Classic Bluetooth Still Has a Job

The experiment changed the story

I originally used a small Cubilux USB-to-TOSLINK adapter to give my computer an ordinary optical audio output. It was simple, driver-free, and it avoided trying to pair the computer directly with a hearing-aid streamer.

That arrangement worked, but during long, everyday streaming sessions my Starkey 312 hearing aids began producing battery warnings, errors and restarts even when the batteries still had useful life.

So I tried something that at first seems backward: I put Classic Bluetooth back into the path.

Why might Classic Bluetooth help?

The 1Mii B06Pro+ is doing more than replacing a cable. It receives a mature Classic Bluetooth audio stream, buffers and decodes it, and creates a new digital audio output for the Auracast transmitter.

That inserts a useful boundary between two very different worlds: a computer audio environment that changes frequently, and an Auracast transmitter that must turn its input into a steady wireless stream for hearing aids.

This does not prove that the Cubilux USB-to-TOSLINK adapter is defective. In fact, the same kind of optical path works well elsewhere in my system when it ultimately feeds Classic Bluetooth to Phonak hearing aids.

Do not blame the optical adapter

The useful lesson is not “optical is bad.” Optical remains an excellent way to move digital audio between boxes, and a USB-to-TOSLINK adapter remains a handy way to give a computer an optical output.

The more interesting question is what happens between the computer and the hearing aids.

Both paths ultimately deliver digital audio to the same Audikast 4. Yet in my system they have not behaved the same way during sustained use.

What disappeared with Classic Bluetooth?

When hearing-aid manufacturers moved toward LE Audio and Auracast, Classic Bluetooth was treated largely as an older transport that could be replaced. But for home users, Classic Bluetooth had been doing more than simply moving sound through the air.

It provided a mature point-to-point boundary between a constantly changing computer audio system and the hearing aids. It handled continuous personal streaming, stable timing and the imperfect audio behavior of ordinary computers.

My original Auracast-at-home arrangement removed that boundary. The computer's USB audio was converted directly to optical PCM and fed to the Auracast transmitter.

The experiment described here puts Classic Bluetooth back into the chain—not into the hearing aids, but immediately ahead of the Auracast transmitter using a 1Mii B06Pro+.

The result so far has been striking. The same hearing aids, batteries and Auracast transmitter that exhibited repeated battery, error and restart behavior with the direct optical feed have thus far operated normally when the source first passes through Classic Bluetooth and the B06Pro+.

The experiment does not require Classic Bluetooth to be “better” than Auracast. It suggests something more useful: the two technologies may have different jobs.

Classic Bluetooth and Auracast are different tools

For years, Classic Bluetooth has handled personal, point-to-point audio: a computer, phone, television adapter or music source connected to one listener.

Auracast adds a different and valuable capability: broadcast audio that receivers can discover and join.

Those jobs overlap, but they are not identical. Adding Auracast does not make the old personal-audio use case disappear.

What the 1Mii B06Pro+ experiment is testing

This is a real home system, not a laboratory test. The computer is being used normally: Chrome with many tabs, Linux system sounds, workspace changes, music, television audio and other everyday activity.

The question is simple: does inserting Classic Bluetooth ahead of the Auracast transmitter restore stable, normal long-duration operation of the hearing aids?

The answer should come from repeated use and complete battery cycles. If the improvement continues, the little Bluetooth receiver will have done more than provide a workaround. It will have identified an important architectural difference worth understanding.

USB-to-TOSLINK is still useful

If the goal is simply to give a computer an optical output, the original method remains useful:

The computer sees an ordinary USB audio device. The streamer sees an ordinary optical input. No special hearing-aid software is required on the computer.

What has changed is my assumption that this is always the best place to stop thinking about the source path. Extended streaming has shown me that the behavior of the complete chain matters.