The mixer strip

Mixing is the process of converting multiple tracks into a stereo or a multi-channel mix where all the instruments can be heard clearly.

Mixing Tools

Levels, panning, equalization (EQ), and compression are the main tools used to achieve a good mix. In addition to these core tools, a wide range of plugin effects can also be used to enhance the sound, such as reverb and delay. 

Introducing the Mixer Strip

The mixer strip is the vertical column that contains various controls related to signal flow. Each track and bus in Ardour has its own mixer strip. The mixer strip is also the main tool we will use in the process of mixing our Tracks. In this chapter, we will get a general overview of the mixer strip, with each section described. We will also provide references to chapters containing information specific to each aspect of the mixer strip.

The Mixer Strip from Top to Bottom

Mixer strips can be accessed from both the Editor window and the Mixer window (shortcut Alt+M to toggle between the two). Mixer strips in either window (Editor or Mixer) mirror each other: any actions performed on a mixer strip in the Mixer window will be reflected in the corresponding mixer strip in the Editor window, and vice-versa. The editor window and Mixer window are more fully explained in the An Overview of the Interface chapter. 

In the Editor Window, you can see the mixer strip of the currently selected track on the left side of the window. If you don’t see it, hit Shift+E to display the Editor’s mixer strip.

Overview

Here we see the entire mixer strip, as it would appear in either the Editor window or the Mixer window.

Regular & Narrow Modes

The mixer strip can be switched between  the regular width and a more narrow width to conserve space. The very top part of the mixer strip, pictured below, switches between regular and narrow modes using the left button. The button with an eye icon hides the mixer strip entirely (you can re-enable it later).

You can easily spot differences between narrow and regular modes: shorter captions on buttons, no legend for the peak meter etc.

Track Name and Routing Button

Continuing from top to bottom, the next section of the mixer strip contains three narrow regions. The first of these regions shows the name of the track (that’s the word “Audio 1” in the image below). The next region, named “1” in the image below, is a button which allows access to the input routing. Please see the Understanding Routing and Recording Audio chapters for more information on input routing. The last narrow region controls phase reversing (we won’t go into details on this topic in this tutorial).

Processor Box

The large black region at the bottom of this section is the processor box. This is where you can add plugins, for example. The signal flow in the mixer strip is top-to-bottom. It starts with the input on top, the topmost plugin in the box is the first one in the effects chain, the one in the bottom is the one applied last.

The processor box will always contain a blue fader processor. This indicates where in the processor chain the main channel fader is located — this is the fader shown in the lower half of the strip. Please see Using Plugins and Using Sends for a detailed discussion of this area.

There are additional views and controls possible in the processor box, as seen on the screenshot above:

1. Inline displays. Some plugins can display a mini-overview of their settings, e.g. an equalizer can display a preview of how various frequency bands are affected. And some plugins are written with just this objective in mind — to provide a quick overview of something in the mixer strip. Ardour comes with two such plugins, an inline scope and an inline spectrogram.

2. Plugin controls. It’s possible to add controls to various plugins in a mixer strip. That way, for the settings that you tweak most often, you don’t need to open a plugin’s window every time, you can just drag a slider left and right with your mouse or scroll the mouse wheel when hovering a control. Press Ctrl to make smaller increments when dragging or scrolling.

To control both these features, use Controls submenu in the right-click menu of a plugin. As inline displays are enabled by default, all you can do is disable it (and then enable back). To enable a control for a plugin, simply click on its name in the menu.

The next portion of the mixer strip includes controls for panning, record, mute, and solo, among others.

Panning

Panning commonly has to do with placement of sounds anywhere between left and right speakers to help separating instruments from one another by placing them in different parts of a virtual room.

Depending on the amount of channels in a track, Ardour will provide a dedicated user interface to control panning. In the screenshot below, a mono track is on the left and a stereo track is on the right:

Please refer to the Panning chapter for more information.

Soloing and Muting

Tracks and busses can have two additional related states: soloing and being muted.

Any track or bus on mute will be inaudible through the Master bus or the Audition. The track mixer also contains a miniaturized Mute button, in between the Record Arm button and the Solo button. Right-clicking on the Mute button gives you advanced options for the behavior of the mute button.

When a track or a bus is soloing, all the other tracks and busses are inaudible through the Master bus or the Audition, unless you solo them. So if you need to play just two tracks out of eight, you don’t have to mute six other tracks, you only need to solo those two. Please note that soloing a bus will not silence any tracks and vice-versa.

When any track or bus is on solo, the solo indicator in the Auxiliary Controls menu will flash red. Clicking the solo indicator while it is flashing will deactivate every solo in the session.

Arm Record

The Rec button arms the track for recording, as seen in the Recording Audio chapter.

Fader, Fade/Peak Meters

The most prominent control present in a mixer strip is the fader, used to adjust the overall gain for the corresponding track or bus. The peak meter shows the peak value of the selected track, and is located directly to the right of the fader. Each peak meter consists of one bar graph in the case of a mono track, and two bar graphs in case of a stereo track. The small rectangular field above the meters shows the highest peak value that has been played on that track so far.

By clicking the right-hand button at the bottom of the mixer strip (it reads “post” in the image above), you will be able to select the metering point, for example the direct “in” from the sound card, the “pre” Fader signal, or the “post” fader signal.

As you can see in the image below, there is a smaller version of the mixer strip in each track, called the track mixer, which contains a horizontal fader, a vertical peak meter, as well as miniature buttons for arm record, mute, and solo. They all mirror those found in the mixer strip for that track.

Please refer to the chapter on Mixing Levels for more detailed instruction about using the fader and peak meters.

Routing

Finally, we reach the bottom of the mixer strip. Here we find the Output Routing button, marked as “Master” in the earlier screenshot, because it connects to a bus called “Master”. This was discussed earlier in the Understanding Routing chapter.

Continuing

Now that we’ve had a look at the main areas of the mixer strip, we can proceed to the Mixing Levels chapter to see how we can start to use it.

Next: MIXING LEVELS