Iv a project where I try to build a "Sampler-Step-Sequencer" with the ability to record your own samples. I use the Teensy 3.6.
So far, I splited it up in two subjects: the recording RAW/Wav files to SD part, and the Polyphonic Sample Trigger/Play part.

For the recording part, i read through PJRCs Audio Library and through the documentation about the Audio Adaptor Board. I think thats good for what Im looking for.
But for the sample-play part I think the Audio board is not powerful enough (or is it?), since I want to trigger up to ~8 samples (max 3 sec long) at the same time / polyphonic. So I came across the Robertsonic's WAV Trigger Board which fits my needs in case of polyphony, latency, etc.

So far so good, but the problem is of course: The two boards have it's own SD Cards which cannot read/write each other, and they have their own libraries with its own update() functions. Here I would appreciate advice from you Is there a way, that those two boards use the same SD card for writing and reading? Or is the Teensy capable of copy those files? Or can I simply wire the two SD slots together for only one card?
Or is there even hardware/boards which fit my needs?

It would be awesome, if you could point me to something where I can start with.
Thank you