Automatic drum tuner |
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申请号 | US13087679 | 申请日 | 2011-04-15 | 公开(公告)号 | US08283544B2 | 公开(公告)日 | 2012-10-09 |
申请人 | Daniel Zuffante; Vishal Kumar; Reid Ellison; Edward Joseph Baronowski; Emmanuel S. Milienos; | 发明人 | Daniel Zuffante; Vishal Kumar; Reid Ellison; Edward Joseph Baronowski; Emmanuel S. Milienos; | ||||
摘要 | Methods and systems for automatically tuning a drum are disclosed. In some embodiments, the methods and systems include the following: (a) exciting a drum head to cause it to resonate; (b) sensing a vibration frequency at one or more points relative to each tension rod; (c) determining a global average vibration frequency of the vibration frequencies for the points relative to each tension rod; (d) comparing the vibration frequencies of each of the points relative to each tension rod to the global average vibration frequency to determine a correction value for each point relative to the global average vibration frequency; (e) automatically turning each tension rod based on the correction value for the relative points; (f) automatically repeating steps (a)-(e) until each of the vibration frequencies of each of the points relative to each tension rod is substantially similar; and (g) automatically turning each tension rod in a uniform direction substantially simultaneously. | ||||||
权利要求 | What is claimed is: |
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说明书全文 | This application claims the benefit of U.S. Provisional Application No. 61/324,637, filed Apr. 15, 2010, which is incorporated by reference as if disclosed herein in its entirety. The most common way to tune a membranous percussive musical instrument usually involves manually adjusting the tension of the membrane in order to achieve the desired frequency. In the case of a drum, the resonant frequency of the drum depends on the tension of the membrane or drum head, which is stretched over and joined with a shell by a hoop/ring that is fastened to lugs on the shell by uniformly spaced bolts, which are commonly referred to as tension rods. The first step in tuning a drum is to “clear” the drum head. This process involves equalizing the tension of the drum head near each tension rod to achieve a uniform vibration throughout the entire drum head. Once this is complete, the drum has uniform resonant properties, which result in a clear tone when excited, and can then be tuned to the desired frequency, i.e., note. This process is fairly time consuming and relies on the expertise and judgment of the user to achieve an accurate result. There are approximately 18 million people in the United States who currently play drums. Unlike other instruments, for example a guitar, drums are very difficult to tune to a desired note. In order to tune a guitar, the tension in each string is adjusted separately in order to achieve the correct frequency. A drum cannot be tuned the same way. A drum head has six or eight tension rods, which sit on the outside of the drum head and are joined with corresponding lugs that are on the outside of the drum shell. When one of these tension rods is tightened or loosened, it will change the tension in the drum head. When the tension at one of these tension rods is adjusted, it will affect the entire drum head, not just the area of the drum head adjacent the particular tension rod. This is a time consuming and imprecise method. Because of the complexity of tuning a drum, there is very little literature beyond the instructions for manually tuning a drum. An example of step-by-step manual instructions for tuning a drum include the following: 1. Choose a tension rod to act as your model tension rod, this will be how you know you have tuned all the tension rods on each tuning pass; 2. Tap the drum head with the stick gently, approximately 2 inches from the tension rod in the direction of the center of the drum, this is your test tone; 3. Continuing with the tension rod on the opposite side of the drum from the model tension rod, tap on the head gently. Using a standard drum key, a hand tool for turning tension rods as known in the art, turn the tension rod until the tone is the same as the original tone; 4. Moving in a star formation tap on the drum head by the next tension rod; 5. Repeat step 3; 6. Repeat step 4 followed by step 3 until you have returned to the model tension rod; and 7. Now test the tone of the center of the drum. If you are satisfied with the tone, then you are done. If not satisfied, then again starting with the model tension rod, turn each tension rod one-quarter turn moving clockwise around the drum until you reach the model tension rod again. Existing products that assist a user to tune a drum reliably using resonant frequency technology are not autonomous and force the user to manually tune the drum. One such product acquires the frequency at each tension rod by using a speaker to drive the drum and a microphone to measure the resonant response. It stores all of the frequencies as the user manually rotates the device from tension rod to tension rod and chooses a mean value that one must tune to in order to clear the drum head. The user can then choose a frequency that he or she wants and turn the lug until the device says it is there. However, this requires that the user iteratively repeat this process of rotating and collecting data until he or she has achieved the desired result. Another known product is an adjustable release torque wrench. The wrench releases at a mechanically determined torque limit. The user, therefore, must turn each lug until the wrench releases, resulting in the torque in each lug being equal. The downside of this design, however, lies in the assumption that torque will directly correlate to tension on the membrane. This would only prove successful if the friction in each lug was equal. In actuality, and as proved in testing, the friction in each lug will vary significantly depending on the level of lubrication and tolerance fit of the actual thread fit. The user is therefore limited to an inaccurate method that