What separates an organ from everything else in the musical universe is it's unparalleled range, incredible number of stop combinations for color, and sheer thrilling power sitting atop a pervading if not thunderous bass sensed at times as purely physical subsonic energy.  To produce the same effect in an electronic organ the employment of subwoofers and some knowledge thereof is needed.  Josef Anton Hofmann was the first audio engineer to describe the placement of woofers inside enclosures bringing these three independent variables into play:  1) small enclosure [cabinet] size, 2) deep [low] bass production, and 3) high [output] sensitivity.  He showed that if engineers pick any two of these parameters, the third one will be compromised.  This principle has become known as Hofmann's Iron Law.  For example, if we want a sub with low bass reach and high output sensitivity, then we have to go with a larger cabinet.  If we have to have a small cabinet due to space considerations but still want high output sensitivity, then some low bass reach will be compromised.  So, in the end, speaker selection is all about trade-offs.  In an electronic organ of even moderate size very low bass reach into the 20Hz range really is a must.  When space is restricted and a smaller cabinet also is a must, then the sub's cone driver will need to be pushed with a lot of watts from a big amp to counteract sensitivity loss.  Today most sub manufacturers want to offer extended bass response in a smaller cabinet, so they tend to put most of their R & D [research/development] efforts into speaker output sensitivity.  While the newer sensitivity ratings are perhaps less than many consumers would like, the wide availability of high-power amps make the trade-off a reasonable one.

How the listener notices bass depends on room nodes.  Very few owners have an ideal listening room in their residence let alone one large enough not to be affected through the bass/deep bass bandwidths.  While the sound from a single subwoofer is omni-directional, it matters where in the room its cabinet is placed [WARNING:  these are heavy, some weigh over 100 lbs.].  More bass will be noticed when it's against a wall, and the most when it's in a corner.  While the music plays, as we move around the room we can notice areas of greater bass in places and in other places suckouts where it isn't nearly as strong.  The preferable way to get around this is to use multiple subs positioned about the room [four will usually fix just about any node problem].  For the lowest Pedal stops to get clean, tight bass from a speaker cone a lot of air has to be moved.  This isn't so proportional to woofer size as one might suppose.  Some 18" woofers aren't rated below 40Hz while some long throw subs no bigger than 12" actually move more air and can reach well down into the 32-foot octave to 18Hz.  On the other hand, larger woofers need to work less hard to attain the same volume.  When loudness alone isn't what we're after, and good subsonic reproduction of the signal with sufficient power is the chief objective, it's entirely possible that a few 12" long throw subs with listed frequency responses in the 20Hz range positioned about the room and pushed with big amps can yield better results than half as many 18" subs. 

The crossover [cut-off] frequency of a subwoofer is the frequency at which the sub kicks in with bass.  Unless one spends thousands of dollars on a super-sized mega-subwoofer powered by an amp of sufficient size to run a radio station single-handedly most home theatre-style subwoofers generally tend to roll off quickly below 30Hz.  This can be counteracted to some extent by using equalizers which boost the signal stream up to a +12dB gain and adjusting bandwidth settings to boost frequencies in the subsonic 20Hz range by the same amount.  In general, when the frequency range of the other bass woofers in the room is known, the sub's crossover, if adjustable, should be set roughly 10Hz above the lowest frequency the other speakers can handle cleanly.  Some careful listening and experimentation is needed until the ear finds a smooth transition between the other speakers and sub.  The idea is to make the slight overlap and blending so seamless that the bass cannot be localized and everything will play in unison.

NOTE:  All loudspeakers [woofers, tweeters, horn drivers, midrange drivers, subwoofers, etc.] used in electronic organ speaker systems are non-linear devices, meaning a type of device whose output is not directly proportional to its input.  This relationship does not plot as a straight line on a graph but rather a curve, indicating a non-linear response.  As such they are not perfect and, like all other electronic audio devices, will have components which generate some very minute but unwanted harmonics which are measurable as total harmonic distortion [THD].  The less THD the better [anything under 2 per cent is considered good], but that's just the nature of the beast.  The subject is an in-depth and very technical topic for those who wish to dive deeply into its details, but, the point is, since it would be impossible to have a loudspeaker with zero THD, the goal is to reduce it as much as possible so that it isn't audible to recording microphones or to the ear.  In the case of organ sound, as with conventional stereo systems, multiple speakers of different types and sizes are a requisite.  When, for example, one master-of-all-work 12-inch woofer receives the instrument's entire audio signal stream the mammoth excursion movements the cone driver makes to generate low bass bandwidths interferes with its ability to make the finer movements required for higher frequencies.  The result (called intermodulation distortion) ends up sacrificing some midrange clarity.  This type of distortion is best reduced by running the audio signal through a crossover network which divides it into different bandwidths which then can be assigned to play through different-sized drivers each built specifically to best reproduce those frequencies.  Multiple subwoofers therefore do more than reproduce bass, low bass, and subsonic bandwidths -- they improve clarity in all the other bandwidths.  Because overdriving of amplifiers and powered speakers also can have them compromised it's a good idea to set their volume levels no higher than around 2/3 maximum -- NEVER all the way up -- to avoid overheating and allow room to accommodate any sudden surges in the signal stream.          

