May. 12, 2016

Conn Speaker Pipes

Conn speaker pipes were first developed and patented in the late 1950's as a new invention to enrich the sound of the Conn electronic organ (patent held jointly by C.G. Conn and Curt Wolfanger, a Conn engineer), and many thousands of these units were manufactured and shipped all across North America and the English speaking world all through the 1960's.
These units enjoyed significant popularity and were a hot seller back in the day to where some franchised Conn dealerships could only sell them on back-order; they were formed of a vertical array of cylindrical anodized metal pipe tubes of differing lengths and scaled diameters permanently tuned to resonate with various frequencies of the musical scale; these were mounted vertically on the baffle of a walnut chest inside of which either one or two pair of 6 X 9 inch oval speakers were arranged end-to-end; these speakers projected sound waves upward against the baffle which cushioned the sound as individual frequencies found their own pipes and caused them to resonate.
In the case of the Conn organ, these speaker pipes were meant for connection with the main (pulse channel) manual voices only (diapason, strings, reeds), not the tibias or Pedal voices.
In some Conn organs there was a set of screw terminals located at the bottom left of the back of the console just below the box with the Leslie socket; these terminals were for connection of the Conn pipes (in parallel) using an audio cable ending in 14 or 16 gauge bare wire; usually there was also a small, 3-way toggle switch on the console to select internal speakers, pipes, or both; with both switches in the "on" position they were putting a 4 Ohm load on the console's internal amp.
These Conn speaker pipes came in several styles:
Model 144-2, Right elevation, only one pair of 6" X 9' inch oval speakers, 28 pipes in 2 rows of 14 each;
Model 144-3, same, with Left elevation;
Model 145-1, Center elevation, two pair of 6" X 9" oval speakers, 48 pipes in 2 rows of 24 each;
Model 145-2, same, with Right elevation;
Model 145-3, same, with Left elevation;
Model 146-2, Right elevation, two pair of 6" X 9" speakers, 12 pipes in single row;
Model 146-3, same, with Left elevation;
The 6" X 9" Cletron speakers used in all seven styles were 8 Ohm each and wired in series parallel to provide an 8 Ohm impedance for the entire unit save for the smaller 144s, which were 4 Ohm.
The pipes of the 144s and 145s were tuned to resonate from around 200 Hz (tenor G) on up; the 146s were designed to resonate about an octave lower than that, filling in the remaining notes of the manual 8-foot octave.
The 144s were known as "mini-pipes" and had only one pair of 6" X 9" oval speakers.
The 145s were the only models offering center elevation (photo), the others being available only in Right or Left elevation types.
The 12 pipes of the 146s were constructed with cosmetic notches about a fourth of the way up, all on the same side, this merely to enhance the visual perspective by simulating the appearance of real metal organ pipes.
These units are inefficient compared with the power needed to run them; the only place from which the sound from the speakers can be heard is from the top of the pipes, their frequency range is limited, and their effects can be easily swamped by turning up treble volumes of other amps; this is all part and parcel of their design however, which is to enrich and supplement the organ's other direct beam loudspeakers already providing proper dB gain and reproduction of bass frequencies.

The dimensions of these units were as follows:
144 Models -- 21.5" W, 8.25" D, 29-7/8 H, Wt. 17.5 lbs.
145 Models -- 42.5" W, 8.25" D, 34"H, Wt. 18 lbs.
146 Models -- 42.5" W, 8.25" D, 63.5" H, Wt. 40 lbs.
Finishes: choice of gold or silver anodized pipes.

As stated, the sound producing portion of the Conn pipes were the 6" X 9" inch oval speakers fully enclosed in the walnut wooden base (photo); the 145s and 146s with their 4 speakers had an impedance of 8 Ohms (2 pair of 8 Ohm speakers, each pair wired in series parallel), whereas the 144s with their two 8-Ohm speakers were wired in parallel with a 4 Ohm load.
