Installation on NixOS

Hey there,

the software works great on Ubuntu.
However, I have some trouble getting it to work on NixOS.
I tried to install Synthesizer V Studio Basic on NixOS 22.11 with the following derivation:

{ pkgs ? import <nixpkgs> { }
, sha256 ? "sha256-dcyAVr/kwEHuCxaSzv4M+kLcrdksQJQd8E6aNOIuaNk="
, version ? "1.8.1-latest" }:
with pkgs;
self.stdenv.mkDerivation rec {
    name = "synthv";
    inherit version;
    system = "x86_64-linux";

    isExecutable = true;

    src = fetchzip {
        inherit sha256;
        url = "${version}/";

    nativeBuildInputs = [ makeWrapper pkg-config ];
    buildInputs = with pkgs; [

    phases = "unpackPhase installPhase fixupPhase";

    fixupPhase = ''
        patchelf \
            --set-rpath "${lib.strings.makeLibraryPath buildInputs}" \
            --set-interpreter ${binutils.dynamicLinker} \

    installPhase = ''
        mkdir -p $out/bin
        cp -r . $out
        ln -s $out/synthv-studio $out/bin/synthv-studio

The app launches and installing one of the lite voice databases also works. However, the program does not generate any voices at all. When pressing play after selecting a voice, nothing happens.

The console output is as follows:

synthv-studio: /nix/store/gd2qv9971z6ahbaibck0p1lbr3zvfmng-curl-7.86.0/lib/ no version information available (required by synthv-studio)
WARNING: could not load app font file.

Could you provide some help or advice on how to debug this problem?
Thanks a lot in advance :slight_smile:

I think the problem is that it tries to write to the read-only filesystem and/or doesn’t work properly if not started from the installation directory.