Sound for Live Production - Part 1
Live productions such as sporting events present many challenges but one of the most daunting is providing good audio for your production.
In this series of articles, we will share our experience in capturing better audio for these productions.
Introduction
The key to good audio for live production, as in all productions is isolation. By isolation I am referring to isolating, or emphasizing your desired audio against the ambient, or unwanted audio. Like almost everything else, the key is improving the signal to noise ratio.
Nobody wants to hear the crowd yelling at the referee, or a parent screaming at their child. It is annoying and detracts your attention from the subject. As simple as it sounds, this is a very difficult challenge. Even the major television networks fail at this. At times it was almost impossible to hear the “on-track” announcers during this year’s Indianapolis 500.
As previously mentioned, crowd noise is often overpowering during broadcasts such as sporting events. The audio mixers work very hard to minimize these unwanted noise sources but it can be an incredibly difficult job.
Announcers
The starting point for improving the audio is obviously the announcers. The program can be ruined for the audience if it is difficult to hear the announcers. There are several steps that can be taken to improve the announcer’s audio.
First, isolate the announcer’s audio as much as possible. Isolation of the announcer’s audio begins with the booth itself. The announcers should be located to minimize background noise as much as possible. Placing them above or behind the crowd can reduce crowd noise significantly. Adding sound barriers around the announcers will also reduce crowd noise. Simple steps such as hanging blankets on the walls around the announcers can provide noticeable improvements.
Second, use directional microphones for the announcers and have the microphones as close to the announcers as possible. By direction microphones we are referring to microphones with cardioid, super cardioid, or hyper cardioid polar patterns. These more directional microphones will capture more of the speaker while rejection ambient noise that would be captured with an omni-directional microphone.
A microphone’s polar pattern indicates how directional it is and is provided by the manufacturer for each microphone. The distance of the line from the center, at each angle, indicates its relative signal strength. However, the scale is typically logarithmic so each 6dB drop reduces the signal level by one half. You can’t just picture this polar pattern on top of your mic unless you change the scale to be linear.
The plots are frequency dependent and are often “optimize” by the manufacturer to make the microphone appear more directional than they are in typical use. For best results, test the performance of several mics for yourself.
Typical polar patterns
Omni-directional: Good for lapel mics, or capturing a large group
It captures sound equally in all directions, so you don’t have to worry about how it is oriented.
Cardioid: Good for stage mics, or lecterns
It captures much more sound from the front than from the rear, but it does capture a significant amount of sound from the sides.
Most “low-end” shotgun mics are cardioid.
Hyper Cardioid: Widely used
It captures much more sound from the front than from the sides, but it does capture quite a significant amount of sound from the rear.
There are many variations on this polar pattern with more or less of a rear lobe.
Most “mid-range” shotgun mics are hyper cardioid.
Lobar: The most directional pattern
These are the most directional but still have a large rear lobe.
Only found in “high-end” shotgun mics.
Shotgun microphones
They are “shotguns”, not “rifles”
They are not as directional as most assume
Test the directionality for yourself.
Shotgun mics are a standard mic element at the end of a long tube
The tube is designed to block sound coming from the side
The tube has to have openings in order to provide decent sound
Head worn microphones can provide a significantly better audio signal than a hand-held microphone, but they are not always available or acceptable. Lapel microphones are not the best option due to the distance from the speaker’s mouth and their typically wide pickup pattern.
If hand-held microphones are used train the announcers to hold the microphone very close to their mouth. If wireless hand-held microphones are used, train the announcer to NOT hold wireless mic on the antennae.
On-Field Sound
Why is “on-field” sound important? It makes the viewer feel a part of the action. To demonstrate the difference that on-field sound can make, we recommend watching a European soccer (“futball”) match and comparing that to an NFL broadcast on a Fox network (as they emphasize on-field audio). You are drawn into the NFL game by hearing the quarterback signals and crunching of the pads. In comparison, you only hear the announcers and some crowd noise during a typical “futball” broadcast. If you would rather, watch this demonstration:
In Part 2, I will share what I’ve learned about capturing better on-field audio.
Meet the Author, Paul Terpstra
Paul Terpstra has more than 35 years of engineering and product development experience. He founded Innalytical Solutions, Inc. in 2004, to provide a wide range of engineering services including forensic engineering, Finite Element Analysis, electromechanical design, machine design, and machinery repair. Paul was recently granted his eleventh U. S. Patent.
In April of 2012, Paul and Patrick Santini, an Innalytical Solutions customer, created Klover Product, Inc. Previously in 2011, they had jointly developed a parabolic microphone for Fox Sports when Fox audio engineers grew dissatisfied with the available products. That original test unit turned out to be the first prototype of the microphone that would later become the Klover MiK 26. The Klover MiK 26 parabolic microphones have been used exclusively by Fox Sports for football broadcasts since 2012.