TV headphones for the old folks with different volume needs...

[MeldrewsMate]

I posted before about my attempts to please my mum, my dad, and their neighbours by obtaining a TV system that would allow dad to have a higher TV sound volume than mum through his headphones.
It's not been fruitful so far.
I copied this from another thread, it has links to optical (SPDIF?) audio outputs...credit to @Lucid
Do you know that there are Optical to analogue stereo convertors?
Here's something simple and inexpensive: Simple DAC - £9.99
Here's one with a volume control so you can set a level going to the headphones: Volume and headphone output £13.99

Read more: https://www.diynot.com/diy/threads/sound-for-hard-of-hearing.561495/#ixzz6nsTrNmUH

Here are my questions:

1. Is an RCA (phono) audio output, from such an equipped TV, independant of the TV's volume setting? ie will it drive a pair of headphones loudly but allow mum to turn the speaker volume down to her level?
2. Essentially the same question for the optical audio output...my logic suggests yes, because their main use is to drive an external surround sound amplifier with the TV volume off.
3. Will a Toslink (optical) cable, one of the two DACs above, and a pair of headphones achieve my aim?

MM

 

[Lucid]

Answers:

1) In general, TVs haven't had RCA/phono out for a very long time; I'm talking a decade or more for the major brands. There will be the odd exception to this, so it's always worth checking if the TV is a much older model or there's some other exception to the rule. For example, TVs with a built-in DVD player such as the Cello brand may well feature RCA out because of the internal DVD drive.

What is more typical is the the red and the white RCA sockets are audio IN. That is to say they're a "sound goes IN to the TV" socket. This is not the same as Audio OUT. That's a "sound comes OUT of the TV" socket. The sockets can't change the signal direction, so connecting two INs together won't result in a signal. The signal flow has to be from an OUT socket to an IN socket if there's to be a working connection. Check the socket labels for confirmation.


However, where there is a functioning RCA output, then the normal practise if for the signal level to be fixed and independent of the TVs volume control.

Once again, exceptions exist, but usually with a software choice of fixed or variable level. It would be extremely unusual for RCA to be variable level with no option to override that

2) Optical is generally fixed level too unless overridden with a software choice. If that is the case, then a true variable control will apply only to PCM stereo signals. It's not possible to have a true variable level control for Dolby Digital. This is a bitstream signal and doesn't work in the same way as PCM.

3) Broadly speaking, yes. Fixed level optical out - set to PCM so that the DAC can convert the signal to analogue stereo. Then connect the analogue stereo OUT from the DAC to the analogue stereo IN on the headphone transmitter.


The caveats are that not every DAC will generate the same audio level after conversion. For example, if the headphone transmitter needs a 1 volt signal to generate full volume, but the DAC only generates half a volt max, then it won't be as loud as being riven by a DAC with a 1 volt output. You need to check the specs of all the devices involved.

 

[Tigercubrider]

You can't say.
Some TVs have a system where there is a separate headphone volume, and the speaker remains "on" but others mute the speakers automatically when headphones are inserted. On top of that, some TVs make the headphone socket a pain to find.

If you can get a line out of the TV, you could run a lead to where they sit, plug that into a headphone amp, and run headphones from there to their seats.

Something like a behinger HA 400 gives 4 outputs with individual volumes, and uses a stereo 1/4" jack plug input. So you would need to connect the other end to the TV which could be almost anything.

There are cheap headphones with built in volume controls.
Another option might be wireless headphones? Many years ago I used an Infra red Sony system the sender used either/or headphone or line level and the headphones had a battery inside, with volume. The advantage of a transmitter is (like radio) extra headsets don't load the system. Plus obviously, no wires to troop over. Downside is batteries