What is ConvoFS?

ConvoFS is a “convolving file system” - a special-purpose file system sitting in between your music collection and media server/music renderer. When you install it, you specify the location of your music collection and an additional location. ConvoFS presents a virtual version of your music collection under the second location. You will see the same folders and files as expected, but the apparent FLAC file sizes will be larger. When you access one of those virtual FLAC files, ConvoFS behind the scenes builds a convolved copy to be served. You can specify the virtual location as the base folder for your music server, be it Minim server, LMS etc. What you hear in your speakers is the DRC processed version of your music. You can also export the ConvoFS mount as a network (“SMB”) share turning your NAS/Linux box into a convolving appliance. ConvoFS does not and cannot ever support Dirac. Also, being file system oriented, it cannot be used for streaming services like Tidal.

Is ConvoFS free?

Yes, ConvoFS is “open source” and distributed under the “GNU general public license, version 2”. This GNU license is one of the first Open Source licenses and dates some 25 years back. Space does not allow to enter into the finer details here, but ConvoFS being Open Source means that it’s free for you to download and use and that if you have the right technical skills, you can inspect the code and improve on it.

What do I need to run ConvoFS?

You need either a Synology Intel (e.g., Atom/Celeron) based, 64 bit NAS or a Linux computer. The Linux computer should preferably run Ubuntu or another Debian based Linux flavor. ConvoFS supports Synology 6.x and may still work under 5.x. Synology NAS devices with known success stories include DS713+, DS1813+, DS716+, DS415+, and DS216+. As for Ubuntu, ConvoFS is being developed using Ubuntu 16.04, but other releases will probably work. DSD upsampling requires quite some computing power, I’ve tested DSD256 upsampling successfully on an Intel dual-core 3GHz i5 machine with playback on an AURALiC Aries Mini streamer.

What other software/hardware products are used with ConvoFS?

ConvoFS is known to be in use with media servers like Minim Server, AURALiC Lighting Server, Logitech Media Server (LMS) and Roon. Users are also using it with JPlay/Daphile. As for stand-alone playback hardware I know of usage with streamers from Logitech, AURALiC, and Linn.

Can ConvoFS replace Acourate/Audiolense/REW/...?

No, ConvoFS is not a replacement for those/similar programs. You generate your filters the way you use to and then upload them to ConvoFS which uses them to convolve your music as you access it.

So what’s the big deal?

The beautiful thing about ConvoFS is that it is media server agnostic - it does not know what’s running on top of it, meaning that media server/streamers whose developers have never thought of doing DRC will suddenly have DRC support. Another nifty thing is that ConvoFS does not build a separately convolved copy of your music collection - convolving is done transparently as needed, and the intermediate data will be discarded after having been served.

Why are only Synology NAS boxes supported and why only Intel models?

I can see no reason that it should not be possible to port ConvoFS to e.g. QNAP boxes but porting and supporting QNAP too would draw too many precious resources. Intel models: two reasons: the Synology binary build ships compiled binaries that would have to be recompiled for e.g. ARM-based Synology boxes. Secondly, I’m afraid that many of the ARM boxes are too weak CPU wise to support convolving.

Why is ConvoFS FLAC-only?

ConvoFS was initially written supporting the FLAC format exclusively because my music collection is all FLAC. There once was and there may eventually again be plans to support more formats. An idea could be that a file like ‘music.mp3’ will appear as a virtual file ‘music.flac’, transparently transcoded into FLAC and convolved. However, there are no current plans - last I looked at it, it caused performance problems.

But what about my MP3/DSD/WAV files?

Don’t worry; they are still accessible through ConvoFS as well as cover art and other non-FLAC files. But they won’t get convolved. If this is a problem, you may choose to convert them to FLAC format.

Does ConvoFS support gapless playback?

If your media server/player does, so should ConvoFS.

How do you pronounce it?

You do it in two parts: ‘Convo’ (substring of the word convolving) and then the single letters ‘f’ and ‘s’ (abbreviation of the word file system).

I’m browsing a ConvoFS share, and it is slow

Due to the concept behind ConvoFS, it will be best suited for use with media servers that once and only occasionally after that build an index of your music. What you experience is most likely that ConvoFS does a lot of partial convolving because your machine reads past the header located at the beginning of every FLAC file. Putting ConvoFS into ‘Index’ mode while browsing speed up things considerably.

What does ..busy (unclean shutdown).. mean?

You may get a message like

‘/volume1/ConvoFS/mount busy (unclean shutdown)(...). Stop your music player and/or -service and try again.;’

when you restart ConvoFS. What it means is that ConvoFS was unable to shut down properly and cannot start. The fix is to make sure that nothing is accessing the mount directory. The classic error is if your media player is on pause rather than entirely stopped. If stopping it doesn’t help, you may have to stop your media server (e.g. Minim Server), restart ConvoFS and then start the media server again. Worst case, restarting your Linux machine/NAS will cure the problem.

Take care

General common sense wrs DRC is also to be followed when using ConvoFS, and it shows with red text whenever appropriate. The principles are to turn down the volume the first time a new filter is used, avoiding loudspeaker tweeters become damaged _should_ the filter file be corrupted or not a DRC filter at all and produce white noise. If you try PCM->DSD upsampling, also read the specific caveat of this document regarding artifacts.