Converting Sample Formats

This page covers the conversion between different sampling rate and quantisation depths. The Acoustica conversion utility (Sound | Convert Sample Format...) allows you perform these conversion.

Changing the Sample Rate

Changing the sampling rate normally introduces a phenomena called frequency aliasing. If you are converting a signal to a lower sampling frequency containing frequencies above half the target sampling frequency, these frequencies are substituted by other lower frequencies, causing annoying distortion. Acoustica features anti aliasing filters to remove this distortion. You can choose between depending on your needs for quality.

Converting to Higher Quantisation Depths

You can increase the perceived quality of low bit recordings by performing noise reduction after the conversion. Select Enhancement|Noise Reduction|Based on User Defined Profile... and select enter a horizontal line at -6 dB multiplied by the number of bits in the original recording. For an eight bit wave file converted to 16 bits or higher, this is a horizontal line at -48 dB.

Converting to Lower Quantisation Depths with psycho acoustical Noise Shaping

Acoustica optionally distributes the quantisation errors when converting to lower bit depths according to the hearing threshold of the human ear. The Psychoacoustical Noise Shaping option in the Convert Sample Format dialog box can be used to turn noise shaping on or off. You can also add a random dither signal to decorrelate the quantisation error from the audio material with the Dithering option.