relies on unrealistic assumptions. Some embodiments of the disclosed subject matter include an automatic drum tuner system. In some embodiments, a spring-loaded, adjustable, locking mechanism that is rotated via engagement with a shaft of a motor is used to ensure the system mounts onto each of the drums tension rods. The locking mechanism is independent of the motor shaft's position. The system is supported by a mechanical frame including adjustable length arms, all with locking pins. In addition, a bipolar stepper motor is mounted to each arm. Geared up 30 times in some embodiments with a worm gear to spur gear connection, the mechanism will allow for the usage of a lower profile stepper-motor. A solenoid mechanism mounted to the frame is configured to strike the drum head to cause it to resonate. In some embodiments, instead of striking the drum head, a speaker is used to excite the drum head and cause it to resonate. Piezoelectric transducers mounted in proximity of each tension rod measure the local frequency near each tension rod. A fast Fourier transform (FFT) or similar algorithm is performed on each output signal to calculate the resonant frequency at that specific point on the drum membrane. Once the fundamental frequencies are calculated for all locations, clearing of the drum head begins. A control system reads the frequencies and measures the peak energy values of the first four fundamental modes. Each of these values from each piezoelectric sensor is stored into a matrix. Using this matrix, a global average is established and each tension rod is assigned a positive or negative value relative to this global mean. Each stepper motor then completes a predefined series of steps either clockwise, or counterclockwise, depending on the relative value assigned to that tension rod. Using an iterative process, the system directs each tension rod to turn in an appropriate manner until the drum head is “clear.” Once cleared, each motor can be simultaneously activated in a uniform direction to change the overall frequency, i.e., musical note, of the drum head. The drawings show embodiments of the disclosed subject matter for the purpose of illustrating the invention. However, it should be understood that the present application is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein: Referring now to In some embodiments and shown in Still referring to In some embodiments, each of tension rod adjustment members 116 includes an external housing 142. Also, in some embodiments, connection ends 118 are spring-loaded, which causes each of the connection ends to retract into a respective housing 142 when not aligned with a respective one of top ends 120. As mentioned above, handle 138 is used to disengage first and second gears 128 and 132. Handle 138 can than rotate freely, turning a respective one of connection ends 118. Once connection end 118 matches top end 120 of tension rod 110, it will snap into place and handle 138 can then be released. Since handle 138 is spring loaded, it will retract and cause the automatic engagement of first and second gears 128 and 132. Referring again to In some embodiments, vibration sensors 144 are not positioned adjacent one of tension rods 110, e.g., sensors are placed half-way between each tension rod instead. In addition, there need not be a 1:1 correlation of vibration sensors 144 to tension rods 110. In some embodiments, the number of vibration sensors 144 is greater than the number of tension rods 110. Regardless of the number of vibration sensor 144, the signal coming from each sensor is localized to achieve a gradient of the resonance. Referring again to As shown in In some embodiments, system 100 includes a mechanical frame 150 that has adjustable and lockable arms 152 joined by a center portion 154. Each of arms 152 is configured to receive at least one of tension rod adjustment members 116, one of motors 118, one of vibration sensors 144. Center portion 154 is typically configured to receive automatic excitation member 146. In some embodiments, system 100 includes a visual display 156 in communication with each of vibration sensors 144. Each visual display 156 displays the vibration frequency measured by an adjacent one of vibration sensors 144 and can be any known display technology in the art suitable for such an application. Visual display 156 is typically mounted to housing 142. Referring now to The disclosed subject matter offers benefits over known designs. Our drum tuner will automatically equalize the tension in the drum head and allow the user to raise or lower the pitch. The automatic drum tuner however, will be displacement controlled, not force, and will deliver a step that directly corresponds to the local measured frequency, and therefore tension, in the drum membrane. The consistency, accuracy, and affordability of the automatic drum tuner will surpass all existing drum tuners on the current market. While common in practice, manual drum tuning is tedious and time-consuming, and achieving accurate pitch on a consistent basis is highly dependent on the user's expertise and judgment. This technology describes an electromechanical device that, when fixed to a standard sized drum, e.g., such as a tom, will automatically tune the drum tom according to user specifications. In contrast to manual tuning (which adjusts each drum head lug in a serial manner), this portable and autonomous device first equalizes the tension of the drum's membrane throughout the entire drum head, and then tunes the drum to the desired frequency by simultaneously addressing all drum head tension rods and lugs. Although the disclosed subject matter has been described and illustrated with respect to embodiments thereof, it should be understood by those skilled in the art that features of the disclosed embodiments can be combined, rearranged, etc., to produce additional embodiments within the scope of the invention, and that various other changes, omissions, and additions may be made therein and thereto, without parting from the spirit and scope of the present invention. |