User Manual (work in progress)

The ins and outs

Input:

The two 1/4" jack inputs require an amplifier pushing out 100w @8ohms per side to for the driver bridges.

Output:

The two 1/4" HiZ outputs com from the guitar pickups and need to plug into gear designed for high impedance.

The Controller:

The controller is a collection of extra gear that handles the input and output of the Resonator and can vary depending on the situation. I recomend using a small rack unit to keep all the gear in one place. A compact mixer on top can handle the variety of inputs and controll their panning and volume before being sent to a rack mounted power amplifier. The signal then leaves the controller and goes to the Resonator inputs, and comes back to the controller from the resonator outputs. Signal processing of the output is the most variable part of the setup and depends entirely on what gear is available and what the situation is but starting with a Di box gives the most flexibility. 

Different ways of resonating.

The resonator strings and the floating driver bridges should be thought of as a complete system, where each part influences the other back and forth. Its not just the driver bridge driving the strings, but also the strings driving the bridge. This interplay creates many complex interactions that affect the way any given input sound will affect the strings. 

The most significant factors that effect the resonance are the frequency range, amplitude, and the attack  properties of the input signal. 

Frequency response:

A single note sine wave from a synth will have the most precise resonance, where the one string in tune will resonate far more than any other in a relatively predictable way. Strings of higher frequency will also resonate along to a lesser extent, primarily the string one octave above, and then also the octave above that with the perfect 5ths inbetween also resonating a bit. 

The resonator strings have a gradual attack time because it takes a number of oscillations before the string gets to its peak resonance, and as is it increases in amplitude so do the overtones from the buzz bridge. As more and more of the string makes contact with the curve of the buzz bridge more and more overtones are triggered in the string adding to the complexity of the sound. As the string in unison with the input sine wave resonates to its maximum it in turn pushes back on the driver bridge more and more which further excites other strings in harmony. 

If the resonator is being driven at one frequency then the whole system of the strings and bridge has quite a bit of momentum so if another frequency is played that is either too close in frequency,  or at an odd interval that doesn't harmonize well then it will take time for the system to fall into smooth resonance at the new frequency. If this period of chaotic resonance is not desired and you want the resonator to follow a chord change that goes down one semitone then stopping the input signal early to let some of the energy decay before driving the bridge with the new frequency will create a much smoother transition. 

Pitch shifting the input signal small amounts will also disrupt the system and create chaotic resonances. 

Attack time:

Percussive sounds with a fast attack and decay tend to have a more chaotic effect on the strings which results in a more reverb like behaviour. This can be modified if strings or drums are carefully tuned to one another  which will accentuate some more pronounced resonance. For example repeatedly hitting an undampened floor tom tuned to a specific note will create a distinct resonance in the strings of the same note.

When using a simple sine wave as input, slowing the attack time can actually quicken the attack time of the resonance because short sharp changes to the frequency of the driver bridge oscillations have a percussive effect that can disrupt the smooth resonance and cause a delay in achieving peak resonance. 

Drive levels and EQ.

The amount of energy put into oscilating the bridge effects the amplitude of the resonance in the strings, and due to the way the buzz bridge works this also affects the tone of the strings. There is a wide dynamic range of output volumes from the resonator, especially when single trings are heavily driven. With lower drive volumes ther is a wider responce across more strings with less dynamic peaks. Depending on the sound source the EQ of the input sound also has a strong effect here. 

When using the signal from an acoustic guitar for example, turning up the bass will make the root note resonance more prominet and also increase the dynamic range as the resonance of the root notes will be more pronounced. Turning down the bass, or increasing the low mids will widen the response and make the resonator more sensitive to the overtones and higher notes in any chords. The high frequency in most cases does not have much effect on resonating the strings because high frequency vribration does not cause resonance in lower octaves. There is too much mechanical resistance in the strings for such high frequences to onscilate the bridge with enough amplitude to really case much resonance in the strings. 

High frequency input does tend to travel down the strings in more of a reverb type way, where the input audio signal is heard by the pickups after travelling back and forth along the strings. This is sort of like a one dimensional plate reverb sound and is often undesired in which case cutting the high frequencies from the input signal is a good idea. 

