The Baldwin C500 Organ Used In These Videos

Some of the music on this Video page was recorded on a Viscount "Symphonia" model digital organ, an instrument of 5 manuals and 84 stops built in Italy which was marketed in the United States under the Baldwin name as Model C500.  Manufactured in blocks of 50 at a time during the 1990's, only one block was ever ordered for sale in the United States, but all 50 were sold.  While it was Viscount's largest instrument in regular production at the time it was discontinued around 1997 when the company turned to producing a line of strictly two- and three-manual church organs.

  This instrument incorporated early DS4 technology which offered sampled voices sourced and separated by division.  These voices were controlled by 7 computers built into the console, 6 of which were "slave" computers, one for each division, all governed by a single "master" computer.  Each of these 6 divisional computers stored sampled sounds of real organ pipes.  All voices, couplers, and tremulants were brought on or retired by means of lighted drawknobs, lighted manual and toe pistons, and lighted rocker tablets which remained in alignment in both on/off positions.  Output channel phone (1/4") jacks in the back of the console allowed for up to 3 separate outputs per division, thus up to 18 external speaker cabinets (3 for each division) could be added.

Also inside the console was a self-contained speaker system consisting of two 12-inch (12") loudspeakers each powered by an 80-watt (80W) amplifier with a total power consumption of 160W.  While this would be satisfactory for home practice purposes, when a single master-of-all-work 12" loudspeaker attempts to reproduce the extreme low of the 32-foot and 16-foot octaves it undergoes mammoth movements which interfere with its ability to reproduce the finer movements required of the midrange and higher frequencies.  This is called intermodulation distortion and tends to rob the sound of realism.  The solution for this is the have multiple loudspeakers of various sizes, each of which accepts its own narrow range of frequencies and is matched in size to the movements required to reproduce the frequency band assigned to it.  At the same time, the most space-effective and power-efficient solution was needing to be sought in an external speaker system.   

The solution in this case was as follows:  individual mono output signals from all 6 divisional channels were routed via 1/4" jacks in the back of the console to a 600W Peavey XR8300 power mixer, amplified and converted to a R/L stereo signal, then looped through a Samson S-Curve 215 15-band dual graphic equalizer, mixed with reverb, and finally routed to a free-standing 1000W Velodyne Servo F-1800RII powered subwoofer with a massive 18" driver and crossover set at 40Hz.  This sub, one of fifteen identical units originally installed in Gesu Church in Milwaukee, functioned to reproduce those mammoth frequencies below the range of determinate musical sound by capturing everything from 40Hz down -- meaning the 32-foot octave and the bottom third of the 16-foot octave.  This filtered audio stream was routed from there to a free-standing 15" Memphis floor-firing sub which captured the lowest frequencies in the musical sound range of 40-120Hz, meaning the top 2/3 of the 16-foot octave and all of the 8-foot bass octave.  The remaining audio stream was then sent to a pair of BSR Colossus R/L stereo cabinets each rated at 200W with each cabinet retaining its own original pair of BSR 2-1/4" ceramic tweeters but retrofitted with all new high performance Memphis (15") and Pyle (8", 4") drivers.  A crossover network in each BSR cabinet divided the audio stream into 4 different frequency bands which were sent to each of its 5 loudspeakers designed to receive them (120-800 Hz to the 15", 800-1200Hz to the 8", 1200-3400Hz to the 4", and above 3400Hz to both tweeters).  This arrangement comprised the RIGHT SIDE speaker system with a power consumption of 1600W.

Additional amplification for the main signal stream was obtained by routing this same mixed R/L stereo output signal to a 65W Roland KC-150 powered keyboard amp which added another 12" loudspeaker and 3-1/4" piezo tweeter.  This amp was daisy-chained to a Roland cube monitor having a 6-1/2" coaxial speaker powered by a 30W amp and a 200W Roland KCW-1 powered subwoofer with 10" driver and crossover set at 60Hz.  This arrangement comprised the FRONT speaker system situated behind the player with a power consumption of 295W.

