The 1Mii DS500 is a phenomenal Bluetooth-DAC combo that exceeded all of my expectations.Songs from my existing audio sources (CDs, iTunes, YouTube) all sound much, much better. And hi-res FLAC songs on the 1Mii DS500 sound out of this world! Vocals sound like the singer is in the room, highs are brighter and clearer with no listener fatigue (ex: imagine the pure sound of a crystal glass “singing” versus the shrill, smeared high notes that most of us are used to).Recommendation: Buy the 1Mii DS500 or the 1Mii DS220, which have the same or better components, specifications, and features than the old “gold standard” Audioengine B1 (ex: the Qualcomm QCC5125 BT chip, LDAC support, and the OLED display) and immediately hear better sound quality from the improved Bluetooth codecs and ESS DAC chip.Deep-dive evaluation of connectivity on multiple platforms:PC (Lenovo running Windows 11 Home) connected via USB cable directly to the DAC:This is the cleanest connection with zero degradation because the data is communicated directly to the ESS DAC through the USB cable (rather than by Bluetooth). The DS500 OLED display shows “USB”. Songs from existing sources and hi-res FLAC songs sound amazing!PC connected via Bluetooth to DAC:Using the PC’s built-in Bluetooth connection, the DS500 displays “48K AAC” (as well as the artist’s name and title of the song). The sound quality (due to the low data rate of AAC) was pretty lackluster (as expected). I then connected a 1Mii B10 Bluetooth audio USB adapter (USB-A) and was able to connect using aptX-HD (the DS500 displays “48K aptXHD” and the sound is fantastic).Android phone (Google Pixel 6A running Android 15) connected via Bluetooth to DAC:Once I activated the Android’s “Developer options”, everything fell into place, and I was able to select both aptX-HD and LDAC under “HD audio”. Note: You must first connect to the DS500 in order for “HD audio” options to be activated and selectable.Android tablet (Samsung Galaxy Tab A9+ running Android 14) connected via Bluetooth to DAC:Encouraged by my success with the Android phone, I thought the solution would be exactly the same for the Android tablet. It was not. Under “Developer options” and “HD audio”, LDAC was displayed on the tablet and on the DS500, but the sound was definitely “NOT” LDAC-quality. Whichever lower-level codec I last selected (AAC, SBC, or aptX) was the actual codec used when I tried to select LDAC. The standard aptX codec sounded much better than AAC or SBC, but not as good as aptX-HD (which was not an option under “HD Audio”). I discovered and read up on USB Audio Player Pro by eXtream Software (which seems to have a lot of good features and is available on the Google Play store). I was about to download and test USB Audio Player Pro when I found the best solution. Once you’ve connected to the DS500 (under Settings/Bluetooth), select the gear icon (settings) next to the DS500 device. The window that opens gives you the option to select LDAC. The DS500 displays “96K LDAC”, and the sound quality is fantastic.Apple Mac, MacBook, iMac, iPhone, and iPad (MacOS and iOS):No testing was done because Bluetooth audio transmission on MacOS and iOS devices are limited to AAC and SBC. BUT any Mac, iPhone, or iPad with a Thunderbolt 3 or Thunderbolt 4 port can connect directly to the 1Mii DS500 (with the appropriate combo USB-C data/power cable) to benefit from the ESS DAC and also decode hi-res FLAC audio files. To my knowledge, there are no Bluetooth audio USB adapters that support iOS devices (ex: iPhone or iPad); however, there are Bluetooth audio USB adapters for MacOS devices (ex: Mac, MacBook) that support the aptX-HD codec (but not LDAC) using one of the 3 USB adapters listed below.Other Bluetooth audio USB adapters:I purchased and planned to evaluate 3 Bluetooth audio USB-C adapters, but once I found working aptX-HD and LDAC solutions with my existing non-Apple hardware, I decided not to evaluate them. The 3 Bluetooth audio USB-C adapters are the Creative BT-W6, the Ugreen BT501, and the Avantree C81-PC. None of them support LDAC, but they all support aptX-HD and aptX-Adaptive. They all have good ratings on Amazon and positive customer reviews and are worth consideration if you own Apple hardware.Only negative:While 1Mii includes a 5V power supply, USB-C power/data cable, RCA-RCA cable, 3.5mm-RCA cable, and optical cable (way more than other manufacturers include), the USB-C power/data cable should be a bit longer (1 m).Audio system used for the evaluation:NAD T752 5.1 receiver, ESS AMT 1 Tower speakers, and Infinity Infinitesimal IV satellite speakers with a SSW-10 powered subwoofer. The AMT 1 Towers are transmission line towers with ESS Air Motion Transformer (AMT) mid-tweeters (ultra-light, ultra-fast pleated Mylar diaphragms that play to 24,000 Hz). The Infinity Infinitesimal IV satellites employ the Infinity EMIT-R tweeter (ultra-fast, ultra-light Mylar diaphragms that play up to 40,000 Hz). These speakers were used because they are capable of faithfully reproducing the transients, details, and nuances of hi-res audio.