[music-dsp] Re: DC Offset

[James Chandler Jr]

> So if I download a demo of either (provided it is available), then
> I can hear your algorithm in action, right?

Hi, Kirill

Yeah, that's a good idea. It would be most convenient to test PeakLimiting
within PowerTracks, which is a multi-track audio program. Band In A Box has
a single track of audio which can be recorded along with the MIDI
auto-accompaniment.

You can download the demo at http://www.pgmusic.com/demo.htm

PowerTracks is a $29 MIDI/Audio sequencer, and its current incarnation uses
mono tracks. If you import a stereo WAV, it will bump the thing into two
adjacent mono audio tracks. Like earlier versions of Cakewalk, remember to
hard pan the two tracks in the mixer, to get a stereo output image on
playback.

We are gonna add real-time effects and stereo tracks in the next version.

A few notes--

1. The "raw" peaklimiter is found in the "Gain Change" plugin. There are
checkboxes for Pre-Normalize, Gain Change, and Post-PeakLimit. If you enable
all three boxes and set the gain to, say, +6 dB, it will scan the file to
determine normalize gain, add the Gain Change figure, and then pump the
result thru the PeakLimiter to avoid overload clipping.

With all three boxes checked, this works similar to L1, where you add gain
then peaklimit the result.

Some other peaklimit plugin designs require you to reduce the PeakLimit
threshold and then add make-up gain, but this seems like an unnecessary
two-step process to me.

Most of the other plugins also have a PeakLimit checkbox you can enable
(which uses the same PeakLimit algorithm). If a user mis-adjusts the knobs
in a plugin, which would result in bad distortion, if PeakLimit is enabled,
it will usually sound OK anyway.

2. If you encounter problems with the DirectX filter hosting, they have
probably been fixed in the latest version. I was squashing bugs until just a
week ago, and a fix is available for download, but I doubt if they have
cracked open the demo version yet to add the fixes.

James Chandler Jr.


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