macOS · for the Roland SP-404 MkII

Make any sample pack
SP-404 ready.

Drop a whole pack. Get it back in exactly the format your SP-404 MkII accepts. No DAW, no Terminal, no cryptic “Unsupported File.”

One-time purchase · works offline · your samples never leave your Mac

It's 404, yo! analyzing a sample pack and showing what each file needs

The “Unsupported File” problem

Pro and Splice packs are usually 32-bit float WAVs — often 96 kHz, sometimes FLAC. The SP-404 MkII rejects them with a cryptic error and no explanation. Fixing them by hand in a DAW, one file at a time, is miserable across hundreds of samples.

Three steps. That’s it.

01

Drop your pack

Drag in a folder or files — your whole sample pack at once.

02

See what changes

Every file is analyzed with a plain-language reason: “32-bit float → 16-bit”, “96 kHz resampled”, “FLAC → WAV”.

03

Make it SP-404 ready

One click. Converted files land in a new folder, your structure preserved, ready for the SD card.

Simple by design

One job, done well.

🗂️

Whole-pack batch

Hundreds of samples in one drag — not file by file in a DAW.

💬

Plain-language reasons

It tells you exactly why each file would fail — something the SP-404 never does.

📁

Structure preserved

Your folders come out the same way they went in.

No needless re-encoding

Files that already work are copied untouched.

🔒

Fully offline

No account, no cloud. Your samples never leave your Mac.

Native & fast

Built with Core Audio. No Terminal, no ffmpeg, no fuss.

The fix, precisely

The documented format the SP-404 MkII accepts on SD-card import.

CodecLinear PCM WAV
Bit depth16-bit — fixes 32-bit float, 24-bit, …
Sample rate48 kHz (or 44.1 kHz) — resamples anything else
ChannelsMono / stereo preserved
MetadataExotic chunks stripped via a clean re-write

FAQ

Why does my SP-404 MkII say “Unsupported File”?

Most often the file is 32-bit float (common in pro/Splice packs), an unusual sample rate, or a format like FLAC. The SD-card import only accepts 16-bit linear WAV/AIFF/MP3 — so anything else is rejected without explanation.

Will it change files that are already fine?

No. Files that already import cleanly are copied untouched — no quality loss, no needless re-encoding.

48 kHz or 44.1 kHz?

48 kHz matches the SP-404 MkII’s internal rate (zero on-device resampling). 44.1 kHz is also accepted. You choose; the app handles the rest.

Does it send my samples anywhere?

Never. Everything runs offline on your Mac. There’s no account, no cloud, no tracking.

Which devices does it target?

Today it’s tuned for the Roland SP-404 MkII. More device profiles may follow.