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Configuring Apollo's I/O for Hardware Inserts in Pro Tools


  • This article covers configuring the I/O of rackmount Thunderbolt Apollo interfaces (Apollo silver w/ TB option card, Apollo 8, Apollo 8p, Apollo 16 w/ TB option card, Apollo 16 mkII) in order to use Hardware Inserts in Pro Tools. If using an Apollo Twin, see the Using Hardware Inserts with Apollo Twin article.
  • If using an Apollo silver or Apollo 16 via FireWire, use the "PT Mode" option (Console > Settings > Hardware) to configure the I/O for hardware inserts. For more information, see the "PT Mode" section in the "Working With Apollo" chapter of the Apollo Software Manual (FireWire)
  • In UAD v9.0 and later, the "Core Audio" panel is labeled as the "I/O Matrix" panel. The Core Audio panel settings in this article apply to the I/O Matrix panel in UAD v9.0 and later as well. 


Console Core Audio Setup

In order to use the “Hardware Inserts” feature in Pro Tools, you will first need to change the default I/O setup on the Core Audio page of Console Settings (Console > Settings > Core Audio).

The Pro Tools Hardware Inserts feature requires that you connect your external gear on the same input and output channels of your Apollo interface, i.e., Line Inputs 1-2 and Line Outputs 1-2. In the default Apollo I/O setup, the first two input channels are Mic/Line/Hi-Z 1 & Mic/Line/Hi-Z 2, however the first two output channels are Monitor L and Monitor R. In order for the channels numbers to correspond, we must insert “null” values for the first 2 inputs so that Mic/Line/Hi-Z 1 lines up with Line Output 1, Mic/Line/Hi-Z 2 lines up with Line Output 2, and so on.

If you are using an original (silver) Apollo or Apollo 16, you can select one of the I/O presets already available that matches your configuration which will align your line inputs and outputs automatically. For example, if you’re using a single Apollo (silver), select the “Single-Apollo PT Legacy” preset from the I/O Preset menu. If using a single Apollo 16 (silver), select “Single-A16 PT Legacy”. Once you have selected the appropriate I/O preset for your system, proceed to resetting the Pro Tools I/O as described below.

Selecting an I/O Preset

If you’re using an Apollo 8, Apollo 8p or Apollo 16 mkII , you will need to manually configure the Apollo’s I/O on the Core Audio page of Console Settings.

To do this, select the first input channel and set it to “none”. Repeat for the second input channel as well.

Inserting “null” inputs for input channels 1 & 2

Reassign input channel 3 to Mic/Line/Hi-Z 1, then use the Cascade switch to change the input channels below in sequence. See Chapter 6 of theApollo Software Manual for details on using the Cascade switch. Note that if you are unable to see all of your input list without scrolling, you will need to repeat the Cascading process from where you left off after scrolling down to reveal the bottom of the list.

Reassigning Mic/Line/Hi-Z 1 to the third input channel

Using Cascade to reassign the remaining input channels in sequence

Note: If you don’t want to waste the first two input channels of the Apollo with empty values, you could also reassign these to a pair of digital inputs such as S/PDIF (Apollo, Apollo 8, Apollo 8p) or AES/EBU (Apollo 16 or Apollo 16 mkII) to get the most out of the 32 I/O channels available in Pro Tools.

Confirm that your line inputs and line outputs now line up as shown above, save your routing using the “Save” button at the top of the Core Audio page, and proceed to resetting your Pro Tools I/O setup.

Pro Tools I/O Setup

Follow the directions below to reset your Pro Tools I/O:

  1. You will first need to make sure that the Apollo is selected as your Playback Engine within Pro Tools. To do this, open Pro Tools and navigate to Setup > Playback Engine and make sure 'Universal Audio Apollo' is selected.

  2. Next, navigate to Setup > I/O and click on the 'Input' tab when the I/O Settings window appears.

  3. On the 'Input' tab, select all paths shown and click 'Delete Path'. Delete all paths on this tab so it is completely empty.

  4. Once all paths are deleted, click the 'Default' button. This will re-populate the tab with the correct paths.

  5. Repeat these steps for the 'Output', 'Bus' and 'Insert' tabs as well.

  6. On the 'Insert' tab, Apollo's MON out uses output pair 1-2, so you have to make this final adjustment to line up your hardware inserts: drag the entire set over one pair so that Insert 1-2 is using I/O 3-4, Insert 3-4 is using I/O 5-6, and so on.


Dragging the Insert Paths to the right

Now that the Apollo’s line inputs and line outputs have been aligned and the Pro Tools I/O reset, you can conveniently route audio to and from your outboard gear from an insert slot within Pro Tools - just make sure to mute the Console channels corresponding to the line inputs that the return signal from your outboard gear is being fed into to avoid double monitoring.

Pro Tools Delay Compensation

Yet another important factor to consider is that you will now have to manage Delay Compensation in Pro Tools manually on a track by track basis - not just turn it on and off globally. It's easiest to describe it with an example, so try this:

  1. Create three stereo audio tracks.
  2. Set the output of Audio 1 to Bus 1-2
  3. Set the Input of Audio 2 to Bus 1-2 and Input enable it
  4. Create a Stereo Send on Audio 1, send it to Bus 3-4 and set it to unity gain
  5. Set the Input of Audio 3 to Bus 3-4 and Input enable it
  6. Insert a hardware pair on Audio 3 (you can use a patch cable between outputs and inputs to pass audio)


Now, look at the Delay Compensation numbers in the Mix Window. You'll see Audio 1 and Audio 2 are all 0 and Audio 3 shows 2351 in the top slot (Delay Indicator).

Drop a piece of audio onto Audio 1 and play it. You'll hear a delay between the two tracks. This is because Audio 2 is not being delayed to match the hardware insert on Audio 3.

Now, Control + Command Click on the bottom number of Audio 2 (Track Compensation Indicator). You'll notice it turns blue and goes to 2351 (the same number as Audio 3).

What you've done is isolated Audio 2 from the delay comp scheme so that Audio 2, which has no hardware inserts on it, has the same amount of delay compensation as Audio 3, which does.

This is a bare bones example, but you can use the same principles as your routing schemes become more complex with busses and other audio tracks.

Just keep in mind where your delays are and which elements need to be delayed and go from there.

Final Note: See the Hardware Inserts section of the Pro Tools manual for your version of Pro Tools for more information on the Hardware Inserts feature. Please note that only a real time bounce to disk will capture the return signal from Hardware Inserts.

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