Tim, I've got to wonder if I'm hitting a brick wall with my equipment. On all the songs I've sent you to make dances of, I cannot score higher than an A on all of them. I've nailed 150 combos on The Typewriter and it doesn't matter a bit
What sort of grade is usually breaking your combo? As you may know, you will lose a combo with a "miss", "boo", or "good" step. Combos only continue with "Perfect" or "great".
When you lose that 150 combo, is it usually a "good", a "boo", or a "miss" that causes you to lose it? "The Typewriter" is one of those songs that absolutely dreadfully difficult to synchronize the music to the steps. I'm pretty dang sure the song never goes out of synch enough to cause a "good" or worse rating, but if your offset isn't set properly, it might.
Press F11 and F12 to adjust the offset while you're playing. Play with it until you're really happy with the offset of the arrows to the music. Ideally, the arrow should be in the center of its "Perfect Point" zone right on the beat. If this isn't the case (you'll have to feel for it to see if it's right), use the following controls while the song is playing to adjust it:
F11: Move the arrows back 20milliseconds
ALT-F11: Move the arrow back 1ms
F12: Move the arrows forward (later) 20ms
ALT-F12: Move the arrows forward 1ms
I'd be surprised if your equipment is causing you to have poorer scores. This game is fully playable on basically any keyboard as far as I know(my laptop keyboard works fine too). If the arrows seem to be jerky or laggy, you may need to lower the graphics settings (lower resolution, lower texture detail, etc). The higher you can get the framerate, the easier this game is.
It sounds to me like either my song is out of synch on your computer (which is very possible. I synched the song for my computer, not everyone's computer), or your computer is jerking or lagging around causing you to mess up at certain points.
Maybe I have slow fingers or something. Maybe I'm the brick wall.
If you're consistant messing up the same part, maybe you need to re-read it more carefully and make sure you're playing the right rhythm. I think you mentioned to me before that you use the speed modifiers to space out the arrows a bit more, as I do; they're always useful.
I don't know what else to say without more information, except maybe play songs until you can AA them. An AA means you have 93% or higher of the maximum possible score; if you score an AA, it means that you are keeping your Perfect count up and your Great/good/boo/miss count down. If you can get your perfect/great ratio really good on easier songs, it will help you get the feel for getting better scores on harder songs.
