The present invention is directed, in general, to a microphone holder and, more specifically, to a microphone support system that incorporates vibration shielding and damping to substantially isolate a microphone from extraneous vibrations.
In modern music performance/recording, mechanical vibration effects on recorded/reproduced audio frequency program material are responsible for perceived (and measured) degradation of the natural transient response of all audio signals captured, stored, replayed, or reproduced by equipment of the prior art. It is a problem that exists at the system level, in all components of the system in one form or another.
The audio industry, since the inception of digital audio in the early 1980s, has faced criticism that digital recordings did not sound as good as their analog counterparts. Indeed, some fine quality recordings were produced by the technology of the late 1950's with analog recording and playback means. This was partially due to the prevalent design techniques used for microphones and microphone stands, along with the materials used in the wiring, and the design of enclosures and chassis. It was also partially due to a more direct signal recording and playback equipment path. That is, there were fewer pieces of equipment to contribute bad effects to the program material, and extra “processing” was not thought of as necessary. Additionally, since the effects of vibration, in some respects, are more detrimental to digital recording and reproduction than to analog processing, the analog recording/playback systems sounded better. In fact, they did indeed capture a better transient response in program material than did the newer digital recordings for reasons disclosed herein.
Microphones are the most susceptible link in the reproduction chain due to their proximity to the original sound source and their natural susceptibility to vibrations. They are self-evidently and inherently, the most sensitive component due to their function, which is to convert airborne vibrations sensed by the element(s) into low level electrical signals for further amplification, storage, analysis, or later reproduction. However, microphone designers have not successfully understood the issue of microphone enclosure vibrations that are also received from the environment, and how they translate into extra modulations which add to the sound already received and are converted by the main microphone sensing element(s). These enclosure-borne vibrations seriously degrade the signal received by the microphone sensing element(s). More specifically, it has been determined that the resonances of various materials comprising the microphone mounting mechanism(s) and stand assembly can cause smeared signal transients.
Common sources of vibration (unwanted inputs to the system) include the program material of interest, “monitoring” equipment used to listen to the desired program material during the recording/reproduction process, internal vibrations generated by power transformers or the mechanisms used to manipulate media (CD or tape transports) used to record or process the desired program material. Even air pressure changes caused by low frequency air handler equipment for HVAC systems (Heating, Ventilation, and Air-Conditioning) can cause vibrations to be introduced into the recorded/amplified program.
The degradation comes in multiple forms, depending on: (a) the type of equipment (analog or digital based signal processing), (b) location in the recording/reproduction chain (microphone or front end processing vs compact disc player playback and power amplifier combination back end processing), and (c) the relative magnitude of the vibration in relation to the signal processing being performed at that stage in the chain. Common effects of the various vibration sources include, but are not necessarily limited to: (a) data clock perturbations in digital systems as a byproduct of the reference crystal vibration (jitter, drift, modulation based on program material), (b) microphonic transfer of vibration to power supply lines which then subsequently modulate the desired program material as a product of amplification, and (c) microphonic transfer of vibration to the microphone electronics through the microphone stand/holder assembly and microphone wiring which then subsequently modulates the desired program material as a by-product of sensing and amplification.
Referring initially to
The major effect of the various vibration sources is the microphonic transfer of vibration to the microphone electronics through the microphone stand/holder assembly and microphone wiring. The vibrations subsequently modulate the desired program material as a by-product of sensing and amplification. In most cases little special care has been taken to isolate the microphone sensing element(s) (not shown) from the microphone body 111. In an embodiment considered to be among the best of the prior art, the microphone holder 140 comprises some form of elastic suspension bands 141 coupled between a circumferential ring 142 and the microphone 110. Various forms of this general method of isolation are disclosed in U.S. Pat. No. 6,459,802 to Young, U.S. Pat. No. 4,546,950 to Cech, U.S. Pat. No. 4,396,807 to Brewer, U.S. Pat. No. 4,194,096 to Ramsey, ostensibly to isolate the microphone 110 from floor-borne, low frequency vibrations. The above listed patents are hereby incorporated by reference. While it is desirable to isolate the microphone/stand combination from floor-borne vibrations, the methods of the prior art subject the microphone elements to significantly larger degradations from airborne vibrations through the microphone enclosure (the microphone body 111 or case) which is generally not protected in any way from airborne vibrations. Extraneous vibrations can be additionally magnified when the microphone (sensor) is suspended via these weblike mechanisms, as in the listed prior art, in an effort to isolate it from the low frequency vibrations transmitted from the floor. This is accomplished at the expense of exposure to the significantly higher levels and wider frequency spectrum of vibration levels available directly through the air. These vibrations must also be addressed in the quest to control the recording/reproduction process in an effort to preserve the transient response of the desired signal to be recorded or processed. With the prior art, the conventional microphone 110 receives, and inadvertently converts to an electrical signal, those vibrations it receives through the microphone body 111 and the microphone cable 160, along with the airborne vibrations sensed by the microphone element from the desired signal. Vibrations in the microphone stand/holder assembly also can cause very small movements of the entire microphone 110, and therefore the element(s) of the microphone while it is receiving the desired signal. Vibrations of the microphone stand 100 also cause a lever arm effect on the suspended microphone 110 which magnifies the effect of small vibrations in the microphone stand 100.
