27 Mar
2021
27 Mar
'21
3:50 a.m.
Hi everyone,
my grandmother needs headphones to watch TV, but wearing them causes her
to miss all the conversation around her. Hearing aids that allow both TV
and microphone input are around 2.5k€. As I'm quite firm with Linux, and
have conducted several Raspberry Pi projects, I wondered if it was
possible to find a DIY solution for this.
I thought of using regular Bluetooth headphones with an integrated
microphone, and a Raspberry Pi that gets fed the TV audio. Now it should
be possible to receive both the microphone audio from the headphones via
Bluetooth and the TV audio via line in, mix both at a custom ratio, and
send it back to the Bluetooth headphones.
I know that it's possible to achieve such a setup using e.g. ardour and
JACK, but I'm looking for an automated solution (e.g. write a script /
small application that launches at boot time for setting up the audio
devices). So how can I configure the mixing using only the command line
or a custom Python/C/whatever application that uses some libraries?
What's the best software stack to aim for? PulseAudio? JACK? Latency
shouldn't be too much of an issue, as my grandmother probably isn't able
to perceive lip sync anymore anyways, but of course it would be great to
aim for the least delay possible.
I'd love to hear some tips and pointers on how to approach this project.
Thanks a lot in advance!
Cheers,
LuKaRo
27 Mar
27 Mar
8:15 a.m.
Hi LuKaRo!
Mar 27 2021, LuKaRo has written:
...
I thought of using regular Bluetooth headphones with
an integrated
microphone, and a Raspberry Pi that gets fed the TV audio. Now it should
be possible to receive both the microphone audio from the headphones via
Bluetooth and the TV audio via line in, mix both at a custom ratio, and
send it back to the Bluetooth headphones.
...
I have never worked with Bluetooth on Linux. Can bluetooth devices show
up as ALSA devices? Or can they be made to appear as JACK devices?
My - unsurprising - suggestion would be to use ecasound. I think sox
works as well. Both speak ALSA and JACK (not 100% on sox). They run
headless and ecasound even has an API that, I think, includes Python, if
you like to be fancy.
PulseAudio would probably not be a good solution. don't know many
commandline tools that support it. It's too much of a desktop thing. :)
If you can get the bluetooth into ALSA that might be the best solution.
It's easy to mix audio from different devices. In JACK you already need
an extra program to bring in audio from a second device (like
alsa_in/alsa_out).
HTH.
Best wishes,
Jeanette
--
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11:55 p.m.
On Sat, Mar 27, 2021 at 02:50:28AM +0100, LuKaRo wrote:
my grandmother needs headphones to watch TV, but
wearing them causes
her to miss all the conversation around her. Hearing aids that allow
both TV and microphone input are around 2.5k€. As I'm quite firm with
Linux, and have conducted several Raspberry Pi projects, I wondered if
it was possible to find a DIY solution for this.
If there is some budget available, then alternative, low- or no-latency
approaches (albeit non-DIY) would be:
1. Old-school analogue approach (<€100 total). Plug TV into stereo
input of mixer. Plug mic into mic input of mixer. Plug headphones
(or Bluetooth transmitter, or induction earrings) into mixer
headphone jack. Adjust levels to taste.
- Small mixer e.g. https://www.thomann.de/gb/the_t_mix_mix_502.htm or
similar (Behringer Xenyx 1002B is an alternative if you want a
post-preamp insert point for a noise gate and/or compressor)
- Gooseneck or measurement microphone e.g.
https://www.thomann.de/gb/the_tbone_tb312s_schwanenhalsmikro.htm or
https://www.thomann.de/gb/the_tbone_gm_5212.htm or
https://www.thomann.de/gb/the_tbone_mm1.htm etc depending on
desired polar pattern (i.e. depending on where you will put the mic
and mixer, relative to the ambient sounds your grandma needs to
hear)
- Optional noise gate if your mixer has an insert jack, e.g.
https://www.thomann.de/gb/behringer_nr300_noise_reducer.htm
- Optional Bluetooth transmitter if she already has Bluetooth
headphones, e.g.
https://www.amazon.de/s/ref=nb_sb_noss?url=search-alias%3Daps&field-key…
- Optional induction earrings or loop, if she wants to use her
existing hearing aids instead of headphones, e.g.
https://www.amazon.de/-/en/Monacor-3-5mm-Jack-Induction-Loop/dp/B003DPH854/
or
https://www.amazon.de/-/en/Geemarc-Iloop-Induction-Sling-Neckloop-black/dp/…
or
https://www.amazon.de/-/en/Geemarc-CLHOOK3-Induction-Earrings-3-5/dp/B00400…
2. Buy her a pair of headphones or earphones that have ambient sound
mixing functionality built in (<€250). E.g. Sony WH-1000XM3.
Good luck!
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participants (3)
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Jeanette C. -
LuKaRo -
Sam Kuper