# Setting the Sample Rate

| ##  | ## Symphony Audio Interface Mode

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When Symphony I/O is connected to a Symphony 64 PCI card, Core Audio (part of the OS X operating system) sets the sample rate of the hardware system, including the Symphony I/O. Audio applications such as Apple Logic, in turn, set the Core Audio sample rate.

When clock source is set to Internal, Symphony I/O's sample rate is determined by the sample rate of the DAW session. If no DAW session is open, the sample rate is determined by the rate set in the OS X utility Audio MIDI Setup.

To set the sample rate in Audio MIDI Setup:

> > 1. Open Audio MIDI Setup (found in Applications > Utilities).

> > 2. Choose Window > Show Audio Window if the Audio Devices list isnʼt visible.

> > 3. Click on Symphony 64 in the left hand devices list.

> > 4. Select the desired sample rate in the Format drop down menu.

> > 5. When clock source is set to any external source such as word clock, Symphony I/O's sample rate is detected from the external source. Be sure to match the sample rate of the external source to the DAW session sample rate.

To set clock source from Maestro software.

> > 1. Click the System Setup tab
> > 2. Set Clock Source to Internal.

> > 3. Choose the desired sample rate in the Sample Rate drop down menu.

Itʼs important to note that when Symphony I/O is clocked to an external source, the sample rate of the external source must be set to match the Core Audio sample rate. For example, if Symphony I/O is locked to an Apogee Big Ben Master Clock, be sure to set Big Benʼs sample rate to the same rate as your DAW audio application session.

| ##  | ## Pro Tools HD Audio Interface Mode

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When Symphony I/O is connected to Pro Tools HD cards, the sample rate is set in Pro Tools software when creating a session. Once a session is created at a specific sample rate, it can't be changed from that rate.

Itʼs important to note that when Symphony I/O is clocked to an external source, the sample rate of the external source must be set to match the Pro Tools session sample rate. For example, if Symphony I/O is locked to an Apogee Big Ben Master Clock, be sure to set Big Benʼs sample rate to the same rate as your Pro Tools session.

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| ##  | ## USB Audio Interface Mode

When Symphony I/O is streaming audio to a Mac via USB, Core Audio (part of the OS X operating system) sets the sample rate of the hardware system, including the Symphony I/O. Audio applications such as Apple Logic, in turn, set the Core Audio sample rate.

When clock source is set to Internal, Symphony I/O's sample rate is determined by the sample rate of the DAW session. If no DAW session is open, the sample rate is determined by the rate set in the OS X utility Audio MIDI Setup.

Please consult the heading Symphony Audio Interface Mode above for instructions to set the sample rate in Audio MIDI Setup

| ##  | ## Standalone Audio Interface Mode

When clock source is set to Internal, Symphony I/O's sample rate may be set in Maestro software or using the front panel encoders.

To set sample rate from Symphony I/Oʼs front panel:

> 1. Press and hold the left hand encoder until the current clock source is shown on the OLED Display.

> 2. Turn the left hand encoder until INT (Internal) is displayed.

> 3. Turn the right hand encoder to the desired sample rate.

> 4. Click either encoder to confirm the new selections.

To set sample rate from Maestro software.

> 1. Click the System Setup tab
> 2. Choose INT in the Clock Source drop down menu, then choose the desired setting in the Sample Rate drop down menu.