Using the spare channel mono output jacks provided in the back of the console, the Swell, Solo, and Echo outputs were routed to a 60W Choice Select Ultra ST2060 PA mixing amp and on to a pair of Sony SS-F6000P floorstanding 4-way tower speaker cabinets each rated at 180W and equipped with a 6-1/2" woofer, 3-1/3" mid-range loudspeaker, and 1" tweeter.  The Choir/Positiv mono output from the console was separately amplified using a 90W (45W X 2) Pyle PFA300 Class T amp and then routed to a pair of Realistic Minimus-77 speakers each rated at 55W and equipped with a 5" midrange speaker and 1" tweeter.  Additional fidelity for the Swell and Great mono output channels was obtained using a 40W (20W X 2) Kinter TA2020-020 Class T mini-amp, and a 40W (20W X 2) Lepy LP-2020A Class D mini-amp, respectively.  The output stream from each of these was connnected to its own Awai SX-WNAJ50 3-way speaker box equipped with a 6-1/3" sub, 4" midrange, and 4/5" tweeter rated at 75W.  This arrangement comprised the REAR speaker system situated behind the console with a power consumption of 230W.  An Upbeat Audio T613-BNC Boosteroo stereo amp also was connected between Duet's sound generator box and its volume pedal [See Below].

Looking ahead, to provide for a future LEFT SIDE speaker system to boost Solo and Echo divisions for balance against the Duet and provide additional power to the big reeds, a 250W Pyle Audio [Radio Shack] MPA-250B stereo amp with R/L signal looped through a Realistic 12-band stereo frequency equalizer with IMX stereo expander have been readied with the capability of powering up to two more pair of floor standing tower cabinets. 

This method of using multiple amps, apportioning their audio output to compatible loudspeakers of various sizes, sharing amplification among divisions, and using the ear to adjust everything was found to produce more than ample sound, a punchy low end, a very bright but not overpowering high end, and tremendously improved midrange clarity.  It allowed the instrument to sound better through any of its triple speaker arrangements -- RIGHT SIDE, FRONT, or REAR -- in any of 7 possible combinations (Right alone, Front alone, Rear alone, Right + Front, Right + Rear, Front + Rear, or all 3 together).  It allows for all stops, including those in the 32-foot octave, to speak with greatly improved realism and power (as soon as a future LEFT SIDE speaker system is made functional the number of possible speaker arrangements will increase from 7 to 15).   

To summarize, this instrument at the present time plays through its own 2 internal 80W amps and dual 12" louspeakers supplemented with 10 (+ 1) more external amps of different sizes [one 1000W Velodyne, one 600W Peavey (+ one 250W Pyle), one 200W Roland, one 90W Pyle, one 65W Roland, one 60W Choice Ultra Select, one 40W Kinter, one 40W Lepy, one 30W Roland, plus Duet's Boosteroo].  These 12 amps drive 2 internal and 34 external loudspeakers of different sizes:  5 subwoofers [18", 15", 10", two 6-1/3"]) -- 11 lower midrange drivers (two 15", three 12", two 8", two 7-7/8", two standard 6-1/2", one coaxial 6-1/2") -- 8 upper midrange drivers (two 5", four 4", two 3-1/3") -- and 11 high end tweeters (four 2-1/4", five 1", two 4/5")] with a total power consumption of 2285W (+ 250W).    

These details are related here to show one way how improved fidelity from a digi organ in a very restricted residential space was made possible using multiple loudspeakers of different sizes with crossover networks and multiple amps matched in power to more closely approximate the real McCoy -- the point being that, when both room and budget are restrictive, it's still possible with patience and the employment of all the console's mono output jacks to gradually assemble over time a space-effective, cost-effective external speaker system for a sampled organ.        

The audio/video was captured using a Sony HD Handycam camcorder mounted on a tripod at a distance of 3-10 feet from the speaker system and elevated 7 feet above floor level.  

Most manufacturers of sampled organs, for marketing purposes, say they record (or sample) every note of every stop (not necessarily every rank).  They may even say that their original samples are 30 seconds long or even 60 seconds long.  They may even boast about what bit-rate, sampling rate, etc., they use.  In actual fact it is very hard to get all notes of a rank in a pipe organ to sample perfectly.  Most ranks have notes which are "off" either in volume or tone.  What they actually put into their instruments therefore is going to be something that is vastly reduced, so, just a basic sampling system doesn't really make a digi organ sound exactly like a pipe organ.  The behavior of a wind instrument also needs to be reproduced.  Therefore things like wind noise ("chiff") as pipes get on speech have been put into digi organs like this one but still they end up sounding a little too focused and straight.  The biggest problem manufacturers face is, what can be done at what price.  Companies experience periodic lulls in sales, there has always been serious price competition, and, in order to stay price-competitive, most sampled organs are seriously compromised.  The marketplace for digi organs is such that, most purchasers want more stops, more manuals, etc., rather than the very highest quality musical result.  This has everything to do with the way manufacturers must design their line of products.

