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Phonak Marvel Bluetooth range

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I have the MR90s. Same issue. When I’m out walking, I can take phone calls through the with the phone in my pocket (Google Pixel), but when streaming music from the phone I have to hold it in my hand. And I don’t mean at my side… I have to hold the phone a little in front of me with my arm bent at the elbow. If I turn my head, the signal drops. It’s hard to get a strong signal from a tiny package like the HAs. Also the lack of bass, as others have said, is because of the open domes. Try putting regular wired ear buds just barely in your ears and you’ll have no bass, compared to sealing them in tight. One other thing: streaming from my TV/home theater is a bit tricky too. The streamer device only seems to work with a plain stereo signal coming in. Multichannel, Dolby, etc. will not stream.

I found an interesting paper about bluetooth propagation through a human body. Here is a link: NUMERICAL MODELLING OF HUMAN BODY FOR BLUETOOTH BODY-WORN APPLICATIONS2.

tl;dr This study is about a phone at waist level and a headset worn in the ear. The case of a headset in one ear transmitting to another headset in the other ear is not addressed. The human body measurably attenuates the signal. Not a surprise.

Here are a couple of quotes:

In the presence of the human body, the path gain value sees a substantial drop of 11.3 in measurement while 11.5 dB, 10.9 dB and 12.7 dB in simulation using high, medium and low resolution body models respectively. This drop is not surprising as the body blocks the line-of-sight between the headset and handset antennas.

These results depict that the human body deforms the radiation patterns of the two antennas due to electromagnetic absorptions in the body tissues and reflections from the body surface. It has caused up to 12 dB reduction in the back lobes and 6 dB increase in the frontal radiations for the handset antenna. The effect is more visible on the headset antenna due to the presence of body mass both at side (i.e., head) and underneath (i.e., shoulder) decreasing its radiation in both directions in XY plane. Effect of the head is dominant in Y Z plane reducing its radiation between 0–90 degrees.

In reply to @rex-hawaii

It’s definitely the conection between the and the phone. Both sides falls out Simultaneous. I can allso force it to happend, i can sit at home in the sofa with the phone behind my back. It streams fine (lots of reflective surfaces) but when i put my hand over the phone, the signal drops out. Samething outdoors, i can stand still only difrence is moving the hand slightly over the phone and the signal drops. Its exactly the same result as turning the head in any direction that will put more body between the phone and right HA cuts the signal.

I’m a doubting Thomas. All I can find is that it’s 2.4 ghz. Tha’s also the same as Roger . Can you point me to a source? Thanks. I also wonder why so many technologies use 2.4 ghz. It’s a vary crowded spectrum!

Did a quick look at this TV Connector with “Airstream Technology “.
It uses proprietary 2.4 GHz streaming protocol.

TV Connector for Hearing Aids | Phonak

The Phonak TV Connector is a wireless accessory that streams TV and music directly to your hearing aids.

Looks like everyone was a little bit right.

OK. I found the FCC site that I could search if I had the FCC id number. I’ve searched for a FCC id number for the TV connector without success. Read through the online manual several times looking for it. I also saw a post on the forum that said you’d looked it up for Oticon, but not Phonak. Can you provide any further direction?

I based my conclusion on what Phonak says about AirStream:

“The TV Connector can simultaneously stream audio signals up to 15 meters to an unlimited amount of connected hearing aids.”

First of all, the 15 meters is weird. I’ve seen radios that work at 10 meters, and BT radios rated for something much bigger, like 40 meters, but never 15 meters.

Secondly, I’ve done quite a bit of work with and data transfers. Even with a proprietary profile, you cannot stream “…top rated sound quality streaming…”. We needed to transmit 300sps of a single channel of 8 or 16-bit data and even with a custom protocol we could barely do that. Dual channels of 8Ksps (even if we downgrade the high end to hearing aid frequencies) is TWO ORDERS OF MAGNITUDE more data.

Here’s a custom BLE (GATT) profile that can transfer 1KByte/sec with handshaking. You CAN go to higher throughputs, but they become very lossy because you can’t afford timeslicing to retransmit bad packets.

Plus, even with custom GATT profiles, BLE must still be paired.

Plus, BLE maxes out at pairing 7 devices, even with custom GATT profiles.

Now, in the past, one of my startups made true one-to-many time-division protocols using WiFi radio chips (same as BT radio chips). But it’s not BT or BLE in any way, shape, or form.

In reply to @MDB

As far as I know, all equipment sold in the USA is required by law have an FCC ID. I can’t recall which specific document I found it in for the Opn, but it was either the user manual or a data sheet. You should be able to find it somewhere.

In reply to @haggis

Here’s another clue that might be helpful. One need only pair the TV connector once. After that, if the aids are set to auto-connect (which is the default I think), then the aids connect very quickly anytime you’re in range if there’s sound and power coming into the TV connector.

In reply to @haggis

I would be very surprised if they are not using . There isn’t a lot of room inside an for two separate receivers. AFAIK, HAs are usually built based on SOC. Again, these devices will support BTC and BLE, but not some random unrelated protocol. The FCC ID should prove one way or the other.

Thanks! Very helpful. Here’s what I found: https://fccid.io/KWC-TVCONNECTV29

No mention of Bluettooth. Just Digital Transmission System. There’s also mention of confidentiality so I’m guessing there was more info on application than is reported to public. I still consider the question open.

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