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Time Compression and Expansion (Stretch and Squish)
The Stretch and Squish filter is a variation on the theme of the Change Speed filter. It allows you to change the cadence (tempo or speed) of a piece of audio while maintaining its pitch at a constant value. You can either slow down the beat or cadence of a piece (Stretch) or speed it up (Squish).
The Stretch and Squish Effect shown in Legacy Mode
The Stretch and Squish Effect shown in Pitch Shift Mode
Stretch & Squish is actually a special case of the speed change filter. It has the ability to maintain a relatively constant pitch while modifying the cadence or beat interval of the .wav file that is being processed. Its primary purpose is for Forensics applications in which a spoken word recording needs to be slowed down for transcription to the written word; however, it can also be used to learn a fast guitar riff by slowing it down, or for other special effect situations. It has a range of adjustability that will allow you to half the cadence in “Stretch” mode which means that it is slowed down. Also, it has the ability to double the cadence of a .wav file in “Squish” mode. Stretching or Squishing a .wav file is accomplished with the Stretch control. If you set the Stretch control to 1.000, the file will play or preview at normal speed. However, if you decrease the number to its lower limit of 0.5000, you can double the speed of the recording. If you increase the number to its upper limit of 2.000, it will now play at half speed. Also, a Size control is provided which allows you to vary the update rate of the algorithm. This control affects the overall sound quality of the filter, which is subjective in nature and left up to the user. The following controls are provided on the Stretch & Squish Filter:
1.000 to 2.000 slows down the file and represents “Stretch” mode
Pitch Shift Mode (Semi Tones): (Range - 12 to + 12) In Pitch Mode (operable only when Legacy Mode is unchecked) you can change the pitch of a file while keeping the tempo (rhythm or cadence) constant. Its range of adjustment is +/- 1 octave wherein +12 represents a one full octave increase in Pitch and – 12 represents a one octave decrease. The calibration is in semitones meaning that the octave above and below the source material is divided into twelfths (12 semitones in an octave). Each unit of measurement associated with the Pitch control represents one note on the chromatic musical scale. You can fine-tune the pitch of the system using the left and right arrow keys in association with the Pitch control. To do so, just click on the pitch control slider and then use the up and/or down arrow keys until you achieve the desired pitch while previewing your file. The exact semitone value being used is displayed in the digital readout located directly above the Pitch control.
The Stretch & Squish Effect includes a set of 6 “Disguised Voice Effect” presets that you can use to shroud human voices behind a sonic veil (making them unrecognizable). You should not “hot switch” between these presets while previewing them, because some of them actually change the algorithm being used to accomplish its effect. Always stop the preview process before selecting another one of these presets to assure proper algorithm initialization.
Note: This effect produces digital artifacts. Artifacts are normal for this type of mathematical manipulation when applied to a .wav file. The greater the amount of “Stretch” or “Squish” applied, the greater will be the degree of artifacts generated by the routine. Quality will decrease as you increase the amount of time compression or expansion.
In “Pitch” mode (operable only when Legacy Mode is unchecked) you can change the pitch of a file while keeping the rhythm or cadence constant. Its range of adjustment is +/- 1 Octave wherein +12 represents an octave increase in Pitch and – 12 represents a 1 Octave decrease. The calibration is in semitones meaning that the Octave above and below is divided in twelfths (12 semitones or half-tones are in one Octave).
Note: With the musical scale of twelve-tone equal temperament further divides each semitone into 100 parts called cents.
The Stretch and Squish filter is a variation on the theme of the Change Speed filter. It allows you to change the cadence (tempo or speed) of a piece of audio while maintaining its pitch at a constant value. You can either slow down the beat or cadence of a piece (Stretch) or speed it up (Squish).
The Stretch and Squish Effect shown in Legacy Mode
The Stretch and Squish Effect shown in Pitch Shift Mode
Stretch & Squish is actually a special case of the speed change filter. It has the ability to maintain a relatively constant pitch while modifying the cadence or beat interval of the .wav file that is being processed. Its primary purpose is for Forensics applications in which a spoken word recording needs to be slowed down for transcription to the written word; however, it can also be used to learn a fast guitar riff by slowing it down, or for other special effect situations. It has a range of adjustability that will allow you to half the cadence in “Stretch” mode which means that it is slowed down. Also, it has the ability to double the cadence of a .wav file in “Squish” mode. Stretching or Squishing a .wav file is accomplished with the Stretch control. If you set the Stretch control to 1.000, the file will play or preview at normal speed. However, if you decrease the number to its lower limit of 0.5000, you can double the speed of the recording. If you increase the number to its upper limit of 2.000, it will now play at half speed. Also, a Size control is provided which allows you to vary the update rate of the algorithm. This control affects the overall sound quality of the filter, which is subjective in nature and left up to the user. The following controls are provided on the Stretch & Squish Filter:
- Stretch or Squish (Ratio):
1.000 to 2.000 slows down the file and represents “Stretch” mode
- [*=1]Size Control (Legacy Algorithm only): 20-240 (mSec)
- 20-100 (Only useful for special effects)
- 100-240 (Useful for Speech and Music without significant distortion)
- Overlap Control (Legacy Algorithm only): 0.2 to 0.6 (Determines the normalized degree of frame overlap and must be adjusted qualitatively. The best sound will typically be found between .3 and .5).
- Reset: Resets the corresponding slider control to its zero effect position.
Pitch Shift Mode (Semi Tones): (Range - 12 to + 12) In Pitch Mode (operable only when Legacy Mode is unchecked) you can change the pitch of a file while keeping the tempo (rhythm or cadence) constant. Its range of adjustment is +/- 1 octave wherein +12 represents a one full octave increase in Pitch and – 12 represents a one octave decrease. The calibration is in semitones meaning that the octave above and below the source material is divided into twelfths (12 semitones in an octave). Each unit of measurement associated with the Pitch control represents one note on the chromatic musical scale. You can fine-tune the pitch of the system using the left and right arrow keys in association with the Pitch control. To do so, just click on the pitch control slider and then use the up and/or down arrow keys until you achieve the desired pitch while previewing your file. The exact semitone value being used is displayed in the digital readout located directly above the Pitch control.
The Stretch & Squish Effect includes a set of 6 “Disguised Voice Effect” presets that you can use to shroud human voices behind a sonic veil (making them unrecognizable). You should not “hot switch” between these presets while previewing them, because some of them actually change the algorithm being used to accomplish its effect. Always stop the preview process before selecting another one of these presets to assure proper algorithm initialization.
Note: This effect produces digital artifacts. Artifacts are normal for this type of mathematical manipulation when applied to a .wav file. The greater the amount of “Stretch” or “Squish” applied, the greater will be the degree of artifacts generated by the routine. Quality will decrease as you increase the amount of time compression or expansion.
In “Pitch” mode (operable only when Legacy Mode is unchecked) you can change the pitch of a file while keeping the rhythm or cadence constant. Its range of adjustment is +/- 1 Octave wherein +12 represents an octave increase in Pitch and – 12 represents a 1 Octave decrease. The calibration is in semitones meaning that the Octave above and below is divided in twelfths (12 semitones or half-tones are in one Octave).
Note: With the musical scale of twelve-tone equal temperament further divides each semitone into 100 parts called cents.