All sampled voices in this instrument are sourced, separated, and stored by division on computers inside the console, one for each manual and Pedal.  A single master computer controls these 6 "slave" computers.  Voices, couplers, and tremulants are brought on or retired by means of lighted drawknobs and lighted manual and toe pistons.  Lighted rocker tablets paired with an 8-position factory-set Crescendo indicator are built into the rail above the top manual controlled MIDI, Voicing Variations, and divisional Reeds Cancels.  All drawknobs and rocker tablets remain in alignment in both on/off positions.  Standard TRS (1/4" phone) jacks in the back of the console allow for up to 3 separate mono outputs per division along with a pair of special combined mono outputs for Great/Choir-Positiv/Pedal and Swell/Solo/Echo, all for connection of external powered speaker cabinets.

The power requirement to run the console is 520W.  Its self-contained speaker system consists of a lone pair of 12" woofers each powered by its own 80W amp having a combined audio output power of 160W.  The console is supplied with adjustable factory reverb, 2 tremolo speed controls [Swell/Echo + Great/Choir-Positiv/Solo], and 2 tremolo depth controls [Swell + Choir-Positiv].  The three external speaker systems [MAIN/MONITOR, PEDAL, & AUXILIARY] involved in its new voice are composed of a non-factory mix of new and pre-owned equipment. 

NOTE:  Input/output jacks are made to work either with balanced or unbalanced signals, or with both.  With a so-called "unbalanced signal" there are only 2 conductors; one carries positive -- the other carries negative and is also used for ground.  The advantage of a so-called "balanced signal" is that because the ground is separate from the negative conductor there is less chance that radio frequency interference will get into the signal stream and create hum.  When an annoying hum is detected in a subwoofer at half volume which gets louder as the volume is cranked up, it's often due to such interference, called a "ground loop."  Switching out the audio cable from dual RCA [unbalanced] plugs to either a single XLR [balanced] plug or replacing the RCA plugs altogether with bare wire connections between the amp and sub is often successful in eliminating hum.  Any trace of hum after that might be further reduceable by setting the sub's crossover at minimum and turning its volume knob down to about 2/3 or where the hum disappears.

CAUTION:  ALWAYS PLAY IT SAFE.  Instead of plugging everything into unprotected wall receptacles, ALWAYS connect the power cords for the console and any other electronic devices [external amplifiers, mixers, equalizers, reverb engines, voice modules, powered subs] to a power strip that has either a built-in circuit breaker (to protect against overloads in amps) OR a surge bar having a surge suppressor (to help protect against sudden spikes in voltage).  Even when surge bars are used, very high voltage surges from nearby lightning strikes may succeed in blowing a fuse inside the console anyway, thus, while they do offer some protection, owners may prefer to switch off surge bars [and power strips] when the organ is not in use.  Power strips and surge bars should always come with a long enough power cord to plug directly into a wall receptacle or receptacle expansion plate, NEVER into an extension cord or second power strip.  To avoid possible fire or electrical shock NEVER daisy chain power strips or extension cords one to another in series [See blog, Conn Speaker Pipes, for more about wiring] as this changes the electrical resistance [impedance] of the circuit.  Also, if the subwoofer or other device is built to receive a 2-socket power cord and none is available, a 3-socket power cord having a separate ground may be substituted IF AND ONLY IF the "square within a square" symbol appears next to the plug-in jack.  This symbol indicates that the device is equipped with an internal Class 2 ground which shields against electrical shock.  In the absence of this symbol, USE ONLY a 2-socket cord, as its negative pole is made to double as a ground; failure to do this can result in deadly electrical shock or fire.

