notefreq: Frequency of a muscical note

In seewave: Sound Analysis and Synthesis

Frequency of a muscical note

Description

This function computes the frequency of a musical note (Equal temperament)

Usage

notefreq(note, ref = 440, octave = 3)

Arguments

note	a numerical or a character vector. See Note.
ref	a numerical vector of length 1 for the reference frequency.
octave	a numerical vector of length for the octave number.

Details

The frequency is computed according to:

f = ref \times 2 ^{octave - 3 + \frac{note-10}{12}}

with:
ref = reference frequency,
octave = octave number, and
note = rank of the note along the scale.

Value

The frequency in Hz is returned.

Note

The note can be given in two ways. The first solution is to give the rank of the note along the scale (e.g. rank 10 for A) or to give its names in characters with the following notation: C, D, E, F, G, A, B.

Author(s)

Jerome Sueur

See Also

octaves

Examples

# Some notes frequency (use apply-like functions when dealing with character strings)
sapply(c("C", "A", "Gb"), notefreq)

# C major scale plot
n <- 1:12
freq <- notefreq(n)
names <- c("C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B") 
plot(n, freq, pch=19, cex=1.5,
     xlab = "Note name",
     ylab = "Frequency (Hz)",
     xaxt="n", las=1, main="Third octave")
axis(side=1, at=n, labels=names)
abline(h=freq, col="lightgrey")

# C major scale sound
f <- 2000 # sampling rate
s <- NULL
for (i in 1:length(freq))
  {
    tmp <- synth(d=0.5, f=f, cf=freq[i])
    s <- pastew(s, tmp, at="start", f)
  }
spectro(s, f, ovlp=75)

seewave documentation built on Oct. 19, 2023, 5:07 p.m.