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Solving the Bluetooth Juggle with a Focusrite Scarlett 2i2 + Roger On iN

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Solving the Bluetooth Juggle with a Focusrite Scarlett 2i2 + Roger On iN

By an age-related partially deaf ex studio technician and Microsoft systems engineer.

The problem

I wear Phonak Audéo Sphere Infinio P90 hearing aids and work from a home office. My iPhone is permanently connected to my aids via Bluetooth for calls. The problem: iPhones only support a single Bluetooth audio connection at a time.

This created a constant “Bluetooth juggle.” Whenever I wanted PC audio (Teams calls, Zoom, music, web) routed to my aids, something had to give — either the iPhone connection dropped, or I was manually swapping Bluetooth connections like a one-armed wallpaper hanger! My Teams callers were used to multiple attempts and retries. Not ideal. Not professional!

Phonak’s Bluetooth connection stack on the Infinio is — frankly — unreliable. No amount of Bluetooth dongles or adapters helped. The problem isn’t the adapter; it’s Phonak’s stack. I tried several solutions including a FlooGoo FMA120 dongle. Same result.

The solution

A Focusrite Scarlett 2i2 (4th gen) USB audio interface feeding a Phonak Roger On iN via the Phonak-supplied simple 3.5mm analogue cable.

Here’s what that looks like on my desk:

  • Legolas (my ThinkPad P71 Windows 11 PC) → USB-C → Scarlett 2i2

  • Scarlett 2i2 headphone output → 3.5mm cable → Roger On iN (sitting in its charging dock)

  • Roger On iN → proprietary 2.4GHz digital radio → Phonak Audéo Sphere Infinio aids

No Bluetooth anywhere in that chain.

Why it works

The Roger On iN uses Phonak’s own proprietary 2.4GHz digital wireless technology — not Bluetooth, and not (a common misconception — FM was Roger’s predecessor; Roger is fully digital). Audio signals are encoded into microsecond-scale packets across 40 channels. This means:

  • No Bluetooth pairing complications

  • No connection negotiation

  • No interference

  • Imperceptible latency (12.8ms by Phonak’s own spec)

  • It just works, every time

Meanwhile, my iPhone stays permanently connected to the aids via Bluetooth for calls, doorbell alerts, and personal audio. That BT connection is never touched, never renegotiated.

When a call comes in on the iPhone, the Roger audio pauses automatically. The call takes priority on the aids. Call ends, Roger resumes. Zero manual intervention at any point.

Why the Scarlett 2i2 specifically

The 2i2 is a 2-input, 2-output USB audio interface — essentially a high-quality external sound card with proper studio-grade DAC converters. It presents to Windows as a sound device, so you simply set it as your default output in Windows Sound settings or in Teams/Spotify/foobar2000 individually.

I chose the 2i2 over a cheap USB DAC for several reasons:

  • Proper headphone amp on the front panel for wired headphones when I eventually replace my last pair

  • Class-compliant USB — Windows recognised it immediately with zero driver installation; the Scarlett Focusrite Control 2 software and drivers are optional but add ASIO low-latency mode and routing control

The 2i2’s line outputs feed my Roger On iN dock directly via the Phonak-supplied 3.5mm jack cable. The Roger On iN dock sits permanently on the desk, always charged via USB C, always connected. When needed elsewhere — a noisy restaurant, a presentation, a meeting — the Roger On simply lifts out of the dock and goes with me. The cable stays in the dock. Drop it back on return, charging and audio resume automatically.

The complete desk audio architecture

ThinkPad P71
  → USB-C → Scarlett 2i2 → Headphone out → 6.35mm to 3.5mm adapter → Roger-supplied cable → Roger On iN dock

iPhone → Bluetooth → Phonak Infinio aids (permanent — personal calls)

Teams or Zoom and other Windows programs: Speaker = Scarlett 2i2, Microphone = Phonak Infinio built-in mics (via Bluetooth to Legolas).

On hearing equalisation

My Infinio aids carry my audiologist’s prescription curve, applied via Phonak Target software. For everyday PC audio via Roger, that curve is active and speech intelligibility on calls is excellent.

For serious music listening I use my AirPods Pro 3, which carry my curve from Apple Health — applied at firmware level across all devices. For that path I also use Peace EQ / EqualizerAPO on Windows with a separate Peace EQ preset to finely tune my audiogram.

Result

  • Zero Bluetooth juggle

  • Teams/Zoom callers get a clean, reliable experience every time

  • iPhone call or doorbell → aids switch automatically, Roger pauses, resumes when done

  • The flakey laptop dock 3.5mm socket is retired from active duty

Total cost of the fix: CHF 160 / ~£140 / ~€165/ ~$205 for the Scarlett 2i2. If you already own a Roger On iN (as I did), that’s the only purchase needed.

