4V File

What are 4V files and how to open them

Are you having problems opening a 4V file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your 4V files.

What is a 4V file?

A .4V file is a Quartet Module file.

Quartet Module (.4V) is a tracking-style music file created by Microdeal for their Atari ST application Quartet. It stores a complete song composed in Quartet: melody and harmony across four simultaneous voices, arranged using the program's staff notation and sequencer tools.

This format is created when the user saves a composition from the Quartet program. Quartet versions 1.0 and later let you enter notes by hand or via MIDI, assign different sampled instrument sounds ("voices") to each of the four channels, and then save the whole composition in a .4V file. Because it's native to Quartet, you generally need Quartet or compatible converters to play or edit .4V files.

Internally the .4V format begins with a header including parameters like playback frequency, tempo multiplier, time signature, and bar measurement note. Following the header are voice-tracks data chunks for voices 1 through 4. Each voice includes sequences of note instructions (play note, slide, rest, voice change, loop, end), and every voice ends with a finish marker. The file's signature includes a specific byte sequence at offset 7 (ASCII "..........V.w") that helps identify it as a Quartet Module.

How to open 4V files

Important: Different programs may use files with the 4V file extension for different purposes, so unless you are sure which format your 4V file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 16, 2026

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