- Written by Rick Vanderwielen, Sports Video Producer Indiana High School Athletic Assn (IHSAA)
In the last several years, small college, high school and amateur sports webcasts have become very popular.
In the last several years, small college, high school and amateur sports webcasts have become very popular.
Documentary work requires not only great video, but great sound too. Here are nine tricks that will help capture the best audio.
Why would you use a small parabolic mic instead of a shotgun mic?
Recording in the field is like camping: you only have the supplies you take with you!
Have you heard that baseball is a disgusting game? It really is.
Whether you are producing a commercial, infomercial, corporate video or even episodic television, you’re going to need to know how to record the human voice.
If your speaker (audio source) is moving around a stage a cable could be a big problem. While wireless microphones provide many benefits including mobility, there are challenges as well.
a. Is your subject willing to hold a microphone or wear a transmitter on their body? Very few wedding couples want to hold a microphone during their ceremony and most brides will refuse to wear a transmitter under their wedding gown.
b. Will the batteries last for the duration of your event? Even news casters deal with this. Batteries die at the worst possible moment.
c. Will there be a number of different wireless microphones in the same venue? This can lead to radio interference that can ruin your audio.
d. If using a wireless handl-held microphone, will speaker be able to keep from placing his hand over the antennae?
Microphone with a cable avoid the technical challenges that wireless microphones face but the cable creates other challenges. A hand-held, or stick microphone, with a cable often creates a tripping hazard if the speaker is walking about. Speakers that are stationary can used lapel or over-the-ear microphones but face the risk of pulling off the mic or pulling out the cord if the speaker walks off before disconnecting the microphone.
Do you want to capture one speaker or several? Do you want to focus in a single bird or capture the sounds of the wildlife all around? These types of questions determine the pickup pattern (or polar patterns). There are a wide variety of articles on polar patterns available from all types of sources. One of our favorites is written by Caleb Ward for PremiumBeat.com. (https://www.premiumbeat.com/blog/6-microphone-pickup-patterns-every-filmmaker-should-know/)
Another good article written by Paul White, is also located on SoundOnSound.com. (http://www.soundonsound.com/techniques/using-microphone-polar-patterns-effectively) We especially appreciate the articles explanation that “polar patterns aren’t always as simple as they first appear”. People often neglect the audio that is captured from the sides and the rear of shotgun microphones but it can cause serious problems if someone begins speaking directly behind a shotgun microphone. If you are a fan of shotgun microphones, you might find this article to be very interesting. (http://www.soundonsound.com/sound-advice/q-how-do-shotgun-mics-work)
The point is this, if you are trying to capture several different speakers, or a quartet, you will want to use a cardioid or an omni-directional microphone. However, if you want to focus in on, or only capture, a single sound source such as a single person in a noisy room, you will want to use a microphone with a supercardioid, hypercardioid, or even a lobar polar pattern.
A pattern that you won’t find explained in many articles is the conical pattern that a parabolic microphone provides. The conical pickup pattern typically extends 15 degrees off of the center axis of the parabolic dish. Parabolics do pick up off-axis noise and some noise from behind the dish but usually much less than any other option.
How far away from the audio source is the microphone? Lapel, or lavaliere, microphones normally must be within in 6 to 9 inches of the speaker’s mouth to provide best performance. Hand-held, or stick, microphones usually need to be within 9 to 12 inches of the speaker to provide the best audio signal. While this is up for much debate, a shotgun microphone will normally need to be no more than 4 feet from a speaker to capture the best audio.
If you want to capture audio from more than 6 six feet away, you need to consider a parabolic collector. Parabolic collectors use a precisely shaped dish to focus all the sound energy from directly in front of the dish onto a single point. A standard electronic microphone is located at that focus point and the combination is referred to as a parabolic microphone. Small parabolic microphones, if properly designed, can capture dialogue from 30 feet or more in quiet situations. The large parabolic microphones you see at football games can capture dialogue from 500 feet or more in quiet situations.
In all cases, there are extenuating circumstances. The louder the environment the closer the microphone will have to be to create a stronger audio signal when compared to the ambient noise. The professionals call this a larger signal to noise ratio. This ratio determines how easy it is to distinguish the audio you want from the noises that you don’t want.
4. Frequency Response
Every microphone has a response curve that shows how it reacts to various audio frequencies. Every microphone will have a graph of the signal level at various frequencies. The curve will also show the highest and lowest frequency that the microphone will capture. A microphone than does not capture audio below 100 Hz, for example would be useless for music, or recording a bass guitar. (A sample response curve can be seen on this spec sheet from Sennheiser https://en-us.sennheiser.com/global-downloads/file/812/MKE_2_4_Gold_C_GB.pdf)
For many microphones this signal curve is not a straight line. This means that some frequencies are captured at a higher level than others. For example, many lapel (or lavaliere) microphones have a range of frequencies that have a significantly higher signal than other. This range of frequencies with higher signal level is usually between 2kHz and 20 kHz. The change in signal level is not constant, however. It increases gradually to a peak and then falls off again.
Using a parabolic collector will also affect the frequency response of the microphone located within it. As higher frequencies reflect off of the collector dish better than low frequencies the parabolic microphone (collector and microphone) will have a response curve that shows a higher signal level at high frequencies and a slightly lower signal level at lower frequencies. It is a common misconception that parabolic microphones will have almost no signal below a certain frequency (related to the diameter of the dish and wavelength associated with the frequency) but this has shown to be untrue. We have demonstrated that a dish just nine inches in diameter can capture audio at frequencies well below the supposed thresholds. Capturing any human dialogue shows that this concept is invalid.
