Under certain circumstances, Time Compression does not drop below 8x. At that setting, you will miss quite a few voice prompts from your crew. I cannot recall the settings, but like if you are at 16x TC, trying to speed along to an intercept point, you won't always see the TC drop, especially if you have already made initial contact with a target via say the radar. Now you are within visual, and the game assumes you know and have marked the target on the NavMap. In that Main.cfg file, you'll see listings like:
SoundEffects=2
CharacterAnim=4
EnemyDetected=8
RadioReport=8
Particles=8
and some of those signify when the particular listing quits, so if you go above 2x TC, you lose some sound effects. Above 4x, you lose some character animations, above 8x and you lose particles, like the fires, etc. Others are what the game will drop to when that condition is met. It should be two separate sections of the listing, but oh well, that's SH4...