When external equalizers are used it becomes incumbent to run scales up and down the manual keys with voices drawn one at a time to determine if any bandwidths sound louder than others and to regulate them so that all frequencies are of roughly uniform strength throughout the compass of the manual.  Additionally, when speaker pipes are in use, it may be necessary to provide a full or nearly full negative dB boost for all bandwidths higher than 8-foot C [64Hz] to keep from swamping the effects of the pipes.  Upperwork including 4-foot stops would need to be drawn carefully and sparingly in the full organ to keep treble frequencies balanced.  Some trial and experimentation is demanded with the ear being the final judge.

1.  The MAIN/MONITOR SPEAKER SYSTEM -- receives low line output from all 6 divisions of the instrument through 1/4 inch jacks in the back of the console.  These connect with a Peavey XR8300 power mixer supplied with dual 300W continuous power amps, minimum impedance 4 ohms, controlling MAIN and MONITOR channels, respectively, each of which is supplied with its own separate built-in 7 band graphic equalizer (EQ).  These settings are identical for both MAIN and MONITOR channels and include a flat signal @ 80Hz and negative boost of -12dB @ 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, & 10kHz.  The Peavey mixer combines these 6 channels into a single mono output signal and then routs it to a TC Electronics M300 dual engine processor which, using its hardware reverb engine, enriches the signal with Large Cathedral reverb adjusted to provide about 4 seconds of decay time upon release of the full organ.  From there the enriched signal connects with a DOD model SR231Qx 31-band dual graphic EQ which boosts both channels with a gain of +12dB.  Bandwidth settings here are set for +12dB boosts @ 20Hz & 25Hz, +6dB @ 31.5Hz, flat @ 40Hz, negative boosts of -6dB @ 50Hz & 20kHz, and all other bandwidths negatively boosted @ -12dB.  This equalized, enriched signal is then returned to the Peavey through both DOD output jacks where a touch of built-in Peavey reverb is added, both channels are boosted by +10dB,  and the signal is routed to the mixer's output jacks.  The Peavey's rear MAIN output jack connects via a splitter cable with a) an Acoustic Audio BR-10 passive 3-way monitor cabinet supplied with its own crossover network, 10" woofer, 4" midrange cone, 10" x 4" horn tweeter, listed frequency response 29Hz-20kHz, and b) with a specially repurposed Audiopipe TXX-BCD3-12 DVC 12" passive, high power subwoofer in an unported box.  This is an extreme excursion dual 4 ohm car audio sub rewired in series @ 8 ohms, rated at 900W continuous power, and has a frequency response of 20Hz [32-foot D] up thru 900Hz.

TIP:  When testing subwoofers it's advisable to first set volume controls at half position or less and perhaps no higher than 2/3 after that, this to avoid compromising the speaker cone in the event of any sudden, extremely strong bass pulses in the signal stream.

      The Peavey's front MONITOR output jack connects via another splitter cable with a ported BIC America PL-200 powered sub equipped with a 250W amp @ 8 ohms and 12" long throw woofer, listed frequency response down to 21Hz [32-foot E], crossover set at minimum [30Hz], and with an unported Polk Audio PSW505 powered sub supplied with a 300W continuous power amp @ 8 ohms, 12" long throw woofer, frequency response down to 23Hz [32-foot F], and crossover set a minimum [60Hz].  This speaker system pushes 300W (Peavey main/Audiopine) + 850W (Peavey monitor/BIC/Polk) = 1150W.  

