Mixing


Topics This Week

In producing a piece of music, we use a mixer and effects devices to combine and process different musical parts. A mixer has a number of channels that accept audio inputs and combines them to produce a stereo output by routing and processing those signals in various ways. Each channel is usually laid out as a strip of controls that is replicated for each physical or virtual input. These controls typically include level, placement in the stereo image (panning), equalization controls, and effect routing controls.


Signal Flow

The key to understanding any audio production system, whether it's a portastudio or a large professional facility, is understanding how audio signals are routed between studio components. Follow this link to see signal flow in a typical recording studio.

Audio Signal Level and Gain-staging

Each component of the system either increases or reduces level. In addition, any time a signal is passed through an electronic circuit in an analog system, noise is added. Ideally, the level at each stage is optimized to provide the highest level without distortion. The ideal signal level will have the least noise. Follow this link for more details on audio levels.

In a virtual studio like Reason, we still need to be aware of audio levels at various stages. Levels in Reason are controlled at three places:

  1. the output of an individual instrument
  2. the channel fader in the mixer
  3. the Master Fader controlling the mix output level
Level Metering provides a way for us to monitor signal level at various places in the mixer. There are some important distinctions in how signal level is displayed. Since the amplitude of an audio signal is always changing, level is measured and displayed at discreet time intervals.

Reason uses peak level meters to display level at:


Mixing Board Connections and Functions

The mixing board is the central nervous system of a recording studio or PA system. Every audio signal passes through it, and is processed, routed, and combined with other source signals to create the final stereo mix of a multitrack production. All mixing boards, whether physical or virtual, share a similar set of components. We'll start with some basics by looking at the Reason mixer, then compare these functions to a common hardware mixer, the Mackie 1604.

The Reason Mixer

The Reason mixer is laid out like many small desktop mixers, and performs three basic functions:

Follow this link for a look at the signal path within a mixer.

The Reason Mixer: 14 Channels, a Master section, and four separate sends and returns.

Within this mixer, there a six basic controls:

Follow this link to learn more about the controls in the Reason mixer.


Signal Flow in GarageBand

 

 


 

Hardware Mixers

The Reason mixer is very similar to most hardware mixers. In Reason however, all the connections are made within an easy, self contained software environment. Things get more complicated in the physical world where there are a variety of signal levels, and connectors to take into consideration. In spite of this, the basic functions and controls will be the same as in the virtual Reason mixer. The Mackie 1604 is a very common hardware mixer used for a variety of applications. Let's compare what we've see in Reason with this device.

Connections in the Mackie 1604


This Week's Assignment


Review Questions
Mixing Vocabulary


Auxiliary input
Buss
Eq
Fader
Gain
Gain-staging
Insert
LED
Master fader
Mixing board (console, desk)
Monitor/cue mix
Mono
Mute
Pan
Peak level
Post-fader
Pre-fader
Preamp
Return
Send
Solo
Stereo
Trim