Each track and bus is represented in the mixer window by a mixer strip that contains various controls related to signal flow. There are two places in Ardour in which you can see mixer strips. The mixer window is the obvious one (and the one we deal with here), but you can also view a single mixer strip in the editor window by clicking the editor mixer button. this image needs replacing with labels and better resolution The mixer strip for a bus is essentially identical to the one for an audio track, but it is missing certain controls that make no sense - you cannot record into a bus, so there is no record enable button, for example. The mixer strips are designed to visually model signal flow. The input button selects the input of the track that this mixer strip monitors. The outputs of the track (the 'tape recorder') are 'hard-wired' to the inputs of the mixer strip. Think of the input to the strip starting at the polarity switch, flowing down through the prefader inserts/plugins/sends section, through the gain fader, past the postfader inserts/plugins/sends section, the panner, and out through the output selector. In the case of a bus, there is no 'tape machine' inserted between the input selector and the actual input of the strip, but the signal flow is identical otherwise.

the button on the top left of the mixer strip is labelled with two arrows separated by a line. Left clicking this button will reduce the horizontal size of the mixer strip. Clicking it again will restore the previous size. The first click also has the effect of shortening the names of controls. Plugin lists become very small in this mode, however more faders are accessible without scrolling. Your needs may vary, hence the existence of this button.

The button opposite the Narrow Mixer Strip Button hides the mixer strip from view. this button has no effect on signal flow or muting. When a mixer strip is hidden, it's entry in the strips list is darkened. To restore the mixer strip to the visible state, click it's entry in the strip list with the left mouse button.

The track name displays the current name of the track as displayed in the editor window. right-clicking on the name brings up a drop-down menu that allows you to rename, activate, deactivate and remove the track. Selecting Rename opens a new window displaying the name of the track. to change it, type your change and press ok. to leave it unaltered, press cancel. Selecting remove opens a new window asking for confirmation of your track removal request. removing a track removes that track from the project. If the playlist used by the removed track is not used by any other track, it will also be removed.

The group button displays the name of the currently selected mix group. if no group is selected, it will read no group. when clicked, a drop-down menu appears which lists the current mixer groups, along with the option no group. if a group is selected, any fader movement on one of the group member faders will be translated to the other members of the group.

The input selector allows you to assign hardware or software inputs to the track that this mixer strip monitors. clicking on the input box makes a drop-down menu appear which lists ready-made combinations of jack ports, along with the options disconnect and edit. You can either select a preset hardware input combination from the drop-down list, or select edit to open the input selector window which allows finer control, such as changing the number of inputs to the track or using software devices as inputs. For more information on this window, see . Disconnect removes all input assignments while leaving the number of ports untouched.

The polarity button, when pressed, inverts the phase of the signal as it leaves the track and enters the mixer strip. it has no effect on the signal being recorded to disk. It has no effect on the timing of the signal, either.

The solo button puts the mixer strip in solo mode. the solo indicator in the editor window will flash if any mixer strip is set to solo, and only those tracks that are set in solo will be routed through the system.

The mute button mutes the output of the mixer strip.

The track speed allows a varispeed setting to be applied to the track. a setting of 1.0 corresponds to the normal playback speed of the session. a setting of 0.5 will play at half normal playback speed. when altered, the track will be redrawn to reflect the new position of the audio resulting from the speed change. The Track Speed Control has three decimal places of precision. A left or right click on the displayed number will raise or lower the track speed by 0.1%. when the speed is not exactly 1, the display will be coloured red. Hovering over the displayed number will allow you to use the mouse wheel to set the desired speed. A middle click on the displayed number will return the speed to exactly 1.

The record enable button arms the track for recording. pressing this will change the way you monitor and meter the selected input signal depending on the state of the monitoring settings in the options editor, as well as the auto input setting in the editor.

The automation mode buttons allow you to select a fader or pan automation mode from a drop-down list. see for more information about automation modes.

