Audioengine D1 & D2 FAQ -  Information courtesy of Audioengine

D1 FAQ

How can the D1 external computer DAC improve my music?
D1 bypasses your computer's headphone output and/or soundcard and sends audio directly through the USB port. The D1 doesn't alter the sound, but provides a much cleaner path from the digital audio file to your music system so you hear the true full potential of your music. 

How easy is it to set up the D1?
Connect the included USB cable from your computer to the D1. If using a Mac, go to System Preferences/Sound, and select "Audioengine D1". If you're using a PC, no setting changes are needed as the computer will automatically find the USB driver. Now play music from iTunes or your favorite media player and that's it - setup really is that easy. 

Is D1 USB input isochronous or asynchronous?
The D1 uses "adaptive mode" USB, which means it will track incoming data coming from the computer and adjust so as not to miss any information. The incoming data is clocked out to the D1 DAC chip, which then re-aligns the bits using it's own internal clock to minimize jitter.

How do I find out more information about DACs and computer audio?
There are some excellent online computer audio forums and a quick search will turn up everything you need to know about the best hardware and software and how to get started on any budget. Computer audio is quickly evolving so we suggest to check and make sure the information you find is up to date. 

When I plug in headphones will the D1 RCA outputs be muted?
Yes, the output will mute and audio will only play through your headphones.
What is the best USB cable length to use with D1?
USB cable performance will vary with construction and length, however, for the best results we recommend using the shortest cable possible (2' or less). 

Can I connect the D1 DAC to a USB hub?
Although D1 may work just fine when connected to most USB hubs, this is not recommended as the data rate may not be fast enough for higher-resolution music. We therefore suggest you select a high-speed USB bus all by itself and don't use a USB port on your keyboard, for example. 

Will the D1 work with USB 1.1?
Yes, however, note that 24/96 HD digital audio pushes the limits of USB 1.1 speeds. Due to this it's highly recommended that you connect to a higher-speed USB 2.0 port.

How do I use the optical input of the D1?
Connect an optical cable and the D1 will sense that an optical input is present and give that input priority. If using D1 with optical outputs from your TV, DVD play, Apple TV, etc you will need an AC USB power adapter (sold separately) to power D1. When using the optical output from your computer, you may power D1 via the computer's USB power and therefore no external power supply is needed. 

The D1 is connected to the optical output of my TV but I'm not getting any sound. What can I do?
In your TV menu verify that "PCM STEREO" is selected and "DOLBY DIGITAL" is off. 

How do I make sure that the D1 DAC is set to 24-bit/96KHz audio?
If using a Mac, open the Audio MIDI Setup utility in Applications->Utilities, choose "Audioengine D1" under audio devices and check that the format is set to 96 and the bit depth is set to 24bit. 

I'm having trouble using my D1 with Foobar in WASAPI and KS mode. What do I do?
In the Foobar control panel, under Preferences->Output, set the buffer length to minimum. A few customers have mentioned that WASAPI mode is more stable when used under WinAmp, so try that as well. 
Is there an easier way for Mac users to get to System Preferences and the Audio MIDI Setup control panels? 
A customer recommended an app called Soundsource - http://rogueamoeba.com/freebies - which is an easy way to switch between audio input and outputs as well as to access System Preferences and the Audio MIDI control panels. 

Will the D1 work with my low-impedance HiFiMAN HE-500 headphones?
The D1 includes a headphone amp based around the TI NE5532 low noise opamp. This headphone amp is able to provide low-impedance, high-fidelity audio to a wide range of headphones and supports headphones with impedances from 20 to 300ohms. 

Is there a recommended "break-in period" for the D1?
Your D1 will sound great out of the box and will get better over time, however, it's best to play music for 40 to 50 hours first before doing any critical listening.

D2 FAQ

What is the best USB cable length to use with D2?

USB cable performance will vary with construction and length, however, for the best results we recommend using the shortest cable possible (2' or less).

Can I connect the D2 Sender to a USB hub?

Although D2 may work just fine when connected to most USB hubs, this is not recommended as the data rate may not be fast enough for higher-resolution music. We therefore suggest you select a high-speed USB bus all by itself and don't use a USB port on your keyboard, for example.

