Video Asylum

Dynamics Compression in DVD 2-Ch Downmix?

218.102.172.158

[ Follow Ups ] [ Post Followup ] [ Thread: Display Email Next ] [ Video Asylum ]

Jack

(A)

Hi,
Sometimes when I watch DVDs in my 2-ch system I found the dynamics of the audio to be compressed.
For example, when there is an explosion then I can hear the overall vol level decreases so that the explosion sound is not as lound as it should be. I found this to varies from movies to movies but in some movies it is really annoying (e.g., "A Sound of Thunder").
My question is: is this really part of the movie or is it due to the downmixing of Dolby-Digital to a 2-ch PCM output by the DVD player? If it is the latter will adding a real surround processor to do the downmix help alleviate this problem?
I have to stick with 2-ch for the time being so any advice would be appreciated. Thanks.
Jack

Follow Ups:

make sure the dynamic range control is off - Joe Murphy Jr 17:57:31 05/23/06 (3)
This is also called the "Night" mode on a few players. Make sure it's OFF or dynamics will get severely squashed. You will also find that many players will downmix the 5.1 soundtrack to 2.0 and leave out the information from the LFE/.1 channel when they do so.
Then there's the fact that Dolby Digital is the MP3 of DVD audio codecs. Like MP3, if you need to conserve bandwidth and put a whole lotta stuff in a little space, it's an excellent codec. However, like MP3, quality is not a word you can associate with the results.
- My DVD player (Panasonic) doesn't seem to have a night mode - Jack 19:33:47 05/23/06 (2)
  Thanks for the suggestion.
  I suspect during the downmixing the DVD player enforces some dynamics compression (to avoid overloading the TV speakers?). I also use a pair of Pinoeer DD/DTS headphones and sometimes I found the sound to be more dynamic through the headphone than through the PCM output.
  Seems like I'll need to consider adding a surround processor to do the downmixing properly.
  I agree with your assessment of DD as I found DTS to sound significantly better even through my virtual surround headphones. It's a pity it is not more widely used in DVD.
  - it's there somewhere - Joe Murphy Jr 23:03:09 05/23/06 (1)
    It may be called Night Mode, Dynamic Range Control or some other similar name. Its function is to compress the low level signals (making them louder) and the high level signals (making them softer). This squeezes everything to the middle so that the volume doesn't have to be turned up to hear the quiet passages or turned down to compensate for the loud passages. It's used mostly for late night viewing/times when you don't want to disturb others with a dynamic soundtrack.
    But if it's ON when it should be OFF, it takes the life out of the soundtrack.
    - Yup, it's off .. - Jack 06:11:05 05/24/06 (0)
      Found the option "Dynamic Range Compression" but it's already off so it's not the culprit.

This post is made possible by the generous support of people like you and our sponsors:

McShane Design

You can not post to an archived thread.