To add a bit of luster to the reeds and help supply needed suboctave [16'] gravity to counterbalance the harmonic brightening of the Conn speaker pipes [See below] this organ's MIDI-out jack is utilized to send MIDI information from the entire organ to a pair of pre-owned Allen MDS-Expander II external modules.  These add-on units, while no longer in production, are made to operate through the MIDI couplers of any MIDI-capable organ's pedals and [up to 3] manuals.  Its supplemental voices include classic organ stops, mutations, and ancient reeds, theatre organ ranks, percussions, and orchestral and other keyboard instruments, and as many as 4 voices out of the 99 program numbers onboard each module may be accessed simultaneously.  In this application a table-top Allen module [A] sends unaltered MIDI information from the console thru to a second drawer-type Allen module [B], and selected voices for both modules are assigned to individual Viscount lighted MIDI rocker tabs situated in the rail above the top manual controlling Swell, Great, Choir/Positiv, and Pedal divisions.  These MIDI-coupler rocker tablets represent 8 additional stops, 2 at a time, which can be either hand registered or captured and stored on general or divisional pistons.  Because the Pedal division is a bit undersized for an organ of this size and certain keys in the middle of the Great are not reliable the workaround has been to use it coupled to the Pedal and transfer the main manual's function to the bottom-most manual [Choir/Positiv].  The 4 Allen voices programmed to play from Module A [tuned sharp] are:  Sw 16' Dulzian, Gt 10-2/3' Flute, Ch/Pos 8' Hautbois, Ped 10-2/3' Principal -- and from Module B [tuned flat] are:  Sw 8' Hautbois, Gt 16' Bassoon, Ch/Pos 16' Bourdon, Ped 16' Principal.  By keeping the volume knobs for both modules at a restrained 10:30 o'clock position and carefully mixing these 8 Allen voices with the rest of the organ [raising its total to 92 stops and 115 equivalent ranks] a very pleasing signature sound has been created.  In this application the modules are tuned differently -- sharp by 4 Cents (4/100ths of a chromatic semitone) for Allen A and flat by 4 Cents for Allen B -- to more closely approach the random tuning characteristics of real pipe ranks.  The output jacks for both modules connect with the Peavey power mixer where their voices play reverbed through both MAIN and MONITOR channels.

2.  The PEDAL SPEAKER SYSTEM --  receives signal from a single Pedal division output jack at the back of the console.  This first connects with an Alesis Nanoverb 18 bit digital effects processor which enriches the signal with Hall 1 reverb.  Since grave sounds travel further in a large space and die away more slowly than acute ones this unit is adjusted to provide about 6 seconds of decay time upon release of the full organ.  The enriched signal is then routed to a DOD model SR831Qx 31-band dual graphic EQ where its single mono channel is given a +12dB gain [all bandwidth settings identical with the above].  The output jack from the DOD connects with an unported Velodyne F-1800RII 18" powered subwoofer supplied with a 600W continuous power amp, 2.5 ohm nominal impedance, frequency response down to 16Hz [32-foot C], and crossover set at minimum [40Hz].  The Velodyne's R/L wire outputs send the Pedal signal stripped of subsonic bass to a BSR passive cabinet retrofitted with a standard Memphis 15" speaker cone wired @ 8 ohms operating with a crossover that captures all remaining bass frequencies from 120Hz on down.  The remaining signal which leaves this cabinet is sent to a pair of BSR Colossus passive 4-way stereo cabinets each retrofitted with a trio of new speaker cones [Memphis 15", Pyle 8", Pyle 5"].  These cabinets both retain their original crossover networks and pair of 2" ceramic tweeters.  Their own crossover network divides the signal stream into 4 bandwidths and sends them to corresponding components [120Hz-800Hz to 15", 800Hz-1.2kHz to 8", 1.2kHz-3.4kHz to 5", 3.4kHz+ to 2"].  The Velodyne's spare line output jacks also connect with an unported Sony SA-WM200 powered sub supplied with a 100W amp, 8" long throw woofer, and listed frequency response 0f 28Hz-200Hz which, in turn, routs the Pedal signal stripped of bass to 2 sets of passive Conn speaker pipes [models 145-3 and 146-3, both silver finish].  This speaker system pushes 600W (Velodyne) + 100W (Sony) = 700W.

   3.  The AUXILIARY SPEAKER SYSTEM -- employs a Rockville RPM80BT 8-channel power mixer equipped with dual 250W continuous power amps which receives signal from the entire organ through 6 individual low line jacks at the console.  The Rockville's built-in 5-band EQ is set flat @ 60Hz with negative boosts of -12dB @ 250Hz, 800Hz, 2kHz, & 8kHz.  The Rockville's high line 8 ohm output signal is routed from there through 3 output channels:  1) firstly to a ported Sony SA-3000 powered sub supplied with a 100W continuous power amp and 12" long throw woofer.  The Sony sub's listed frequency response is down to 20Hz [32-foot D#], and with its crossover set a maximum [200Hz] all notes from about 8-foot tenor G# and below speak through it.  This unit is side-firing, situated to the right of the console, and disperses sound in that direction.  Its wire output terminals send signal stripped of bass to 2 more sets of passive Conn speaker pipes [Models 145-1, 146-2, both gold finish].  Each set of these speaker pipes is rated for an 8 ohm load, equipped with 2 pair of Cletron 6" X 9" oval speakers wired in series parallel, and designed to operate only at treble and high midrange frequencies with a practical downward limit of 200Hz corresponding to the 8-foot tenor G# note [208Hz].