The Resonator takes in sound just the same way as a stereo loudspeaker does, so it requires an approximately 100w amplifier to power it.
A simple home stereo amp will do the job fine, but I have found that studio monitor rack mountable amps are the most convenient. Using a higher wattage amp will be ok provided the volume is managed, but it should be noted that using an amp over 100w will pose a risk of overheating the driver coils. The aluminium Bobbins with cooling fins do a good job of dissipating heat under all normal operating scenarios but sustained excessive power input can overwhelm the cooling capacity and cause the coil to overheat. Thermally responsive paint on the coils gives a visual indicator to the operating temperature which should not exceed 90 degrees Celsius for any extended period of time. This is more than enough power handling to give very powerful resonance, and and more power beyond what is needed adds very little in terms of the instruments output.

Tuning.

Getting the resonator closely in tune with its source sound will have a big impact on the amount and quality of the resonance that will be achieved. Using a clip on guitar tuner, or tuner pedal can get you close, but it must be done by ear for good results. 

This means fine tuning by ear to the instrument being used to drive the resonator or for general use a synth or piano with a neutral even temperament is best. A simple sine wave synth with a slow attack and long decay will work well. Using headphones or speakers for monitoring play each note on the source instrument, then pluck that same note on the resonator and adjust the tuning accordingly. When you get close simply playing the source note while the resonator is active and adjusting the tuning of that string on the resonator while watching and listening to how much that string is resonating will get the best results. Using a sustain pedal with a synth helps to keep both hands free for this part. 

For live use a mixer in the controller setup that allows for headphone monitoring of selected channels to allow tuning onstage without sending the signals to FOH is a good idea. Just like a guitar, changes in temperature and humidity will cause variations in the tuning. 

Setup Diagrams

Controller in depth.

Input signal Pre amp.

A small mixer works best to take in all the possible audio sources that could be used and control the panning and EQ for drving the amplifier but a two channel preamp could be ideal in certain circumstances. A cheap mixer or preamp can be used because this audio is only sent to the driver and not heard directly, but it is important to have panning and EQ available. Panning can seperately control the audio going to the high and low registers, and the Low and Mid balance of the Eq has a strong effect on the way the resonator responds to sounds. 

Amplification. 

The one thing that the resonator must have, is an amplifier to drive the resonating. A home stereo amp can do the task, but a rack mountable stereo monitor amp is better for its simplicity, reliability and single rack unit size. 

The outputs from 2 X Hi-z guitar pickups.

The output of the reaontor is exactly the same as the output of 2 electric guitars, with one output for each register of strings. I recomend using a Rack mounded Di for maximum flexibilty of processing the high impedance output from the pickups, and from there anything from guitar amps and or pedals, to rack gear, or amp simulators or even entirely In the box digital processing can polish the sound up nicely.

Wiring and setup diagrams for some controller options

Servicing

Warranty.
All parts are covered by a standard 5 year warranty for repair or replacement of any parts that fail during normal use or due to manufacturing defect.
All parts are designed to be easily serviceable where possible and easily replaceable with basic tools for those parts which are custom fabricated should they need replacing.

Coils: If driven properly the coils should last a long time. Care should be taken to not overload the coils for extended periods of time as this will cause excess heat to build up which can burn through the enamel on the copper wire and cause short circuits in the coil, or over time degrade the Epoxy resin that holds the coil on the bobbin. The cast aluminium design of the bobbins and aluminium bridge clamp is designed to quickly conduct heat away from the coils and dissipate it into the environment, so having some airflow over the driver bridges is very important. 

Damper: Over time the cable that connects the damper bar to the foot pedal may stretch and need adjusting which can be done from the clamping screw on the foot pedal mounting plate. 

Strings: As the strings are not played like guitar strings and therefore dont corrode from sweat and dull from a build-up of skin and gunk they should last a long time. If the tone has dulled over the years then they can be replaced. We sell replacement sets of strings as sourcing 36 individual single strings would be inconvenient and unnecessarily expensive. 

Buzz Bridge: over time the buzz bridges will wear down from the vibration of the strings and will need to be reshaped or in severe cases replaced. This will require releasing the tension on all the strings and removing at least one of the riser post screws that support the Bridge plate