Highly recommended for any Phonak Roger user who has given up fighting Phonak’s inadequate Bluetooth.

Setup: Phonak Audéo Sphere Infinio (P90) · Roger On iN · Focusrite Scarlett 2i2 4th gen · ThinkPad P71 · Windows 11

Questions? Feel free to ask here.

Probably applicable to other BT aids but only tested as above - ymmv!

6 people in this conversation12 min readJump to latest
@bulk said:

Focusrite Scarlett 2i2 (4th gen)

Wondering if this will work somehow with my Starkey Genesis aids. Need to do some research (I have a work iphone and personal iphone, plus a work macbook and a future Mac Studio). Even without the future Mac Studio purchase, I already have Bluetooth juggle issues. :frowning:

I did something like this when I was still working. I found the analog signal dropped if the audio was quiet for too long (min and half or so?) and then didn’t pick up again fast enough when conversation started again. I went to a usb to toslink converter, and ran toslink to the dock. Then switched to using a TV connector. My new Roger On can plug into the computer using USB, but I’d already retired by the time I got the v3 Roger. If your setup works for you, then that is great!

WH

There’s another way to do this with a much lower overall cost.

You could use one FMA121 as an receiver plugged into the iPhone, and another FMA120 on the PC as an Auracast transmitter for Teams/Zoom audio. In this setup, only the playback audio is transmitted — you would still use the PC’s own microphone.

The FlooCast iOS app will forward the received Teams audio (via Auracast) to the Bluetooth connection between the iPhone and your hearing aids, so the iPhone remains connected to the hearing aids as in your current setup.

When a phone call comes in, the iPhone will automatically pause the Auracast audio playback and route the incoming call tone to the hearing aids. You can then pause the Teams/Auracast session, answer the call, and resume playback afterward.

Another benefit is that this setup effectively makes your Phonak hearing aids Auracast-enabled, without needing to wait for a future firmware update from Phonak. Even if Phonak later adds native Auracast support, some useful features may still be limited — for example, support for Auracast announcements that are not continuously transmitted.

In addition, the plug-in solution with the FMA121 frees the hearing aids from scanning, which may help reduce battery consumption, as iOS does not currently support Auracast natively.

Auracast™ Receiver - FlooGoo FMA120 — LE Audio / Auracast™ USB...7

The FMA120 upgrades phones, laptops, TVs, and other sources via USB audio—no driver required on Windows, macOS, or Linux. It adds aptX Adaptive (incl. Lossless) and Auracast™ broadcast, plus unicast for music and voice with -capable...

That’s a neat idea! I already have a FMA120 but gave up. Now I see the FMA121 is the second part of that link! I might even buy one and try it out. The Scarlett 2i2 is a nice thing but I’m only using a small part of it’s capabilities. Thanks for your feedback!

It’s always great to see that we can provide something that solves a real problem.

Later on, if Phonak releases an update for the hearing aids, you may no longer need the FMA121 as an add-on receiver for your phone. You could then switch it back to transmitter-mode firmware and use it with other audio sources that have headphone outputs. Switching between broadcasts is simple, much easier than swapping Bluetooth connections.

For my situation Ranson’s solution doesn’t quite work, for two reasons:

Call handling is manual. Your setup requires pausing Teams/, answering the call, then resuming afterward. My Roger setup handles this automatically - iPhone call arrives, Roger audio pauses instantly, call ends, Roger resumes. Zero intervention. That seamless switching was the core requirement I was solving for, so manual pause/resume is a dealbreaker.

Double-encode latency. The relay chain (PC → Auracast → FlooCast → mSBC → aids) involves two lossy encode/decode stages and stacks latency: Auracast ~40ms plus the iPhone BT relay on top. Roger’s proprietary path is a single encode direct to the aids at 12.8ms. For Teams calls the difference is probably imperceptible, but for music it’s audible.

The cost argument is fair - two FMA dongles would have been cheaper than the 2i2, though the 2i2 also gives me a headphone amp, ASIO for foobar2000, and inputs for when I eventually get around to learning bass guitar!

For anyone reading this thread who hasn’t bought anything yet and doesn’t own a Roger system, Ranson’s approach is a legitimate lower-cost alternative worth considering - particularly the battery benefit he mentions. But if you already have Roger, the wired path wins on simplicity and latency.

In reply to @bulk

You’re right about those two limitations. Here are some additional details for completeness.

The need for manual handling is mainly a limitation of the current FlooCast mobile app, which we plan to improve in future releases. There are also some restrictions on iOS itself, meaning automatic resume while the app is running in the background may not always work reliably. However, automatically pausing or stopping playback when a call arrives should be fully achievable.

