I have a real-time audio application where I need to overlay audio samples in an output audio stream. The Teensy memory can't hold the samples, so they well be held on an SD card. I need high speed access to the SD so I'm going to use raw 512 byte mode. I need to make calculations for accessing arbitrary 512 byte blocks. It seems like I could make calculations for read speed, but I'm sure there's twelve catches. Can anyone offer data on block SD reads for Teensy 3.6 and 4.0?