How to Read a Pipe-Organ Stoplist

A stoplist is fixed at the moment its source wrote it down, and it stays there while the organ moves on. The archived Aeolian-Skinner opus lists say this about themselves: their stoplists show the organs as they were when they left the factory, and the lists are meant to supplement the firm’s published opus list, not replace it. The Aeolian-Skinner Archives publishes revisions carried out by Skinner or Aeolian-Skinner themselves and expressly leaves out later work by other builders. A stoplist from that archive is therefore a baseline for original state. Where an instrument as found differs from it, the difference is evidence of later change rather than of an error in the list, and the archive cannot describe or date that change.

The Pipe Organ Database applies the same logic one record at a time. On September 1, 2026, a stoplist there was a sub-record beneath the instrument: one instrument could carry several, each chosen from a labeled list that names its source, and ‘Source not recorded’ was a live value sitting alongside named sources such as ‘Centennial celebration program’. So the first thing to read on a database stoplist is not the first division but the source label and, where the record gives one, the date.

Three kinds of stoplist reach a reader, and they carry different weight. A factory specification is the builder’s own document: a Möller sheet headed ‘M.P. MÖLLER / Hagerstown, Maryland / Opus 8414 1952 / Original Specifications’ records a small E-P unit instrument of 5 voices, 26 stops by the sheet’s own count, and 377 pipes, with Great, Swell and Pedal all enclosed. An archive stoplist is held or compiled by an institution, such as the Aeolian-Skinner lists above or a database stoplist credited ‘Courtesy of the OHS Archives’, as the selected stoplist on the Möller Opus 7087 (1942) record is; only some database stoplists carry a credit of that kind.

A contributed stoplist is a transcription supplied by whoever had it. The database’s stoplist for Austin Opus 22 is sourced to a centennial celebration program rather than to a factory document, and the record for Wicks Opus 3447 carries a stoplist annotated ‘Stoplist copied from console photos’. A list copied from photographs records what the photographs showed, which is evidence of a different kind from a builder’s sheet, and the label is what lets you tell them apart.

The number beside a name is a pitch designation, and it comes from the length of the largest pipe in that voice. The Wicks Organ Company glossary states it for its own customers: a stop is an individual voice composed of one or more ranks of pipes, and its name includes a number such as 16 or 4 that designates its pitch according to the length of its largest pipe. Other builders and reference works define the word stop differently, but the pitch convention is what the figure means on the list in front of you. The figures 16, 8, 4 and 2 name four different pitches, and a Pipe Organ Database stoplist renders each division with the pitch, the name and the pipe count for every entry.

A full published specification can carry more than that. The Mechanics Hall specification of E. & G.G. Hook Opus 334 (1864) lists 52 stops as the specification counts them, 64 ranks and 3,504 pipes across four manual divisions of 58 notes and a 30-note Pedale, with wind pressures of 89 mm for Pedale and Solo and 76 mm for the remainder. That is one exceptional instrument, the firm’s largest at the time, and the page does not say whether the pressures are original. It shows what the fullest kind of stoplist looks like, and it shows a stop figure and a rank figure standing as two different numbers on the same page.

A Roman numeral before a name marks a mixture, a voice made of more than one rank, and the figures that follow give its composition by interval rather than by pipe length. Organ Supply Industries lists stock mixture compositions that way: II Mixture 12-15, III Mixture 15-19-22, 19-22-26 and 22-26-29, IV Mixture 12-15-19-22, and V Mixture 15-19-22-26-29. The numeral matches the number of intervals listed and is read as the number of ranks in the mixture, so a stoplist that gives the numeral without the composition tells you how many ranks, not which intervals. A supplier catalog establishes what that supplier offered in 2006; it does not establish what any builder chose or what any installed instrument contains, and naming and composition vary from builder to builder.

Below the divisions, a fuller stoplist lists couplers, pedal movements and a summary line, and those lines describe the console rather than the pipework. On September 1, 2026, a Pipe Organ Database stoplist page rendered the venue and city, a work-history header, the divisions with each entry’s pitch, name and pipe count, a COUPLERS list, a PEDAL MOVEMENTS list, and a closing line reading ‘ACTION: Elec. Key & Stop VOICES: 12 STOPS: 12 RANKS: 12 PIPES: 660’. Those four figures are four separately kept counts whose agreement is a property of that instrument; on an extended instrument the figure for stops, in whichever sense the record keeps it, runs ahead of the figure for ranks. Parkey OrganBuilders defines the console as the part of the organ that contains the keyboards, pedalboard, stop controls, swell shoes and capture action, and recommends that a written specification state the number of available memory levels or channels; that is one firm’s guidance to its clients, not a rule about what a specification must contain.

The action abbreviation in a summary line is shorthand. A 1998 tutorial by James H. Cook hosted on the Organ Historical Society website explains that ‘M’ conventionally describes the connection between key or stop and chest and leaves the chest type to be inferred, whereas ‘ES’, ‘DE’, ‘EM’ and ‘EP’ describe how the chest is built and leave the connection to be inferred, and that ‘EP’ alone is applied to several quite different chest designs. What those designs are, and what they say about an instrument’s period, is the subject of the neighboring page on mapping chests, consoles, relays and components to a period, not of the stoplist.

