alg1 <- function(sound) {
	sy <- as.vector(sound$sound)
	sx <- 0:(length(sy)-1) / sound$rate
	fy <- abs(fft(sy))[1:(length(sy)/2)]
	fx <- 0:(length(fy)-1) * sound$rate / length(sy)

	# Gregor
	thr <- quantile(fy, 0.9) # take the maximum 10%


	# Philipp
	zx <- fx
	zy <- zx * 0 # Just initialize
	harmonics <- 5
	for (i in 2:(length(zx))) {
		idx <- seq(from=i, by=i-1, to=length(zx))
		if (length(idx) > harmonics) {
		 	idx = idx[1:harmonics]
		}
		zy[i] <- sum(fy[idx]) / length(idx)
	}