If the glitch is in my source files, please send me a pm about it. 😃 It might be something that I’ve already fixed.

As far as the mono audio goes, using two channels is probably the best option, but the diagram should still be the single dot. This is pretty standard on commercial film releases.

Using only a single channel will force the audio to the center speaker. This is fairly straight forward when encoding to AC3 or DTS, but lossless sources like PCM or FLAC will require setting the channel mask bit on the file to 2. Without setting that bit, the audio may only be played from the left speaker. The disadvantage to using a single channel is that most users have better speakers for the FL and FR channels than they do for the center. Those users may prefer to have the audio coming from their better two front channels than from a single inferior center speaker. Many surround systems do not use a full range speaker for the front center channel. Using a single channel source, playback through the two front speakers may be difficult to achieve without altering the setup of your AV Receiver.

Achieving correct center-channel playback from a two channel mono source will simply require engaging pro-logic decoding. Since the Left and Right Channels are identical, the decoder will send the entire signal to the center speaker. The main disadvantage to the two channel format is that when encoding to AC3, it wastes useable bitrate and therefore quality on that second audio channel.