In most cases little special care has been taken to isolate the microphone sensing element(s) from the microphone body. Generally, the microphone itself is, in the presumed best form of the prior art, suspended in air via elastic webs, ostensibly to isolate it from floor-borne low frequency vibrations. While it is desirable to isolate the microphone/stand combination from floor-borne vibrations, the method of the prior art subjects the microphone assembly to significantly larger degradations from airborne vibrations through its enclosure (the microphone body or case) which is not protected in any way from extraneous airborne vibrations. Ideally, the best mounting mechanism would reveal the main (desired) sensing element(s) to the sounds to be converted into electrical signals, while keeping the body of the microphone, and therefore the remaining electronics inside it, isolated from extraneous airborne vibrations. With the prior art, the microphone receives and inadvertently converts vibrations it receives through its case and the microphone wire, along with the vibrations sensed by the main (desired) element from the desired signal. Consequently, any vibrations, including extraneous solid-body vibrations, received through the microphone body ill or its holding mechanism 140, stand 100, and cabling 160 get combined with the desirable sounds from an intended source impinging on the main microphone element (s); thereby the net combination of these signals becomes the overall signal produced by the microphone 110, microphone holding system 100, and cabling 160.
Accordingly, what is needed in the art is a microphone support system that does not suffer from the transmission of extraneous vibrations to the sensing element(s) of the microphone.
To address the above-discussed deficiencies of the prior art, the present invention provides a microphone support system that substantially isolates a microphone from extraneous vibrations comprising a base assembly, a microphone support rod, a microphone sheath, a microphone cable, and a microphone cable sheath. In a preferred embodiment, the base assembly is configured to dampen at least some of the extraneous vibrations communicated to the support system. The microphone support rod is coupleable to the base assembly and is configured to support a microphone. The microphone sheath substantially surrounds the microphone and is coupled to the microphone support rod wherein the microphone sheath is configured to substantially isolate the microphone from at least some of the extraneous vibrations. Furthermore, in the preferred embodiment, the microphone cable is coupleable to the microphone, and the microphone cable sheath substantially surrounds the microphone cable and is configured to substantially isolate the microphone cable from at least some of the extraneous vibrations.
In another embodiment, the present invention provides a method of manufacturing a microphone support system that substantially isolates a microphone from extraneous vibrations. The method includes: (1) providing a base assembly configured to dampen at least some of the extraneous vibrations communicated to the support system, (2) coupling a microphone support rod to the base assembly and configuring the microphone support rod to support a microphone, (3) coupling a microphone sheath to the microphone support rod and substantially surrounding the microphone, the microphone sheath configured to substantially isolate the microphone from at least some of the extraneous vibrations, (4) coupling a microphone cable to the microphone, and (5) coupling a microphone cable sheath to and substantially surrounding the microphone cable, the microphone cable sheath configured to substantially isolate the microphone cable from at least some of the extraneous vibrations.
The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.
