1. From the Process menu, choose Bit Depth, and then choose Bit-Depth Converter from the submenu.

2. Choose a preset from the Preset drop-down list or adjust the controls as desired:

   1. Choose a bit depth from the drop-down list.

      Increasing a file's bit depth cannot improve the quality of the existing audio, but does allow higher resolution for processing.

   2. Choose a setting from the Dither drop-down list if you're decreasing the file's bit depth and want to add dither noise to mask quantization noise. For example, if you want to burn a 24-bit audio file to an audio CD, dithering will produce a cleaner signal than a simple bit-depth conversion.

      Setting	Description
      Half Rectangular	Eliminates distortion caused by conversion to a lower bit depth, but the noise level is dependent on the signal. This setting uses a maximum dither noise amplitude of 0.5 LSB (least significant bit).
      Rectangular	Identical to Half Rectangular, but with a maximum dither noise amplitude of 1 LSB (least significant bit).
      Triangular	Eliminates distortion caused by conversion to a lower bit depth and eliminates noise floor modulation by producing a slightly higher noise level.
      Highpass Triangular	Eliminates distortion caused by conversion to a lower bit depth and eliminates noise floor modulation by producing a slightly higher noise level. Noise is shifted to higher frequencies than standard triangular dithering.
      Gaussian	Does not perform as well as rectangular or triangular dithering, but may be suitable for some material.
      POW-r	Uses the POW-r dithering algorithms for best dithering quality.

      In general, Highpass Triangular with noise shaping produces the most favorable results.

   1. Choose a setting from the Noise shaping drop-down list to apply noise shaping to your signal. Noise shaping lowers the perceived noise floor of the signal by shifting most of the noise into the upper frequencies of human hearing.

      Setting	Description
      Off	Does not apply noise shaping.
      High-Pass Contour	Moves noise into high frequencies. The frequencies to which the noise is shifted (shaped) are close to the Nyquist frequency, so you should not apply noise shaping to files with a sample rate below 44.1 kHz. For example, a 22 kHz signal has a Nyquist frequency of 11 kHz. If you move most of the noise into that range, you are putting it into a sensitive area of human hearing and will produce a worse-sounding signal.
      Equal Loudness Contour	Distributes noise equally into high and low frequencies.

      When the POW-r dithering algorithm ist used, you can select from three noise shaping modes. Which dithering mode sounds the best depends mainly on the audio signal.

      Setting	Description
      POW-r #1	This function uses a special dithering curve to minimize quantization noise.
      POW-r #2	This function uses additional noise shaping across a wide frequency range to extend the dynamic range by 5-10 dB.
      POW-r #3	This function uses additional, optimized noise shaping to extend the dynamic range by up to 20 dB between 2 kHz and 4 kHz. The human ear is most sensitive to this frequency range.

3. Click OK.

For more information about using processing dialog controls, click here.

Right click the Bit Depth box on the status bar and choose a new bit depth from the shortcut menu.