M-Audio AP-012403 owner manual

If you activate both sets of input and output channels, you will notice that the 24-bit setting in the Sample Depth column is grayed out and the “Maximum sample rate” is shown as 48000 Hz.

NOTE: Whenever S/PDIF Input is selected as an Active Port, the Audiophile is expecting a digital signal at that port and to lock to the sample rate of that signal. When S/PDIF Input is selected and there is no signal present at the S/PDIF Input port, or the S/PDIF signal is not recognized or invalid, the Audiophile USB will not operate properly. Most likely, you will hear audio from the Audiophile, but it will be running at an odd sample rate and sound like it is playing at the wrong speed.

DD/DTS Pass-Thru:Just below the Sample Depth column, you will see a checkbox labeled,“DD/DTS Pass-Thru.” If you are using a Software DVD player and wish to send encoded multi-channel audio such as Dolby Digital or DTS to the Audiophile USB’s S/PDIF output port, then check this box. If you are only sending stereo audio (standard PCM—not encoded surround) to the S/PDIF output port during normal operation, then leave this box unchecked.

If you have this box checked, you can still send stereo digital audio to the S/PDIF port without any problems. However, you will notice that when the DD/DTS Pass-Thru box is checked, ONLY the S/PDIF port is active in the Active Ports column. Unchecking the DD/DTS Pass-Thru box will restore the port selection to the previous configuration.

Latency: Driver “Latency” can be selected from a range of values shown in a drop-down list located just below the “Maximum Sample Rate.” The default setting when the Audiophile is first installed is “Very High.” Because slower computer systems require larger sample buffers to avoid dropouts in the audio stream, a higher latency value is often necessary.

How low you will able to set the Latency will depend on several factors, such as your system’s performance and the performance of the music program itself. To test your system for lower Latency, try the “very low” setting first (as shown in the previous screenshot), and if your system stutters or performance falters, try the next higher setting until the system performance stabilizes. Once you are satisfied with any of the control panel settings, click OK to close the Audiophile USB Control Panel.

Version Numbers: The lower left corner the Audiophile USB Control Panel page displays the ASIO Driver Version, USB Driver Version, and the Firmware Version numbers currently in use. This is useful when checking for driver updates on the M-Audio website, or in the event that you need to call tech support and give them your system information.

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