Speaking only of Willis reeds, which I know best, Father Willis took his 8ft chorus reeds to A58, or G56 depending on the manual compass, the Clarions usually breaking to flue pipes at F#43. I do not recall a Father Willis chorus reed (on 3” or 3.5”wg) carried to C61. Willis Tubas were and are harmonic from F#19, with reeds carried to the top note, even C61, the pressure of at least 12.5”, usually 15” sometimes 20”wg and more being necessary to generate sufficient power from the tongue.
From the time that Willis stopped making their own shallots after the Great War, the sets were 61 note for 8ft reeds and 49 notes for Clarions. The sets were used complete for pressures above, I think, 6”. For lower pressures the upper shallots discarded in favour of flues, usually from G#57, G#45 for Clarions. In April 1941, the Willis works were destroyed by enemy action and the firm’s considerable stock of shallots of all kinds were lost. In 1947, a large number of new sets were ordered from W P Williams & Co with pre-war configuration to replace the lost stock. Five years later the majority of the sets from the order were still outstanding, but the market (for Willis) had become clearer. The outstanding order was cancelled and a reduced order was substituted, with the range of the 8ft chorus sets reduced to F54, F42 for Clarion sets. The reduction of the shallot compass of chorus reeds was, I believe, because the soft brass with which Father Willis worked, some stock of which remained when the factory was destroyed, was no longer available in acceptable quality. It was difficult to get the power from half-hard brass tongues in the higher reaches with pressures under 4.5”, particularly on pitman chests when the curve has to be reduced to make the speech quick.
Some many years ago I saw in a church in Antwerp a 2-manual Merklin organ with a Clairon 4ft on the enclosed division that broke at C25 to an 8ft pitched Cornet, I think of three ranks, but may be more. The idea appealed to me (as a non-player), but I was never able to persuade any organist to endorse my enthusiasm.
I have seen (but not recently) organists strike out Clarions from proposals on the grounds that:
1. they are the first to go out of tune
2. they can be simulated with the Swell octave coupler
3. a Swell Flute 4ft or 2nd Mixture is more useful.
On the question of the audible quality of treble pipes, the frailties of our hearing do not prevent the upper partials being generated from properly constructed and well-voiced pipes in accordance with Nature. The participation of these partials in the resulting difference and summation tones adds to the richness of the treble effect for those who can hear it. No organ builder with his heart in the business can bear to see some “it’ll do” rubbish pipe flopping in a large rack board hole where a recalcitrant reed treble has been removed.
If I have retained anyone’s attention to this point I should like to seek assistance on the unrelated matter of Father Willis non-stretto (no overhang) Keys and Willis short compass Swells in a separate thread.