There are many ways to give a song, or part of song, a nice twist. This is a cool addition that can massively alter the sound and, with enough time and fiddling, will yield some cool results. By using the built in plugin in Reaper known as ReaFir, you can subtract random parts of audio to make a cool lo-fi effect.
This is an extremely useful plugin that can be downloaded with Cockos's ReaPlugs bundle for FREE! It comes with several useful modes but the one we are looking into is the subtract mode.
This mode is normally used by myself to subtract noise e.g a fan or white noise from a recording. The way it works is by sampling a part where only the noise is present and building a sound profile of acceptable frequencies to subtract.
Normally by selecting subtract on a point otherwise silent from the audio you want to keep it will only subtract the background noise.
But what if you select a valuable bit of audio and build a sound profile from that?
In this case it will subtract the frequencies heard in that sample, appropriate to how loud they are. This is where the cool effect comes in. Say you decide to select a half second of your song, it will decide to remove those frequencies. Depending what bit you select, certain notes may be much less prominent.
I like to select a section with a drum hit e.g. snare. If you then play that section of music it may sound drastically different, often giving it a low quality vibe or sounding like it is playing through a completely different medium.
Taken from a video on Youtube, below shows the process on removing noise. All you have to do is change what bit you are sampling to build up cool subtractive noise profiles and wreck havoc on your sound.