Using stands like the DS1s and DS2s will angle the speakers upwards, which can be a positive thing depending as well as other variables in your setup.  The closer the speakers tweeters are aimed to your ears, the more you will perceive higher frequencies, which are very directional, and using these stands can achieve this.  Some customers prefer having the tweeters off axis a bit, as this results in a less pronounced high end moving the focal point lower.

There are a ton of options and it really comes down to personal preference, so we highly recommend trying a few different placements / toe-in / toe-out etc. to see what seems to work out best in your setup.

The cable included with our products is standard speaker wire (16 AWG), so you should be able to find something like this most anywhere that carries electronics or audio gear.  16 AWG should be good up to around 25 ft or so.  If you'd like to go farther than that we'd recommend 14 AWG.

The best way to attach the plug into the USB adapter is to go in at an angle. The plastic on the plug should have a more rounded side; we would suggest putting that side in first and then push down the other end (you may need to pull the tab out to make it easier to insert). One thing to look out for is the metal prongs on the body- when inserting the rounded end of the head, make sure the top prong is being inserted into the slot of the head; usually, if the first prong goes into the slot, the other prong should go into the other slot with no problems.

Both the D1 and the D2 work great with a Chromebook! We were able to test them out with a couple of Chromebooks here in our offices and didn't run into issues with them.

We've tested the D3 with a couple of Chromebooks and found that while the computer will recognize the D3, we couldn't get any audio.  The Chromebook does not have the right audio playback software that is necessary to support 24-bit audio, which the D3 requires to work.

The DAC built into speakers like the A2+ and HD6 is solid and makes sure you get a consistent experience.  With that said, DACs like the D1 would bring you extra features like a dedicated headphone amp and easily accessible volume knob. In the case of the HD6s, this could also free up the optical input to use with another source, like a television, if you want. If you're considering the D1 with your A2+s, it would be considered an upgrade from the A2+s DAC.

You should be able to incorporate the Airport Express with the D1 easily. All you would need to do is run an optical cable from the output of the Airport Express into the optical input of the D1. Then all you would need to do is connect the D1's RCA output into the analog input of your Audioengine Speakers or your AV receiver.

Optical takes priority on the D1, so if you had something like a computer hooked up via USB and another device hooked up via optical, whenever the optical connection was active it would be automatically switched to that.  That means that, depending on how the second device's optical out behaves, it might automatically switch back to USB when nothings playing, or you might need to power down the device (or unplug it) to get USB back. If the second source's optical output does not shut off, one option would be to use an optical switch.  You could connect both the computer and other source to the optical switch, and the switch to the D1.  Then you'd have an easy way to see which was active and switch between them.

Our DACs should still work great with computers that feature USB C ports. In order to use our DACs with USB C, you can use a USB B to USB C cable to connect the DAC to your computer. For the built-in DAC for the HD3, you would just need a micro USB to USB C cable.

You shouldn't have an issue using our products with the new Tidal Master service. We've been keeping a close eye on Tidal and the new MQA format that they're offering through their HiFi membership; basically, when using Tidal through it's desktop application, the application itself will decode the MQA file to a 24/96 file that can be read by any DAC connected to your computer, whether it is MQA-certified or not. This basically means that any of our USB/optical DACs (such as the D1, D2, D3, A2+, HD6, etc.) will work great with the MQA files streamed through Tidal Masters through the desktop app.

The D1 will work with any device that can operate as a USB host, can provide enough power via USB, and includes generic drivers for standard USB audio playback.  A device with Android 5.0 or later should have both USB host mode and native plug-and-play functionality for USB audio, so you could connect the two together using a USB OTG cable along with a standard USB cable.

You should be able to use the D1 with an iPad or iPhone with the right connections. In this kind of setup, you'd just need Apple's USB camera connection kit and a powered USB hub.  Here's how you would connect everything together:

iPad/iPhone w/ USB CCK --USB-> Powered hub --USB-> D1 --RCA/Mini-> Speakers/Headphones

The iPad or iPhone should just automatically start playing audio over USB when its connected.