Converting sample types

Higher values retain more high frequencies, but the conversion takes longer. Lower values require less processing time but reduce high frequencies.

• When you convert from mono to stereo, the Left Mix and Right Mix options specify the relative amplitude with which the original mono signal is placed into each side of the new stereo signal. For example, you can place the mono source on the left channel only, the right channel only, or any point in between.

• When you convert from stereo to mono, the Left Mix and Right Mix options control the amount of signal from the respective channel that will be mixed into the final mono waveform. The most common mixing method uses 50% of both channels.

Enables or disables dithering when converting to lower bit depths. If dithering is disabled, bit depth is abruptly truncated, producing a crackly effect on low-volume passages caused by quantization distortion.

Although dithering introduces a small amount of noise, the result is far preferable to the increased distortion that you would otherwise hear at low signal levels. Dithering also lets you hear sounds that would be masked by the noise and distortion limits of audio at lower bit depths.

Controls how dithering noise is distributed relative to the original amplitude value. Usually, Triangular provides the best tradeoff among signal‑to‑noise ratio, distortion, and noise modulation.

note: Triangular (Shaped) and Gaussian (Shaped) move slightly more noise to higher frequencies. For additional control, set Noise Shaping options.

Determines which frequencies contain dithering noise. By introducing noise shaping, you may be able to use lower dither depths without introducing audible artifacts. The best shaping depends on the source audio, final sample rate, and bit depth.

note: Noise Shaping is disabled for sample rates below 32Khz because all noise would remain in audible frequencies.

High Pass

With a crossover set to 7.3 kHz, drops dithering noise to -180dB at 0 Hz and -162dB at100 Hz.

Light Slope

With a crossover set to 11 kHz, drops noise to -3dB at 0 Hz and -10dB at 5 kHz.

Neutral

Light is flat up to 14 kHz, ramps noise up to a maximum at 17kHz, and is again flat at higher frequencies. Background noise sounds the same as it does without noise shaping but is about 11dB quieter.

Heavy is flat up to 15.5kHz, placing all dithering noise above 16kHz (or wherever you specify the crossover). Sensitive ears may hear a high pitched ringing if the crossover is too low. If converting 48 or 96 kHz audio, however, the crossover can be placed well above 20 kHz.

Tip: Choose a Neutral shape to avoid sonically coloring background hiss. Note, however, that hiss will sound louder than with other shapes.

U-Shaped

Shallow is mostly flat from 2 kHz up to 14 kHz but gets louder as audio approaches 0 Hz because low frequencies are much less audible. Medium places a little more noise in the highs above 9 kHz, allowing for lower noise below that frequency. Deep increases noise above 9 kHz even more, but also lowers it much more in the 2-6 kHz range.

Weighted

Light attempts to match how the ear perceives low-level sounds by reducing noise more in the 2-6 kHz range and raising it in the 10-14 kHz range. At high volumes, hiss may be more noticeable. Heavy more evenly reduces the most sensitive 2-6KHz range at the expense of more noise above 8kHz.

Specifies the frequency above which noise shaping will occur.

Specify the maximum amplitude of noise added to any one frequency.

Varies the distribution of noise across frequencies.

After you create a preset, it appears in the Presets list at the top of the dialog box. If you want to delete a preset, choose it from the list, and click the Delete button .