Apple Setup:

Introduction

For an Apple computer there are some options that allow you to record with the Ayre A/D converter. For more information on software choices, please refer to the Recording section after completing the following setup process.

Computer Requirements

There are a few minimum requirements that must be met to achieve reliable recordings to your system from the Ayre A/D Converter. These requirements are as follows:

Computer Setup

Setting up your Mac to get the best sound is quite simple. Here are the steps:

1. Apply power to your Ayre A/D converter. After applying power, connect the USB cable from the A/D converter to your computer USB port.

On the Dock select the “Finder” app.


Select “Places - Applications”, scroll down the list and click on the “Utilities” folder.


Find the “Audio MIDI Setup.app”.


2. Open the “Audio Midi Setup” application and select “Audio Devices”.


In the properties section, select the Ayre USB A/D converter and choose the maximum sample rate in the “Audio Output” section. Normally this will be “192000.0 Hz”. Most recording software will allow you to record at sample rates below this maximum setting, so by setting it to the maximum value here, we prevent the OS from limiting the maximum sample rate.

The Ayre A/D converter will automatically operate in Class Two mode when connected to an available USB 2.0 port on your system. Due to the much higher data transmission rate, it is very important to ensure that the USB cable used and port that the A/D converter is connected to will allow reliable communications. Please see the section on USB Cable Requirements in the general Analog to Digital section if you have not already. To determine whether your USB port is shared or unshared, follow the steps below.

Determining Whether a USB Port is Shared or Unshared

While old or poorly designed USB controller chips can cause problems with Class Two Audio, please remember that the latest version of Snow Leopard is required to reach speeds of 192 kHz. Since Snow Leopard only runs on Intel-based Apple computers, these are all fairly new machines and generally you should not run into any problems in this regard.

However, there is one cardinal rule—for Class Two Audio the Ayre USB A/D converter cannot share a USB controller with any other devices.

To ensure that the Ayre USB A/D converter is running on its own dedicated USB controller is largely a matter of trial-and-error. Normally the physical USB port will be connected to a "smart" controller that automatically changes from USB 1.1 (Full Speed) to USB 2.0 (High Speed or "Enhanced), depending on the requirements of the attached peripheral device. However, there will not be a dedicated controller for each port, so sometimes it may be a bit of a trick to find an arrangement whereby the Ayre USB A/D converter has its own dedicated USB controller.

Many Apple computers will already have internal devices (laptop cameras, IR receivers, Bluetooth external devices (mouse, keyboard, iPod dock, hard drive, et cetera) connected. The more devices connected, the more difficult it becomes to ensure that the Ayre USB A/D converter has dedicated access to a High Speed USB controller. Sometimes it will be helpful to disable any unused USB devices to allow more flexible configuration of the necessary devices.

To determine which USB devices are connected to which controllers, go to "Apps - Utilities - System Profiler".

On the left side click on "Hardware - USB". On the right side will be a section labeled "USB Device Tree". With the Ayre USB D/A converter plugged into the computer (the green USB indicator light is on), the goal is to have the USB device labeled "Ayre USB Interface" as the sole device under a controller labeled "USB High-Speed Bus".

To achieve this you may need to try connecting various combinations of USB devices into the USB ports. Each time you change the connection, you will need to select "View - Refresh" from the Menu Bar at the top of the screen. Should you run out of available USB ports, you may need to purchase a USB port expander (hub). Often these are built into peripheral devices such as keyboards or displays. When using a USB hub, only connect slower Full Speed (USB 1.1) devices through the hub whenever possible.

Do not connect your Ayre USB A/D converter to your computer through a hub, as this may cause dropouts, clicks, or other disruptions. Do not share the controller labeled "USB High-Speed Bus" in the System Profiler with other High Speed devices (external hard disk drives, iPod connectors or docks, et cetera).

Troubleshooting

Should your Ayre USB A/D converter stop responding, go to "Apps - System - Sound". If the "Ayre USB Interface" is not listed under Input, try "re-booting" the A/D converter by unplugging the USB cable for ten seconds and then reconnecting it. This is a semi-common experience when using an iPod, which is a High Speed device. Unless it has been determined that the iPod connector (or dock) is on a separate USB controller during the setup process, connecting the iPod will "kick off" the Ayre USB A/D converter from the "USB High-Speed Bus". While "re-booting" the Ayre A/D converter will solve the problem temporarily, you will need to reconfigure the USB connections to your computer to avoid future problems.

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