# Sound Processing

Amazing Slow Downer is processing the sound in real-time during playback using advanced DSP (Digital Signal Processing) techniques. Slow down type The Slow Down Type drop down menu beneath the Equalizer lets you select between different slow down algorithms. Type IV has the overall best sound quality but also uses a lot of processing power and might not work on slower computers. Type I, II and III uses very little processing power but also has worse sound quality. If you are running OS X 10.3.9 or higher, you will also have a Type V that is similar to Type IV but with lower sound quality. Depending on what type of music and what instrument you are focusing on, use the one that suits your music the best. You may also bypass the processing completely. Use key command [A] to toggle between various types, key command [D] to disable/enable processing. Stretch / Speed The slider labeled Stretch adjusts the Time Stretch (slow down factor). This is where you select the amount (expressed as a percentage value) by which the recording should be stretched. A positive value will slow the music down while a negative value will play it back faster. 100% means that the time is stretched by 100% and the music will be played back at half the tempo. Speed / Stretch You may want to display the slow down factor as speed change. In this case, 100% means full speed, 50% means half speed, 25 % means quarter speed etc. Select Speed instead of Stretch in the Preferences - Controls dialog. To reset to the original speed, hold down the Option key while clicking on the slider. Use key command [T] to toggle between full-speed and the previous setting. See Default Keyboard Shortcuts for other useful key commands for setting the speed. Pitch The slider labeled Pitch adjusts the pitch i.e. the tuning and transposition. To adjust the tuning, move the slider by dragging the handle or by clicking in the area between the handle and the arrows. As an example: to change the key from C to E, raise the pitch by four semitones. Key command: [/] or [*] on the numerical keypad. To adjust a tune that is slightly above or below standard concert pitch, click the left or right arrows. Key command: Shift + [/] or [*] on the numerical keypad. The current setting is displayed at the status bar at the bottom of the screen. Holding down the Option key while clicking on the slider resets it to a zero position. Use key command [P] to toggle between no transposition and the previous setting. Note: Raising the pitch an octave is sometimes useful when transcribing bass lines and low-pitched instruments. Mix - Left/Right The slider labeled Mix adjusts what channel or mix of channels you are listening to. Normally you use both channels - center position. However, sometimes the instrument you are transcribing is more prominent on one or the other of the channels. You may then choose to listen to only the left, only the right or any mix of the channels you like. The music is always sent to both the left and right channels of the sound card. Holding down the Option key while clicking on the slider resets it to a center position. Keyboard shortcuts: [+] / [ - ] (Numeric keypad) - Increase/decrease speed. [ * ] / [ / ] (Numeric keypad) - Raise/lower pitch in semi-tone steps, add [Shift] key for cent changes. The current settings are shown in the status bar at the bottom right of the window. You can also double click on the digits in the statusbar and type in the desired values ## Volume slider Adjusts the playback volume, key command [Up/Down arrows]. Stereo playback on/off The ST check box lets you toggle between stereo and mono playback, key command [S]. Graphic Equalizer - EQ This lets you boost or cut the volume at different frequencies. For example, you can boost the mid-range to hear a particular instrument more easily. The graphic equalizer has seven preset frequency bands ranging from low bass to high treble - 60, 150, 400,1000, 2400, 6000, and 15000 Hz. Moving the slider upward boosts the selected frequency band, moving it downward cuts it. Boosting the audio signal too much may result in clipping or distortion. ## Holding the [Option] button down while clicking on a slider sets the volume of the selected frequency band to a flat position. Holding [Option] + [Shift] down while clicking on a slider sets all the sliders to a flat position. You can store and recall up to ten presets for the EQ. Press [Control] + [Shift]+ [0]...[9] on the main keyboard to store your settings and [Shift]+ [0]...[9] on the main keyboard to recall your settings. Right/control click on a EQ slider to display a drop-down menu that duplicates the keyboard commands for storing and recalling the presets. If you don't need any equalization, turn it off by un-checking the EQ button, keyboard shortcut [Q]. Karaoke / Vocal Remover - KA The word "Karaoke" is Japanese for "empty orchestra". With the Karaoke function enabled, you may, by using a stereo cancellation algorithm, reduce or remove vocals or certain instruments from a song. The idea is that what are recorded and placed in the middle of the stereo field may be removed, leaving behind what is unique in the left and right channels. The result depends on how the material is recorded, some songs will yield excellent results, others not. Note that the source must be a stereo recording. Amazing Slow Downer has two different versions of the stereo cancellation algorithm, one that results in mono output (the ST button unchecked), the other with stereo output (the ST button checked) where the stereo image will be kept intact. Use the Mix slider to "zoom in" the instrument/vocals, it may not always be recorded in the exact middle of the stereo field. The Karaoke function will usually also remove the bass, kick/snare drum etc. Use the EQ “Low” slider(s) to "get back" some of the lower frequencies and the “High” slider(s) to "get back" some of the higher frequencies. Raising the “Middle” slider(s) will bring back the center channel that was removed. In stereo mode, having all three sliders all the way down will add nothing back and in mono mode, having all seven sliders in the middle position will add nothing back. Use this to practice to music with vocals/soloists removed or to ease transcription with unwanted instruments removed, keyboard shortcut [K]. Note: DRM protected files from the iTunes store has the following limitations: Minimum speed is 25% - quarter speed Can not save the file Equalizer has bass and treble controls only The Karaoke function is disabled The Mix slider has no effect The stereo on/off switch has no effect The Hold function is disabled