Whats the tech inside?
If you’re like me, one of the first things you think when you see a new piece of hardware is: What’s inside!?
So let me explain a little about the technology used in Natus One.
Natus One is based on a very robust and well proven technology platform which is essentially built to transmit audio as data using radio frequencies in the 2.4GHz spectrum. It has been used in devices like wireless speakers, soundbars and gaming headsets, and has shipped in millions (yes millions) of units.
It is the most interference-resistant 2.4GHz technology available and it transmits uncompressed audio in 48kHz/16-bit PCM form with no audible interference. Although the unlicensed 2.4GHz band is crowded with Wi-Fi and other wireless technologies, we work within that band because it’s the only globally available band in the unlicensed ISM (industrial, scientific and medical bands), and we of course want Natus One to be a global product.
To deliver audio over the air with as little interference as possible, we combine dynamic frequency selection, intended to ensure a clear channel is always used, with multiple error-correction technologies that don’t cause dropouts and don’t require the use of latency-inducing buffering;
To transmit over one of 40 possible 2MHz-wide channels, we first scan the spectrum when turned on, find a clear channel and then we stay on it. We continuously scan the entire spectrum, and once we see any interference on the current channel, we hop to another clear channel already selected in advance from the scanning sequence. That differs from other frequency hopping techniques that continuously hop between a fixed set of frequencies. When they hop into a bad channel, they avoid that channel in the future, but that technique doesn’t always work well because it doesn’t stay in a channel long enough to know if there is a problem.
Also to prevent interference, we use two separate antenna systems on both the transmit and receive sides and automatically switch between the two to deliver the best signal.
If interference occurs despite these precautions, we use forward error correction and other techniques to avoid the dropouts and latency problems created by data-oriented technologies such as Wi-Fi and Bluetooth, which resend data packets that are not received;
Resending lost data is fine (and needed) for pure data applications, but can create interruptions in audio as well as noise clicks and pops. Retransmitting lost data would also require the use of a memory buffer that would add a high amount of latency, which would render the product useless for audio applications.
Instead of retransmitting lost data into a buffer, we use two techniques similar to those used in the Redbook-CD standard to prevent audio-signal dropouts: forward error correction and interpolation. To prevent distortion resulting from short bursts of interference, forward error correction techniques send redundant data. To overcome very rare longer burst of interference, we can conceal the error by filling in, or interpolating, lost data, as does the Redbook CD standard. As a result, the technology easily overcomes up to 6ms interference bursts, which can be caused by turning on a microwave oven.
The result is high-quality audio over interference-free channels, sampled and streamed uncompressed at 48kHz/16-bit PCM. Thats even slightly better than CD’s 44.1kHz/16-bit PCM standard. Other wireless technologies compresses audio signal - in two different ways;
Other digital systems such as Bluetooth employs lossy data compression using technologies such as aptX, AAC, SBC or even MP3 before sending over the air. This is easily detectable and takes away crucial details in music.
The other type of compression is on analog radio system such as most professional wireless IEM systems. In order for them to be able to transmit over FM they cut gain at a certain level which leaves your beautiful sine waves more like square waves. FM also introduces noise/hiss on top of your signal which intensifies the further you get away from the transmitter. Natus One uses no compression whatsover, and because it is a digital system we do not have any FM noise/hiss.
To reduce the chances of interfering with other 2.4GHz products in a home, our solution dynamically raises and lowers power output as the distance between transmitter and receiver changes. Dynamic power output also improves our battery efficiency.
The battery is a 1000mAh Li-ion rechargeable battery and at 80% volume that gives us ~24 hours of continuous use and finally the amplifiers are designed to drive headphones between 30 - 100 Ohm and have an output of 100mW at 100 Ohms load.
Most of the technology is compressed into a single chip on the board which makes the product and production very stable, and with all those facts there was no doubt in our minds about which technology to use.