I need something to slow down the playback speed of the song.
I hear about soundtouch but when I followed this link
http://www.surina.net/soundtouch/
There is a zip file. I don't know how can add it to foobar?
I'm looking forward....
What you are looking for is foo_dsp_soundtouch (https://hydrogenaud.io/index.php/topic,46000.0.html). Unfortunately the download link is not available anymore. I have it installed and it still works on foobar2000 v.1.3.15. I can upload it to you, if you wish, or you can try foo_dsp_effect (http://www.foobar2000.org/components/view/foo_dsp_effect) which is supposed to have the same features and more.
I have a copy of the source files for foo_dsp_soundtouch if anyone would like them.
I have a copy of the source files for foo_dsp_soundtouch if anyone would like them.
As have I, and it's probably just as irrelevant as your source code, as it hasn't been updated past the 0.8.x API, which changed drastically with the 0.9 release.