The Interpret Sample Rate command lets you hear how an audio file sounds at a different sample rate. (See Understanding sample rate.) This command helps you identify files that specify an incorrect rate in the file header. To then permanently convert the sample rate, choose Edit > Convert Sample Type.
Although you can work with sample rates ranging from 6000 to 192,000 Hz in Adobe Audition, your sound card may not be capable of playing all rates properly. To determine supported sample rates, consult the documentation for the card.
The sample rate of a file determines the frequency range of the waveform. When converting the sample rate, keep in mind that most sound cards support only certain sample rates.
To quickly access the Convert Sample Type dialog box, double-click the Sample Type section of the status bar. (See Display the status bar.)
Higher values retain more high frequencies, but the conversion takes longer. Lower values require less processing time but reduce high frequencies.
Use higher Quality values whenever you downsample a high rate to a low rate. When upsampling, higher values have little effect.
The Convert Sample Type command is the quickest way to convert a waveform to a different number of channels.
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.
The bit depth of a file determines the dynamic range of the audio. (See Understanding bit depth.) Adobe Audition supports up to 32‑bit resolution. You can raise the bit depth of a file to gain a greater dynamic range, or you can lower the bit depth to reduce the file size.
Some common applications and media players require 16-bit or lower audio.
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.
Reduces signal-to-noise ratio
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.
With a crossover set to 7.3 kHz, drops dithering noise to -180dB at 0 Hz and -162dB at100 Hz.
With a crossover set to 11 kHz, drops noise to -3dB at 0 Hz and -10dB at 5 kHz.
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.
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.
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.
If you need to make the same conversion on multiple files, you can save time by using a sample rate conversion preset.