H2 Designs

Let's Get Nerdy – Part 1

We've had some interest in the underlying technology of MIYO – there are a lot of things that make something like MIYO tick. Literally, for instance, with its two audio clocks. So, we want to get specific and talk about some of the innovations at work in MIYO.

PART 1: CLOCKING AND CONVERSION

To get audio out of your computer, MIYO basically says ‘Hello. I am a USB audio device.” Then, 1’s and 0’s magically start going 'down' the USB cable (asynchronously, of course) and end up at MIYO’s digital-to-analog converter, or DAC. The DAC then takes those 1’s and 0’s from your computer and turns them into physical waveforms.

So, you might guess that the DAC has a lot to do with how audio coming out of your computer sounds. It sure does, and we are using the best DAC that Texas Instruments makes, the PCM1792A. It’s awesome, with 129 dB Dynamic Range (A-weighted) and other great specs. You might spot it in some other very high end products. But any great DAC needs a great clock – two in our case.

The clock tells converters when the next sample step should happen, and if the clock isn’t very stable, you end up with distortion, poor stereo imaging, and other artifacts. This oversimplification of decades of audio research can be boiled down to a critical factor: jitter, a measure of how the amount of time between samples (a very tiny slice of time) varies. In very good audio systems, jitter is measured in picoseconds (trillionths of a second). Studies suggest we can hear the effect of jitter down to 20 ps, and many people believe even lower.

MIYO’s typical jitter is crazy low at .5 ps, or 500 femtoseconds (quadrillionths of a second). Understanding this scale is difficult, but consider this: traveling at the speed of light for that much time, you could barely cross the tip of a pencil.

Few audio devices can claim this kind of stability. MIYO is definitely the only device in its price range that does this. To achieve this, we’re using state-of-the-art MEMS oscillators (to our knowledge, this is a first in audio design), and we’re using the very best from SiTime.

Did we mention that MIYO’s input is also amazing? We’re using the Texas Instruments PCM4220, which has 123 dB Dynamic Range (A-weighted). The above clocking discussion applies here as well, and again, very few devices can compete at this level.

MIYO is punching WAY above it’s class in terms of price and portability. And its clocking and conversion is only part of the story; in part 2 of ‘Let’s Get Nerdy’ we’ll discuss another aspect of MIYO that sets it apart – power.