When trying to conceal a microphone size is obviously a major concern. A hand-held, or stick, microphone is hard to conceal unless the camera shot is extremely tight. A miniature microphone is the obvious choice. There are many varieties of miniature microphones available. These range from larger lapel microphones worn on the speaker’s clothing to tiny units worn over the ear or concealed in the speaker’s hair.
6. Intended Use
A factor that is easily overlooked is the intended use of the captured audio. If the signal from the microphone is being recorded there is more latitude in range and pickup pattern than if the signal is being used for sound reinforcement. By sound reinforcement we are referring to an amplifier and speakers. Feedback is the constant challenge for sound reinforcement, or loud speaker, systems.
The audio coming from the loud speakers can be captured by a microphone and re-amplified. That signal can be captured and amplified again. That cycle can be repeated many times if just a fraction of a second leading to the annoying squeal we have all experienced.
Proper location of the microphones and loudspeakers are the best solution to feedback. However, keeping the microphone as close to the speaker (sound source) as possible and using as focused pattern as possible will help to reduce the potential for feedback.
Parabolic microphones are very focused but their extreme range, or sensitivity, makes it challenging, but not impossible, to use them for sound reinforcement applications. Very low gains (amplification) must be used with a parabolic and they must be “aimed” to avoid reflected sound coming from the loud speakers.
It may seem obvious that moisture is a concern at an outdoor event but your microphones can also be affected by sweat. If you are using a miniature microphone wore on the lapel, or over the ear, or even in the hair, consider using moisture resistant microphones. Microphone manufacturers, such as Countryman Associates, are producing microphones that can operate submerged in water. (http://www.countryman.com/b3-omnidirectional-lavalier-microphone)
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, electomechanical 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 Products, Inc. Previously in 2011, they had jointly dveloped a parabolic microphone for Fox Sports when Fox audio engineers grew disatisfied 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 exclusiely by Fox Sports for football broadcasts since 2012.
One of the most common questions we get from beginning video producers is “how do I get my video to be more like what I see in movies and TV?”
The unique shape of the parabolic collector allows anything coming into the dish, that is parallel to the center line of the dish, to be focused onto a single point.
There is obviously a need to use external audio recorders when you need to record more than two channels or when you need the absolute highest quality sound.
So, you've bought a shiny new digital video camera and you're blown away by the image quality. But what about the audio?
Impedance is very important because selecting the wrong impedance mic can cause immediate and sometimes serious problems.
In a scripted sitcom, the audience never sees a mic.
A good wired microphone is perfect for reliable high quality audio, but sometimes the wires get in the way.
Signal flow is the universal language behind the path of audio in any recording and production scenario.
If you gather ten sound engineers in a room and ask them what’s the best way to record something, don’t be surprised when you get ten different answers.
The types of microphones being used and microphone placement is determined during the planning phase.
Audio-Technica has been at the forefront in helping wireless users navigate the 600 MHz changes resulting from the FCC’s spectrum auction.
Demystifying On-Camera Wireless Systems
Has the selection of microphones offered by your favorite electronics store ever overwhelmed you? Have you stared in awe at the vast array of silver or black, big or small, expensive or cheap microphones available to you?
The miracle of film and television is a result of a perceptual phenomenon known as "persistence of vision."
Recently, a sound design forum that I belong to debated on what the audio levels should be in a film. I, of course, chimed in. I was surprised that there were so many different opinions. The group is a good cross section of the sound design community being made up of amateur, prosumer and professional participants. However, despite this eclectic group, there was no definitive answer. There were some guidelines and a general understanding, but still no definitive answer. So, how do you go about mixing sound to picture? I'm glad you asked!
Learn the attributes of sound, how we hear, measure and record sound.
This installment of our blog series on Basic Audio Techniques for Video provides more solutions for hiding lavalier microphones while rigging talent.
So, you've got a small budget and you finally believe that the audio you capture for your project is just as important as the video, (we told you so!) but you can only purchase one mic.
This installment of our blog series on Basic Audio Techniques for Video explains the basics of working with wireless mic systems.
Visuals aren’t the only thing to consider when you’re scouting locations. Audio is just as important. Just because a location looks good doesn’t mean it sounds good.
In this installment of our blog series on Basic Audio Techniques for Video we’ll explain how to select the proper handheld mic for filming.
The boom pole is used to suspend a microphone over the actors on set.
In this installment of our blog series on Basic Audio Techniques for Video we’ll explain how to select the right shotgun microphone for different situations on set.
Two minutes of extra work on the set or in the field can save you hours of headache in the edit bay. You just need to remember to do it.
In this installment of our blog series on Basic Audio Techniques for Video, we’ll explain how to use a boompole.
The Boom—Why, Isn’t That Old Fashioned?
Great sounding audio is key when producing a high quality video.
The primary objective of the production sound mixer and the boom operator is to capture clean dialogue on set.
Hands down the most over-looked element of any television production is the audio.
The boom pole is a extendable pole used to position a microphone in the proper proximity above the actors on set.
A few months ago, I was watching an episode of Family Guy.
Clean, clear audio is an essential aspect of any professional production, but many (if not most) videographers underestimate its importance.