Boom Box Surround

With modern computers and audio cards, it is easy to achieve multi-channel audio. My notion of "Boom Box" surround is an affordable way to achieve surround sound using two existing portable stereos or even two home stereos. The idea is to immerse the listener in an environment using four speakers (quadraphonic sound.) This method of surround sound requires four independent channels of amplification. A typical, portable CD/Stereo unit has two discrete channels of audio. Therefore, in order to achieve quadraphonic sound, two portable stereo units are necessary. The result of this project is two stereo compact discs, each programmed for one of the two pairs of speakers. The compact discs should be identical in length, and started on their respective units in tandem.

The image below illustrates the use of panning to make a source sound "move." The process requires at least two stereo tracks in any audio editor. The top track (light blue) is programmed for the front left and right speakers. The illustration represents the use of panning envelopes to cause the sound to migrate between the left and right speakers. When the black line is at the top of the track, the sound travels to the left speaker and when at the bottom, to the right. This process is used on the bottom track (light green) to achieve the same type of movement in the rear left and right speakers. It would be nice to have the audio editor assigned to four independent channels via an audio card; however, with a little imagination it is not necessary. In the illustration below, I have removed sections of audio to remove the sound from one pair of speakers while it is sounding in the other pair. Fades are utilized for smooth transitioning between the pairs of speakers. (more below...)

Use volume envelopes to move the sound between the stereo pairs. The example below illustrates volume as a means to cause one track to "appear" at one pair, and then at another. The top track (light blue) represents a continuous region of audio with automated volume control. On the bottom track (light green,) a copy of the same region of audio is placed. The top track is intended for the front stereo compact disc, while the bottom track is for the rear. While the volume envelope is at maximum for the front track, it is kept at a minimum for the rear. Combining volume envelopes with panning envelopes is an excellent way to achieve movement with in the four speakers. On the top track, panning envelopes are represented in grey. (more below...)

Upon completing the project, select the entire composition and prepare to compile the multiple tracks into one stereo file. To engineer the front CD, mute those tracks intended for the rear CD and "bounce" a stereo file. Then, without losing the initial selection, reverse the process by muting those tracks not intended for the rear CD and make a stereo file. Keeping the overall selection the same for both "bounces" will ensure both compact discs are identical in length.

Now, put each compact disc in a portable stereo player, stand in the middle, and press play at exactly the same time on both. Each unit should, although not synced to each other, should play in tandem. If engineered correctly, sounds should appear to move around the listener's position.

Here are two example files, beesfront.mp3 and beesrear.mp3. Download them and play them back in tandem on two stereo units.

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