Sitar

Electric Guitar

Acoustic Guitar

Electric Bass

Acoustic Bass

Piano

Veena

Urhu

Mandolin

Violin

Cello

Banjo

Auto-harp

Double Bass

Harp

Pedal Steel

Kalimba

Psaltery

Zither

Baglama

Swarmandal

Resonant Steel/Iron everyday objects

+ other instruments with steel strings not yet tested

*All listed above must be of the steel string variety

-Sine wave-like string resonance + harmonic overtones

-Pitch modulation / pitch bending behavior

-Pseudo feedback tonalities

-Polyphonic “magnetic strumming” of strings can be achieved by starting the disc at a lower RPM and pulsing the motor faster, either with the “Rev Button,” the “Thumbwheel,” the “Touch Plate,” or the “Control Voltage Input”. Magnetic Strumming not only affects the fundamental pitch of a string but can be heard affecting and accentuating various harmonic overtones.

-”Pitch blending” interactions between dominant resonant string(s) pitch and brushless motor speed. As the motor/magnet RPM speed comes into “alignment” with the resonance of surrounding strings, you will sometimes hear two pitches beating against one another before sliding/bending into place, resulting finally in a swell in volume and greater string vibration. This can be happening to multiple strings simultaneously.

-Multiple strings can be affected while the RPM is steady. For example, you may hear the fundamental pitch of multiple strings resonating while higher harmonics are activated on others. Different RPMs can provide different additive harmonic combinations between the same strings (or chord) being held.

-There are three small magnets and three larger magnets aligned in overlapping triangular patterns on the disc. The smaller magnets help provide higher-order harmonics and the larger magnets help create greater string movement and lower-order harmonics.

-Higher RPMs often lead to higher strings resonating and higher harmonic overtones. Lower RPMs often lead to lower strings resonating and less harmonic overtones.

-When using Ferrous with an electric guitar (or other instrument with pickups) the preferred placement is above the fretboard. Keeping the rotating disc at least 5” away from magnetic pickups ensures less of the motor sound mixing with the resonating string sound (unless this is a desired effect).

-When using an electric guitar, placement lower on the neck can create interactions between magnetic disc and pickups with overtones of resonating strings. When placed directly over magnetic pickups, pitch is derived from the rotation of the magnets, and the volume is derived from the distance between Ferrous and the pickups. **Never place the magnetic disc directly onto pickups because this can damage them.

-It can take some time to get used to placement, distance, holding methods and how your instrument and chord changes interact with the RPM/Speed of the spinning disc. After you familiarize yourself with this interplay the results will be much more rewarding and responsive.

-A very important thing to note is that every time you change the RPM on Ferrous or a note/chord on an instrument the interaction between them has shifted. The results between instrument to instrument will also be different based on specifics like string thickness, string iron content (more is better! some Cello and Violin strings have low Iron content we've found so less movement).

-Hold Ferrous about 1/2” (1.3cm) from the steel strings while the disc is rotating. Move closer or further away to adjust volume/resonant strength. When placed close to the strings the result can be strong string vibrations resulting in the strings colliding with the fret board or the rotating disc.

-When Ferrous is held close to the strings of an instrument you will feel the strong magnetic pull. For guitar, one stabilization method is to use the thumb and pointer finger by resting them on the outside edges of the fretboard. This acts as a way to ensure proper distance between the strings and rotating disc.

-Pulse speed from low to high to 'magnetically strum” multiple strings.

-Use the threaded standoff (with rubber tip) as a rest between strings on a guitar fretboard for more relaxed and controlled playback.

-By holding Ferrous 90° to the neck of a guitar, one can use their ring finger and pinky to modulate speed with the touch-plate below. To do this you should set the RPM slow.

-Hold Ferrous near magnetic pickups to hear bass-heavy distorted beating of the magnets rotating. RPM also defines pitch of resulting sound.

-When using Ferrous with exposed piano strings, the magnetic pull can cause the rotating disc to come into contact with the strings causing a loud buzz. This can also happen when the resonance builds to such a degree that the strings vibrate far outside of their normal bounds and contact the underside of the unit. A helpful method for stabilizing height is to slightly protrude the thumb and pointer finger past the flat bottom surface of Ferrous and rest them on the surrounding strings. This way the strings directly under the disc are left free to move. There are also 4 rubber feet that come with Ferrous. To attach them, remove one of the 4 silver screws place the rubber foot over the hole with the "cup" facing upwards and re-set the screw through it before moving onto the next screw/rubber foot.

Size: 5.25” x 2.5” x 1” / 13.33cm x 6.35cm x 2.54cm

Weight: 0.4 lbs / 0.15 kg

Materials: Birch plywood encloser + PCB/Fiberglass interface and disc + neodymium magnets + repurposed hard drive motor + negative space cutouts for exposed battery access.

Controls: Thumbwheel for speed adjustment (+ on/off). Pushbutton for momentary full speed RPM or pulse. Touch-plate for pressure sensitive speed control. Control Voltage input for external speed control.

Visual: Downward facing yellow LED for string illumination

Assist 1: A provided threaded standoff with rubber tip can be added near the LED as a fretboard rest between strings. This stops the disc from touching guitar strings and provides a more controlled experience.

Assist 2: Four small rubber feet which can be added to the four screws using a phillips head screw driver. These can be useful for instruments with many strings like Pianos and Zithers. The feet can rest on surrounding strings as the disc resonates strings below.

Power: **9v Battery

**Ferrous ships with a rechargeable 9v battery. As a bonus the (mini)USB charging port is left exposed so you don’t have to remove the battery during charging. Be weary of some 9v Rechargeable batteries (and particularly those that are less than 1300mAh) as some may not be able to provide enough power to properly power the brushless motor. ***Also note that 9v Carbon Zinc batteries do not supply enough power!