The following is information that may or may not help you to help me. I just thought I'd include it just in case: I practice my bass show notes, cadence, warm ups, etc. every day on my Vater pad with either my Aungst indoors or my Ralphies.

When I go to band practice and try to play the diddle splits in the cadence or in the show, I can never quite squeeze them out, though I can play them fine at home. It's hard enough for me to take all that I polished on my pad and turn it vertically, but I feel like now I rely on the rebound, which just isn't especially great on a bass like it is on a piece of rubber attached to a hunk of wood.

Basically, I've got a case of the pad hands, but, somehow, on a bass. How do I stop it?

I would start by practicing on a softer surface, one that works out the muscles when playing rolls a little more than a piece of rubber (pillow, couch cushion, etc.). Another option could be the Vic Firth HH BassPad. A couple of my students got one recently, and the results are noticeable very quickly.

Is it even possible to do diddles on any of those surfaces? O__o

Yeah, I agree with LDLSnare, practicing on a surface where you really have to pull the diddles out will help. Eventually yours hands will become so used to that extra bit of muscle needed to diddle on something other than rubber. As I understand it, a diddle is just two strokes on the same hand, so the problem is you're dependent on having the bounce from your pad do all of the work, with your hand just sort of holding down the stick. With slower diddles or a less rebounding surface you have to increase the amount of actual re-hitting in the motion. Practicing on a pillow, or a thick paperback book, etc. makes you aware of that need. Once you teach yours hands to do that harder-working diddle, it becomes automatic when doing them on even the most energy-sapping bass drum. Just in my experience.

Thank you! I'll get started today with that.

Get a heavyhitter basspad. they work really well and it's the same feel as a bass drum(but smaller which is good because it forces you to play in the center once you play your actual drum)

or try practicing on a wall or something that allows you to play vertically

Yea, The HH Bass pad is great, but I also play bass 2, so I can sort of rely on the rebound. if you play on a lower bass, then couch cushions would probably help, and maybe using the mallets on them, because snare sticks give you more bounce because they are longer.

I play first, but, still, you have to admit, you'd rather play those sixteenth note diddle runs on a slab of plastic on wood.

haha, yea I would

take your drum home...no matter how perfect you get it on any pad (including the hh bass pad) it will never sound like that on the drum. you have to learn to clean thigs with the rebound of your specific drum