Aeolus Tuning

I’m sure there are those true pipe organ masters who would disagree with me, but I think having Aeolus release with the standard Mean Tuning is probably not what most people want. Many will select Aeolus and think something is wrong with it. :grinning:

Some portion of users will not necessarily know that running X11 forwarding through ssh will enable the display of the native Aeolus UI. The native Aeolus display allows retuning the whole instrument for the Equally Tempered scale.

IMO, I think distributing Aeolus tuned for the expected Equally Tempered scale would be easier on most users and a lead to a more enjoyable out of the box experience.

Agree 100%. The default should be the Equally Tempered scale. It was sure strange for me, too, when I opened Aeolus organ at first :slight_smile:

Interesting discussion! I haven’t used this engine much but my initial opinion was how realistic it sounded. That may have been due to the life-like tunings. There are many other organ sounds available which have the “expected” tuning. Ideally we should expose tuning in the UI if possible. I wonder if changing the out-of-box experience may undermine Aeolus impact? As stated, I am not a frequent user so don’t have a strong opinion but thought it worth mentioning :slightly_smiling_face:.

Oh boy. This can of worms :grinning:

It’s the original developers descision to go with Werckmeister III temprement, and it’s mostly a descision informed by a choice to put authenticity over convention. Most professional organists play organs that were built hundreds of years ago, the majority are not tuned to A440, neither do they use equal temperament. (Peterborough Cathedral Organ was recently re-tuned buy adding sections onto the pipes) In that regard most organists are not expecting to play organs tuned to equal temperament. Aeoleus wants to go for an authentic experience so the defaults are set that way. Hauptwerk go exactly the same way. Having said that I expect Modartt have gone with equal temperament. What we need to ask regarding the default is. Do we let the developer have his wish for a more authentic sound, or do we say Zynthian is here to make life easier and more predictable for its users.

We should probably go with the developer’s wishes.

I would also agree that it certainly sounds authentic out of the box, but that authenticity means most equally tempered players simply don’t know how to play it. It then likely becomes a quicky discarded novelty for all but the experienced or those willing to dig into X11 forwarding.

The question is would it be possible to expose the tuning setting and somewhat lengthy retuning procedure in the limited Zynthian UI? The Zynthian logo would be animated for quite a bit longer than the normal load times while Aeolus retunes each rank of the organ. It’s an interesting process to watch in the Aeolus UI. I assume it’s generating/updating a bunch of wave tables?

From a users perspective forewarned with this information, would probably completely change their reaction to it.

Perhaps a comment option for each engine displayed in the engine/effects gui display ?.
It would seem a good idea to restrict it to a known number of characters. The three banked nature of setBFree would probably be worthy of a mention for instance. It is very easy to reject engines simply after an initial uncomfortable interaction with them.
The centre screen area i available for this sort of information and would seem a good point to provide further information.

It would also allow documentation in the wiki to be made more standardised . . .

I’ve stuck this in a feature request, please add anything that seems relevant . . .


Totally agree.

As a long time organ player, I also was surprised by the default tuning in Zynthian. On the one hand, I know that Fons had chosen it with reason.
On the other, many organ players play organs in equal temperment, but of course you’ll also find historic instruments (often restored to their original tuning). Not many organists have the luck to have access to such an instrument.
Last but not least, a temperment other than equal is useful for baroque music, but not that handy for music of later periods.
Concerning Hauptwerk, it is based on sample sets of real instruments. I’ve never used it, but I would expect that each Hauptwerk set by default is tuned to the tuning of the sampled instrument.
Aeolus, however, was not modeled after a real instrument, despite that fact its default rank set is similar to what you could find in a german baroque instrument.
My digital pipe organ console can be set to various temperments, but it does not remember the setting. Instead I have to change it after each “Reboot”. This obviously was implemented with reason, as it would confuse some players in case the instrument (e.g. in a chapel) was used by different people.
Since changing the tuning in Aeolus requires that it re-renders its precomputed “waves”, I’d vote for equal temperment being the default and either leaving it up to its native UI to change it or even providing an option in Zynthian to choose anything other than equal.

Just my two cents,


Hauptwerk can retune samples on the fly. My uncle uses it and has a three manual console in his front room.

Edit: it might depend on the sample set.

After I figured out the right MIDI channel settings, I started to play the popular Chaconne in F minor of Johann Pachelbel. It sounds horrible in Aeolus’ default tuning, which makes me assume that Pachelbel used an instrument with any other tuning than Werckmeister III :slight_smile: .

It sounds better in the key of d minor, but well, Pachelbel definitely wrote it in f minor.



Hi @christeck!

Welcome to the Zynthian community!!

OK. I will add the option to change the tunning and set the default to equal … but … you should send a nice recording of your favorite organ piece with Zynthian … :face_with_monocle:



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I did a quick and dirty recording of the Chaconne. I hope it gives you a better clue what I’m talking about:

The most problematic probably are the important intervals between f and a flat as well as the fifth between d flat and a flat.

Here’s recording of a practice session at a historic french instrument of 1766. It was restored to its original state in 2011, including its temperment and being tuned about 3 semitones below 440 Hz. Unfortunately the backgroud music was running in the cathedral that day, thus the additional noise:

Enjoy your Zynthian,


One further parameter maybe worth exposing is the reverb, or at least reducing its default volume a bit. It’s quite heavy.

Use the Alsa Mixer to reduce overall output, And while I’m sure @jofemodo will fiddle with Aeolus you can create an effects layer and run the output of the layers through a reverb effect.

Hi @zynthianers!

I’ve added a new menu to the Aeolus engine, so you can now select the temperament you want, retuning when it’s changed from the last time. This change also allows to use the zynthian’s fine tuning adjustment for changing the tuning frequency of aeolus. So, 2 birds with one shot.

Note that temperament is saved on snapshots and restored (and aeolus retuned if needed) when the snapshot is loaded. Tell me if you think this is annoying …

TODO: Change the default (first run) tuning temperament for SD new images

Warning: I’m not sure, but perhaps i introduced a bug on aeolus snapshot restoring. I’m investigating the case …


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Thanks a whole bunch. After the update, Aeolus remaind silent at first run, which was gone after a reboot.
Dream come true. Since I started with Linux audio about twenty years ago, I ever wanted a low latency open source audio machine. Zynthian brought it.
There are some bugs in the playing, but I immediately wanted to play the Chaconne in f minor. Despite the very first run, I recorded it:




I presume the idea saving the setting with a snapshot is just right. In case I wanted to play a series of pieces of various periods, I’d probably create a shapshot for each of them. And I could decide to play a broque piece using, e.g., Kirnberger III and a romantic piece in equal temperment.


Ohhh! Great! I added the video to the wiki:

Of course, more videos will be welcome … :innocent: :face_with_monocle:

Thanks a lot!