When most people think of capturing audio from long distances, they think of shotgun microphones. They are seen on news cameras and at sporting events. They must reach out and grab sounds, right? Well, not exactly.
Shure, one of the leading microphone manufacturers, lists this misconception as one of the Top 8 Microphone Myths. To quote, “The reality is that microphones do not reach out and grab the sound from a distance. They merely measure pressure variations right at the diaphragm itself.”
It may be worth reviewing how shotgun mics work. The Sound on Sound website explains, “All shotgun mics employ a standard directional capsule — usually a supercardioid — but with a long, hollow, slotted ‘interference tube’ attached to its front surface.” The interference tube is used to “cancel out” sound coming from the side of the microphone.
Many common “shotgun” microphones utilize a plastic and paper tube instead of an interference tube with slots. Our experience is that this design provides very little directionality. The photo on the left is a Rode Video Mic Pro with the foam cover removed.
Regardless of the design, the interference tube does not provide any amplification. They are simply attempting to block out off-axis sounds. Any amplification has to come from an electronic amplifier built into the shotgun microphone itself. More amplification leads to more “electronic noise.”
The Sound Shark, however, provides a mechanical amplification of approximately six times, due to the characteristics of the collector dish, for the sound coming from in front of the dish. The amplification of the sounds coming from the front of the dish, while the peripheral sound is not amplified or blocked by the dish itself, provides the directionality of the Sound Shark.
Shure, one of the leading microphone manufacturers, lists this misconception as one of the Top 8 Microphone Myths. To quote, “The reality is that microphones do not reach out and grab the sound from a distance. They merely measure pressure variations right at the diaphragm itself.” and “The one specification of a microphone that loosely corresponds to the concept of reach is directionality or the microphone’s polar pattern. The directional characteristic of a microphone describes how much sound it picks up from ambient sources compared to how much it picks up on-axis.”
Many believe that all shotgun microphones have very tight pickup patterns similar to the polar pattern on the right. Unfortunately, this polar pattern shown is for a lobar microphone, while only very few shotgun microphones have a lobar pattern. Most low-cost shotguns have a cardioid polar pattern, while medium-cost shotgun microphones have hyper-cardioid or super-cardioid polar patterns. (This Premium Beat web page provides a great explanation of these polar patterns.)
It may be worth reviewing how shotgun mics work. As the Sound on Sound website explains, “All shotgun mics employ a standard directional capsule — usually a supercardioid — but with a long, hollow, slotted ‘interference tube’ attached to its front surface.” and “The idea of the interference tube is that the wanted on-axis sound passes straight down the length of the tube to the capsule diaphragm unimpeded, but the unwanted off-axis sound has to reach the diaphragm by entering the side slots.” As Shure explains, “On-axis sounds share a uniform path length to the microphone capsule. Because they arrive at the same time, they end up being what we call “in phase” and are thus accepted by the mic element and passed down the audio circuit.”
However, the interference tube has its own issues. As the Quora website states, “The design has drawbacks: different frequencies have different wavelengths, and therefore, each frequency is affected in a different magnitude. This causes “coloration” for off-axis sounds as components of the original waveform are attenuated differently according to frequency. This is unavoidable because of the principle of operation.” and “Take a look at the pickup pattern of a lobar microphone. all frequencies are equally represented at 0 degrees, but they are attenuated as you go off axis in differing amounts, resulting in coloration vs. the original sound spectrum.” (The referenced pickup pattern is shown on the right.)
Many common “shotgun” microphones utilize a plastic and paper tube instead of an interference tube with slots. Our experience is that this design provides very little directionality. The photo on the right is a Rode Video Mic Pro with the foam cover removed.
Regardless of the design, the interference tube does not provide any amplification. They are simply attempting to block out off-axis sounds. Any amplification has to come from an electronic amplifier built into the shotgun microphone itself. More amplification leads to more “electronic noise.”
The Sound Shark, however, provides a mechanical amplification of approximately six times, due to the characteristics of the collector dish, for the sound coming from in front of the dish. The amplification of the sounds coming from the front of the dish, while the peripheral sound is not amplified or blocked by the dish itself, provides the directionality of the Sound Shark.