The way the external speaker system of this instrument is configured and the specific way its divisions are tuned generates a signature sound unique to itself.  The entire organ's pitch is adjustable up or down from A440 by means of a general pitch control knob.  The other 5 divisions are made tuneable up or down to the Great by means of their own individual pitch control knobs, all of which are situated out of sight under the bottom manual within reach of the organist's left hand.  Since the ear will tolerate a little sharpness but not the same degree of flatness, the Echo, Swell, and Pedal divisions of this organ were tuned slightly sharp and the Solo and Choir/Positiv divisions slightly flat to the Great by very minute but differing amounts.  This helped to impart a random, chorus effect to the sound of coupled divisions without introducing any disturbing undulations, or beats.

To more closely approximate the random chorus sound of a pipe organ, different divisions of this instrument can be coupled to create full ensembles on the Great and Pedal where ranks of different pitches may be tuned true (Great), others very slightly sharp (Echo, Pedal), another a tiny bit more sharp (Swell), others very slightly flat (Solo), and others a tiny bit more flat (Choir/Positiv).  While in a pipe organ mistuned ranks (celestes) are never drawn in fuller ensembles, in a digi organ like this one some of these celeste stops, as long as they don't create a disturbing pitch "warble," can be included with advantage in fuller ensembles to simulate those minute pitch variations among real pipe ranks.  In this organ all celeste ranks automatically draw the "mate ("mate" ranks are given their own drawknobs in this organ, save for the Echo Celeste), and, with manual division tremolos in this organ being adjustable for depth and speed, compound tones of great beauty are possible by coupling voices -- some mistuned (celestes), some tremmed, and some untremmed -- located in different divisions.

This instrument came with 2 percussion stops (Great Chimes & Solo Harp).  The top octave of the Great Chimes (C#50 to C61) was wired to double back an octave, but, unlike the Chimes in many pipe organs, it did go all the way down to bottom C1 and thus represented 49 equivalent bars.  The Solo Harp ran all the way up to top C6 without doubling back and thus comprised 61 equivalent bars.  Every stop in this organ including Chimes and Harp was equipped with 2 voicing variations (A and B) controlled by tilting tablets which permitted the organist to select from 168 equivalent ranks.  The A voicing reflected more traditional voicing whereas on B the change in harmonic content in the strings and reeds resulted in a different tone, brighter in many cases, the open flutes changed to stopped, and the Principals and Diapasons became either brighter or more bland and flutey-sounding.

The Choir Hohl Flute on A, for example, is open with more harmonic content but stopped and hollow-sounding on B;  both A and B are good for solos, with or without Tremolo.  The Great Flute Celeste is awfully strong but good if it's turned down a bit.  The Great Rohr Flute is a big burbley flute full of color.  The Solo Gamba on B coupled to the Swell Principal, Viole, and Great Salicional on A is very French-sounding.  The Cromorne is also very French-sounding on A, more like a Clarinet on B.  The Bassoon on A is very realistic for an actual Bassoon and on B is brighter in the mid-range and rounder in the bass.  The Cor De Nuit on B is also very French-sounding.  The Vox Humana is quite good on A where it's mixed with a soft helper stop and on B it's all by itself.  The Principals and Diapasons on B are big, flutey, and lose some of their characteristic tone.  Save for being paired with the Tuba to add volume for carrying a line over the top of the full organ, the Solo Diapason (as it often is with many large pipe organs where it is inserted in the division having the largest chorus reed battery) is probably the most useless stop in the organ.

