here - also the amount of the offset is somehow changing
when I play with different parameters (but I did not find out a
real correspondens).
That sounds like it could be related to denormals. They can build up
after you stop tracks, I'm not sure why it would have this effect
though.
However, when I use the "Single band
parametric" and the shelves
alone I don't get an offest (which should be the same code ?).
The effect may be exaggerated with multiple stacked filters? Dunno.
I also made some other small additions to your plugin
collection:
- single low and high shelving filters (see attached files): they
are the same code as in "triple band parametric with shelves",
because I often need only a single shelving filter
- in the "single band parametric" the slider to change the
frequency was linear, I changed this to logarithmic (file attached)
Maybe you could include those plugins/changes in your collection,
at least for me they are quite usefull.
Great, thanks. Do you think you could bundle up the changes into the
new files and a patch for the existing ones in a tarball? I'm off on
holiday tomorrow, but I'll incorporate it when I get back.
Cheers,
Steve
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7 comments
4 participants
participants (4)
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Georg Holzmann -
Steve Harris -
Steven Chamberlain -
Tim Goetze