Will the D2 work with USB 1.1?

Yes, however, note that 24/96 HD digital audio pushes the limits of USB 1.1 speeds. Due to this it's highly recommended that you connect to a higher-speed USB 2.0 port.

How do I make sure that the D2 DAC is set to 24-bit/96KHz audio?

If using a Mac, open the Audio MIDI Setup utility in Applications->Utilities, choose "Audioengine D2" under audio devices and check that the format is set to 96 and the bit depth is set to 24bit.

I'm having trouble using my D2 with Foobar in WASAPI and KS mode. What do I do?

In the Foobar control panel, under Preferences->Output, set the buffer length to minimum. A few customers have mentioned that WASAPI mode is more stable when used under WinAmp, so try that as well. 

Is there an easier way for Mac users to get to System Preferences and the Audio MIDI Setup control panels?

A customer recommended an app called Soundsource - http://rogueamoeba.com/freebies - which is an easy way to switch between audio input and outputs as well as to access System Preferences and the Audio MIDI control panels. 

Is there a recommended "break-in period" for the D2?

Your D2 will sound great out of the box and will get better over time, however, it's best to play music for 40 to 50 hours first before doing any critical listening. 

Is the D2 USB isochronous or asynchronous?

The D2 uses "adaptive mode" in it's USB receiver. This means that the USB receiver (Texas Instruments 1020B) will keep track of the data coming in from the computer and adjust so as not to miss any incoming data. Due to the nature of the wireless link, the data then becomes asynchronous before arriving at the Receiver. Thus the D2 acts as an asynchronous USB DAC with the added benefit of being 24/96 bit-perfect wireless. 

Will the volume control on the D2 Sender affect my audio?

No. The volume information is transmitted via a completely separate I2C channel over the air and is used at the output of the internal DAC of the D2 Receiver.

Will the D2 interfere with my other wireless devices?

The D2 is designed to play well with most wireless devices, especially computers and routers. We do, however, recommend that you locate the D2 at least 12" from other wireless products. 

What can I do to further ensure that all my wireless devices work well together?

If you use a wireless 802.11g router, set the channel to either 1 or 12. If you have a 2.4G WLAN-N access point in your home, make sure it is set to 20MHz bandwidth and not 40MHz. 

How many wireless "zones" can I set up with D2?

The D2 Sender can simultaneously broadcast to (3) D2 Receiver units. See the Pairing section in the D2 Setup Guide for pairing additional receivers. 

Why does D2 have a digital optical but no coax interface?

We chose optical over coax inputs and outputs for D2 (and D1) primarily because TV's, Apple TV, and computers all have optical ouputs. Regarding optical vs. coax quality, there are various thoughts and theories on which is better but our experience is that as long as optical is implemented correctly and the connectors are high-quality, it is essentially the same digital SPDIF signal. 

Can I use D2 to connect my computer wirelessly to another DAC in my audio system?

Absolutely! If you use the USB input of the D2 Sender, then connect the D2 Receiver optical output to your DAC and the D2 will act as a wireless 24-bit USB-to-SPDIF converter and stream high-resolution digital audio to your favorite DAC. You can also use the optical input on the D2, in which case the D2 will act as a wireless optical link to your DAC.

Can I use a third-party (non-Audioengine) AC power adapter to power my D2 Sender and/or Receiver?

The D2 AC power adapters have been specifically designed to provide stable low-noise power to the D2 so only use the included Audioengine power adapters. Using any other power adapter will compromise the audio quality and may damage your D2.

Can I take my D2 to another country with a different voltage?

Yes, D2 uses switching power supplies so they will automatically convert to the different voltage. The AC power cord is detachable which makes it convenient to replace the AC plug with a different type if you don't want to use an adapter plug. 

What is the AC power cord type for Audioengine D2?

We use 2-pin non-polarized IEC 320-C7 cables, which is common and can be purchased at most electronics stores. 

How does D2 differ from the Audioengine W1 or W3 wireless adapters?

D2 offers bit-perfect 24/96 transmission, while the W1 and W3 wireless are 16-bit adapters (16/44.1 and 16/48KHz).