Against the background of the special effects demanded of new organs and promised to their clients by the builders, for example the Schwiegel, Waldhorn, Quintadena (Scheelpipen), Trumpets, Shawms, Zinks, Rauschpipe, Drums and ‘other unusual stops’ promised by Hans Suys at Antwerp Cathedral in 1509, Arnolt Schlick wrote a splendid, forthright little book on organs, publishing it in 1511 under imperial auspices and indeed apparently intending it as a kind of standard code of practice for organ builders in Maximilian’s empire. Schlick lived in the central Palatinate court town of Heidelberg, and no doubt his influence was wide. The organ described in his Spiegel contained about 15 stops, ‘not too many of the same type’, as shown inTable 4. Schlick said that, in addition, the Hauptwerk might contain a Krummhorn and the pedal a Klein Octaff and Zymmel, but that the latter two do not belong there. All stops should be playable separately so that the pedal if required could take the cantus firmus. The Hintersatz should not contain the very low ranks of the ‘large Mixture’ (by which he may have meant the old Blockwerk), nor the ‘low-pitched 3rds and 5ths’ sometimes met with. There is little point in making separate 51/3' stops, while the addition of various little chests such as Brustwerke merely increases cost and produces ‘much sauce for little fish’. Reeds are not unreliable if properly made, and Schlick thought a competent organist could soon learn how to make the necessary minor adjustments to them. Stop-levers (preferably not push-pull) should be conveniently placed, not too long or too heavy to work from the keyboards.
Thus Schlick knew an organ of Principals, Mixtures, flutes and reeds; two manuals and pedal; probably a manual coupler; different open metal pipe scalings (circumference to length 1:5, 1:6 or 1:7); and conical metal pipes, but not, evidently, stopped pipes or wooden ones. He recommended a compass of F–a'' and a pitch level about a tone lower than that of today (his a' = c374–92, depending on the diameter of the pipe). The pipe metal was pure (or mostly pure) tin and the Principal was doubled (two open metal ranks of different scale). While recommending an irregular tuning with an A that could also serve (if ornamented) as G in a cadence on A, Schlick recognized that some preferred a regular mean-tone temperament (with major 3rds slightly larger than pure), but saw little use for split sharps as a means of dealing with problems of temperament.
Some of Schlick’s general attitudes to organs are informative. He felt that eight or nine stops in the Great were all that were needed; they should be clearly different in tone; and the second manual was to be regarded as a kind of small positive, in no sense a match for the Great. The organ was used in connection with the liturgy, he observed; the priest at the altar was given notes for most mass movements from the Gloria onwards. And since the organ had a particular part to play in such music as sequences, it was placed near the choir for convenience. The pedal may have been transmitted from the Great; certainly it should have stops of the same pitch as the main manual. The pedal must have separable stops like the Great; it should not be made up only of suboctave stops, as it then inverts the harmony. (This must presumably be a double reference to organs with extra large pedal pipes always sounded by the pedal keyboard, and to the practice, then probably rather new, of using the pedals to play inner tenor or cantus firmus lines.) Reed stops can be made well (some are mentioned that sounded new though nine years old). As to Mixtures, neither those consisting of 5ths and octaves nor those of 3rds and 5ths should contain low-pitched ranks. The full chorus should be able to play chords (that is, the 5th ranks in Mixtures should not produce too dissonant a sound when the 5th C–G or the 3rd C–E is played); at the same time, the precise number of ranks in a Mixture depends on the size of the church. Manual keys should not be too long or short, too wide or narrow, nor spaced too far or too near; the given measurements suggest relatively stubby keys with an octave span about the same as on modern instruments.
Some of Schlick’s own music in Tabulaturen etlicher Lobgesang (1512) is contrapuntal in a way that closely anticipates later organ chorales which use the theme imitatively in three or four parts; in such pieces the pedal took the tune when it appeared in the bass. Schlick also knew pedal playing in two, three and even four parts, as well as pedal runs; for none of these functions would the old Trompes have been useful. The inner-voice cantus firmus technique, however, apparently requiring pedals for music from the Buxheim Organbook onwards, should not necessarily be taken at face value: such organ ‘scores’ must often have been open to various interpretations or playing methods, and what appear to be third-staff pedal parts in the Buxheim Organbook may (at least in some instances) simply be an easy way of avoiding part-crossing problems.
The largest chapters of the Spiegel are concerned with tuning (seeTemperaments, §3), the making of chests, and the bellows. Schlick’s advice is always very practical; for example, the wind must be generous (presumably for homophonic textures on full organ), the organ constantly played (even during Advent and Lent), and only the best and most experienced builders trusted. The little book thus surveys the whole field of organ activity – building, playing, composing – and even the long chapters on chests and tuning are full of good, pithy advice. For its size and single purpose, the Spiegel has never been bettered.