DIY "FM Link": Bluetooth "Remote" Microphone

Hearing Aids
#1

A used Zoom H2 Recorder goes on eBay for about $100. It was designed to record music, speeches, top quality digital audio in 2 or 4 channel stereo. It has a headset (/headphone) jack to monitor what is being recorded or what would be recorded while the recorder is PAUSE’d… Depending on the audio quality you select and the capacity of the SD Memory Card you an easily stream and/or record 8 hrs or more with a good set of rechargeable ‘AA’ NiMH batteries.

We are going to substitute that headset by a Bluetooth transmitter. I bought a Sony TMR-BT10A Bluetooth Transmitter second hand, on eBay, for $15 (+postage). I bought and tried other BT transmitters. They all work but the Sony has a good range and acceptably good analog-to-digital conversion speed (meaning the delay is small). It has a built-in Li-Ion rechargeable battery but requires an awkward-for-travelling charger. Its usable range is somewhere between 3 to 10 meters, as always with Bluetooth, subject to “pollution” of the 2.4GHz band (WiFi, cordless phones, cell phone headsets, microwave oven, etc.).

So about $100 - $150 spent, plug the Sony TMR-BT10A Bluetooth Transmitter into the headset jack of any gadget and pair it with the iCom.

Next, plug the Sony TMR-BT10A Bluetooth Transmitter into the headset jack of the Zoom H2, press RECORD once and you’ll hear what it would record if you pressed RECORD a second time. And, if indeed you choose to record, you will hear up to 30ft away what is being recorded. Place the Zoom H2 near the pulpit, head table or theater stage or …

Somewhat similar to the Phonak products, the Zoom H2 has “tons” of sound processing options for “recording” single instruments, bands, orchestras, lecturers / speakers, indoors, outdoors, noise… it comes with a wind blocker, etc.

This Phonak FM alternative is far superior in some situations and the exact opposite in others. However you can modify my receipe, substituting any other analog or digital recorder with a headset monitor jack for the Zoom H2. Likewise for the Sony TMR-BT10A Bluetooth Transmitter. You will end up owning two tools which can be used separately, one to record and another to transmit sound to your iCom from any device with a headset output jack.

Soon I’ll present a $10 wireless microphone feeding the DAI input of my iCom. I got the BOLUN Wireless Mini Clip-on Microphone Transmitter Receiver and a DAI cord but need to adapt the 1/4" microphone plug to the DAI cable.

Note: Be careful when you use FM for personal, private conversations, gatherings or meetings because eavesdropping is generally as easy as tuning a suitable receiver to the same frequency. Bluetooth is substantially more secure !

For TV-Viewing this FM Transmitter here is more suitable !!

#2

Could you plug the Sony TMR-BT10A Bluetooth Transmitter into an FM Receiver (such as used in church) and connect via BT to the iCom? Currently I plug my iCom into the FM receiver.

#3

I answered that, yes of course, but why? Many of these cheap made-in-China FM receivers have the “campus radio” frequency band, 70MHz and up, the same FM as used in churches, concert halls, auditoriums… Such an MP3 player with bultin FM receiver you’ll buy on eBay for much less than $20 “9-out-of-10” times !

#4

answered that, yes of course, but why?

I have an FM Radio with the “campus frequency” already and that’s actually what I plug into. I was just wondering if I could BT it to my iCom and eliminate the wire.

And, no, you did not answer this…you were talking about pluging into a recorder, and I’m asking about plugging into a receiver.

BTW, you seem to have a little bit of an attitude problem when answering our questions (noticed this on another thread). Please bare in mind everyone is not as techie as you are and may need to ask questions to clarify what they think they’ve read from your posts.

#6

I try my best to write as concisely as possible and expect from my readers to read what I write. If hearing isn’t your only problem, I gladly help. English is my 4th language, I wrote ‘any’ believing ‘any’ to mean the opposite of ‘none’. For your benefits I now bold-faced and underscored “…sound from any headset output jack to your iCom”. BTW, I use headset / headphone as if they were synonymous. As a techie I shouldn’t. Here it would have been better to write “…sound from any headphone output jack to your iCom”. Lastly, it is unreasonable of you to expect me to know if your receiver has such a feature, what size plug you will/would need (should be 1/4" or 3.5mm) or whether it is mono or stereo.

Since last fall I came here to learn from everyone’s questions (= problems and concerns) and answers (= the do’s and don’t). In gratitude I came back here to contribute my experience. If it helps some, and I know I will, it was worth my effort !

So here is your chance to contribute: Research everything about this church setup, this receiver, and post it here !!

#7

Simple. It’s an FM system the church installed and they have 8 receivers and single earpieces that hang on the ear. Anyone wanting to use it just needs to ask one of the ushers for a receiver/earphone. It is the Listen FM System, transmitting at frequency 72. The earpiece plugs into a 3.5 mm jack. The receiver has volume control.

#8

Andreas, Can you plug a condenser mike into the TMR-BT10A to hear a lecturer? I used the Zoom link but the price is out of site.
IRV FENTON

#9

Andreas you sent me something re the tmr-bt10a and a mike but my pop up protection didn’t let me get it. irv.fenton@verizon.net

#10

Andreas, I am using the Sony tmr-bt10a on my T.V. with the Icom but I have to use a preamp or it isn’t loud enough. I tried a button mike but volume too low. I’m still trying to find away around the Zoom Link.
Irv.fenton@verizon.net

#11

Andreas, When I use any kind of mike with the icom there isn’t enough volume. Is there an answer for this that is portable?

#12

The iCom can stream sound signals to your HAs from 3 types of sources:

  1. Bluetooth (any compatible BT-source)
  2. 3.5mm headphone jack (from any mono/stereo low-Ohm headphone output source)
  3. DAI jack (mono microphone input or any weak or attinuated audio signal)
A condenser-microphone(-cartridge) needs a kind of "help" a magnetic coil microphone doesn't need. YOU must be very clear, identify what it is you have or will get. Find out how/where it can be used, plugged in - just one device or a family of devices, like all camcorders...

I started answering here (on June 26), only to realize this better be more researched and posted as a new thread. I’ll do that as part of my $10 wireless microphone feeding the DAI input of my iCom project as soon as I have spare time. I got the BOLUN Wireless Mini Clip-on Microphone Transmitter Receiver and a DAI cord but need to adapt the 1/4" microphone plug to the DAI cable.

#13

Assume you could… You might be disappointed with what you hear !!!

The Phonak FM links reuse / recycle the same fantastic sound recovery / processing technics developped for the world’s best hearing aids. There’s gotta be a difference !

That’s why I chose the Zoom H2 Recorder as my microphone. It lets you select the best “recording option/program” for it’s 8 built-in condenser mics. If you choose well you should come close to Phonak’s FM links, certainly better than a make-shift setup employing just one bare naked microphone.

Lastly, if it’s for a few or even just one church, classroom, auditoriium, etc. which already has a P/A system, you ought to make them plug an inexpensive FM Transmitter into the venue’s amplifier. Best possible sound quality at least cost ! See DIY TV Link / TV FM Link

#14

Andreas, I don’t go to church but sometime go on a tour where I would like to hear what they are saying. FM xmiters a recievers are not the problem but finding a mike with some gain is. I’m going to be testing the Aerielle Tech. xmiter rec but the mike is still the problem. Look it up, you will find it interesting.
Irv