American football is a beautiful and complicated sport. Broadcasting football as part of the audio team is also quite complex relative to other sports but is so fulfilling when done correctly. One particularity of American Football broadcasting is the parabolic microphone dishes on the sideline.
Why Are Parabolic Microphone Dishes Used In Football? Parabolic microphone dishes are used in American Football broadcasting to capture the sound of the players and the football. Parabolic mic operators move along the sideline, typically following the line of scrimmage and point the long-ranging mic toward the action to capture the sound of the play.
In this article, we’ll take a closer look at what parabolic microphones are as well as their role in American Football broadcasting.
What Is A Parabolic Microphone?
A parabolic microphone is a type of microphone system that includes a parabolic dish and a small omnidirectional microphone. Although the microphone is omnidirectional, the system itself is highly directional and long-range.
Parabolic microphones are generally carried by an operator and therefore have handles. Depending on the size of the dish, the handles could be designed in various ergonomic ways.
How Do Parabolic Microphone Dishes Work?
As we’ve discussed, a parabolic microphone system is made of 2 key components:
- A small omnidirectional microphone: this is the transducer that converts incoming sound waves into audio signals. It is placed at a focal point (the centre of the imaginary sphere). This microphone points toward the middle of the dish.
- A parabolic (semispherical) disc: this dish reflects incoming sound waves toward the microphone at the focal point.
The parabolic microphone system must also have the proper mounts in its design to hold the microphone in place at the focal point. Handles and even straps are included so that the parabolic microphone can be easily carried by an operator but are not essential to the basic functionality.
The Klover Mic 26 (pictured below) is an example of a parabolic mic system with all the design features mentioned above:
The working principle of the parabolic microphone system is easy to visualize. Let’s have a look at a simplified diagram of a parabolic mic and incoming sound waves:
The sound waves that enter the parabolic dish are effectively reflected toward the focal point where the microphone can convert them into audio.
Although the dish is designed to reflect these waves toward the centre, not all waves will hit the microphone diaphragm at the same angle. Therefore, omnidirectional microphones are used since they are equally sensitive to sound from all angles.
This may seem a bit counterintuitive if we think of the parabolic microphone strictly from a directional standpoint. The parabolic mic system is highly directional yet its microphone is omnidirectional.
For more information on omnidirectional microphones and microphone directionality, check out my articles What Is An Omnidirectional Microphone? (Polar Pattern + Mic Examples) and A Complete Guide To Directional Microphones (With Pictures), respectively.
What about sound from the rear? Comparatively speaking, the rear sound will be of lesser amplitude since the front of the mic will be experiencing concentrated sound reflections. Besides, the “rear” of the microphone actually points in the direction that we want to pick up sound.
The directionality and long reach of parabolic microphone systems are phenomenal, often outperforming shotgun microphones (though both are used in American Football broadcasting).
Let’s talk about the directionality and reach of the parabolic mic system.
Directionality And Reach Of The Parabolic Microphone System
So we know that the microphone capsule itself is omnidirectional yet the parabolic system as a whole is ultra-directional. The reasons for this are simple.
First, the dish stops sound coming from the rear from hitting the microphone. Like the inner portion of the disc, the out portion reflects sound waves. The only difference is that these outer reflections are redirected away from the mic diaphragm. Because the disc is not permeable, sounds from the rear are not captured by the mic. This is half the battle when it comes to frontward directionality.
Second, the dish reflects sound waves directly to the front perfectly into the mic capsule. This makes the parabolic system very sensitive to sound directly in the front.
Third, sounds from the sides (and slightly to in front of the dish) only partially enter the dish and so only get partially reflected into the mic capsule. Sounds for the sides that are slightly to the rear of the dish hit the outer shell and do not reach the microphone.
Fourth, the omnidirectional mic is also capable of picking up sound from the front though it points toward the centre of the inner dish.
The result is a highly directional pick up pattern which makes it easy to point the parabolic mic system in the correct direction.
As for reach, the microphone capsule is not only exposed to direct sounds and the reflections of the greater environment (as most microphones are).
Rather, parabolic mic systems reflect the sound waves the pass by the microphone (from the front) back into the microphone. This sort of natural amplification means that the parabolic microphone will be extra sensitive to the sound in its primary direction.
The result of the parabolic design is a long microphone reach. Parabolic mics are capable of capturing sound from very long distances, making them highly effective at capturing the game sound on the opposite side of the field.
A larger dish means a further reach and wider directional pattern.
The Parabolic Microphone And American Football
American Football is a full-contact sport that requires superb communication between players. Tackles, punts and play calls are all excellent opportunities for the audio team to add realism to the broadcast.
Of course, we can’t place microphones on the field (though sometimes we can wirelessly mic up players) but we can set up along the sideline. The majority of the action during most plays tends to be a fair distance from the sideline and so we need a long-range and directional microphone to capture the sound. That’s where the parabolic mic comes in.
There’s another issue though. The line of scrimmage is dynamic and the plays are in motion. Therefore, setting up a single, stationary microphone will be ineffective.
Luckily, parabolic microphones can be held by human operators that move up and down the sideline along with the line of scrimmage. The system can also easily be pointed toward the action at any given moment. It is this mobility combined with the long reach and directionality that make parabolic microphones a go-to weapon in the game of American Football broadcasting.
The Parabolic Microphone Operator
The parabolic microphone operator is tasked with following the play throughout the game with the parabolic microphone system.
Though I’ve only done this job a few times at the college level, it’s a great experience and an interesting way to watch the sport.
Typically the operators are only monitoring their own microphone rather than listening to the part line of the broadcast (directors, producers, etc.) so it’s always best to assume the mic is being sent to air even when the play is dead.
It’s helpful to have a wireless microphone for extended mobility. The few times I’ve done this job I was limited by the cable. Not so much by cable length but by the fact that I had wired cameramen on either side of me and was set up on the same side as the teams. Dragging cable through large crowds is a sure way to get tangled and trip people which would negatively affect performance.
Of course, a cable puller could be handy to help clean up the loose cable behind the parabolic operator but I digress.
The goal of the parabolic operator is to capture the sound of tackles, play calls, kicks, and anything else that takes place on the field. This means pointing the dish toward the action and following it closely while moving up and down the sidelines.
Are shotgun mics condenser mics? Shotgun microphones are based on the small-diaphragm condenser (SDC) pencil microphone design. These microphones are all essentially top-address SDC with long interference tubes extending from their tops. These tubes allow for the extreme narrowing of the polar pattern at the condenser capsule.
To learn more about shotgun microphones, check out the following My New Microphone articles:
• The Lobar/Shotgun Microphone Polar Pattern (With Mic Examples)
• Why Are Some Microphones Long & What Are Interference Tubes?
• Best Shotgun Microphones For A Camera
• Best Boom Microphones For Film
How does a microphone work physics? Microphones work as transducers, converting mechanical wave energy (diaphragm movement due to sound waves) into electrical energy (analog audio signal). Dynamic mics work on electromagnetic induction while condenser mics work on electrostatic principles.
For all the information you need on how microphones work, check out my article How Do Microphones Work? (A Helpful Illustrated Guide).