Each voice in this organ is independent with no unification or duplexing.  The Pedal Fourniture V is the only mixture in the organ which extends throughout the compass of its clavier without breaks and is thus of the proper class of mixture to adopt for this division.  All manual mixtures save for the Plein Jeu have one or more breaks.  The Swell Plein Jeu III is wired to sound through only the bottom half of the Swell manual's compass; from F#43 it drops back to replay notes from the previous octave and thus sounds with the same quality and strength of tone above that note.  All 5 manual 16-foot stops are wired to sound clear down to bottom C1 without breaking back to the tenor octave.  All 5 manual 2-foot stops and those of higher pitch either break back in the top of their compass or have "dead notes" which are unwired to sound above the limits at which a functioning pipe can be inserted in an organ.  These are as follows:


2' Super Octave G56, 6 dead notes


2' Flautino G56 -- C61, 6 dead notes

1-1/3' Larigot doubles back from C#50 -- B60 over 11 notes (C49 and C61 are dead notes)

III Plein Jeu doubles back from F#43 over 19 notes


2' Doublette G56 -- C61, 6 dead notes

1-3/5' Tierce D52 -- C61, 11 dead notes

1' Sifflote G44 -- C49, G56 -- C61, 12 dead notes


2' Octavin G56 -- C61, 6 dead notes


2' Flautino G56 -- C61, 6 dead notes

This represents a total of 111 equivalent small pipes in the manual divisions which do not sound.  When this is factored we find an instrument capable of commanding the equivalent of 5,779 sounding pipes on the A voicing variation, and the same number on B.  This means that it would take a total of over 11K individual and separate organ pipes (11,558 to be exact) to make available to the organist the same tonal spread and range of pitches.

Three phone jacks per division provided in the back of the console allow all 6 divisional output channels to be sent to as many as 18 Viscount external speaker cabinets.  The console is Guild standard, supplied with Fatar premium keybords, MIDI friendly, and equipped with lighted MIDI rocker tablets for MIDI program changes by division which make it capable of storing sounds from an external sound module on its piston memory.  It may also be retrofit with Hauptwerk sample sets, should that be desired.  Separate divisional cancels which operate by pressing the various divisional labels situated at the top of the stop jambs are also provided.  The combination action is computer capture with 8 programmable memory banks.  Additional controls provided include Ventil tilting tablets which silence reeds or mixtures (duplicated with toe studs), a Pedal to Great (Automatic Pedal) reversible piston, a reversible Tutti piston and toe stud, "O pistons" which remember starting hand registrations, all the usual intermanual and manual to pedal couplers, a registered Crescendo shoe with 8 lighted positions, separate expression shoes for the Swell, Choir/Positiv, Solo, and Echo divisions, an All Swells to Swell piston which makes the Great and Pedal expressable through the Swell shoe along with all the other divisions, divisional Tremolos adjustable for depth and speed, adjustable Great, Pedal, and Master Volume, adjustable Brilliance control, transposer, pitch control, divisional generator tuning, and headphone jack.

One notes the absence of sub and super intramanualcouplers and the presence of only 5 manual 16-foot stops.  Due to the type of technology in this organ, the Tutti and Crescendo are non-programmable.  One also notes that its designers evidently wanted the Pedal division to be fully prepared to solo an alto or soprano part; 4 Pedal stops are of 4-foot pitch and one is of 2-foot pitch.  The Pedal division is also a bit undersized perhaps for such a large organ, having only 16 stops altogether, but this organ was the stock 3-manual (model C500) manufactured at the time to which Solo and Echo manuals were simply stacked above the Swell.  The stock 4-manual organ (model C400) was built the same but lacked the Echo manual and its associated sound colors, which meant that only the 5-manual (model C500) was supplied with a Vox Humana, Cor De Nuit, Erzahler Celeste, Festival Trumpet, and a Bombarde reed battery with mixture.


GREAT (26 ranks)

16' Principal, 8' Principal, 8' Bourdon, 8' Flute Celeste II, 8' Salicional, 4' Octave, 4' Rohr Flute, 2-2/3' Nazard, 2' Super Octave, V Cornet, IV Mixture, VI Fourniture, 8' Trumpet, 4' Trumpet, Chimes, Tremolo

SWELL (16 ranks)

16' Lieblich Gedeckt, 8' Principal, 8' Gedeckt, 8' Viole, 8' Viole Celeste II, 4' Geigen, 2-2/3' Nazard, 2' Flautino, 1'1/3' Larigot, III Plein Jeu, 16' Contra Fagott, 8' Trompette, 8' Hautbois, 4' Trompette, Tremolo