NOTE:  Conn speaker pipes [See blog, Conn Speaker Pipes, May 12, 2016], one of several attempts invented to improve the sound of electronic analog organs, are strictly treble and upper midrange units.  The Conn theory was that individual frequencies generated by the upward firing speakers inside the pipe box would find their own tuned pipes and make them resonate.  What Conn engineers also observed when the pipes were tuned was that they not only resonated at fundamental primes but also at higher overtones of the harmonic series.  So, besides providing a dispersion of sound vertically upward throughout the listening space and a subtle but measurable buildup and decay of sound when keys are pressed and released, respectively -- pneumatic effects which can be heard but not counted -- these units impart to manual stops a very discernable brightness to individual voices.  Therefore, for best results the treble bandwidths reaching any other speakers used with these speaker pipes should be equalized [suppressed] at the same time.  Use of these speaker pipes also demands a ministering art of registering combinations since they brighten all pitches above 8-foot tenor G# [200 Hz].  When multiple units are connected they reinforce harmonics so well that the only upperwork needed for the plenum or full organ may be a single octave [4-foot] stop and one or two soft mixtures, all coupled from a secondary manual.  In order to avoid overdriving, since these are strictly treble units, SHIELDING THEM FROM ALL BASS AND LOW MIDRANGE FREQUENCIES IS AN ABSOLUTE MUST.  This is best accomplished by filtering the signal stream with a powered subwoofer before it arrives at the pipes and setting the sub's variable crossover at 200Hz which strips the incoming audio signal of bass and low midrange bandwidths.

2) A second 8 ohm line out from the Rockville connects with a ported Klipsch KSW200 powered sub equipped with a floor-firing 12" bass reflex woofer, 200W continuous power amp, and a listed frequency response down to 31Hz [16-foot C].  With its crossover set at minimum [40Hz] its speaker out jacks rout the remaining signal stream to a ported Sony SA-W3000 powered sub supplied with a 100W continuous power amp and 8" long throw woofer.  The Sony's listed frequency response is down to 20Hz [32-foot E], and its cutoff is set at maximum [200Hz].  Its wire output terminals rout the remaining signal stripped of bass to yet another 2 sets of Conn speaker pipe cabinets [Models 145-2 and 146-2, both silver finish] each equipped with the same passive Cletron 6" x 9" oval speakers wired the same way.  Line level output jacks from the Klipsch also connect with a ported JBL Sub150 powered sub equipped with a 150W continous power amp, 10" bass reflex woofer, and listed frequency response down to 35Hz [16-foot C#].  3) The third 8 ohm line out from the Rockville connects with a ported BIC America Formula F-12 powered subwoofer equipped with a 150W continuous power amp, 12" long throw woofer, frequency response down to 25Hz [32-foot G], and crossover set at 40Hz.  Mono signal from the entire organ is also sent via console out jacks to a DOD model 231 series II 31-band graphic EQ which boosts the signal with a gain of +12dB [all bandwidths settings identical with the above].  The equalized, boosted signal is then routed to a Radio Shack MPA-250B stereo amp rated at 250W continuous power.  The Radio Shack's wire outputs then connect with a) an unported Definitive Technology ProSub1000 powered subwoofer supplied with a 250W amp, 10" long throw subwoofer pressure coupled to a 10" low pass radiator, listed frequency response down to 18Hz [32-foot D], crossover set at 50Hz, and b) another Audio BR-10 passive 3-way monitor cabinet supplied with its own crossover network, 10" woofer, 4" midrange cone, 10" x 4" horn tweeter, and listed frequency response of 29Hz-20kHz.  A separate Choice Select ST2060 amp rated at 60W continuous power which receives inputs from all [5] manuals.  This amp is specially employed to run one more set of speaker pipes.  With its treble/bass controls set flat the manual signal from this amp is routed to a pre-owned specially custom-built PVC pipe speaker box [created in Lodi, California by the McCurdy Corporation] made of 12 general purpose 3-1/2" diameter PVC [polyvinyl chloride] cylindrical pipes of equal diameter [3-1/2"] bundled together and positioned vertically on end over a wire baffle situated above a round opening in the top of a square, hollow wooden box, inside of which is mounted a single upward-firing Radio Shack passive 12" woofer wired to play all frequencies arriving from the amp.  This unit is positioned behind the console and disperses sound in that direction.  These pipes cut to various lengths are engineered to sympathetically resonate with fundamental low midrange and upper bass frequencies generated by the 12 chromatic semitones from 200Hz [4-foot A] down one octave to 100Hz [8-foot A].  It's practical upward range actually extends one semitone above 8-foot tenor A to about 226Hz, overlapping slightly the lower limit of the Conn model 146 speaker pipes and extending their effects an octave lower without noticeable break.  An output jack from the Choice Select also connects with a ported Sony SA-WMSP1 powered sub supplied with a 50W amp, 8" woofer, and listed frequency response down to 28Hz [32-foot A].  This speaker system pushes 500W (Rockville) + 100W (Sony) + 450W (Klipsch/Sony/JBL) + 150W (BIC) +  500W (Radio Shack/DefTech) + 110W (Choice Select/Sony) = 1810W.

