prepComb: Preparing the combination/concatenation of Wave or WaveMC...
In tuneR: Analysis of music and speech

Description Usage Arguments Details Value Note Author(s) See Also Examples

Preparing objects of class Wave or class WaveMC for binding/combination/concatenation by removing small amounts at the beginning/end of the Wave or WaveMC in order to make the transition smooth by avoiding clicks.

1	prepComb(object, zero = 0, where = c("both", "start", "end"))

`object`	Object of class `Wave` or class `WaveMC`.
`zero`	The zero level (default: 0) at which ideal cut points are determined (see Details). A typical alternative would be 127 for 8 bit `Wave` or `WaveMC` objects. If `zero = NA`, the mean of the left Wave channel (for a `Wave` object) or the mean of the first channel (for a `WaveMC` object) is taken as zero level.
`where`	One of `"both"` (default), `"start"`, or `"end"` indicating at `where` to prepare the `Wave` or `WaveMC` object for concatenation.

This function is useful to prepare objects of class Wave or class WaveMC for binding/combination/concatenation. At the side(s) indicated by where small amounts of the Wave or WaveMC are removed in order to make the transition between two Waves or WaveMCs smooth (avoiding clicks).

This is done by dropping all values at the beginning of a Wave or WaveMC before the first positive point after the zero level is crossed from negative to positive. Analogously, at the end of a Wave or WaveMC all points are cut after the last negative value before the last zero level crossing from negative to positive.

An object of class Wave or class WaveMC.

If stereo (for Wave), only the left channel is analyzed while the right channel will simply be cut at the same locations. If multi channel (for WaveMC), only the first channel is analyzed while all other channels will simply be cut at the same locations.

Uwe Ligges ligges@statistik.tu-dortmund.de, Sarah Schnackenberg, based on code from Matthias Heymann's former package ‘sound’.

bind, Wave-class, Wave, WaveMC-class, WaveMC, extractWave, and noSilence to cut off silence

Wobj1 <- sine(440, duration = 520)
Wobj2 <- extractWave(sine(330, duration = 500), from = 110, to = 500)
par(mfrow = c(2,1))
plot(bind(Wobj1, Wobj2), xunit = "samples")
abline(v = 520, col = "red")  # here is a "click"!

# now remove the "click" by deleting a minimal amount of information:
Wobj1 <- prepComb(Wobj1, where = "end")
Wobj2 <- prepComb(Wobj2, where = "start")
plot(bind(Wobj1, Wobj2), xunit = "samples")