The word stop has two working definitions, and a count made under one cannot be compared with a count made under the other. The American Guild of Organists glossary defines a stop as the knob or tablet that pulls a rank of pipes into play, which places the word on the control. The Organ Historical Society glossary defines a stop as one or more ranks of pipes of consistent tonal design activated by a single control from the console or keydesk, which places the word on the pipework and treats the control as its activator; the Wicks glossary likewise calls a stop an individual voice made of one or more ranks. A rank, in the sense both glossaries rely on, is a complete set of pipes of one construction and tonal design. Under the control definition, the names on a stoplist count controls; under the pipework definition they count voices; under neither do they count ranks. Whenever a document gives a number of stops, find which sense it is using before you compare it with anything.

Extension and unification let a few ranks carry many names, and that is the largest single gap between a stoplist and the instrument behind it. Unification makes one rank available at several pitches or on several divisions; extension lengthens a rank’s compass so it can supply further pitches. The arithmetic is stark. A worked comparison published by the Theatre Organ Fact Finder shows one extended flute rank of 97 pipes supplying the same four pitches, 16, 8, 4 and 2 foot, that four separate straight ranks of 61 pipes would supply with 244 pipes. A second example makes five labeled voices from two extended ranks using 158 pipes where five straight ranks would need 405, so the rank count falls from five to two while the list still shows five names.

A documented three-rank Möller Artiste carries twenty-one speaking stop labels drawn from three ranks by extension and duplexing, and an owner reading its list should treat the number of stop controls as a poor guide to the instrument’s tonal resources. The 1948 Artiste at St. Xavier Chapel shows the pattern: its Great, Swell and Pedal are drawn from a small group of ranks, Diapason Conique, Lieblich Gedeckt, Salicional, Quintadena, Lieblich Flute and Oboe, with Octave Conique, Quint, Super Octave, Salicet, Nazard and Piccolo derived from them. That is one documented specification; the ratio differs between Artiste sizes, and these figures describe that instrument rather than a firm-wide extension scheme.

The pipe comparison equates pitch availability, not musical result. When two pitches drawn from the same extended rank are played together, a pipe already speaking for one key cannot also speak for another, so a C major chord drawn at 8, 4 and 2 foot from a single rank comes out with notes missing. The Organ Historical Society’s unit-actions page calls this cancellation and lists it with two other disadvantages, voicing disparities across the pitch levels one rank must serve and tuning problems for mutations derived from a unit rank, while also describing where unit action is used. Those are stated limitations of the technique, not a verdict on unified instruments, and the sources do not agree on a verdict.

The Theatre Organ Fact Finder argues that extended voices lose the independence a traditional chorus needs, and that theater organs tolerate heavy extension because their ensemble is built by mixing tone colors rather than by developing a chorus; Jack M. Bethards of Schoenstein & Co. argues that unification is legitimate when unified voices act as flexible couplers of individual voices rather than replacing straight ones. For reading a stoplist the disagreement can stand unresolved. What matters is that the list cannot show which of its names share pipes unless the document says so.

Two stoplists showing the same name at the same pitch do not describe the same sound. Organ Supply Industries requires a customer ordering pipework to supply the starting scale, material, operating wind pressure, pitch, open or closed toes, chest type, room size and voicing instructions, which shows that a voice of a given name is built to order against variables that no stoplist carries. That is what one supplier required in a 2006 catalog, and the step from those variables to an audible difference goes slightly beyond the order form itself. It is still the way to read a shared name: as a label for a kind of voice, not as a match.

A Pipe Organ Database stoplist is a contributed record with its own source label, and the label is the first thing to weigh. On September 1, 2026, the database was openly editable by contribution: every instrument and builder record carried public controls reading ‘ADD NOTE’, ‘ADD WEBPAGE’, ‘ADD IMAGE’, ‘ADD DOCUMENT’, ‘ADD STOPLIST’, ‘ADD CONSOLE’, ‘ADD CROSS REFERENCE’ and ‘SUGGEST AN EDIT’. Where a record held no stoplist, the section did not disappear; it displayed ‘No stoplist details are available. If you have stoplists, please consider sharing them with us.’ followed by an ADD STOPLIST control. Each stoplist was also its own addressable page under /stoplists/, and the site’s sitemaps enumerated about 30,600 of them on that date.

An instrument record holds, where known, the builder, opus number and year, any ‘Originally’ builder and opus for rebuilds, location, rank and pipe counts, categorized images, one or more stoplists with an attributed source, console records, an extant and playable status, dated contributor notes, documents, audio and blower records. Field presence varies record by record, and the console and control-system fields are contributed rather than surveyed.