In its final configuration the project to upgrade this instrument with 3 external speaker systems has involved adding 2 mixers, 11 subwoofers [7 ported, 4 unported one of which is passive] and 42 woofers/tweeters/horn drivers including 193 speaker pipes all powered by 14 additional amplifiers.  When fully engaged not counting both Allen modules, both reverb engines, and the trio of 31-band equalizers the instrument's power draw is 4180W.  Speaker cones range across 10 sizes:  one 18" SUB, three 15", six 12" SUBS, three 12", two 10" x 4" horn tweeters, two 10" SUBs, two 10", three 8" SUBS, two 8", twenty-four 6" x 9" ovals, two 5", two 4", & four 2".

The goal of this project was to create improved tone quality, ambience, and power from an older digitally sampled instrument as a cost-effective, next-best alternative to a total replacement or rebuilding.  By hunting down new and repurposed electronics and cobbling various units together in carefully calculated ways over time, and with painstaking and patient experimentation using the ear to adjust variable volume, balance, treble/bass, equalization, and artificial reverb controls, the combinational tone with all systems running has been transforming -- something to treasure and entirely sufficient to satisfy the serious organist.  Judging by the results in this case, it's entirely possible for such efforts to end up being a satisfying and signal achievement.  The audio power becomes vastly multiplied, individual stops speak with more realism, and the speaker pipes add a shade of brightening and omni-directional pneumatic effects.  Perhaps most importantly, it no longer becomes necessary to go to the building to experience the desired acoustical resonance of the instrument when practicing, the instrument sounds and behaves closer to the real thing, and its richness allows it to be listened to for long periods of time.   

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 comes close but doesn't really make a "digi" organ sound quite the same as real pipes.  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.

With its Echo (5th) manual and rack so far away, intramanual couplers absent, and the crescendo shoe non-programmable, there are certain challenges to playing this organ, but its sound stands or falls on how its divisions are tuned, how its voices are then mixed and coupled between divisions, and how its reverberation characteristics and external speaker systems are configured.  If its divisions are all tuned exactly true to the Great the sound is completely wooden and lifeless, but if tuned too far away from true the beating is nasty and very objectionable.  The trick is to find that sweet spot which has each division tuned just barely different from true but not enough to produce objectionable undulations.  These minute tuning differences are essential to the mimicry of a real pipe organ where every pipe speaks extremely close to true pitch, but not quite.  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, it was decided, using the ear to adjust the amount, to tune the Echo a very tiny bit sharp and the Solo a very tiny bit flat so that, when the hands go to the Solo and the Echo is blended in, the random tuning effect of a pipe organ is suggested.  Similarly the Swell was tuned just a tiny bit more sharp than the Echo, the Choir true to the Great, and the Pedal just barely sharp to the Great.  This was accomplished by drawing the loudest 8-foot reed in each division, coupling them one at a time to the Great Trumpet, listening for beats, and adjusting divisional tuning knobs accordingly.

The mistuned ranks (celestes) inserted by the builder in a pipe organ typically are never drawn in fuller ensembles, but in an organ like this some of these celeste stops such as the Echo Celeste, Solo Gamba Celeste, and Choir/Positiv Unda Maris, as long as they're not too assertive and don't create a disturbing pitch "warble," might possibly be drawn with advantage in fuller ensembles to simulate the random effect of minute pitch variations among real pipe ranks.  Some very patient trial-and-error experimentation is needed, of course, it's a bit tricky, but the ear is still the best judge as to how much of this "pitch seasoning" may or may not be good for the sound recipe.  In this organ all 8-foot celeste stops automatically draw the "mate" rank tuned true which is given its own drawknob, and, with manual division tremolos in this organ being adjustable for depth and speed, compound orchestral-styled tones of great beauty are possible by coupling divisions including some mistuned celestes possibly with some tremmed voices thrown in.

