Franck bezog sich bei seinen (gedruckten) Registrierangaben explizit auf die Orgel in Sainte Clotilde, die einige Besonderheiten aufwies. Die Vorworte entsprechender neuerer Ausgaben weisen explizit darauf hin. Kurz: Das Récit war eher klein und nicht so dominant wie die Récits späterer Cavaillé-Coll-Orgeln. Franck zog daher - teils zu Verstärkung, vielleicht aber auch zur Klangfärbung - zu den Fonds die sehr fein intonierte Hautbois.

Er zog sie aber auch zur Trompette, wenn diese als Solostimme eingesetzt wurde. Also muss sie doch etwas "gebracht" haben, sonst wäre das sinnlos.

Natürlich, aber das liegt wohl auch wieder in den Eigenarten von Ste Clotildes Orgel begründet. Ich erlaube mir mal aus Rollin Smiths' Buch zu zitieren:

"From the amount and variety of descriptions of its tonal characteristics, the Récit was the most astounding division. Containing but ten stops, it lacked a 16' stop, a principal and a mixture.

'The quality of the Récit was something of a miracle. Undoubtedly, a number of technical reasons contributed to this: the dimensions of the swell box, the responsiveness of the shutters, its location at the back of the organ case, the large sonorous space surrounding the box on all sides giving it an extraordinary reasonance, the acoustics of the church and, above all, the genius of the builder. All these factors produced a miracle.'[29]

Goodrich's general statement - "The Récit is a manual of ample resources and great power when the box is open, affecting materially the whole ensemble of the organ."[30] accurately describes the Récit of the organ of Sainte-Clotilde. André Marchal commented that

'...the Récit on Franck's instrument was very small, sounding very well when the box was open, but when closed the reeds would disappear behind the foundation stops of the other manuals.' [31]

Dufourcq adds that "The marvelous swell box of the Récit enveloped all that it enclosed with mystery and poetry."[32]
This phenomenon was well understood by Franck who frequently calls for the tutti of the Récit coupled to the 16' and 8' Fonds of the Grand-Orgue and Positif. In such a combination Duruflé writes that:

'... [the] Récit took on surprising prominence. Due to the excellent responsiveness of the swell shutters, sometimes the full ensemble surged to the forefront, sometimes it ebbed, allowing the Fonds 16-8 to predominate ... What more ideal sonority could one desire than that of the ensemble of Récit stops for translating a thought which had been precisely inspired by these timbres?'[33]

The timbre of the two solo reeds of the Récit was unique when compared to other similar stops made by Cavaillé-Coll and especially when compared to stops of similar names as constructed by foreign builders. The Basson-hautbois was used by Franck as a solo stop in only one instance: the Prélude and Variation of Opus 18. And it is strengthened by the addition of the Bourdon and Flûte. Always it is added to the three foundation stops "to render appreciable the nuances produced by the opening and closing of the swell box."[34]
The Trompette, on the other hand, is Franck's preferred solo voice and, as such, appears in five works: Fantaisie, Op. 16, Prière, Cantabile, Choral I and Choral III. This Trompette was small, "almost an Hautbois, of very great finesse and flexibility."[35] It was quite powerful, but with "... a light, clear, smooth quality; its use in combination with the Hautbois and foundation stops ... results in a rich and warm ensemble tone."[36]

29 Maurice Durufle, "Mes souvenirs sur Tournemire et Vierne," L'Orgue, No. 162 (April-June 1977) 4.
30 Goodrich, The Organ in France, 22.
31 Andre Marchal, "Andre Marchal talks to Rodney Baldwyn on the occasion of Cesar Franck's 150th birthday," Organist's Review, No, 58 (Dec. 1973) 13.
32 Dufourcq, Franck, 19.
33 Durufle, "Mes souvenirs," 4.
34 Cellier, L'Orgue moderne, 61.
35 Ibid., 74.
36 Bonnet, "Preface," 2.

Gruß
Karsten