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Electronic Theatre Controls Inc

Output level conventions in Express consoles

The console uses both a highest level, or pile-on, convention and a last action convention to determine levels for channels affected by more than one control. Channels may be defined to operate with either convention.

HTP channels


The behavior of a pile-on channel is defined by the Highest Takes Precedence (HTP) rule. The console reads all output levels it receives for an HTP channel and sets that channel to the highest of them. A channel controlled by a submaster always obeys the HTP rule, but the Blackout key, Grandmaster control and parked channels all have priority over levels set from the keypad.

For example, if an HTP channel is included in both a submaster and a cue that has played back and is in a fader, the console sets the channel at the higher of the two levels. Or, you may use the keypad to select that channel and set it to any level, regardless of the levels set either by the cue or the submaster.

HTP channels in the console are called “normal” channels.

LTP Channels

Channels may also be defined in the console to follow the Latest Takes Precedence (LTP) rule. An LTP channel obeys the latest command to set its level. When the command is to fade to a level, an LTP channel can fade either in a physical fader (in the foreground) or in a background fader. Each LTP channel has its own background fader.

An LTP channel fades in the foreground if its level moves to a new level in the next cue. When a channel is fading in the foreground and no change in that channel is commanded by the next cue, the fade continues in the background. A cue stops running in the background when the last of its channels stops fading in the background. Up to 600 cues may run in the background at once.

For example, consider three cues recorded for channels Chan 1, Chan 2 and Chan 3, all of which are set as LTP channels.

The cues contain percentage levels for these three channels as follows:

  Chan 1 Chan 2 Chan 3
Cue 1 25 0 0
Cue 2 25 50 0
Cue 3 50 50 50
  • When Cue 1 starts, channel Chan 1 starts fading to level 25 with Cue 1 timing.
  • If Cue 2 starts before Cue 1 ends, channel Chan 1 continues fading in the background with Cue 1 timing and channel Chan 2 starts fading in the foreground to level 50 with Cue 2 timing.
  • If Cue 3 starts before Cue 2 ends, channels Chan 1 and Chan 3 start fading in the foreground to level 50 with Cue 3 timing; channel Chan 2 continues fading in the background with Cue 2 timing.

Enabling LTP

You can set a channel’s status to LTP or HTP as long as the channel is not used in Fixture Patch. If the channel is patched to a fixture, the personality controls the HTP/LTP status. All attributes (channels) are set to LTP by a personality except the intensity attribute. All channels not patched to a fixture default to HTP (considered “normal”).

Set channels to HTP or LTP, either singly or in ranges, in the Channel Attributes display using the following procedures.

Keystrokes: Action:
1. Press [Setup] [1][1] [Enter]. Selects the channel attributes display
2. Press [1] [Thru] [1][0] [Enter]. Specifies channels 1 through 10
3. Press [→] [→] [→] [→]. Move to LTP field
4. Press [1]. Sets channels to LTP

Working with LTP channels

Background overrides

Cues running in the background can be stopped, adjusted or otherwise controlled with background overrides.1 There are five override options, as shown in the table below.

Background Override Operations
1. Clear Cue(s) Clears cue levels.
2. Cancel Cue(s) Stops the fade or effect.
3. Finish Cue(s) Takes proportional control of cue levels immediately.

4. Master Cue(s) on X-Wheel

Takes proportional control of cue levels immediately.
5. Alter Rate of Cue(s) on X-Wheel Adjusts cue timing.

Control background overrides as follows:

Keystrokes: Action:
1. Press [Stage] [S3],
Background Overrides.
Selects the Background Overrides list
2. Press [5] [Enter].a Specifies cue 5
3. Press [#] [Enter]. Specifies the override operation you want performed

a. Identify which cue contains a particular channel from the About Channel display, covered under About Channel.


LTP channels may be used to preserve an effect in certain channels regardless of levels in the effect. Also, multiple effects can run simultaneously, and other looks can be provided concurrently with effects.

These features are available in the console when you use LTP channels. When an effect cue is sandwiched between two other cues, LTP channel levels in the effect cue are ignored when determining which control takes precedence. A cue that runs after an effect skips over the previous effect cue to determine what happens to levels. If there is a move in the current cue with respect to the same channel in the cue before the effect, the channel fades in the current cue and is “stolen” from the effect. If no move, the channel continues in the effect.

Blocking cue

A cue running in the background ends when its last fading channel has finished or a background override ends the cue prematurely. Sometimes, however, you would like to end a background cue prematurely.

The way to do that is to follow the background cue with a blocking cue. A blocking cue does to timing what an allfade cue does to level. As soon as an allfade cue is started, all unused channels are forced to zero.

Similarly, when a blocking cue starts, all channels running in background cues are faded to completion in the blocking cue’s timing. A blocking cue ends all background cues.

Aside from its initial effect on background cues, the blocking cue runs from that point on just like any other cue, including the possibility that it could be forced to the background itself by the next cue.

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