Hi,
I’m new to this forum, and help with the following would be appreciated: at my age (81+) I have the inevitable hearing deficits that make it difficult to hear in certain environments, one of which is the playback of movies without subtitles. I though that I would try some types of equalizations, both low and high pass filters and noise and click reduction, for starters. What I’ve done so far is to rip the audio track from an mp4 video file, and then open the ripped file in Audacity to apply the various effects in order to maximally increase intelligibility. Then I can add the modified audio to the original mp4 as a separate track.
If you watch The News Hour on PBS you are listening to an audio track for which intelligibility, even for me, is near 100%. Whatever is being done to that audio is something akin to what I want to do to my ripped tracks.
If any of you have any suggestions, I eagerly await them.
Thanks
We can’t guess how you want things to sound. To begin with, a lot depends on what equipment you are listening on.
I would imagine you want to include compression in your list of effects.
Please post a sample of what you regard as good audio and a sample of audio that you want to improve. Please see https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1 for how to post a sample.
Gale
I think experimenting with equalization is your best bet. If your TV has tone controls, turn-up the treble.
With the equalizer, try boosting frequencies in the 3-7kHz range (or higher). Boosting the high frequencies will bring-out the “T” and “S” sounds. Of course, it won’t help to boost frequencies that are completely above your hearing range, but it won’t hurt either.
You might also try cutting the mid-low range (maybe below 300 or 500Hz) by a few dB. But… I’m just trying to give you a starting point… Don’t listen to me, listen to your ears! 
If you are using the speakers built-into your TV, these may also be contibuting to the problem. So if your TV has connections for an external speaker, a slightly-better speaker might be worth trying.
I hooked-up an external speaker for my mother and we positioned it near her chair so that she could better-hear the TV without blasting-out everone else. I also added an on-off switch to the speaker so she could switch it off and converse during commercials, etc.
High & low pass filters are not likely to do much for you. A high-pass filter passes only the high frequencies while blocking the lows, and a low-pass filter passes low-frequencies while blocking the highs. You don’t want to block anything.