What Is an SFZ File?

How to Open, Edit, and Convert SFZ Files

Screenshot of several SFZ files in Windows 10
SFZ Files.

A file with the SFZ file extension is a SoundFont Compressed file.

When used in a compatible player, an SFZ file expresses certain parameters that sample audio files should follow, like velocity, reverb, loop, equalizer, stereo, sensitivity, and other settings.

SFZ files are just text files that are normally found in the same folder as the audio files they refer to, like WAV or FLAC files. Here's an example of a basic SFZ file that shows the code an SFZ player would use to structure certain audio files.

How to Open an SFZ File

Any text editor can be used to view the code of an SFZ file. Notepad is included in Windows or you can download Notepad++, which may be easier to use.

Again, because SFZ files are just plain text files, they don't actually do anything in and of themselves. While you can certainly open the file in a text editor to read what it will do in a compatible program, nothing will actually take place unless you use an SFZ player.

So to actually use an SFZ file instead of just edit it, your best bet is to use a free program like Polyphone, which I think is one of the better SFZ players and editors. When editing an SFZ file in this program, you can save it back to the SF2, SF3, or SFZ file format. You can also use this program to export an open sample file to the WAV format.

Plogue's free sforzando software can also open an SFZ. It works in Windows or macOS by having you drag the SFZ file into the program.

As long as the syntax is correct in the SFZ file, both the instructions and the accompanied audio files will be recognized by the program. I highly suggest reading through the sforzando User's Guide if you plan on using this program.

Some other tools that are similar to the two above that can open and use SFZ files (and maybe SF2 files as well) include Rgc:audio sfz, Garritan's ARIA Player, Native Instruments' Kontakt, and rgc:audio's SFZ+ Professional.

Tip: If you're using Kontakt to open the SFZ file, you have to make sure that the "show foreign formats" option is enabled. Find that option in the Files menu next to the Import button, within the View drop-down menu.

How to Convert an SFZ File

Since an SFZ file is just a text file, you can't convert the .SFZ file itself to an audio format like WAV, MP3, or any other audio file. You can, however, convert the audio files that the SFZ file points to by using a free audio/music converter. Remember, the audio file that you want to convert is probably in the exact same folder as the SFZ file.

The free Polyphone tool I mentioned above can be used to convert the actual SFZ file to a Soundfont file with the .SF2 or .SF3 file extension, via the File > Export soundfont... menu.

You shouldn't have to convert SFZ to NKI (a Kontakt Instrument file) for use in Kontakt since that program can natively open SFZ files.

Of course, if you do need your your SFZ file to be in some other text-based format like TXT or HTML, it's as easy as opening the text in the text editor and then saving it to a new file.

Advanced Reading on SFZ Files

You can find more information on the SFZ format at Plogue's forum and Sound On Sound.

Still Can't Open Your File?

The most likely reason for why your SFZ file doesn't open with the programs linked above is that you don't actually have an SFZ file. Double-check that the suffix reads ".SFZ" and not just something similar.

The reason you need to check the file extension is because lots of files share some of the same file extension letters even though they don't open with the same programs or are used for the same purposes. Opening an unrelated file in the programs above might be why you can't get your file to open.

For example, you might really have a Windows Self-Extracting Archive file that ends in .SFX that just looks like an SFZ file.

You'll most likely get an error if you try opening an SFX file in an SFZ opener or editor.

The same is true for others like an SFC, SFPACK, SFK, FZZ, SSF, or SFF file.

The idea here is to check the file extension and then research the one you're dealing with, to figure out how to open the file or convert it to a new file format.

Was this page helpful?