The additional latency introduced by the relay approach is essentially the tradeoff for working around the current lack of native support in the Phonak hearing aid firmware. With a proper native implementation, an FMA120 configured for the lowest latency settings can achieve around 24 ~ 30 ms end-to-end latency (from the moment a sample is encoded on the transmitter side to the moment it is rendered on the receiving device), rather than the commonly quoted ~40 ms figure.

As a reference, Starkey provides firmware for their Edge/Omega hearing aids with multi- links enabled, and call handling works fully automatically (including PC/FlooGoo audio pausing and resuming when calls arrive and end). We did not implement anything proprietary specifically for Starkey — this is achievable within the current Bluetooth standard if hearing aid vendors choose to support the use case.

Why do you need the Scarlett versus 3.5mm audio from the laptop to Roger dock? Why does USB audio to the Roger On (undocked or does it also work docked?) not work?

If one does not have a Scarlett this seems a costly and complex solution with another failure and management point.

Stronger such as with an EPOS dongle may have been good enough. Anyone use that with Sphere?

Edited

All fair points - let me be more transparent about the real reasons.

Why not 3.5mm direct from laptop?
The real driver wasn’t the laptop socket - it was the juggle caused by the combination of Phonak’s unreliable negotiation and the iPhone’s single Bluetooth audio connection limitation. Any path routing audio to the aids via Bluetooth meant constant connection battles every time a call arrived. The wired Scarlett → Roger path eliminates Bluetooth from the PC audio chain entirely, which is what solved the juggle. A direct 3.5mm cable to the Roger dock would have achieved the same thing - and for anyone with a reliable headphone output, that’s the free solution. My dock socket being flaky was a secondary bonus to fix, not the reason.

That said, one aspect worth mentioning: the Scarlett presents Windows with a proper studio-grade sound card rather than relying on the laptop’s onboard audio. For everyday listening - music, web audio, Teams call quality - the difference in DAC quality is audible, particularly if you use equalisation software like Peace EQ / EqualizerAPO. The onboard Realtek chip in most laptops and docks is functional but unremarkable. If you care about what you’re hearing through your aids or headphones, a clean source matters. I now hope to be able to buy a nice pair of wired headphones that I will connect to the Scarlett output. Of course, I’ll still have to pick up the iPhone if that rings, but my late evening quality listening times are rarely interrupted by calls.

Why not USB audio direct to Roger On?
It does work - Phonak supplies a USB-C audio cable for exactly this. I own it. I should have mentioned this as the simplest possible solution: laptop USB-C → Roger On dock directly, no Scarlett, no extra hardware. This is the minimum viable path.

Does the dock pass audio through when Roger On is seated?
Yes - the dock has its own audio input and passes it through to the Roger On whether docked or undocked. Docked is actually preferable for permanent desk use: always charged, cable stays in the dock, lift Roger On out and take it to a noisy restaurant or presentation fully charged.

Is the Scarlett overkill?
For the Roger path alone, yes. My reasons for choosing it go beyond Roger: I use Peace EQ / EqualizerAPO for hearing compensation on other devices and wanted clean converters at source, I have a wired headphone amp requirement, and I’m planning to learn bass guitar and wanted the instrument input. If your only goal is getting audio to Roger reliably, a direct cable is the right answer.

EPOS dongle / stronger BT?
Unlikely to help. In my experience the issue isn’t Bluetooth signal strength - it’s Phonak’s connection negotiation stack on the Infinio, which is unreliable regardless of dongle quality. I tried the FlooGoo FMA120 (a well-regarded dongle) with the same result. If anyone has had success with an EPOS dongle specifically with Sphere Infinio I’d be genuinely interested to hear it - but I wouldn’t bet CHF 100+ on it.

So the minimum viable solution for most people is probably: laptop headphone out → 3.5mm cable → Roger dock or laptop USB-C → Phonak USB-C cable → Roger On directly. Both cost nothing if you already own Roger. The Scarlett is a personal choice layered on top.

@bulk said:

the dock has its own audio input and passes it through to the Roger On whether docked or undocked

Is that accurate? The dock communicates wirelessly with an undocked Roger On?

Very interesting thread! Thanks for all the contribution. Maybe some of the people could also give me a hint on the following. My Airpods sound way better than my hearing aids (Phonak Sphere I90). And even more importantly, they have great active noise cancellation. What I expect would give great results for me is using the hearing aid as a sound processer, including all the fancy stuff not present in the airpods - such as frequecy shift, compression, limitation etc. - but then sending the signal to the airpods, rather than the receiver in the ear canal. Specifically this would allow using the active noise cancellation together with the hearing aid functionality. Any ideas?

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