Re: [linux-audio-dev] LFO Phaser LADSPA plugin in details
Hi, Fons! === On Monday 12 March 2007, you wrote: === > On Mon, Mar 12, 2007 at 12:53:28AM +0300, Andrew Gaydenko wrote: > > > Will anybody find a minute ot two to explain me how does the plugin > > work - I mean a user POV rather technical realization details. > > (Assuming you mean my plugin from the MCP package) > > This is an emulation of an analog phase delay line phaser. > > "Input gain (dB)" Just what is says it is... > > "Sections", The number (1..30) of first-order allpass filters that > form the delay line. The phase shift of each section is zero at LF > and goes up to 180 degrees at HF. > > "Frequency", (in octaves) the frequency at which each filter section > produces 90 degrees phase shift. The range is 12 octaves. Halfway > is middle C. > > "LFO frequency (Hz)" Frequency of the LFO that modulates the "Frequency" > parameter above (0.01 to 30 Hz). > > "LFO waveform". Sets the waveform of the LFO, from falling saw, over > triangle, to rising saw. > > "Modulation gain", The amount of modulation by the LFO output. > > "Feedback gain". The gain (-1..1) of the feedback from the delay > line output back to the input. > > "Output mix". The first half crossfades between the inverted delay > output and the input, the second half between input and the normal > delay output. Mid position is input, i.e. no effect. > > > So if you set "Sections" to N, the phase shift in the delay line will > vary between 0 at LF and N/2 cycles at HF. The "Frequency" setting will > determine the shape of the phase curve and consequently the set of N/2 > frequencies where the delay output is in antiphase with the input. > Setting "Output mix" to +0.5 will produce nulls at these frequencies. > Setting it to -0.5 will produce maxima at these frequencies. "Feedback" > will modify the effect in complicated ways. Finally the LFO makes the > set of frequencies move up and down, producing the phasing effect. > Thanks! I'll play with the plugin having your words in front of me :-) (have you found a chance to look at the qloud?) Andrew
Re: [linux-audio-dev] LFO Phaser LADSPA plugin in details
On Mon, Mar 12, 2007 at 12:53:28AM +0300, Andrew Gaydenko wrote: > Will anybody find a minute ot two to explain me how does the plugin > work - I mean a user POV rather technical realization details. (Assuming you mean my plugin from the MCP package) This is an emulation of an analog phase delay line phaser. "Input gain (dB)" Just what is says it is... "Sections", The number (1..30) of first-order allpass filters that form the delay line. The phase shift of each section is zero at LF and goes up to 180 degrees at HF. "Frequency", (in octaves) the frequency at which each filter section produces 90 degrees phase shift. The range is 12 octaves. Halfway is middle C. "LFO frequency (Hz)" Frequency of the LFO that modulates the "Frequency" parameter above (0.01 to 30 Hz). "LFO waveform". Sets the waveform of the LFO, from falling saw, over triangle, to rising saw. "Modulation gain", The amount of modulation by the LFO output. "Feedback gain". The gain (-1..1) of the feedback from the delay line output back to the input. "Output mix". The first half crossfades between the inverted delay output and the input, the second half between input and the normal delay output. Mid position is input, i.e. no effect. So if you set "Sections" to N, the phase shift in the delay line will vary between 0 at LF and N/2 cycles at HF. The "Frequency" setting will determine the shape of the phase curve and consequently the set of N/2 frequencies where the delay output is in antiphase with the input. Setting "Output mix" to +0.5 will produce nulls at these frequencies. Setting it to -0.5 will produce maxima at these frequencies. "Feedback" will modify the effect in complicated ways. Finally the LFO makes the set of frequencies move up and down, producing the phasing effect. -- FA Follie! Follie! Delirio vano รจ questo !
[linux-audio-dev] LFO Phaser LADSPA plugin in details
Hi! Will anybody find a minute ot two to explain me how does the plugin work - I mean a user POV rather technical realization details. Andrew
[linux-audio-dev] note: apps.linuxaudio.org
There have been a few edits on our "deveopment"-wiki apps-devel.linuxaudio.org ! sorry for the confusion: http://apps.linuxaudio.org is the "real" site. http://apps-devel.linuxaudio.org/ is our *test server* that we use to experiment with PHP, plugins, designs, software updates, etc - it's actually a 1:1 mirror, but not intended for the public. - we ought to set up a jailed webserver behind openvpn for testing, but we're just not there yet :( robin
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
Christian wrote:
> Robin Gareus schrieb:
>>> usleep( iTick-( passedTime-startTime ) );
>> AFAIR usleep is not exact! - did you
>> echo 1024 > /proc/sys/dev/rtc/max-user-freq ?
>
>> try sth like:
>
>> void select_sleep (int usec) {
>> fd_set fd;
>> int max_fd=0;
>> struct timeval tv = { 0, 0 };
>> tv.tv_sec = 0; tv.tv_usec = usec;
>
>> FD_ZERO(&fd);
>> if (remote_en) {
>> max_fd=remote_fd_set(&fd);
>> }
>
>> select(max_fd, &fd, NULL, NULL, &tv);
>
>> }
>
>
>
> Interesting timing approach.
> But I can't find remote_en and remote_fd_set in the man pages.
> What does these arguments stand for?
sorry, cut the 3 "if(remote_en)" lines - I was too quick with pasting &
sending the mail - remote_en is some global var. that allows to
interrupt the sleep, if some other-event occurs... - actually you'd only
needed "select (0,&fd,0,0,&tv);"
anyway clock_nanosleep seems better; at least it takes less code
to set it up. I did not know about it, and it's even POSIX, how cool!
#robin
