Volume threshold of DVD vs. VHS media

Factual Questions
1

I have one of those dual DVD/VHS player combos. When I watch VHS stuff, my TV volume can be set at about 65% to ensure comfortable hearability. With DVD stuff, it’s something like 85% to 90%.

I thought it might be a weird quirk of my player, but even the DVD player on my computer needs to be set at 85% or so. It’s not like I have hearing damage.

What’s the deal?

2

Perhaps it’s a combination of these factors:
[ul]
[li]I imagine that as VHS is only ever in Dolby 2.0 at most, and not 5.1 like most DVDs, and therefore has a downscaled mix, that may have some effect on the volume levels.[/li][li]It may also be because of how the audio is electronically read on a tape.[/li][li]Or simply a quality level because of how crappy VHS is.[/li][li]Or it may be because different production houses deal with VHS than with DVDs, and use different settings.[/li][/ul]

3

Dynamic compression. The range of loudness between quiet sounds and loud sounds is reduced purposely on VHS tapes, by both boosting quiet sounds (like speech), and damping loud sounds (like explosions). Partially for bandwidth reasons, partially because lots of people don’t want an explosion in a movie to actually be 120 dB. DVDs, however, don’t use dynamic compression, since lots of people with DVD players want to get the full movie experience. Which means that speech is quieter on a DVD, so you have to turn up the volume.

However, most DVD players can add dynamic compression on the fly so you can watch a movie with explosions without waking up the neighbors. Check out the DVD player audio settings, and look for something like “compression” or “loudness”.

4

Our stand-alone DVD player also has lower volume level than anything else. There’s no good technical reason for it - the output amp can be designed with enough gain that the signal level is the same as all other audio equipment.

My guess is that it is. With the greater dynamic range of DVDs, maybe they keep the average program level 20 dB below the normal reference level to allow plenty of headroom for the occasional sonic boom.