I have been eagerly reading the manual since I have a 555 incoming and I was slightly put off by hearing about the slow Autostart. There may be a possible solution but until I get my 555, one of you guys will have to test this to see if it works.
It says in the manual that the Autostart level is set a pre-specified amount, but it does not say what this amount is, and after going through the manual it seems there is no way to change it.
However, there may be a workaround.
In the "Other Settings" section of the manual it says that you can boost the overall output level by +12db, but Roland says that with a lot of samples playing altogether at full level there may be a headroom problem, and you may end up with clipping.
However, by raising the overall output level, this will trigger the Autostart sooner (assuming that by raising the output level it does not raise the Autostart trigger level).......and hopefully you will hear the attack transient of your kick drum.