CHOIR/POSITIV (14 ranks)

8' Principal, 8' Hohl Flute, 8' Dulciana, 8' Unda Maris II, 4' Principal, 4' Stopped Flute, 2' Doublette, 1/3/5' Tierce, 1' Siffote, IV Mixture, 8' Cromorne, Tremolo

SOLO (13 ranks)

8' Diapason, 8' Major Flute, 8' Gamba, 8' Gamba Celeste II, 4' Gemshorn, 4' Orchestral Flute, 2' Octavin, 16' Bassoon, 8' Tuba Mirabilis, 8' French Horn, 8' Cor Anglais, 8' Orchestral Oboe, 4' Tuba Clarion, 8' Harp, Tremolo

ECHO (18 ranks)

16' Dulciana, 8' Cor De Nuit, 8' Erzahler, 8' Erzahler Celeste II, 8' Echo Celeste II, 4' Flauto D'Echo, 4' Erzahler Celeste II, 2' Flautino, III Mixture, 16' Bombarde, 8' Festival Trumpet, 8' Bombarde, 8' Vox Humana, 4' Bombarde, Tremolo

PEDAL (20 ranks)

32' Contra Bourdon, 16' Principal, 16' Sub Bass, 16' Violone, 16' Lieblich Gedeckt, 8' Octave, 8' Gedeckt, 4' Super Octave, 4' Flute, 2' Block Flute, V Fourniture, 32' Contra Bombarde, 16' Fagott, 8' Trumpet, 4' Clarion, 4' Schalmei


Swell to Great, Choir/Positiv to Great, Solo to Great, Echo to Great, Swell to Choir/Positiv, Solo to Choir/Positiv, Echo to Choir/Positiv, Solo to Swell, Echo to Swell, Echo to Solo, Great to Pedal*, Swell to Pedal*, Choir/Positiv to Pedal*, Solo to Pedal*, Echo to Pedal*

(* with toe piston)



18 DIAPASONS -- Pedal Principal, Octave, Super Octave, Great Double Principal, Principal, Salicional, Octave, Super Octave, Choir/Positiv Principal, Dulciana, Unda Maris, Principal Octave, Doublette, Swell Principal, Geigen, Solo Diapason, Echo Double Dulciana

26 FLUTES -- Pedal Lieblich Gedeckt, Subbass, Gedeckt, Flute, Blockflote, Great Bourdon, Flute Celeste, Rohr Flute, Nazard, Choir/Positiv Hohl Flute, Stopped Flute, Nazard, Tierce, Sifflote, Swell Lieblich Gedeckt, Gedeckt, Chimney Flute, Nazard, Flautino, Larigot, Solo Major Flute, Orchestral Flute, Octavin, Echo Cor De Nuit, Flauto D'Echo, Flautino

6 STRINGS -- Pedal Violone, Swell Viole, Viole Celeste, Solo Gamba, Gamba Celeste, Echo Celeste

22 REEDS -- Pedal Contra Bombarde, Fagott, Trumpet, Clarion, Schalmei, Great Trumpet, Trumpet Octave, Choir/Positiv Cromorne, Swell Fagott, Hautbois, Trompette, Trompette Octave, Solo Bassoon, Tuba Mirabilis, Tuba Clarion, Cor Anglais, French Horn, Orchestral Oboe, Echo Double Bombarde, Bombarde, Festival Trumpet, Vox Humana

This instrument also plays host to the sound generator box and rack-mounted LED control panel [See menu bar, Videos, Duet Control Panel subpage] of an early model Duet virtual theatre pipe organ (VTPO) MIDI-configured to play from the bottom 3 manuals and pedals of the console [See blog, Virtual Pipe Organ (VPO), Part II, for details].  Duet, a product of MIDI Concepts LLC, is so-named because it's a complete organ rather than an expander module.  It's portable, easy to install, can be made to work with any MIDI-fied digi organ, pipe organ, or digi keyboard with attachable pedals, and plays through the host instrument's speaker system.  It supplies a "total-package" 3/24+ unit theatre organ minus console and keyboards without disabling the host instrument's own voices.  Sound fonts have been sampled from Wurlitzer, Barton, Page, and Kimball theatre pipe organs, and separate Barton and Wurlitzer voicing variations for Duet's Tibia Minor and Vox Humana enables the organist to control the equivalent of 2 additional ranks.  In this application an Upbeat Audio T613-BNC Boosteroo volume booster powered by two AA batteries was used to double the amplification of Duet's stereo output signal, and an Ernie Ball 25K Ohm stereo volume pedal was used to express it.

