Upper end Mixture work

Possibly this question shoulb be in the tecnical questions section.
Typical of French organs, especially Cavaille-Coll's, are those shimmering top end Mixtures that stand out in the upper registers so well when the Tutti is being used. The Caen and Metz sample sets I have don't have that upper end Mixture sound I am looking for so I have to increase the brightness. However, this makes them too loud or bight for less than tutti registrations.
Can a single stop ( i.e. a Mixture) be under control of a balanced swell pedal without increasing the volume of the entire division ?

[mdyde]

Hello Antoni,

Which stops are enclosed within virtual swell boxes (and are thus under expression) is defined by the sample set producer within the organ definition file. It isn't something that the user can change, I'm afraid, except potentially by getting a customised organ definition file made.

E.g. somebody like Jake (subbass32 forum user) offers services for customising non-encrypted organ definition on a consultancy basis, but that wouldn't be possible in the case of the MDA Metz because it's encrypted. The only other option would be to get somebody to make an entirely new custom organ definition file for you from scratch (e.g. using the Custom Organ Design Module), but that might be quite a lot of work, and may not sound exactly the same as the original in other respects (since the original would have been tweaked by the sample set maker).

Another option for Caen is to buy the 4 manual extension. It has three additional mixtures, two on the GC and one on the POS, so you could voice them for different purposes. The only thing you lose from Caen is the original tuning, and almost all the extensions are sourced from Caen samples. Assigning the GC and GO to the same keyboard, it works well as an enlarged 3 manual.

viewtopic.php?f=6&t=13254

I think this is a consequence of the Hauptwerk sampling process, and I believe I have commented on it before. With a tutti registration, the mixtures sound different than they would if you just record the mixture by itself. This is most pronounced on a Baroque organ, but it is also noticeable on a Romantic organ. Cavaille-coll composed and voiced his mixtures differently than most Romantic builders. He typically used standard flue type pipes, but as he went up the rank, he boosted the lower pitches of the mixture, sometimes even adding pipes lower than the speaking pitch! So what you're hearing isn't totally the pipes, it's the harmonics of the lower pitched pipes interacting with the pitches and harmonics of the higher pitched pipes.

The other side of the equation is that I feel Cavaillé-Coll didn't intend the mixtures to be used the way we would think. Yes, they should crown the plenum, and be able to be added to other stops for Baroque revival, but he always intended them to be quieter than we habitually have them in Hauptwerk. In most real organs, having the plenum registered tends to starve the mixtures a bit of air, and I think this is in general how they are supposed to sound. So, Cavaillé-Coll voiced them, particularly the lower pitched pipes, to emphasize the harmonics to give that shimmering character. However, it's my opinion that in most Hauptwerk organs, the mixtures aren't quite right. When I program a CODM file, I usually starve the mixtures of air at least a little bit using the wind model, and I think that much improves them.

Now, one drawback of both Metz and Caen is that the mixtures aren't typical for a Cavaillé-Coll in a way. For Caen, Jiri from Sonus Paradisi has his opinions about how mixtures should be, and at least the last time I checked they don't quite sound right to me. For Metz, it has a simpler mixture composition that's absent of so many of the lower pitched pipes (which is what Cavaillé-Coll tended to do towards the end of his life, and which Mutin continued). So, it's not easy to get them to sound *exactly* as Cavaillé-Coll intended.

This is all a roundabout way of saying that it's tricky. What I would do, however, is to voice them to have the volume so that it works with the quieter stops, but then boost the harmonics so that they work with both. It won't be perfect, it's better if they respond to the wind model, but that requires some ODF changes (or a CODM file, as has been alluded to). The mixtures won't crown the plenum as aggresively as you're accustomed to, but trust me that is more what Cavaillé-Coll had in mind. He usually slotted his principals, which boosted the harmonics, and he and many organ builders of the time felt it was better to have good harmonics coming from the principals than to try to augment them with a mixture. As a result, many Romantic plenums have rather understated mixtures (at least in real life, they seem to be always more aggressive in Hauptwerk!), but it isn't unusual for them to have boosted harmonic content, and also in real life, more warmth and interesting interplay between a sounding note and the notes/harmonics of other notes played with it. Some Romantic organ builders actually used more narrow (string scaled) pipes for their mixtures, and I think it was to help boost the harmonic content. The downside though is that they are quieter than their flute scaled counterparts! They tried to raise the pressure on them to make them louder, but this made them more shrill.

Of course, that's my opinion, your mileage may vary! I usually play organs as released by the sample set producer, it's only on my own CODM files that I voice them according to how I think they should sound. The mixtures on Metz have always sounded a bit too aggressive to me, but I still love it, and it's the organ I play the most.

Whenever I get a new sampleset I fiddle with the voicing, the tuning and the pitch. (I am a professional for harpsichord maintenance amd tuning, and have perfect pitch). This week I got the Nordbroek organ, which I really love. I listened to quite a few Youtube recordings of the real organ,many of which are well-recorded, and tried playing the same pieces with the same registrations. I spent at least 3 full days with voicing and feel I have a good working compromise for now. I have done that with most of the organs I have. I almost always reduce the mixtures. Voicing note by note, by eliminating the most agressive notes (amplitude and/or brightness) goes a long way toward making the mixture acceptable.

I don't have much experience with real historic organs and am not very knowdgeable about romantic organs or repertoire. I do have Caen and enjoy it. I don't have an elaborate audio setup, two speakers and a subwoofer, which I actually don't use much. I mostly prefer headphones (AKG 712) although I think I should cut back on them to minimize hearing loss. I don't play loud, usually.

Back to your query, I have a few thoughts. Most of these romantic orrgans are in big, sometimes very big churches. The variations in sound from the console to the floor below are very large. I think there's a large range of different perspectives to be experienced on site. You can feel comfortable choosing the sound you like to hear.

There are many tricks for boosting or dampening mixtures. One can add or substract quints, 2' principals (or even flutes), of course manual 16' stops, extra 8' or 4' pipes, even flutes. and couplers. I often couple a second manual without the mixtures. One fellow in his live Nordbroek recital seemed to avoid coupling the two manuals for plenums, that definitely toned down the mixtures. Play with the distance to your speakers and where they are facing. Mine also have controls for highs, lows and volume. Also fiddle with the balance between direct and distant perspectives on the sample-sets. When voicing, you don't have to isolate the stop you're working on. The final voicing takes place with the combinations you know and want to sound good. For me, that could be flûtes 8 and 2, sesquialtera with 8 and 4, reeds with 4' flute, mixtures with principal chorus.

There should be a way to get very close to what you are looking for. And after all the tinkering, I eventually just settle into music-making and find my ears adapt to the sounds and there is joy!

Good luck!

RS