The wooden base contains no amplifier, as some have wrongly supposed; the speakers are passive and require about 40 watts of amplification power to operate.
Each pipe, while permanently tuned at the Conn factory to resonate at a different frequency of the musical scale, is able to resonate either as a fundamental or a harmonic upper partial tone.
Conn engineers had a demonstration of this where a small microphone could be dropped inside any given pipe; this microphone was connected to a regular guitar amp; they used a set of 145 pipes labeled as to their tuned pitch; while holding down middle "C" on the organ, the microphone would be lowered into ANY "C" pipe, and a "C" was heard coming from the guitar amp; then, while still holding middle "C", the microphone would be lowered into a "G" pipe, and one would hear a "G" [3rd harmonic, or 2nd upper partial tone] coming from the amp, and likewise with an "E" pipe, an "E" [5th harmonic, or 4th upper partial tone] would be heard coming from the amp; the sound emitted was non-directional; engineers also noted a very slight bit of reverb after the key was released as the sound within the pipes quickly dissipated.
Additionally, when the speakers were energized by held note(s) from the organ, the column of air in each pipe had to be put in motion before the sound could escape, resulting in the volume building up gradually before the tone blossomed out the top of the pipes in all directions; as the metal walls of the pipes which were tuned to the fundamentals of the note(s) being played would begin to resonate the other pipes tuned to the harmonics of those notes also would resonate; the result of all this resonating and pneumatic action within the walls of the pipes was a harmonically enriched wall of sound lacking the beam effect produced by ordinary cone speakers alone -- and, when the keys were released, the column of air within the pipes would not come to rest immediately, allowing the tone to linger for a minute split of a second before dying away completely.
These same acoustical effects, while subtle, cannot be duplicated merely by adjusting equalization or the treble control of an amplifier.
These pipes were of a fixed tuning but could be connected to play through ANY make or type of electronic organ; they could be positioned to stand vertically or placed on a shelf horizontally, like real horizontal trumpet organ pipes, with the weight of the chests making them stable enough for the pipes not to require supporting bracing.
Some individuals who own the 146 pipes have reported that these longer pipes resonate better when the cosmetic notches on them are closed with tape.
These units have no input jacks; the way they're hooked up is that a two-conductor audio cable connected with the console or external speaker cabinet and ending in bare wire is attached to the pair of screw terminals at the bottom of the pipe chest, each chest thus receiving a single mono channel of audio.
Back in the day Conn made a pipe connection interface box that was intended to help compensate for the lower efficiency of these speaker pipes and to provide easy switching between the console speakers and the pipes; it was a nice thing to have, but was not really necessary.
Hooking up these units to a Conn or any other electronic organ today presents a consideration of critical importance called impedance (the resistance offered by the circuit to the transmission of an electrical current).
Every amplifier connected to a speaker system is rated for a minimum impedance load (in Ohms); in Conn organs the simplest way to attach these pipes was to hook them up in parallel with the main pulse channel for the diapasons/strings/reeds and have them powered by the console's internal amplifier; it's important to understand however that connecting a set of Conn pipes in parallel like this effectively reduces the impedance load to the console's internal amp which is already powering the rest of the console's self-contained speaker system.
NOTE: When you put 2 resistances (impedances) in series, they total (for example, a pair of 4 Ohm cabs wired in series (i.e., with separate audio cables to each cab from the amp) results in an 8 Ohm load for the amp (4 + 4 = 8 Ohms); but when you parallel 2 resistances they total in reciprocal, thus splitting the load and effectively lowering the resultant Ohms; while the formula for calculating this is a bit complicated, when you parallel 2 resistances of the same amount, the effect is, you get half; the same 4 Ohm cabs daisy chained in parallel (only one audio cable from the amp), for example, results in only a 2 Ohm impedance (1/4 + 1/4 = 2/4 = 1/2 = 2 Ohms, which is well below the 4 Ohm minimum rating of most amps.