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, principals, and diapasons either become brighter or more wide-scaled and neutral in tone if not stopped and hollow-sounding.

As for the tonality of individual stops, the Great Principal is extremely big like an English 1st Open.  When a leaner chorus is desired the Salicional could be substituted which is more like a 2nd Open in tone and strength; on B it's voice is less assertive, keener, with a prominent 12th.  The 16-foot Principal is also very big and on B inclines to a dull tone with less harmonic content.  The Flute Celeste is paired with the Bourdon and is extremely strong but good if the Great volume knob is turned down all the way.  The 4' Rohr Flute is a big, burbley flute full of color in its lower range and good for solos.  The Great Trumpets, as expected, are very loud and dominating.  The Swell Principal is a 4th Open in strength and in combination with the Viole is very French sounding.  The Swell flutes are all good and, as expected, are available at 6 pitches.  The Swell reed chorus stands on a big Contra Fagotto and two Trompettes of medium strength at 8' and 4' pitches, respectively.  The Hautbois is equally strong and rather dull in tone.  The Principal in the Choir/Positiv is a 3rd Open in strength.  The Hohl Flute is open on A, stopped and hollow-sounding on B with less harmonic content, but good for solos on A or B, with or without Tremolo.  The Cromorne on A is very French-sounding, on B more like a Clarinet.  The Solo Diapason is strong, rather neutral in tonality, and finds its best use as a helper stop, adding desirable power to any big reed without appreciably affecting its tone.  The Gamba and its paired Celeste are good and, curiously, are both identical on A and B.  The Gemshorn is bright but not overbearing, and the Octavin is very assertive, almost piercing in tone.  The Bassoon on A is very realistic for an actual Bassoon; on B it's brighter in the midrange and rounder in the bass.  The Orchestral Oboe, as expected, is thin and keen, an excellent solo stop, and can be coupled for adding definition to a chorus without dominating.  The Cor Anglais is very big and rather dull in tone.  The Echo Cor De Nuit is very French sounding, particularly on B.  The Erzahler is a bit strong, most beautiful on A, and thinner and brighter on B.  The Bombarde chorus is a bit refined and raspy in tone, full of harmonic content but unexpectedly tame in strength.  In an age where there are so many vile examples, the Vox Humana in this organ is especially good and "a Vox to die for."  On A it's mixed with a very soft helper stop, and on B it's all by itself.  The Pedal Principal on A sounds like an English Open Wood, and on B it's dull and flutey in tone.  The Violone is quite good.  The Fagott is very big and dominates when introduced.  The 4' Schalmei is very nasal but good in Pedal solos with the 4' Stopped Flute in the Ch/Pos coupled.  Curiously, the Contra Bourdon, tonally, is not a flute voice -- it inclines instead to a non-imitative string tone and would be more properly labeled "Contra Violone."  When supplied with sufficient external amplification, equalization, and subwoofer speakers this stop, along with the Contra Bombarde, is valuable in adding depth and gravity to the fullest ensembles.

This said, and speaking from experience, a good premise when playing this organ is to view the Solo as part of the Swell, and, if the hands happen to go to the Solo, the Echo can be blended in.  This is easily accomplished with manual coupling.  But because the top manual is so far away, the Pedal division is a bit undersized for an organ this large, the inordinate strength of the Great stops [and, more recently, a few dead notes on this manual], and the fact that a lean full organ minus large scale flutes and big, tubby-sounding diapasons and principals may be preferable, the Great might be used with advantage as a coupling manual to the Pedal with the Choir/Positiv tuned true to, and being substituted for, the Great.  This also allows 2 valuable stops available from the Allen expander module to be made available in the buildup to full organ.  The Allen 10-2/3' Principal can be assigned to the Pedal and drawn with the Pedal 16' Principal to generate the differential tone of a 32' Principal.  Similarly the Allen 10-2/3' Flute can be assigned to the Great and coupled to the Pedal with the Pedal 16' Sub Bass drawn to generate the differential tone of a 32' Sub Bass.  The added gravity and color these 2 voices provide complements the Pedal's independent 32' foot Contra Bourdon [which sounds more like a Violone] and 32' Contra Bombarde.    Each voice in this organ is independent with no unification or duplexing, and the Pedal Fourniture V is the only mixture stop in the organ without breaks.  All others have one or more breaks, and the Swell Plein Jeu III sounds only through the bottom half of the Swell manual -- at F#43 it drops back, thus, above that note it sounds more assertive than expected.  All (6) 16-foot manual stops run clear down to the bottom without breaking back.  Voices of 2-foot pitch or higher either break back in the top octave or end at the top with some factory-programmed dead notes. 

