Hardware Reference
In-Depth Information
To apply an effect, specify the effect followed by any parameters after the output file
or device.
In this example, we'll start a monitoring loop on the Pi and apply a reverb effect to
our voice live as it plays back through the speakers:
pi@raspberrypi ~ $ sox -t alsa plughw:1 -d reverb
How about that? Sounds like we're stuck in a cave. Let's see what parameters the
reverb effect takes:
pi@raspberrypi ~ $ sox -t alsa plughw:1 -d reverb ?
usage: [-w|--wet-only] [reverberance (50%) [HF-damping (50%) [room-scale
(100%) [stereo-depth (100%) [pre-delay (0ms) [wet-gain (0dB)]]]]]]
The parameters inside the brackets are all optional, and the values inside the
parenthesis are the default values. By changing the reverberance parameter,
we can turn the cave into a huge mountain hall:
pi@raspberrypi ~ $ sox -t alsa plughw:1 -d reverb 99
Or we could be stuck crawling in an air duct:
pi@raspberrypi ~ $ sox -t alsa plughw:1 -d reverb 99 50 0
Our next example is a cult classic—the freaky David Lynch phonetic reversal speech:
1. Write down a sentence that makes your skin crawl. ("The owls are not what
they seem, and the cake is a lie too" will do).
2. Read your sentence backwards, from right to left, and record it to a file
named
myvoice.wav
:
pi@raspberrypi ~ $ sox -t alsa plughw:1 myvoice.wav
3.
Now play back your recording using the reverse effect:
pi@raspberrypi ~ $ sox myvoice.wav -d reverse
4.
Should you want to sneak this sample into your friend's playlist later, use the
following command to save it with the effect applied:
pi@raspberrypi ~ $ sox myvoice.wav freaky.wav reverse
