BlumBox.quark

The Blumlein Box (aka BlumBox) is a collection of stereo imaging transforms and analyses packaged together as a SuperCollider Quark.

Credits

Developed by Emmett Miller with the guidance of Dr. Joseph Anderson, whose paper Classical Stereo Imaging Transforms--A Review serves as the basis for this project, and DXARTS at the University of Washington.

Installing

Requirements

BlumBox.quark was developed on SuperCollider 3.12.2. Though previous versions may be compatible, it might not be a bad idea to install the latest SuperCollider update.

To install the quark, run the following in SuperCollider: supercollider Quarks.install("https://github.com/emillwe/BlumBox.quark");

If you've already installed BlumBox, you can make sure all dependencies are up to date using the QuarksGui: supercollider Quarks.gui

The Transforms

The Blumlein Box implements the following 9 stereo transforms:

MS to LR

Transforms a signal from the MS domain to the LR domain

LR to MS

Transforms a signal from the LR domain to the MS domain

Rotation

Rotates a stereo signal, preserving relative positions in the stereo field

Width

Widens or narrows a stereo signal

Balance

Stereo panning as implemented on most consumer electronics--compresses a stereo signal towards the L or R axis

Middle Panorama

Rotates the M-axis of a stereo image, leaving the S-axis in place

Asymmetry

Rotates the S-axis of a stereo image, leaving the M-axis in place

Left Panorama

Rotates only the L-axis of a stereo image

Right Panorama

Rotates only the R-axis of a stereo image

The Analyses

The Blumlein Box also includes the following 5 stereo imaging analysis functions. Each has the option to return either an instantaneous or time-average value.

Power

Returns the power of a stereo signal

Balance

Distribution of power along the L-R axis.

Correlation

Degree of similarity between left and right channels, i.e. the distribution of power along the M-S axis

Angle

Apparent source direction in radians of a stereo image

Radius

Encoding radius of a stereo image

References

1. Anderson, J. L., "Classic Stereo Imaging Transforms: A Review", published in Spanish in Basso, G., Di Liscia, O. P. & Pampin, J. (editors)(2009). "Música y espacio: ciencia, tecnología y estética". Buenos Aires, Universidad Nacional de Quilmes.

2. Streicher, Ron., and F. Alton Everest. The New Stereo Soundbook. Audio Engineering Associates, 2006.

3. American reprint: Blumlein, A. D. (1958). "British Patent Specification 394,325 'Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems'" (PDF). Journal of the Audio Engineering Society. 6 (2): 32–40.