GREAT

2' Super Octave G56 -- C61, 6 dead notes at the top

SWELL

2' Flautino G56 -- C61, 6 dead notes at the top

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

CHOIR/POSITIV

2' Doublette G56 -- C61, 6 dead notes at the top

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

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

SOLO

2' Octavin G56 -- C61, 6 dead notes at the top

ECHO

2' Flautino G56 -- C61, 6 dead notes at the top

This represents a total of 111 equivalent small pipes in the manual divisions which have been made not to sound.  When this is factored in, the instrument commands the equivalent of 5,779 sounding pipes on either A or B voicing variation.  With the Allen module contributing the equivalent of another 430 sounding pipes to Memories One & Two, the instrument now plays with 92 stops, 115 ranks, and over 6K [6,209] pipes. 

Three phone (1/4") output jacks per division, plus two special output jacks for the entire organ, 20 in all, provided at the back of the console allow it to send as many separate output signals to external amps and/or 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.  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 console controls included as standard are 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, "0 [zero] pistons" which remember starting hand registrations, unison intermanual and manual to pedal couplers, 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.

The biggest challenge with performing solo repertoire on this instrument is settling upon a scheme for drawing and coupling the voices to approach something of the sound world the composer knew.  It works well for the player when the premise is that the Solo is part of the Swell; this makes for a massive voice palette for coloration of sounds and a massive dynamic palette with compound flexibility and expression for nuancing the music.  If the player's hands happen to go to the Solo, it works well to have the Echo blended in. The same can be said for coupling the Swell to both the Great and Choir/Positiv and coupling the Choir/Positiv to the Great.

This organ of 84 stops, for its size, is overly supplied with upperwork (octave stops and higher) and undersupplied with manual Doubles (there are only 6 in the whole instrument, however all of them go all the way down to bottom C without doubling back).  Being somewhat deficient in manual suboctave tone means that when drawing the full organ pretty much all manual Doubles need to enter and the percentage of upperwork demand reduction.  The Great sub coupler, in particular, an essential element of the sound universe known to 19th and early 20th century French organists, especially Franck, Widor, and Vierne, a coupler which had much to do with the way they notated their compositions, is entirely lacking.  Without it, big final spread chords above middle C sound thin and less sonorous when performed exactly as written -- in which case it might benefit to experiment at changing the manuscript mentally by adding a note to the bottom of the final left hand chord or with the right foot high in the pedal to help provide the missing gravity.  As stated, in an organ like this with divisional tuning, voices from different divisions including even a celeste or two may need to be drawn and coupled in combination to get something of the same random chorus effect of a pipe organ.  Individually some of the voices are quite beautiful and very useful on A Voicing, on B Voicing, or both.  Then again, some of them are so dull or shrill in tone that they have little use on A or B, dated technology being largely responsible.  Curiously, the Pedal division of 16 stops, relatively few for an instrument of this size, is supplied with 6 stops of superoctave (4-foot) pitch or higher but only 5 stops of that all-important unison (16-foot) pitch.  The pair of add-on Allen modules have largely made up for insufficient suboctave manual tone, supplied additional power, and have expanded the instrument to 92 stops and 115 equivalent ranks.  

STOP LIST

Allen MDS expander II module A voices appear in blue.

Allen MDS Division II expander module B voices appear in black.

GREAT (26 + 1, +1 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, [10-2/3' Gross Flute, *16' Bassoon]

SWELL (16 + 1, +1 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, [16' Dulzian, *8' Hautbois]

CHOIR/POSITIV (14 + 1, +1 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, [8' Hautbois, *16' Bourdon]

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 + 1, +1 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, [10-2/3' Principal, 16' Principal]

COUPLER PISTONS

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*

*Manual to Pedal couplers duplicated with toe pistons

CONSOLE SHOWING ONE OF TWO ALLEN MDS EXPANDER II VOICE MODULES

CONSOLE LEFT STOP JAMB

CONSOLE RIGHT STOP JAMB