The SMP format uses a RIFF-like 32-byte header, but with big-endian fields (unlike WAV’s little-endian ones): a “RFWV” magic number, followed by the total file size, sample rate, channel count, and bit depth. Immediately after the header sits a fixed block of roughly 480 extra bytes that don’t correspond to the actual sample. This appears to be leftover data from the sampler’s internal recording buffer — a byproduct of flash memory not being wiped between takes, so a trace of a previous recording lingers there. Past that block, the real audio begins: standard interleaved 16-bit little-endian PCM, sample-for-sample identical to the exported WAV (aside from occasional single-bit rounding noise, inaudible in practice).

With the format mapped, converting .SMP files to standard .WAV is straightforward — just parse the header, skip the buffer remnant, and wrap the PCM data in a proper WAV container. You can use the converter provided on this website or take a look at the corrsponding github repository if you want to get a deeper inside into the code: https://github.com/andymann/roland-smp-to-wav-converter

Since everything is happening in your browser locally you can also point to complete folders and have them converted recursively. Tests on my side all went cool – it just works.