For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Referring now to
Details of two embodiments of the microphone holder will be addressed below with reference to
In one embodiment, the base assembly 270 comprises vibration-isolating feet 271, a vibration-resistant sub-base 272, vibration-absorbing receptacles 273, a non-resonant base 274, and a base assembly cover 279. In a preferred embodiment, the non-resonant base 274 comprises a circular base made of carbon fiber material such as is produced by Black Diamond Racing, Inc. (BDR), a division of D. J. Casser Enterprises, Inc., Milwaukee, Wis. In one embodiment, the diameter of the non-resonant base 274 may be between about 16″ and 18″. In a preferred embodiment, the non-resonant base 274 may have a threaded hole 275 for coupling to the first vertical support pole 221. In another embodiment, an upper surface 276 of the non-resonant base 274 may have a threaded flange (not shown) coupled to it for coupling to the first vertical support pole 221. One who is skilled in the art is familiar with the use of threaded flanges for coupling threaded poles to flat surfaces. Performance of the recording/reproduction system was noticeably better with the threaded hole 275 embodiment.
In one embodiment, the vibration-absorbing receptacles 273 may comprise carbon fiber “cones” 273a, “pucks” 273b, and “pits” 273c. The cones 273a, pucks 273b and pits 273c may be ones available from BDR. The cones 273a comprise solid carbon fiber formed as a cone with an imbedded threaded rod 273d. In a preferred embodiment, the non-resonant base 274 may have a plurality of threaded holes 274a in a lower surface 277 thereof to which the cones 273a and pucks 273b may be coupled in a point-down configuration. The pucks 273b also comprise carbon fiber similar in appearance to a hockey puck with a central hole 273e. The pits 273c are coupled to an upper surface 278 of the sub-base 272 and have a depression 273f on one surface that receives the point of a cone 273a. In the illustrated embodiment, the pits 273c may include an imbedded threaded rod 273g used to coupled the pits 273c to the upper surface 278 of the sub-base 272. In a preferred embodiment, at least three pairs of pucks 273b, cones 273a, and pits 273c are employed.
In a preferred embodiment, the vibration-resistant sub-base 272 comprises a circular oak plywood disk of a similar size to the non-resonant base 274. In one embodiment, the sub-base 272 is 1.25 inch thick, circular oak plywood that is a substantially non-resonant material. In one embodiment, the sub-base 272 may additionally be coated with an additional, non-resonant material, such as a fiberglass-reinforced epoxy resin, to further reduce susceptibility to vibration. A suitable fiberglass-reinforced polyester/epoxy resin is Evercoat®, a product of the Fibre Glass-Evercoat Company of Cincinnati, Ohio. In one embodiment, an upper surface 278 of the sub-base 272 may have threaded holes (not shown) configured to accept mounting bolts for BDR “Thick Pits.” The Thick Pits have deep dimples 273f on their exposed surface to receive points of the cones 273a. The vibration-resistant sub-base 272 absorbs, through the vibration-absorbing receptacles 273, at least some of the vibration that may impinge upon the entire microphone support system 200.
In a preferred embodiment, the sub-base 272 has vibration-isolating feet 271 coupled to an undersurface 280 of the sub-base 272. The vibration-isolating feet 271 serve to substantially isolate the vibration-resistant sub-base 272 from at least some of the floor-borne vibrations. In a preferred embodiment, the vibration-isolating feet 271 may comprise rubber bushings. In another embodiment, the rubber bushings may be a type 6 (ribbed bushing) or type 7 (ribbed ring) commonly available from the McMaster-Carr Company of Atlanta, Ga.
The base assembly 270 may further comprise a base assembly cover 279 substantially surrounding the sub-base 272, the vibration-isolating feet 271 and the non-resonant base 274. The base assembly cover 279 couples to the base assembly 270 by surrounding the first vertical support pole 221 and substantially shields the base assembly 270 from at least some of any extraneous vibrations, including airborne vibrations. The vibration-isolating feet 271 substantially isolate the sub-base 272 from floor-borne vibrations.
The base assembly 270 is coupled to the first vertical support pole 221 as detailed above with or without a flange. In turn, the first vertical support pole 221 is coupled to the second vertical support pole 222 with the first support pole vibration-conducting coupling 224. The second vertical support pole 222 is coupled to the adjustable support pole 223 with the second support pole vibration-conducting coupling 225. In a preferred embodiment, the first and second support pole vibration-conducting couplings 224, 225 are constructed of substantially non-resonant material such as a brass collet and a brass jamb nut. However, these first and second support pole vibration-conducting couplings 224, 225 are vibration conducting, and will serve to conduct any vibrations impinging upon the microphone body 211 down into the base assembly 270.
