Change:
<del> { lib, stdenv , fetchgit , alsa-lib , aubio , boost , cairomm , cppunit , curl , dbus , doxygen , ffmpeg , fftw , fftwSinglePrec , flac , glibc , glibmm , graphviz , gtkmm2 , harvid , itstool , libarchive , libjack2 , liblo , libogg , libpulseaudio , librdf_raptor , librdf_rasqal , libsamplerate , libsigcxx , libsndfile , libusb1 , libuv , libwebsockets , libxml2 , libxslt , lilv , lrdf , lv2 , makeWrapper , pango , perl , pkg-config , python3 , readline , rubberband , serd , sord , soundtouch , sratom , suil , taglib , vamp-plugin-sdk , wafHook , xjadeo , videoSupport ? true }: stdenv.mkDerivation rec { pname = "ardour"; version = "6.9"; # We can't use `fetchFromGitea` here, as attempting to fetch release archives from git.ardour.org # result in an empty archive. See https://tracker.ardour.org/view.php?id=7328 for more info. src = fetchgit { url = "git://git.ardour.org/ardour/ardour.git"; rev = version; sha256 = "0vlcbd70y0an881zv87kc3akmaiz4w7whsy3yaiiqqjww35jg1mm"; }; patches = [ # AS=as in the environment causes build failure https://tracker.ardour.org/view.php?id=8096 ./as-flags.patch ]; nativeBuildInputs = [ doxygen graphviz # for dot itstool makeWrapper perl pkg-config python3 wafHook ]; buildInputs = [ alsa-lib aubio boost cairomm cppunit curl dbus ffmpeg fftw fftwSinglePrec flac glibmm gtkmm2 itstool libarchive libjack2 liblo libogg libpulseaudio librdf_raptor librdf_rasqal libsamplerate libsigcxx libsndfile libusb1 libuv libwebsockets libxml2 libxslt lilv lrdf lv2 pango perl python3 readline rubberband serd sord soundtouch sratom suil taglib vamp-plugin-sdk ] ++ lib.optionals videoSupport [ harvid xjadeo ]; wafConfigureFlags = [ "--cxx11" "--docs" "--freedesktop" "--no-phone-home" "--optimize" "--ptformat" "--run-tests" "--test" ]; # removed because it fixes https://tracker.ardour.org/view.php?id=8161 and https://tracker.ardour.org/view.php?id=8437 # "--use-external-libs" # Ardour's wscript requires git revision and date to be available. # Since they are not, let's generate the file manually. postPatch = '' printf '#include "libs/ardour/ardour/revision.h"nnamespace ARDOUR { const char* revision = "${version}"; const char* date = ""; }n' > libs/ardour/revision.cc sed 's|/usr/include/libintl.h|${glibc.dev}/include/libintl.h|' -i wscript patchShebangs ./tools/ substituteInPlace libs/ardour/video_tools_paths.cc  --replace 'ffmpeg_exe = X_("");' 'ffmpeg_exe = X_("${ffmpeg}/bin/ffmpeg");'  --replace 'ffprobe_exe = X_("");' 'ffprobe_exe = X_("${ffmpeg}/bin/ffprobe");' ''; postInstall = '' # wscript does not install these for some reason install -vDm 644 "build/gtk2_ardour/ardour.xml"  -t "$out/share/mime/packages" install -vDm 644 "build/gtk2_ardour/ardour6.desktop"  -t "$out/share/applications" for size in 16 22 32 48 256 512; do install -vDm 644 "gtk2_ardour/resources/Ardour-icon_''${size}px.png"  "$out/share/icons/hicolor/''${size}x''${size}/apps/ardour6.png" done install -vDm 644 "ardour.1"* -t "$out/share/man/man1" '' + lib.optionalString videoSupport '' # `harvid` and `xjadeo` must be accessible in `PATH` for video to work. wrapProgram "$out/bin/ardour6"  --prefix PATH : "${lib.makeBinPath [ harvid xjadeo ]}" ''; LINKFLAGS = "-lpthread"; meta = with lib; { description = "Multi-track hard disk recording software"; longDescription = '' Ardour is a digital audio workstation (DAW), You can use it to record, edit and mix multi-track audio and midi. Produce your own CDs. Mix video soundtracks. Experiment with new ideas about music and sound. Please consider supporting the ardour project financially: https://community.ardour.org/donate ''; homepage = "https://ardour.org/"; license = licenses.gpl2Plus; mainProgram = "ardour6"; platforms = platforms.linux; maintainers = with maintainers; [ goibhniu magnetophon mitchmindtree ]; }; } </del>

Discussion:
is adding ardour 7.0 to the repository. As noted by 7.0 still experiences crashes. Thus we've opted to keep version 6.9 around for a little while for people to optionally use as a more stable base for their projects. Once ardour 7.x (package name ) is deemed stable, ardour 6.x (package name ) should be removed from nixpkgs.
updated to in preparation for 8.0, so this issue should be either closed or updated. Fwiw, maintaining the package of the last stable release of the previous major version seems like a good tradition for Ardour.
Thanks for pointing that out. I agree that keeping (at least) the last version around is helpful for some people who can't update for one reason or another. If someone objects, they can create a new issue.