Ribbon microphones once dominated commercial broadcasting and recording industries as a preferred high-end microphone technology. First invented by Walter H. Schottky and Dr. Erwin Gerlach and further developed by Dr. Harry F. Olson of RCA corporation in the late 1920's, Ribbon microphones widely commercialized in the 1930's exhibited superior frequency responses and higher-fidelity output signals compared to other microphones of the time.
A ribbon microphone typically uses a thin piece of metal immersed in magnetic field generated by surrounding magnets. The thin piece of metal is generally called a “ribbon” and is often corrugated to achieve wider frequency response and fidelity. Ribbon microphones became vastly popular and became a primary broadcasting and recording microphone until mid-1970's.
However, the classic ribbon microphone architecture was susceptible to significant disadvantages. First, a typical ribbon microphone contained a fragile ultra-thin ribbon, typically made of corrugated aluminum, which could break easily if the ribbon microphone casing was subject to a gust of air through its microphone windscreen. Second, most ribbon microphones could not produce as high output signal level as condenser or dynamic moving-coil microphones. The lack of high output signal level for ribbon microphones usually required careful pre-amplification matching and tuning, which was cumbersome and contributed to reduced ruggedness and reliability compared to condenser and other dynamic microphones.
By the mid-1970's, dynamic moving-coil microphones (i.e. coil wire on a diaphragm suspended over a magnetic field) and condenser microphones (i.e. capacitor microphones) evolved technologically for higher sensitivity and signal-to-noise ratio (SNR) to compete effectively against ribbon microphones. For example, improved condenser microphones exhibited substantially higher output signal level than ribbon microphones, thereby simplifying pre-amplification process and improving reliability of recording or broadcasting equipment.
Although a typical condenser microphone had the tendency of exaggerating upper frequency ranges whenever inherent harmonic resonances occurred in a diaphragm of the microphone, the exaggerated upper frequency was actually preferred by some since the recording industry exclusively used analog tape mediums for audio recording. Most analog tapes suffered generational signal losses and could not accurately capture high-frequency ranges, which made the use of condenser microphone-based recording equipment more acceptable. Similarly, although dynamic moving-coil microphones fundamentally possessed higher resistivity to sound waves than ribbon microphones, improved dynamic moving-coil and condenser microphones provided ways to compensate for a relatively low high-frequency response. Therefore, by the mid-1970's, most ribbon microphones were rapidly replaced by more portable, rugged, and user-friendly condenser and dynamic moving-coil microphones. By the end of that decade, ribbon microphones were widely considered obsolete.
However, despite several drawbacks as mentioned above, ribbon microphones possess fundamental advantages as recording and broadcasting industry become fully adjusted to the digital era. As Compact Discs and solid-state non-volatile memory (e.g. NAND flash memory) became recording media of choice for highly digitized recording and broadcasting equipment, the high-frequency exaggeration and distortion provided by condenser microphones were no longer desirable. Many audio engineers and music lovers began to favor more natural and linear reproduction of sound, which meant that ribbon microphone's fundamentally higher fidelity in higher frequencies received attention once again. Ribbon microphones also provide a generally richer and fuller sound reproduction compared to condenser and dynamic moving-coil microphones with digital audio recording and broadcasting equipment. In recent years, there has been a resurgence of demand for retrofitted ribbon microphones of yore and a need for newly-designed ribbon microphones, especially in the high-end audio industry.
Unfortunately, ribbon microphones typically still exhibit an undesirable trait called “proximity effect,” which may prevent their widespread application. In particular, when a musician, a singer, or another sound source is situated very close to a ribbon microphone, the ribbon microphone tends to dramatically increase the bass (i.e. lower frequency) response disproportionately, compared to the higher frequencies above the bass range. In the field of audio engineering, this is generally known as the “proximity effect.” The disproportionate bass response relative to higher frequencies may get progressively worse, resulting in an accentuated bass effect, if the sound source is moved closer to the ribbon microphone during a musical performance or a recording session.
The proximity effect in a ribbon microphone may distort sound production quality to be overly “dark,” or provide inadequate higher frequency responses, depending on a current distance between a sound source and the ribbon microphone. Utilizing ribbon microphones in some sound production and recording environment sometimes necessitate substantial frequency manipulation with an equalizer to mitigate the proximity effect.
Therefore, it may be beneficial to provide a novel ribbon microphone or another type of microphone that minimizes or removes the proximity effect within the casing of the microphone. Furthermore, it may be beneficial to provide a convenient user interface that enables the user to switch between a voice application and a music application to mitigate the proximity effect. In addition, it may be beneficial to provide a novel microphone and a user interface for switching between the voice application and the music application with an actively-powered preamplifier integrated inside the casing of the microphone. Furthermore, it may also be beneficial to provide a novel standalone inline preamplifier with a user interface for switching between the voice application and the music application with proximity effect filtering.
USPTO Backgrounds
USPTO Backgrounds