The pulsing tone that some people are hearing is apparently a faint time-code audio bleed that was on the original masters, but something about DVD audio has amplified it enough to make it noticeable. A bug in Apple's DVD software for the Macintosh causes the DVDs to be unplayable. Apple has just released a new version of the player software that fixes this, you can get it on their website. The replication plant used the wrong master tape. Second pressing Bubblegum Crisis DVDs feature full-disc headshots of the main characters.
Subtitles appear malformed and white in color with a black border.
This will differ notably from the correct subtitles, which appear evenly proportioned, and in yellow with a black border. Correct subtitles are found on all 3 first pressing discs and on discs 1 and 2 of the second pressing. Japanese audio portion not available. Various set-top DVD players may not recognize the Japanese audio tracks. Make sure the disc meets the first three criteria above.