Patent Application
20120097009
The inventions described below relate to the field of percussion musical instruments, specifically that of hybrid acoustic and electronic drums.
Acoustic drums have existed for thousands of years. Modern materials have created drums with improved characteristics and sound over their ancient predecessors.
Electronic percussion instruments have been known since the late 1970's. They offer a wider range of potential sound variety than acoustic drums, as well as the possibility of quiet operation in situations where the high sound level of acoustic percussion is undesirable.
Acoustic drums have different playing characteristics than their electronic counterparts requiring a musician to translate their style from an acoustic drum to its corresponding electronic instrument.
A hybrid drum as described below combines the characteristics of both acoustic and electronic percussion apparatus enabling a musician to have a single instrument and have either acoustic or electronic output. A hybrid drum includes a multilayer drum head with a built-in force sensing resistor (FSR) sensor such that the FSR drum head replaces the drum head of the acoustic drum and can be used to perform acoustically and or electronically. The FSR sensor is built into a double layer, double-head acoustic drum head, wherein one layer of the double head system has the FSR element printed on it, while the other layer of the double layer head has the inter-digiting conductive fingers printed on it and facing the FSR element. A conductive tail extends from one of the drum head layers and is operably connected to an electronic module secured to the drum shell.
A hybrid drum includes a drum shell and a multilayer drum head having at least a first layer and a second layer, the drum head is secured to the drum shell by a rim using a plurality of tension rods with the first layer secured to the second layer and the second layer secured against the drum shell, enclosing the drum shell. The first layer of the multilayer drum head has an upper surface and a contact surface, the upper surface for contacting the implements for generating the musical sounds such as drumsticks, mallets, fingers and hands. The contact surface of the first layer including a deposited layer of electrically conductive material forming a portion of a force sensing resistor. The second layer has a lower surface and a contact surface and a contact tail. The contact surface engages the contact surface of the first layer and completes the force sensing resistor, the force sensing resistor thus formed is operably connected to the contact tail. The second layer lower surface engages the drum shell and at least partially encloses the drum shell. An electronics module is secured to the drum shell and is operably connected to the FSR sensor or sensors through the contact tail.
Hybrid drum 10 of
Force sensing resistor sensors (FSRs) are comprised of a thick-film semiconducting material deposited on a non-conductive substrate. The material exhibits changes in its electrical conductivity, proportional to the amount of force (pressure) applied to it. Typically, electrical contact is made to the FSR material by means of conductive traces printed above or below the FSR layer and/or on a second substrate, the FSR and trace surfaces positioned facing each other and in intimate contact. Unlike piezo material, FSRs can respond to constant steady-state pressure, since they are electrically resistive as opposed to capacitive. A wide variety of FSR sensor functionality is possible depending on the geometries of the elements. As FSRs are resistive instead of capacitive, they offer virtual immunity to crosstalk. Positional information is easily derived from FSR-based sensors, either by placing multiple FSR areas within the striking surface (usually on a common substrate) or by configuring the conductive traces such that a “potentiometer” topology is created, allowing sensing of both pressure and (continuous) position. The latter approach, while providing continuous position information, requires switching of the circuit topology between force and position measurement configurations, and this will add complexity.
Referring now to
Referring now to
Referring now to
For some systems this might be enough, but frequently some form of processing is required since the biased sensor alone is a high impedance and unable to drive a more common lower impedance input or one expecting a higher voltage excursion. Initial processing may be provided on circuit board 24 or on some other suitable component of electronic module 18. The simplest of these is an amplifier with a high impedance input, such as a field effect transistor (FET) or an op-amp based amplifier. Both provide the required high impedance input and voltage gain. This can be enough to feed signal 26 into a drum sound module, for example, that are often designed for a piezo electric sensing device.
For systems that are able to detect the various features of a pulse (for instance, rate of rise, height, width), a simple amplifier is not always suitable since the amplified pulse profile follows that of the sensor. Since the sensor may not produce pulses that are expected by the module input circuit, a pulse shaper is needed. Rather than using a traditional pulse shaping circuit, the sensor voltage pulse may be directed into a digital system that is able to sense the pulse. From the various features of the sensor pulse, it is able to synthesize a parameterized output pulse to match the expected pulse.
Further, many physical sensors are implemented with a number of distinct regions, each providing a pulse. The above digital system can be extended to provide multiple input and outputs to match the distinct regions. Referring now to FIG. 9, FSR resistor layer 34 includes several distinct drumhead regions are identified for example, center zone 36, main zone 38 and rim zone 39.
Thus, for a number of different configurations, an FSR based drum head can produce pulses to satisfy the input characteristics expected from other sensors but with the advantages of the FSR.
Referring now to
With a shunt mode sensor configuration as illustrated in
Referring now to
Referring now to
In use, first layer 20 is superimposed over second layer 21 and is oriented with first layer contact surface 20C facing second layer contact surface 21C. With drumhead 13 formed with this orientation, hybrid drum 10 with hybrid drumhead 13 may be played by a musician as an acoustic drum by striking upper surface 20U of first layer 20 within playing zone 25.
It may also be necessary to vary the physical and or electrical parameters of the interdigiting fingers of the trace layer to accommodate different drumhead tensions encountered across the surface of an acoustic drumhead. For example, center zone 36 will have less tension than rim zone 39 leading to potentially unmeasurable hits if both zones have the same trace dimensions. It may be necessary to change trace dimensions, or another suitable parameter, over different areas of a drumhead to provide accurate and unambiguous sensing of the hits to the drumhead. In addition the physical and electrical parameters of the FSR layer such as thickness and or resistance profile may also be varied to provide different performance parameters. The physical and electrical parameters of a linear pot configuration may be varied to provide different performance parameters.
While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
