X-Y oscilloscope: optional 45° rotation so mono becomes a straight line

[vincentvandercruyssen]

Hi, thanks for this component. In X-Y oscilloscope mode I can’t find a way to rotate the plot by 45 degrees. I’d like mono (L = R) to appear as a straight vertical or horizontal line. If this is already possible, which setting should I tweak?

[stuerp]

What signal are you feeding it? There is no 'tweak' to rotate the output. The component just interprets the raw input it gets from foobar2000. The left channel is used for the X axis; the right for the Y axis.

I'm not an audio engineer but for a vertical line I think you'd need a 2-channel signal with no samples on the left channel (or all zeroes).

Have a look at foo_input_signal to generate algorithmical signals.

Does that help?

[vincentvandercruyssen]

Hi, thanks for your response. Many stereo vectorscopes intentionally apply a 45° rotation (or an equivalent Mid/Side mapping) so that mono collapses to a vertical line, which is much faster to read visually.

This is explained here:

I was wondering whether such a display transform could be added as an optional mode. I wanted to check, since this behavior is quite common in other scopes.

[stuerp]

It does not sound difficult to implement. There has been little feedback on the XY oscilloscope. Within reason I'm open to feature suggestions.

Since I have no experience with other implementations, do you have any pointers to best practices or other documentation?

[vincentvandercruyssen]

I don’t have hands-on implementation experience, but I found that stereo goniometers/vectorscopes are commonly described as an XY oscilloscope view (Left on X, Right on Y) with the display rotated by 45° to make stereo phase/width easier to read.
https://support.apple.com/en-al/guide/logicpro/lgcef24f4081/mac
https://www.rtw.com/blog/welcome-to-our-blog-1/focus-the-audio-vectorscope-17

[stuerp]

Have a look at https://github.com/stuerp/foo_vis_spectrum_analyzer/releases/tag/v0.10.0.0-alpha5