Our Fourth Patent

  • In July 2020, after three years, 64 Audio was awarded its fourth patent for our groundbreaking technology dubbed TIA, which stands for tubeless in-ear audio. 
  • U.S. Patent #US10721549B2 was issued on July 21st, 2020 for the implementation of direct radiating drivers in micro acoustic chambers. 

We’d like to take this opportunity to tell the story of Tia as it was experienced by its developers.

The Beginning

The story of Tia is the story of Fourté. Traditionally IEMs require balanced armature drivers (BA) to be fitted onto a vinyl tube to deliver the sound from the spout of the driver to the end of the IEM canal. Understanding that this tube has always played a negative role in coloring the raw sound of the drivers, the first step was eliminating the tube to see if the BA behaved more naturally; similar to a large scale speaker where you don’t encounter this implementation of tubes.

Tia Driver

A positive result from eliminating the tube prompted 64 Audio’s R&D team to press into unlocking more of the potential of these BA drivers, quickly turning into a BA with an exposed/open face. Before sourcing what is now known as the Tia Driver, we initially cut the drivers open ourselves to test this; sometimes even sanding the side of the drivers off to expose the diaphragm. The results astounded the team and this open-face balanced armature driver was here to stay.

Tia Driver

To see how these new drivers behaved in an earphone they were placed in various positions within an empty IEM shell. Upon first listen, although far from perfect, it had interesting sonic qualities that were obviously going to turn into something revolutionary. 

From The Shell To The Canal

Tia Driver Placement

Based on our knowledge of IEM pinna compensation, the high frequency Tia driver was originally placed completely outside of the ear canal. Although this quickly changed, it revealed the potential beauty of having open drivers in an open shell with no tubes or dampers. However, in order to increase the high-frequency (HF) extension, we moved this Tia driver around and discovered that the closer it got to the canal stem, the better the extension and HF clarity was. Closer was key, to the point where the Tia high-driver ended up in the canal/stem of the IEM. This was bitter sweet because it opened us up to many production challenges and potential manufacturing roadblocks, but the results of this discovery were worth the struggle.

Tia Acoustic Chambers

With the HF band sorted, R&D moved on to the rest of the frequency spectrum, quickly encountering an unavoidable dip around 3khz-6khz. In this open form, the mid Tia driver seemed to lose some of its extension in the lower treble, being open and further back in the shell. Because of the way this larger tia driver performed in the mids, the team were intent on harnessing its power. After experimenting with a variety of enclosures and structures within the shell, a small wall structure, directly in front of the low-mid Tia driver’s diaphragm, showed a positive result. This wall is a sort of divider within the shell between the Tia low-mid and dynamic low driver. The key to this wall structure was a small gap between its top and the back of the faceplate. Controlling this gap, we found a sweet spot that extended the response of the Tia low-mid driver from 3khz to about 5khz.

Tia Acoustic Chambers

A major part of this patent is the use of the shell, and the air inside of the shell, as the transport medium rather than tubes or the air inside those tubes. The acoustical impedance isn’t coming from a tube but rather from the shell itself. These structures, chambers, and the air volume within the shell are used to shape the frequency response.

Tubeless BA Driver

Even with the positive results in the high-mid band, the upper mid/lower treble was still lacking between 2khz-6khz. An additional high-mid driver was required, to sit between the Tia Low-mid and Tia High drivers. Sourcing a fully open version of this very fragile high-mid BA wasn’t possible at the time, so it was implemented within the shell in its standard form; sound radiating from a spout but still radiating into the shell without the use of a tube. The design was finalized with two fully open Tia drivers, low-mid and tweeter, a tubeless upper-mid BA driver, and a tubeless dynamic driver for the low frequency band. 

Passive Radiator In An IEM

In the long list of groundbreaking tech packed into Fourté, its ‘passive radiator’ has received the least attention. This membrane between the shell and the faceplate is passively excited by the vibrations of the drivers within the shell. Surprisingly this element increased the unique width of the soundstage of Fourté. Since soundstage is difficult to measure, Fourté’s passive radiator was implemented purely as a result of listening tests. 

Tia Single Bore

The use of the tia driver in the canal is of massive importance to 64 Audio because it opened up the possibility to use this tia technology in almost all of our custom and universal fitting IEM models. Since 2017 every 64 Audio custom and universal IEM has been designed using at least one of the three elements of the Tia system: open balanced armature drivers, a single-bore design, and acoustic chambers.

Single Bore

The three models that feature the complete patented Tia system are Fourté, Trió, and most recently Duo. Along with their incredible resolving ability, these three models each embody the out-of-head sonic experience that Tia is now known for.

Learn more about each of these models below!




Also, be sure to check out this blog post about our latest Tia model, Duo!