Setting up and configuring Symphony I/O for Pro Tools HD

The following instructions describe the use of Symphony I/O with Pro Tools HDX, HD Core/Accel and HD Native PCI cards. Note that with Release 4.2 and greater, Symphony I/O (in Pro Tools HD audio interface mode) emulates an Avid HD I/O interface. With Release 4.1 and lower, Symphony I/O emulates an Avid 192 interface. When working with Pro Tools software and Symphony I/O, it may be helpful to keep in mind the following principles of operation.

  • Each installed I/O Module is detected in Pro Tools' Hardware Setup as an Avid HD I/O interface, and transmits and receives 16 channels of audio with the Pro Tools HD PCI card.
    • When 1 I/O Module is installed (or 1 I/O Module plus a Mic Pre Module), Symphony I/O is detected as 1 HD I/O, providing 16 bi-directional audio channels.
    • When 2 I/O Modules are installed, a single Symphony I/O is detected as 2 HD I/Os, providing 32 bi-directional audio channels (as shown below).
  • Symphony I/O's clock source is set from Pro Tools software; Symphony I/O's sample rate is set by the Pro Tools session.
  • Any other Pro Tools hardware commands (mostly in the Hardware Setup window) are ignored by Symphony I/O.
  • Other Symphony I/O settings, such as levels and formats, are made in Apogee Maestro software, which communicates with Symphony I/O via the USB connection. Symphony I/O is detected in Apogee Maestro as a USB device. 

A Symphony I/O in Pro Tools HD mode is compatible with the following:

  • HDX
  • HD Native PCIe
  • HD Native Thunderbolt
  • HD Core/Accel/Process PCIe

For the rest of the instructions, we will refer to whichever HD card(s) or HD Native Thunderbolt box you’re using as “the HD card”.


1.  Confirm that you have Pro Tools HD v8.1.1 or higher installed on your Mac or PC, along with the applicable HD driver (a separate install) and a connected iLok with HD license.

2.  If you’re using more than one Symphony I/O, make sure the unit that’s going to be connected to Port 1 has two I/O modules installed, as explained in greater detail here.

3.  Power up the Symphony I/O and make sure it's in 'Pro Tools HD' mode by pushing in and holding on the right-side front-panel encoder and scrolling through the different modes until you get to 'Pro Tools HD' and then push in on the encoder again to restart the unit in 'Pro Tools HD' mode.

4.  You can not daisy-chain Symphony I/Os off of Avid interfaces or other Symphony I/Os. Since the Symphony I/O can contain 32 channels of I/O in one unit, it needs a dedicated port on the HD card. Connect the first Symphony I/O to Port 1 of the HD card (if you’re using an Avid or Digi interface and you already have it connected to Port 1, you can connect the Symphony to Port 2 of the HD card). Connect any additional Symphony I/Os to the next port on the HD card(s). Keep in mind that each Symphony I/O will need its own port on any HD card.

5.  If you are using only one Symphony I/O and no other Avid or Digi interfaces, you can skip to the next step. If you’re using multiple interfaces, you will need to connect them all via Loop Sync, using BNC cables. Connect the Loop Sync output of the 1st interface to the Loop Sync input of the 2nd interface.  Connect the Loop Sync output of the 2nd interface to the Loop Sync input of the 3rd interface and so on.  Once you come to the last interface in the chain, send its Loop Sync output to the Loop Sync input of the 1st interface.  If you’re using a Digi Sync I/O or an Avid Sync HD, you would do the same thing, except you would treat the Sync I/O  or Sync HD as the 1st interface and start by sending its Loop Sync output to the Loop Sync input of the 2nd unit and so on until you bring the Loop Sync output of the last unit in the chain to the Loop Sync input of the Sync I/O or Sync HD. Your Sync I/O or Sync HD must be connected to your HD card using the serial cable that was included with it to use it.

6.  Make sure all Symphony I/Os and any other HD interfaces are connected properly and powered up and then launch Pro Tools HD.

7.  After Pro Tools HD has launched, click on the ‘Setup’ menu in Pro Tools and select ‘Playback Engine’. Confirm that HD, HDX, or HD Native is selected as the ‘Current Engine’.  If it’s not, select it and click ‘OK’.  If it wasn't already selected in the Playback Engine and you had to select it, you will need to quit/relaunch Pro Tools after doing so.

8.  Click on the ‘Setup’ menu in Pro Tools and select ‘Hardware’.  Confirm that the expected interfaces show up in the correct order under the ‘Peripherals’ column in the upper left-side corner.  Keep in mind that each I/O module in a Symphony I/O will show up as one Avid HD I/O.  Once you have verified this, click ‘OK’ to exit.

9.  If you are not using a Sync I/O or Sync HD, you can skip to the next step.  If you are using a Sync I/O or Sync HD, click on the ‘Setup’ menu in Pro Tools and select ‘Peripherals’ and go to the ‘Synchronization’ tab.  Under ‘Synchronization Device’, select ‘Enable Sync HD’.

10.  Click on the ‘Setup’ menu in Pro Tools and select ‘I/O’.

11.  Once the I/O Setup opens, select all of the channels in the left-hand column and hit ‘Delete’ on your keyboard.  After you’ve deleted them, click the ‘Default’ button in the lower part of the screen and confirm that the "Compensate for delays…” checkbox is checked. Follow the same steps for the input, output, bus, and insert tabs in I/O Setup. Once you have gone through these steps in each tab, click the ‘OK’ button to confirm changes and exit.

12.  You are now ready to use Symphony I/O with Pro Tools HD.

*  Keep in mind that the first 2 analog outputs of Symphony I/O will default to a -20dB level for using the Symphony I/O as a monitor controller. If you are using an external monitor controller and would like all of the Symphony I/O’s outputs to be at 0dB line level, first make sure your external monitor controller is turned down all the way.

There are 2 ways to set the main first 2 analog outputs to 0dB Line Level:  you can raise or lower the level of outputs 1-2 from the front-panel by using the left-side knob to set the control for speaker (the speaker icon will be visible) and then using the right-side knob to raise the level to 0dB (make sure you're not setting the headphones to 0dB) or from launching 'Apogee Maestro' from your Applications folder, going to the 'Output' tab, scrolling all the way to the right until you see the Main Output control knob (with the speaker icon), and clicking on the drop-down menu and changing the selection to 'Line'.

*  If you would like to change the headphone routing on the Symphony I/O, you will need to launch 'Apogee Maestro' from your Applications folder and go to the 'Output' tab. Scroll all the way to the right until you see the 2 headphone level knobs.  Click on the drop-down menus next to them and you will see a list of all the available outputs you can send to the headphones.