Sixteen-foot manual stops appeared as early as the 15th century, and no era of organ design has been without them since. But there have been good and bad times for 16' manual tone with dual peaks of popularity when they outnumbered pedal 16's in the 16th and 19th centuries. In the 17th and mid-18th centuries, pedal 16' became more numerous, but it wasn't until the 1950-1970 era in American organ building that the manual 16' suffered its worst decline. The small number of manual 16' stops in recent American organs has little historic precedence, and is considerably less than current European practice. Here are two reasons for the low opinion that many Americans have for 16' manual tone.
First, the heavy and opaque sound of a Great 16' open diapason from the 1900 era, or the dull Swell bourdon or keen 16' string have given such stops a deservedly bad name. The classically orientated student would find little use for such stops and conclude that all manual 16's were detrimental.
Second, there is a widespread but mistaken notion that 16' manual tone was a unique romantic excess and that Baroque organs, if they had manual 16's at all, certainly were never played with these stops on. In fact, it would take a 60% increase in the number of manual 16's in current American organs to reach the level of occurrence these stops had in Bach's time. An added misunderstanding equates 16' manual tone with large organs in large rooms. Only recently have good manual 16's begun to return to small instruments, and some practice and residence organs have them with excellent results.
To understand the history of the problem, the following chart shows the ratio of manual to pedal 16' stops in various times. As an example of what these ratios mean, if an organ had four manual 16's and three in the pedal, then its ratio would be 4/3 or 1.33. If another organ had two manual 16's and four pedal 16's, then its ratio would be 2/4 or .5.
||Manual to Pedal Ratio
But ratios have little to do with art or tonal design, except as they help us to understand trends and patterns. This simple analysis does not evaluate the important variations in manual 16's that occurred from country to country. An interesting but statistically indefensible analysis of the ratios of various pitches from 1548-1959 can be found in the Organ Institute Quarterly, Vol 8, No.4, 1960. Since 1970, both European and American builders have been using more manual 16's as our understanding of historic organs has improved. The difficulty is always to get good manual 16's, since bad ones are so wasteful of space and money. Rational tonal design must include good manual 16' tone, and we are now slowly coming out of the recent depression.