Duet is a stand alone Unit Orchestra with 256 note polyphony registered from 208 stops and fully capable of accompanying silent motion pictures all by itself.  It was designed by former Conn organ engineers and developers and supplies sounds of uncanny realism taken from Wurlitzer and Barton theatre pipe organs, sampled pipe by pipe, tremmed and untremmed.  Its control panel makes primary control available by means of 10 combination piston buttons positioned along the piston row at the bottom of the control panel.  These piston buttons are separated into 2 groups of 5 pistons each, all programmable either as generals (or divisionals) to suit the player.  Left to right these ten pistons read "pp, p, mf, f, ff, 1, 2, 3, 4, 5, and C for "cancel").  Eight more effects pistons are situated to the right of these, which read "Ooga, Bell, Whistle, Horse, Bird, Phone, Siren, Gong," with Bell being a railroad crossing signal bell, Whistle being a train whistle, and Horse being the sound of a shod horse walking on hard pavement.  All piston buttons are white, thumbnail size, and ten separate memory levels are supplied, thus a total of 100 different combinations may be stored in piston memory.

Duet in this host instrument plays through its FRONT and RIGHT SIDE speaker systems with a total power consumption of 1895W.  It enlarges control however to 194 equivalent ranks, and with its voices and their own very slight differences in pitch on their own swell shoe it imparts new powers of spatial chorus, compound flexibility, and expression which when coordinated with the instrument's own voices and shoes can create some thrilling combinations of stunning realism and beauty.  These effects are rather astounding for electronics and blend in an uncanny way with the host instrument, even with real pipes.  Duet's voices are divided into stereo Left and stereo Right by its sound generator to simulate the Main and Solo chambers, respectively, of a theatre pipe organ.  The lighted stoptabs on its control panel which play through stereo L (Main) are marked with a circle, and those which play through stereo R (Solo) are marked with a circle having a dot in the center, just like in a theatre pipe organ, which indicates to the organist from which side of the theatre the sound will emerge.  Adjustable volume and reverb and some special synthetic stops aboard Duet (Echo Chorale II, Mezzo Chorale II) when combined with the other voices add a light or full theatre depth, respectively, and a feeling of spaciousness.  Depending upon the way its output audio stream is channeled through amps, speaker size, and positioning, Duet simulates the "surround sound" theatre experience.

Duet is thus quite a product which, in this installation, provides the host instrument with a great many highly desirable suboctave and unison manual and pedal stops, couplers, tremulants, tuned percussions, and traps.

Additional unified voices Duet makes available to the Choir/Positiv [Duet Accompaniment] manual include three 16-foots (Viol Celeste IV, Bourdon, Vox Humana), sixteen 8-foots (Post Horn, Harmonic Tuba, Open Diapason, Horn Diapason, Tibia Clausa, Tibia Minor, Clarinet, Kinura, Orchestral Oboe, Saxophone, Oboe Horn, Vox Humana, Salicional, Viole Celeste IV, Quintadena, Concert Flute), six 4-foots (Octave, Tibia Clausa, Tibia Minor, Viole Celeste IV, Vox Humana, Flute), one mutation (2-2/3' Twelfth), and 2' Piccolo.

Additional unified voices Duet makes available to the Great manual include eight 16-foots (Post Horn, Harmonic Tuba, Tibia Clausa, Clarinet, Saxophone, Salicional, Bourdon, Vox Humana), sixteen 8-foots (Post Horn, Brass Trumpet, Harmonic Tuba, Open Diapason, Horn Diapason, Tibia Clausa, Tibia Minor, Clarinet, Kinura, Orchestral Oboe, Saxophone, Vox Humana, Salicional, Viol Celeste IV, Quintadena, Concert Flute), six 4-foots (Clarion, Octave, Tibia Clausa, Tibia Minor, Viol Celeste IV, Flute), 5 mutations (5-1/3', 3-1/5', 2-2/3', 1-3/5' Tibia Clausas, + 2-2/3' Twelfth), three 2-foots (Tibia Clausa, Fifteenth IV, Piccolo), and 1' Fife.