These dark areas above and below the fader allow you to place inserts, sends and plugins into the signal path before and after the fader respectively. you may also easily reorder them whilst playing. collectively, the objects that belong in these boxes are called redirects. If there are redirects present in the channel, they can be reordered by dragging them vertically. because plugins and inserts can have different numbers of inputs to outputs, sometimes you may reach a situation where the inputs and outputs cannot be all connected sensibly. in this case, your reordering change will be disallowed by the program. Right clicking within the dark area will bring up a drop-down menu which allows you to manipulate the redirects in various ways. new plugin selecting new plugin will open a dialog which lists the plugins available on your system. selecting a plugin which is compatible with the number of streams in the channel at that point will result in the plugin being placed in the redirect box in an inactive state. this is indicated by the brackets around the plugin name. double-clicking the plugin name will bring up a window that allows you to control the parameters of the plugin statically (including bypass) or using automation. all plugins that report their latency are time-compensated automatically in ardour. new insert places at least two new jack ports at that point in the mixer strip (one input, one output). these ports will then be available to any jack client (including Ardour itself), allowing another program (or channels within another program) to be inserted across the channel. hardware ports may also, of course, be used, allowing the insertion of outboard equipment. the insert will then appear in the redirect box in brackets indicating that it is inactive. to activate or deactivate an insert, right-click on it and select activate. double-clicking on the insert will bring up a dialog which allows to to assign its inputs and outputs to other jack ports. new send selecting new send will first bring up a dialog box that enables you to select the number of outputs the send has, along with the destination of each output. closing this dialog will reveal the name of the send in brackets, indicating that it is inactive. to activate the send, right click on it and select Activate. double-clicking on the send brings up the previous dialog, which will now include a fader which is provided for level control. clear selecting clear in the menu removes all redirects from the mixer strip (pre and post fader). you can remove an individual redirect by holding the shift key and right clicking it. cut, copy, paste these items allow you to cut, copy and paste plugins, including their current settings, between Redirect Boxes. rename selecting rename will bring up a dialog displaying the name of the selected redirect. change the name by typing into the text area and pressing ok. select all/deselect all these two options select or deselect all plugins in the channel. this could be used, for instance, in preparation to copy all plugins from a channel to another one, along with the current settings. activate/deactivate selecting either of these will activate or deactivate the currently selected redirect(s) respectively. deactivate is the equivalent of bypass. note that you can bypass a plugin from it's parameter window as well as from here. activate all/deactivate all selecting either of these will activate or deactivate all redirect(s) in the mixer strip respectively. deactivate is the equivalent of bypass if you're a plugin. edit selecting edit brings up the controls relevent to the selected redirect. this is the equivalent to holding control and right-clicking on a redirect. note that the right click method will not bring up the controls of the selected redirect, only the one beneath the mouse pointer.

This button cycles between three metering modes, which determine which signal is fed to the meters. the modes are pre-fader (the signal at the input to the fader), post-fader and input (the level at the track input). left clicking cycles through the three modes one step at a time, while middle-clicking alternates between the current setting and the setting two steps ahead. this allows one-click direct a/b comparison between all available monitoring points.

this control displays the current gain of the fader to the nearest 0.1dB. left clicking on the value will lower the gain by an amount dependent upon the fader position the graduations become smaller as the fader nears 0dB gain. right clicking increases the gain by the same amount. middle clicking resets the gain to 0dB.

Right clicking on the meter bars allows you to select the range of signal levels displayed by the meters. the selected range will be displayed as a column of numbers next to the meter. /*XXX this feature is currently not working*/ Gain Level Display

This control displays the highest peak since the last peak meter reset. Resetting the peak meter is achieved by left-clicking the displayed number. The peak meter monitors the signal selected by the Pre/Post/Input Button .. the same signal as the meters. It should be noted here that 0dBfs corresponds a value equal to the maximum input or output level of your audio hardware, independent of it's bit depth.

