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Audio Production Rooms | Audio Basics

Audio Basics

Before You Start
 

  • Consider your environment - If you are not recording in the Audio Rooms, try to limit ambient noise coming from your environment. 
  • Hydration - Make sure you have consumed enough water that day and have a sealed bottle of water available. 
  • Wear appropriate clothing - Do not wear clothing that ruffles or makes noise easily.
  • Choose the right microphone - Understand different microphones and make sure you have placed the speaker in the right position. View a summary of microphone information
  • Choose the right device - Review the options in our guides for portable recording and recording remotely, or record in our Audio Rooms.
  • Understand digital audio files - Choose your audio file properties.
  • Accessories - Make sure you have sufficient headphones, SD cards and batteries. Headphones and SD cards are available for loan from the Service Desk.
  • Decide on software - Review your options for editing and/or recording in our guide and leave time for editing.
     

Types of Microphones and Inputs


There are two main types of microphones - condenser microphones and dynamic microphones. Each is constructed differently in order to convert sound waves into electrical signals.

Condenser microphones - These microphones need phantom power. This means that whatever you are plugging it into wil need to provide the microphone with 48V of power supply. Zoom H5, Zoom H6, and audio interfaces have the option to provide phantom power. Condenser microphones are more sensitive and record quieter sounds more easily.

Dynamic microphones - Dynamic microphones DO NOT need phantom power. You can plug them in to any kind of interface or recorder without needing phantom power. These microphones can handle recording louder sounds than condenser microphones.

Microphone pickup patterns - Each microphone, whether condenser or dynamic, also has a specific pick-up pattern, or way of picking up sound. The diagram below shows where different pickup patters pick up the sound around a microphone in the middle.

Pickup patterns displayedPolar pattern figure eight by Galak76 licensed under the Creative Commons Attribution-Share Alike 3.0 Unported. Polar pattern cardioid by Nicoguaro licensed under Creative Commons Attribution 4.0 International.

  • ​Omnidirectional - Picks up sound evenly 360 degrees around the microphone. You may also potentially pick up unwanted noise.
  • Bidirectional - Picks up sound primarily at either side of the microphone. This microphone pattern is good for interviews where you have two people facing each other and you would like to place the microphone in-between the two speakers.
  • Cardioid - These microphones will pick up far more sound at the front of the microphone than in the back. Think of a stage - you’ll use these microphones when you want to pick up a singer, but not the crowd. Super-cardioid mics have even more concentrated sensitivity at the front of the microphone, making it very directional.

Bidirectional and cardioid microphones are directional. They need to be pointed in the right direction to optimally pick up a speaker.

Microphone input types - Professional microphones often require XLR cables. These cables deliver a high quality signal using three prongs that plug into an input with three holes. XLR cables are available from the Service desk and need to be booked separately from microphones.

 

xlr cables
The female end of the cable on the left (plugs into the microphone) and the male end of the cable on the right (plugs into your recording device). XLR cable connectors by Omegatron is licensed under Creative Commons Attribution-Share Alike​ 2.0

You may alternatively have a microphone that connects using a 3.5mm or 3/8 inch jack. This input can sometimes be plugged in directly to a portable recorder, or connected to a 1/4 inch input using an adapter. You can borrow 3.5mm to 1/4 inch adapters and XLR to 3.5 mm adapters from the Service Desk.

Audio jack that is 3.5mm long. 
Audiojack 3,5mm stereo by Galak76. The 1/4 inch jack looks very similar to the 3.5mm jack, but it is double the length.

 

Microphone Set-up

Once you have selected your microphone and have the correct cords or adapters, you can consider microphone placement and levels.
 
Microphone placement - You can adjust the position of the mic further or closer to the speaker to control their volume. 
Transom.org recommends placing the mic at around at least six inches away from your speaker. Positioning the microphone slightly to one side reduces puffs of air caused by p-sounds, or plosives.

The mic position should look something like this:

Mic position


Checking levels - Remember to check the gain level on the interface or audio recorder for each input to make sure it is not contributing to too high or too low levels. Gain controls how strong of an audio signal is sent through the interface or recorder. Remember, dynamic microphones like the Rode Procaster will require more gain than condenser microphones. Read NPR’s FAQ on levels on your recorder or interface to avoid peaking (reaching the top of the meter).

 

Summary of microphone types, pickup patters and placement:
 

Microphone

Input

Type

Pickup Pattern

Directional?

Best Use

Optimal mic placement 

Rode Procaster

XLR

Dynamic 

Cardioid

Yes

Spoken voice

2 -3 inches away, gold dot on microphone facing up.

Reporter

XLR

Dynamic

Bidirectional

Yes

Interviews

At chest height held in-between speakers.  

Lavalier Microphone

3.5mm

Condenser

Omnidirectional

No

Interviews

Place the mic in the area of the speakers sternum.

Vocal Microphone

XLR

Dynamic

Cardioid

Yes

Vocals

Spoken voice

Approximately 6 inches away from the speaker.

Rodelink Wireless Lavalier

3.5mm

Condenser

Omnidirectional

No

Interviews

Place the mic in the area of the speaker's sternum.

Pencil microphone

XLR

Dynamic

Cardioid

Yes

Best suited for instruments

Dependent on the instrument

Shotgun (with Boompole kit for use with AV camera)

XLR

Condenser

Supercardioid

Yes

Filmmaking 

Point mic downwards a few feet away above your subject.

 

Understanding Digital Audio Files


There are properties of digital audio files that are important to understand. One property is if the file contains separate channels of information for the left and right direction.

  • Mono audio files will not drift from the left to the right based on a sound drifting from the left to the right. It contains the same information for both sides. You’ll hear the exact same information in the left and the right speaker for example.
  • Stereo audio files will store the left and right positions of sounds recorded around the device or microphone in separate channels. You can hear something different in your right speaker versus your left.

Stereo and mono 

If you are not sure if you should record in stereo or mono, view this guide. In general voices can be recorded in mono, while ambient sounds and music can be recorded in stereo.

File format There are two main audio file formats:

  • WAV - A larger, higher quality file that is ideal for recording and editing. Recommended for recording.
  • Mp3 - Easily shared, but is not desirable for editing. Best for final export.
You should also review audio file quality options. The higher the number for sample rate and bit rate, the higher the file size. Consider storage storage space and how you are using the audio.
 

Sample rate - How many “pictures” of the sound in data or samples are captured per second (measure in kHz). This is a similar concept to pixels for photographs - the more pixels or samples, the better quality you get. 44.1 kHz is high enough quality for most projects.

Bit rate - Simplified, this measures the level of detail in each sample. 16 bit is CD quality and 24 bit is supported by iTunes. 

Follow these guidelines when you are unsure what to record in:

  • Standard44.1 kHz, 16 or 24 bit 
  • Audio for video projects: 48 kHz, 24 bit
  • Advanced audio production (not recommended): 88.2 kHz, 96 kHz and higher
     

Further reading


Bartlett, B., & Bartlett, J. (2016). Practical recording techniques : the step-by-step approach to professional audio recording  (7th edition.). New York, NY: Routledge.

Available online