Contributed does not mean unreliable; it means the source label carries the weight. A stoplist credited ‘Courtesy of the OHS Archives’, as the selected stoplist on the Möller Opus 7087 record is, rests on an archival document. A stoplist labeled ‘Source not recorded’ cannot be treated as archivally grounded, whatever it contains. Between the two sit transcriptions from programs and photographs, and stoplists attributed to the latest firm in a chain of work. One stoplist page heads its list ‘HINNERS ORGAN CO., 1918’, followed by ‘Unknown Builder, 19__ – Moving & Re-installation’ and ‘John L. Becker, 1978 – Electrification with Additions’, and its title attributes the stoplist to the most recent of these, ‘Stoplist Details: John L. Becker 1978’. That list describes the organ after the 1978 work, not the 1918 instrument, and the header is what tells you so.

Documented cases show the kinds of disagreement to expect; each is a single record on a stated date, not a measure of how often this happens. One record for First Presbyterian Church, Morristown, Tennessee, read through an unaffiliated mirror of the database, carries a header of ‘Schantz Organ Co.’, opus 1116, year 1973, while the stoplist attached to the same record is labeled ‘Op. 1306’ and 1974: the indexed field and the document the record is built from disagree inside one record.

The record for Wicks Opus 3447 in American Fork, Utah, carried no year and no rank count on September 1, 2026, and its stoplist is the one copied from console photographs. A self-published Utah Valley survey pairs the same opus number with 1980, yet the Wicks opus numbers the database itself associates with 1980 run from 5487 to 6148, roughly two thousand above it, and the pairing is also inconsistent with the other five in the survey’s own list. None of the three sources resolves the other two. A record without a year is a gap, not evidence that the instrument is undated, and an out-of-band pairing is one to test rather than to repeat. Even the database’s own totals disagree: on September 1, 2026, its landing page counted 30,713 stoplists while its stoplists index reported 30,757, with no derivation published for either figure.

None of this makes the database a poor resource. It makes it a documentary record whose entries carry their own provenance, and reading a stoplist there means reading the provenance before the pitches.

A stoplist, as the Pipe Organ Database renders one, does not record wind pressure, tuning pitch, temperament, or whether the instrument has been restored, modified, relocated or rebuilt, and the database’s instrument record carries none of those as structured fields, nor any field for windchest type. Some full specifications add wind pressures, as the Mechanics Hall page does; the database’s stoplist and instrument record do not. On September 1, 2026, a populated instrument record carried the builder, opus number and year, venue, address, a rank count, images, a stoplists section naming its source, a consoles section, tabs for details, notes, documents, audio and blowers, a status sentence and attributed notes, with no field for wind pressure, chest type, tuning pitch or temperament and no structured flag for alteration.

Where windchest type appears at all it sits inside the stoplist behind an expander: the reader must open the stoplist and click a division name carrying the information marker, and the expander then shows Position, Chest Action, Stop Action and Notes for that division. Only marked names expand, and stoplists entered as unstructured text have no expanders.

Whether the organ still exists is a separate question again. On September 1, 2026, the database’s instrument search treated ‘Show Only Currently Extant Instruments’ as an opt-in filter, so an unfiltered search, and the stoplist it leads to, can belong to an instrument the database does not record as extant. The Organ Historical Society states that its Pipe Organ Registry examines the originality of the stoplist as one variable alongside builder, age, location, restoration or alteration, condition and association, which is the right frame: a stoplist is one class of documentary evidence, to be set beside the evidence on the instrument itself. How windchests, consoles, relays and components narrow an instrument to a period is the subject of the neighboring era-mapping page. How the classes of evidence on the instrument are weighed together is the subject of the physical evidence hub this page sits under.

When the question is what an organ originally contained, look for the builder’s own specification; when the question is what it contains now, look at the organ. A factory specification sheet, such as the Möller ‘Original Specifications’ for Opus 8414, records the instrument as the builder specified it, and as of August 31, 2026 the Pipe Organ Database hosted Möller factory documents of that kind alongside its contributed stoplists. Such a document can be the only surviving evidence of original content. A 2024 note on the First Presbyterian Church, Washington, Pennsylvania record works from a 1946 Möller stoplist document that marks certain ranks as belonging to an existing instrument, and uses it to separate 1946 pipework from 1968 and 1971 additions; the same note warns that the specification’s Antiphonal division contains errors, so a factory document is authoritative and still not infallible.

A hosted stoplist document for Westminster Presbyterian Church, Portland, Oregon shows another shape: one instrument carrying two builders’ opus numbers, M.P. Möller Opus 6974 of 1941 rebuilt in 1957 by Balcom & Vaughan as their Opus 635, the 1957 work replacing the console and adding twelve ranks to the original nine while keeping all of the original ranks. Read a document like that as two stoplists laid over each other, each with its own date.

Beyond the factory sheet, the record vocabulary that identifies an instrument runs through opus lists, contract files, shop records, design specifications and dedication programs. Where those records sit, how they are requested, and how the database’s entries relate to them belong to the archives and databases pages of this identification section rather than to this page. What none of those documents settles is the present state of the pipes, windchests and console, and that is settled the same way each time: by inspection, and by writing down what the inspection finds against the best-dated document in hand.