The fader changes the signal level within the mixer strip before the post-fader plugins, which are before the output ports. 6dB of gain is allowed. there are several shortcuts available for the fader. Using the scroll wheel of your mouse while hovering above the fader will coarsely change its position. Holding the control key whilst mouse wheeling will give you finer control. Holding the shift key and clicking the fader will reset it to unity gain. Holding control and pressing the middle mouse button whilst over the fader will allow you to bind a midi control to it, provided you have an available midi device set in the options menu.

The number of meters displayed next to the fader is dependent on the number of inputs or outputs the channel has, whichever is greater. The meters provide a colour-graduated scale from -50 dBfs to +6dBfs. They display the instantaneous value of the signal at the monitoring point selected by the Pre/Post/Input button. 0dBfs corresponds a value equal to the maximum input or output level of your audio hardware, independent of it's bit depth. Exceeding 0dBfs does not correspond to running out of headroom within the mixer, or in any signal path subsequent to that point within the Jack server. It merely means that if that signal is connected directly to a hardware port whose resolution is less than the 32-bit floating point resolution that Ardour uses (i.e. a soundcard), then that port will exceed it's maximum output level, resulting in distortion. hitting 0dB within the mixer (or any point in the Jack server) means that you have approximately 100dB of headroom remaining. as it is unlikely that you will reach this point, it is not represented in any special way by the meter. Naturally, if the input is selected as the monitoring point for the meter, exceeding 0dBfs means that the input of your a/d converter has clipped.

The panner in Ardour is actually two panners. Because any mixer strip in Ardour can route any number of streams of audio anywhere, the idea of panning can be a complex one. To allow for the current stereo-centric mainstream world as well as the multi-speaker experimental one, one of two styles of panner will appear here depending on the number of outputs the channel strip has. In the simple case of mono channel input / stereo output, a single panner will be present. The current pan position is represented by a dot (the dot is the audio stream) which lies between the letters 'L' and 'R', which represent the left and right outputs respectively. To change the panning position of the stream, move the mouse while holding down the left mouse button. the dot will follow your mouse pointer. To introduce sudden changes to the pan setting, place the mouse pointer over the desired position and click the middle mouse button. The pan control will immediately snap to the mouse pointer position. The panner may be bypassed by right-clicking the control and selecting bypass from the drop-down menu. The panner will immediately be bypassed. The increased level you notice when the panner is bypassed is due to the way panning works. It is not a bug. XXX what gain law is used in the panner? In the case of a stereo input / stereo output combination, two panning controls will appear, one corresponding to each audio stream. You can link the controls together in two different ways in this situation, using the direction arrows next to the link button. Panners can be linked to travel either in opposite directions or to maintain a consistent stereo width across the travel of the control. These two modes are represented by the orientation of the two arrows next to the link button, which point in either the same or opposite directions. The link button must be engaged before you can change the link mode. To link all the panners in a mixer strip, left-click the link button, then select the desired link mode by pressing the button marked with arrows. Let's get a little more complicated by adding another output to the mixer strip. From this point onwards, the panning positions are represented with numbered dots on a square field. Orange dots represent the outputs, and the numbered dots represent the streams. the position of the outputs change according to the number of outputs in the strip. This happens in order to allow the most useful arrangement of the available space. At some point, adding an output will cause the outputs to line up from the top left of the panning square towards the centre. this is to allow for the 'multi-speaker big sweep' to occur - where the sound is panned from speaker to speaker around the room in sequence. Don't forget that you can bypass the panner by right clicking and selecting bypass from the drop-down menu. this may simplify your multi-speaker setup, as often in this type of project panning between all speakers or outputs is not required on all tracks.

The output selector allows you to assign the outputs of each mixer strip. left-clicking the output selector causes a ready-made list of output ports to appear in a drop-down menu, along with edit and disconnect options. Selecting Edit will allow you to change the number of outputs the channel has, as well as select software and hardware ports to route signals to. For more information on the window that appears when you select this option, see the . Disconnect will leave the number of output ports unchanged, but remove all assignments to output ports.

This is the text area below the output button. it allows you to enter any notes that you feel may be relevant to that track. The notes are stored when you save the session.