schOPE readme

Schope
One Scope To Rule Them All
© 2007 Schwa

Schope is a flexible signal analysis tool that provides several ways to visualize multiple audio sources at once. Audio can be visualized in various viewing modes, or domains. Some controls affect all domains, and some don’t.

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Input Channels.

Schope has 4 input channels, each drawn in a different color. You can route any type of signal to any of the input channels. Here are a few useful routing examples:

  • Route a dry audio signal to one scope channel and the same signal after applying an effect to another scope channel. This allows to you see exactly how your effect (compressor, EQ, etc) is changing the audio signal.

  • Route different instruments to different scope channels to give you guidance in separating each track into its own sonic space. For example, EQ scooping the bass to make room for the kick drum is easy when you can see the two frequency images superimposed.

  • Route multiple captures of the same audio source (for example, top and bottom snare mics, or guitar DI and amp mic) to different scope channels to find phase problems and see exactly how manual time adjustments will help or hurt.

Input Channel Controls and Displays.

  • In/out button: controls whether that channel is displayed or not.

  • Offset knob: adjusts the manual time offset for that channel. For example, an amp mic recording will be slightly delayed when compared to a DI capture of the same performance; this knob allows you to find the exact manual adjustment needed to line up the signals. The current offset is displayed beneath the knob.

  • RMS strength: displays the power of only the visible portion of that channel’s audio signal. If only a small window of time or frequency is displayed, the RMS display shows the power contained within that window.

  • Save/load (Reaper only): for channels 1-3, saves the most recent 1 second of that channel’s input buffer as a wav file. For channel 4, loads the first 1 second of a wav file into the input buffer. This allows any view to be frozen, saved, and loaded at any time.

Time Domain Controls.

In this view, waveform peaks are drawn, representing the strength of the audio signal over time.

  • Zoom handles: the vertical zoom handle to the left of the display controls the amplitude scale. The horizontal handles beneath the display control which portion of the 1-second input buffer is displayed: moving the left handle zooms the time window, and moving the right handle pans the display. (The RMS strength display for each channel will reflect only the visible part of the the waveform.)

  • Trigger handles: if a trigger level is set, each channel’s waveform is frozen when it breaks that level. If a channel fires a trigger, that channel’s display is held until the next trigger fires on that channel. This allows easy display of only the interesting part of a rhythmic recording, such as a series of drum hits.

  • Mouse: the first click pauses the display. Dragging vertically controls amplitude zoom, and dragging horizontally pans time. (If there is no more buffer left in the pan direction, dragging horizontally is equivalent to time zoom – watch the horizontal zoom handles as you drag to understand exactly how you are affecting what’s being displayed). Shift-click resets the cursor to a new position, and right-click releases the pause).

  • Scrub (Reaper only): scrubs across the time display. This is useful for finding clicks, or locating exactly where transients start.

  • Sync Host (Reaper only) : syncs the host DAW’s edit cursor to the scope cursor. This is useful after you have used the mouse or scrubber to locate exactly where in the waveform an edit needs to occur.

  • Pause (Reaper only): toggles playback pause, which freezes or unfreezes the current display.

  • Bypassing Schope freezes the current display, which can then be zoomed, panned, and examined in different modes.

Frequency Domain Controls.

In this view, spectral density is drawn, representing the strength of the audio signal across frequencies. Hovering the mouse over the spectrum drawing will display the exact frequency and note equivalent.

  • Zoom handles: the vertical zoom handle to the left of the display controls the amplitude scale. The horizontal handles beneath the display control which portion of the frequency spectrum is displayed. (The RMS strength display for each channel will reflect only the visible part of the spectrum.)

  • Mouse: the first click pauses the display. Dragging vertically controls amplitude zoom, and dragging horizontally pans frequency.

  • Pause (Reaper only): toggles playback pause, which freezes or unfreezes the current display.

  • Bypassing Schope freezes the current display, which can then be zoomed, panned, and examined in different modes.

  • FFT size: controls how many samples of audio signal are used to generate the frequency drawing. An audio frequency only exists within a certain window of time, so FFT size is a tradeoff between time accuracy and frequency accuracy. The more time is allowed to capture frequencies, the more accurate the frequency display is, but the less the display reflects what is happening right now. The less time allowed, the more the display reflects what is happening right now, but the less accurate the frequency display is.

  • Blend: controls how smoothly the frequency drawing updates itself.

  • Perceptual filter: adjusts the frequency drawing by an equal-loudness contour, so that two frequencies with the same amplitude on the drawing represent equal perceived loudness.

  • Noise filter: draws the variation in the signal at each frequency. A pure tone should have very little variation; music will have a great deal of variation.

Phase Domain Controls.

In this view, the phase of the signal is drawn. There are two phase view modes: channel phase (or goniometer) mode, and signal phase mode.

Channel phase mode is used to visualize the stereo image: scope channels 1 and 3 are interpreted as left channels, combined and drawn along one diagonal, and channels 2 and 4 are interpreted as right channels, combined and drawn along the other diagonal. A balanced stereo image will have most of its strength along the vertical axis of the graph, a panned signal will have more strength along one diagonal. A signal with phase problems will have most of its srength along the horizontal axis (because the phase misalignment causes the left and right channels to always have opposing polarity).

Signal phase mode is used to visualize the phase of each channel individually. This is useful for detailed phase comparison of the same source audio after two different processing paths.

  • Zoom handles: the vertical zoom handle to the left of the display controls the amplitude scale. The horizontal handles beneath the display control which portion of the 1-second input buffer is displayed: moving the left handle zooms the time window, and moving the right handle pans the display. (The RMS strength display for each channel will reflect only the visible part of the the waveform.)

  • Mouse: the first click pauses the display. Dragging vertically controls amplitude zoom.

  • Pause (Reaper only): toggles playback pause, which freezes or unfreezes the current display.

  • Bypassing Schope freezes the current display, which can then be zoomed, panned, and examined in different modes.


If you have any support needs, or questions on usage or anything else
regarding this plugin, please visit the forums at stillwellaudio.com. Woo hoo!