Additional unified voices Duet makes available to the Swell manual [Duet Solo] include eight 16-foots (Post Horn, Brass Trumpet, Harmonic Tuba, Open Diapason, Tibia Clausa, Clarinet, Saxophone, Salicional), fifteen 8-foots (Post Horn, Brass Trumpet, Harmonic Tuba, Open Diapason, Horn Diapason, Tibia Clausa, Tibia Minor, Clarinet, Kinura, Orchestral Oboe, Saxophone, Salicional, Oboe Horn, Quintadena, Vox Humana), three 4-foots (Octave, Tibia Clausa, Tibia Minor), and 2' Tibia Clausa.

Additional voices Duet makes available to the Pedal include one 32-foot (Diaphone), five 16-foots (Open Diapason, Salicional, Harmonic Tuba, Tibia Clausa, Bourdon), and nine 8-foots (Post Horn, Harmonic Tuba, Open Diapason, Tibia Clausa, Clarinet, Saxophone, Salicional, Viol Celeste IV, Concert Flute). 

Among the other resources it lends are 4 separate tremulants [Main, Solo, Tibia Clausa, Tuba/Diapason] all beating at different depths and speeds, Great Sub, Super, and Unison Off couplers, 5 Great to Solo ("Blackpool") couplers (16', 8', 5-1/3', 4', 3-1/5'), separate 8-foot couplers for manuals to pedal, Solo to Great, and Solo to Accompaniment, Accompaniment Super coupler, Solo Pizzicato coupler operable on Great and Accompaniment, voices separated into Main [left] and Solo [right] chambers, 8 Double Touch stops for any keyboards so equipped, 10 tuned percussions, 11 traps, 8 effects, and Piano with 2 voicing variations (Standard, Rinkie Tink) available on the Great and Accompaniment at 16'-8'-4' and 8'-4', respectively.  Duet augments the host instrument with 2 Diapasons (bright Horn Diapason, full Open Diapason), 2 Flutes (Quintadena, Concert Flute [Bourdon]), all of the usual color reeds (Clarinet, Saxophone, Orchestral Oboe, Oboe Horn, Kinura), 2 highly imitative strings (Salicional, Viole Celestes IV), a full-toned Harmonic Tuba [Tuba Horn], bright Brass Trumpet, very edgy Post Horn, robust 32-foot Diaphone, Wurlitzer Solo Tibia Clausa available at 8 pitches (16', 8', 5-1/3', 4', 3-1/5' 2', 1/3/5', 1'), and 2 voicing variations (Barton, Wurlitzer) for Tibia Minor and Vox Humana ranks.

To summarize, Duet adds to this organ a third Pedal stop of 32' pitch, 24 stops of 16' pitch, 56 stops of 8' pitch, 15 stops of 4' pitch, 5 stops of 2' pitch, a Great stop of 1' pitch, and 6 off-unison mutation stops.

These voices and features have proven to be a remarkable complement to this organ providing a tonal counterbalance much desired:  it doubles the 5 available Pedal stops of 16-foot pitch to 10 and doubles the 5 available mutation stops to 10, adding a stop of 5-1/3' pitch where there was none; it quadruples the 3 available Pedal stops of 8-foot pitch to 12; it adds 3 stops of 16-foot pitch to the bottom manual where there were none; it adds 11 new couplers which weren't there before, and the host instrument's couplers are operable on all of Duet's voices; this unit vastly expands the tonal spread of this organ with imitative orchestral string and reed ranks, percussions, and traps permitting the organist to control a massively enlarged palette for coloration of sounds and dynamic shadings for dramatizing and nuancing the music.  Duet also comes with a S/G switch which, when working from a single digi keyboard, allows stops programmed to the Solo to replace stops programmed to the Great to play above middle C, with stops programmed to the Accompaniment always playable below middle C, this note being the split point.

Duet was a unit built upon order, only about 200 of them were sold, and MIDI Concepts LLC has all but discontinued its production ... nevertheless it contributes greatly to any installation, pipe or electronic, to which it may be paired.