Hooking them up this way will make the amp work harder and, if the circuit's impedance is below the amp's minimum Ohm rating, the amp will heat up and get fried; thus how the Conn pipes are hooked up makes all the difference in whether or not the amp powering them will survive.
Since according to Ohm's Law the voltage in the circuit is the product of the current (in amps) and the impedance (in Ohms), and since the wall socket voltage remains constant, whenever speaker units are paralleled the impedance load is reduced and the current in the circuit increases; this, again, as stated, makes the amp run hotter, and if the Ohm load is below the amp's minimum rating the connections will fry the amp and ruin it.
Conn solid state amplifiers were not quite as particular about impedance as tube amps were, but, like all amplifiers, they were rated for a minimum 4 Ohm load.
REMEMBER: As cabs are daisy chained one to another they're being added in parallel and the Ohm load always drops, so, one would never want to run a load that the amp is not rated to run at; again, the lower the Ohm load, the harder the amp has to work.
When Conn pipes are in the best condition one hears up close a certain something that wasn't there before -- a subtle brightness in and spatial dispersion of the sound -- but since these units are now 40 to 50 years old, and dust, dead insects, pet hair, and other debris can accumulate on the upward facing speaker cones, one may not get the best results without taking the units apart, vacuuming and cleaning them up at least, and even replacing the speakers if they're spoiled.
The usual choice for those owners who have done extensive renovating of these units has been 6" X 9" oval car audio speakers from suppliers like Parts Express; today's replacements are all 4 Ohm however (8 Ohm 6" x 9"''s are no longer made).
Since Conn used 8 Ohm speakers specially made by Cletron in these pipe units, if the wooden base is retrofit with new speakers the wiring needs to be adjusted to make sure the new hook-ups still put a decent (8 Ohm) load on the amp.
It's important for owners and technicians to understand and appreciate that this invention operates on the principle of sympathetic resonance, that it sacrifices some audio efficiency in order to obtain certain unique acoustical effects including enriched harmonics and the same kind of softened attack and decay characteristics associated with the real sounding organ pipes.
When these units are compared up close and side-by-side with gently driven direct beam loudspeakers a perceptible difference is heard; where distanced from them as in a large hall or church setting that difference is dissipated somewhat, but in the smaller setting of a home or den the Conn pipes impart audible features to the sound which are truly singular.
In one application, when a 145 and 146 unit were both hooked up to the same console running on dated technology and placed within a few feet of the bench, ALL of the stops sounded brighter to the player, the upperwork was more assertive, the reeds had a much keener edge, and it became possible to secure colorful and balanced ensembles with fewer stops.
These units also contribute much to the sight perspective, have always been in limited supply, and today are still hard to find among private sellers; their size often allows them to sit on top of the console with the rack up, and they do look awesome there; pricing of them these days seems to be all over the place depending upon their condition as it seems they're easily damaged during shipment and not very amenable to shipping given their shape.
As far as speaker systems go in general, these units are not meant, and were never meant, to be known for actually reproducing sound; their frequency response is limited to a narrow midrange band, and their dB output is deliberately low vs. power consumed simply because most if not all of the sound doesn't get out of the wooden base -- it all emerges at the tops of the pipes pointed at the ceiling.
Those who test this invention by swamping it in an avalanche of other direct beam loudspeaker sound particularly with high treble boost are prone to wrongly assess its purpose; this product, while it is certainly a unique souvenir of a time when an analog electronic organ was something of a novelty, was never ever, repeat never, designed wholly "for show" rather than actual function.
Musicians these days would not be spending, in some cases, hundreds of hours, traveling hundreds of miles, and spending hundreds of dollars plus a good deal of elbow grease searching to locate these preowned units, obtain them, and clean them up and restore them if, after they were brought home and hooked up, these speaker pipes did nothing but look pretty.
If the user knows how to test them, listens for the audible difference they make in the quality of tone, and that difference happens to be satisfying, then it isn't fake at all -- it is nothing of the kind.
It is reality.