Audio


Here's where you make the settings concerning the playback and processing of the music.

Sample rate:
The highest frequency a digital audio recording can reproduce is half the sampling frequency. This means that a higher setting will increase the audio quality but will also increase the time taken to process it.

A CD is always recorded with a sampling frequency of 44100 Hz, MP3/AIFF files may have been recorded with any sampling frequency.

You may here choose to lower the playback frequency and thus decrease the processor work by selecting the 22050 Hz or 11025 Hz items.
The 44100 Hz item leaves the sample frequency of a CD unaffected but may lower it for an MP3/AIFF file.
The "No change" item does not at all change the sample frequency.

Note: Audio files with a lower sampling frequency will not be "upsampled" to the given setting.


Pre-filter
When using a sample frequency setting of 11025 or 22050, you may need to filter out some of the higher frequencies. If higher pitched sounds, such as a hi-hat, sound distorted, check this item. This increases the processor work.


Slow Down Quality
The sound quality setting for the corresponding slow down type - higher means better but uses more processing power.


Read Buffer Size
A bigger setting may work better on slow computers, a smaller setting makes the program reacting faster for pitch and speed changes.
If you experience dropouts in the playback, try using a bigger setting.


Pitch change affects speed
Normally changing the pitch does not affect the speed or vice versa. However there may be situations when you do want this to happen.
Say you have recorded something from a tape recorder running at a slightly different playback speed than the original recording or if you are recording old 78 rpm records at 45 rpm. You would then want a pitch change to affect the speed as well. If so, enable this item. This will disable the Speed/Stretch slider and only the Pitch slider will be active.

To find out how to set the Pitch slider, either use your ears and adjust it until you are satisfied or pick up your home calculator, take a deep breath and read on. Here's an example:

A 78 rpm record played at 45 rpm has a speed ratio of 45/78 = 0.576923 which means that the speed and pitch is lowered by the same number. Expressed in semitones that equals to 12*log2(0.576923) = -9.52259 semitones. So to get the music back to the original speed and pitch, raise the Speed slider to 9.52. Simple?

Another use of this function is to set the Pitch slider to -12. This will slow down the music to half speed and lower the pitch one octave. You will then get a feeling how transcribing was done before software as Amazing Slow Downer was available. Not everything was better in the old days.