Symphony I/O: Troubleshooting

How do I use Symphony I/O connected to ProTools HD for audio output of other apps?

– Make sure Symphony I/O is in “ProTools HD” AIM (Audio Interface Mode for ProTools HD, HD-Native, HDX) by pressing in and holding on the right-side front-panel encoder until it comes to the AIM menu. It should say “ProTools HD”… if it doesn’t, scroll through the menu until it does and then push in on the encoder again to select it. The Symphony I/O will power down and then restart in ProTools HD AIM.

– Make sure the Symphony I/O is connected to a ProTools HD (HD, HD-Native, or HDX) card and that you have installed the proper ProTools software.

– Make sure ProTools is NOT open. Also make sure any application you want to use is closed.

– Open Audio MIDI Setup (Applications> Utilities> Audio MIDI Setup) and select the ProTools hardware as the computer’s default output.

– Open up the desired application- for example, iTunes, play an audio file and you should see the ProTools CoreAudio driver open up and see/hear the output on the Symphony I/O.


Clicks and Pops on the Mac

Tip – When experiencing clicks and pops on a Mac, try raising the buffer size in the audio app. In
Logic, for example, choose Logic Pro > Preferences > Audio, click the Devices tab, then the Core
Audio tab, and set the I/O Buffer Size to the next highest number.

How do I set my software’s I/O buffer?

The I/O Buffer setting found in most audio software is one of the most crucial, but often ignored, settings in a Mac-based recording system. When choosing a buffer setting, a compromise between the latency through the application and the amount of computer processor power accessible to the application must be made.Latency– the slight delay between the moment you play a note and hear it in your headphones after conversion and processing.

A lower buffer setting results in lower latency but less available processing power. If the application can’t access enough processor power, processor overruns may occur, resulting in audible clicks and pops or error messages that interrupt playback and recording. A higher buffer setting, on the other hand, results in greater amount of accessible processor power (i.e. less chance of overruns) but increases the latency. Determining the best setting requires some trial-and-error in order to find the best compromise.

Keep in mind that as tracks and plug-ins are added to a software session, processor requirements increase. Thus, the buffer setting that works during the early stages of a session might result in processor overruns during later stages. The best strategy is to set the buffer to a lower setting during recording and accept certain limitations on plug-in usage, and then raise the buffer during mixing to utilize the computer’s full processor power when latency isn’t an issue. With the processing power of today’s Macs, you may find that adjustment of the buffer isn’t necessary, and you can leave it at a setting for low latency and still access a sufficient amount of processing power when adding tracks and plug-ins. If you do encounter clicks, pops or software errors, don’t hesitate to experiment with the buffer setting. Please consult the section on Working with GarageBand, Logic and Mainstage to determine how to se the I/O buffer setting is found in your audio application.

When recording, the input is delayed in my headphones

Decrease the I/O buffer size in your audio application. See “How do I set my software’s I/O buffer?” for more information.