That's why...... Today is improving tech better than 6 years ago. That's time, they do not have built-in Digital (HDTV) Turner as ATSC. LCD HDTV was very expensive.
5 years ago, they had few built-in HDTV Turner. Today, All HDTV have built-in ATSC (HD Turner) and NTSC. Next few years, NTSC will be gone.
Our twin sons (college students) are hearing. They told me that CC and Voice are not same time (just behind or earlier). Just few seconds different. That's big deal.
We did try few different way on "Smallville" HDTV and non-HDTV.
Fios HDTV box - use HD program - poor quality (fad some letters - hard time to read CC)
Fios HDTV box - use non HD program - flash CC (disappear - no way to read in 1 sec)
Fios Standard TV Box - great CC (little behind or earlier)
Tivo HD Box - use HD program - 50 percent missing CC but great quality CC
Tivo HD Box - use non-HD - not yet test
Antenna - Over the air - HD program great CC but one thing weak signal.
Antenna - Over the air - non-HD - still normal CC as standard TV - sometime weak signal
Antenna gave me too much adjust to find better image.