Additionally, the first vertical support pole 221, second vertical support pole 222 and the adjustable support pole 223 may be surrounded or coated with a vibration-damping coating 221a, 222a, 223a. The vibration-damping coating may be a flexible rubber. Suitable flexible rubber coatings are also available from McMaster-Carr. In another embodiment, the vibration-damping coating may be polystyrene foam. In yet another embodiment, the vibration-damping coating may be polyethylene foam. In still yet another embodiment, the vibration-damping coating may be elastomeric foam. In a similar manner, the first support pole vibration-conducting coupling 224 and the second support pole vibration-conducting coupling 225 may be constructed of brass, which is substantially non-resonant. In this embodiment, the second vertical support pole 222 and the adjustable support pole 223 may be advantageously hollow and therefore filled with a vibration-damping filler 222b to effectively dampen the normal resonant modes of the support poles 222, 223 while allowing high frequency vibrations to be transmitted to the absorbing base assembly 270. In one embodiment, the vibration-damping filler 222b comprises lead and sand. In a preferred embodiment, the vibration-damping filler 222b is a 50/50 mixture by volume of #7 or #8 lead shot and play sand.
Referring now to
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The illustrated embodiment of
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In the illustrated embodiment of
Referring now to
In a preferred embodiment, the base assembly 670 comprises vibration-isolating feet 671, a vibration-resistant sub-base 672, and vibration-absorbing receptacles 673. In the illustrated embodiment, the base assembly 760 also includes support cones 674 that are coupled to the horizontal support pole 622 and are configured to rest upon the vibration-absorbing receptacles 673. All components below and including the vertical support pole 621 are analogous to and may be identical to similar components of the microphone support system 200 of
Referring now to
Thus, an improved microphone support system with vibration damping material applied to, or used in construction of, each component of the microphone support system has been described. The effect is to substantially inhibit the effects of unwanted extraneous vibrations that would otherwise impinge upon the microphone and its body, thereby causing undesirable alteration of the signal to be recorded or reproduced by the system electronics.
While the preferred embodiment as described includes a number of enhancements associated with each of the above listed elements of the microphone support system, one who is skilled in the art will recognize that at least some improvement in a recorded/reproduced audio signal may be realized by some smaller set of individual enhancements to the listed elements.
Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.
This Application claims priority from provisional application No. 60/346,590 entitled “Mechanical Vibration And Group Delay Effects on Recorded/Reproduced Audio Frequency Program Material,” to Ronald L. Meyer, filed on Jan. 7, 2002, which is commonly assigned with the present invention and incorporated herein by reference as if reproduced herein in its entirety.
Number | Name | Date | Kind |
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3653625 | Plice | Apr 1972 | A |
3924083 | Hagey | Dec 1975 | A |
4194096 | Ramsey | Mar 1980 | A |
4396807 | Brewer | Aug 1983 | A |
4449020 | Seebinger | May 1984 | A |
4514598 | Plice | Apr 1985 | A |
4546950 | Cech | Oct 1985 | A |
4569708 | Tanaka et al. | Feb 1986 | A |
4955578 | Fidi | Sep 1990 | A |
5048789 | Eason | Sep 1991 | A |
5154381 | Malinao | Oct 1992 | A |
5340066 | Ditch | Aug 1994 | A |
5435871 | Streit | Jul 1995 | A |
5490599 | Tohidi | Feb 1996 | A |
5497965 | Mathieu | Mar 1996 | A |
5713553 | Cooper | Feb 1998 | A |
5863015 | Hsu | Jan 1999 | A |
5893541 | Michaelson | Apr 1999 | A |
6007032 | Kuo | Dec 1999 | A |
6168030 | Morris | Jan 2001 | B1 |
6316706 | Sammons | Nov 2001 | B1 |
6459802 | Young | Oct 2002 | B1 |
6487298 | Hacker | Nov 2002 | B1 |
Number | Date | Country |
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688730 | Mar 1952 | GB |
2000-135875 | May 2003 | JP |
Number | Date | Country | |
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20030127572 A1 | Jul 2003 | US |
Number | Date | Country | |
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60346590 | Jan 2002 | US |