eMotion LV1 Tutorial 6.3: Extras – Delay and Delay Compensation

Feb 27, 2017 | 8,232 Views

Learn how to time-align and sync plugin latency in racks, channels, busses, groups and more with delay compensation the eMotion LV1 live mixing console.

eMotion LV1 can host plugins on every channel and buss. Different channels will likely use different plugins, each of which can impose different delays.

When racks, channels, or busses are summed, they must be time-aligned as a group. Otherwise, the different signals in the buss will be out of sync. In order to get things to line up, all the signals in the buss are delayed to sync with the signal with the greatest latency. This process is called plugin/buss latency compensation.

In this example, channel 1 has a total latency of 100 samples, a result of the plugins in its rack. Channel 2 shows only 10 samples of latency, and channel 3 has none at all. When these three busses are summed, channels 2 and 3 must be delayed. Channel 2 gets a delay of 90 samples, and channel 3 picks up the entire 100 samples. These three busses are now time-aligned, and the total latency is 100 samples.

To learn a channel’s latency, go to a plugin’s drop-down menu. The latency section shows how much latency the selected plugin is declaring to the latency compensation engine. It also shows the total latency of this plugin rack.

When busses are summed with other busses, it’s likely that more latency compensation will be needed. This process continues until the mixer output.

To see the effect of multiple-buss latency compensation, go to a main out, or group, or aux—any channel in the signal flow that’s later than the input. Rack Latency: now shows the latency of the rack, plus all the busses preceding it. If you move later in the signal flow, the Total Latency will likely increase.

You can set whether or not a plugin’s delay is included in latency compensation calculations. Let’s say you have several plugins in a rack, each with little or no latency. Now, add a latency-heavy plugin and the whole rack will be delayed accordingly, because of latency compensation. If it’s really important that all of the plugins in the rack are aligned, you’ll just have to live with that latency. But if the plugin with lots of latency is not terribly sync sensitive, you can turn off latency compensation for that plugin only. The plugin will still work, and it will still be delayed. But it won’t be a part of delay compensation calculations.

You can also set how the mixer manages output delay. There are two output routing latency modes:

In the ENTIRE MIXER ALIGNED mode, all mixer outputs are aligned with each other. The whole mixer is subject to the total delay of all the busses, so all mixer outputs line up with the buss with the highest latency.

ALIGN BY MIX BUSS / DELAY GROUP allows each output to be delayed independently. If desired, you can group together several I/Os to form a delay group. The outputs within a delay group align with each other, and they can be delayed together as a group.

I/Os are assigned to delay groups in the Channel window.

Open the Direct Output panel and assign channel direct outputs, if you’ve not already done so.
Select an output from the list. Use the drop-down Delay Groups menu to assign the output to a delay group.
Drag up and down over the Delay value box to add delay to the group. You can change the delay value of an I/O, even if it’s not in a delay group.
To suspend an I/O from the group’s latency calculation, click the ON button.

Go to the Patch window to get an overview of delay group patching.

Select Delay view. On the patch you’ll see the delay group assignments that you made in the Channel window.
Click or drag on the patch grid to add or remove delay group assignments.
If you don’t see the expected I/O channels, click on the I/O’s icon to expand the view.

Group delay is shown next to the delay group name. A delay group is not an audio group. It’s a control group. Assigning an output to a delay group does not affect its routing.

In this lesson, we’ve looked at the basics of delay compensation, and how it’s applied in the eMotion LV1.

Remember, each buss probably has a different delay, because of different processing. So each time busses are summed, the signals must be time aligned. This is done by delaying signals with the least latency to match those with the most.

To better manage delays, you can remove specific plugins from latency calculations. Delay groups let you control the delays of several outputs

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