I’m pretty sure SD card won’t have any impact on BB capacities except for the amount of WAV samples for different kits etc. that could be loaded on one, which there is plenty of room for. The BeatBuddy uses a Texas Instruments single board ARM CPU that has a fixed amount of RAM on it. Unless SS can confirm otherwise the limit is likely how much the QT-5 player can buffer based on the platform that it is running on, ie. a BB2 would be needed for doing full songs or multi-track Midi that would conain more than 500 notes. Same issue with 100MB kit size, it needs to buffer all samples in the current kit into a limited memory space.