What is the SYX file format?
.syx files belong to the category of audio files. The content of a .syx file consists of unprocessed MIDI data transmitted directly from MIDI instruments such as synthesizers, drum machines, and effects processors. This data is not modified or processed at the file level - .syx files store raw binary data.
Each .syx file is a raw byte stream containing one or more System Exclusive (SysEx) messages as defined in the MIDI 1.0 specification. Every message begins with the status byte 0xF0 (Start of SysEx) and ends with 0xF7 (End of SysEx). Between these markers, the payload includes a Manufacturer ID followed by device-specific command and data bytes - each with bit 7 clear (values 0-127). There is no file-level header or index; a .syx file is simply a concatenation of consecutive messages.
.syx files are used by SysEx utilities and DAW software to record unprocessed MIDI messages. In this way, a backup copy of any MIDI instrument - for example, a synthesizer patch bank or drum machine preset - can be created on the hard drive of a computer. Some manufacturers, such as Roland, append a checksum byte before 0xF7 to verify data integrity, though this is not required by the MIDI specification.
The data recorded in .syx files can then be restored to the originating device, processed in dedicated audio programs, or copied to external storage for archiving. MIDI 2.0 (2020) retains full SysEx compatibility. Common tools include MIDI-OX on Windows, SysEx Librarian on macOS, and amidi (part of ALSA utils) on Linux.
Security & safety
RISK: LOWPure binary MIDI data; no executable content. Sending an incorrect SysEx dump to a synthesizer can overwrite patches or (rarely) corrupt device settings - always verify the SYX file matches your specific device model before transmitting.
Format details
in a nutshellPrograms that open SYX files
Windows3 apps
MIDI-OX
Free View → SysEx; use Send SysEx File to transmit the .syx to your synthesizer via MIDI interface.
Cakewalk by BandLab
Free Use the SysEx View (Insert → Sysx) to send/receive SysEx files to/from connected MIDI devices. 
macOS2 apps
SysEx Librarian
Free Drag the .syx file into SysEx Librarian, connect your synth, click Play to transmit. 
Linux1 app
amidi (ALSA utils)
Open-source amidi -p hw:1,0 -s file.syx - sends the SysEx file to the specified MIDI port. Technical details
deep spec| File type | Binary MIDI SysEx message dump |
| MIME type | audio/midi |
| Start-of-message byte | 0xF0 - reserved MIDI status byte marking the beginning of every SysEx message |
| End-of-message byte | 0xF7 - reserved MIDI status byte marking the end of every SysEx message |
| Data byte value range | 0x00-0x7F (bit 7 always 0 in data bytes; only 0xF0 and 0xF7 have bit 7 set) |
| Manufacturer ID | 1 byte (standard) or 3 bytes when first byte is 0x00 (extended ID for additional manufacturers) |
| File-level header | None - file is a raw concatenation of one or more F0…F7 messages with no wrapping structure |
| Checksum | Device-specific; Roland uses sum-of-data mod 128 as a byte before 0xF7; not mandated by the MIDI spec |
| Typical file size | 100 B - 500 KB for single-device patch dumps; bulk bank exports can exceed 1 MB |
| Encoding | Binary byte stream; each data byte is 7-bit (values 0-127) |
| Common uses | Synthesizer patch backups, drum machine presets, effects processor settings, firmware transfer |
| MIDI 2.0 compatibility | SysEx messages retained unchanged in MIDI 2.0 (2020) |
| Platform support | Windows, macOS, Linux |
| Released | 1983 (MIDI 1.0 specification) |
| Latest version | MIDI 1.0 (SysEx unchanged); MIDI 2.0 (2020) retains SysEx compatibility |
| Open standard | Yes · royalty-free |
| Specification | www.midi.org |
SYX conversions
Community Q&A
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