Normalize My Audio

August 22, 2006 10:53 AM

I want to normalize the audio output of my DVD player within a certain range. Is this possible?

I'm tired of having to turn up the volume when someone is whispering in a movie, only to turn the volume down when the next action scene comes along. I'd like to have it so that the movie isn't too loud or too quiet.

I know you can normalize audio on the computer - i've done it when making a mix cd from a variety of sources and i want the songs to all be relativley equal in volume.

Do any dvd players offer this functionality? I realize that to do it proper, it needs to analyze the audio of the entire dvd before playing so that it can determine the "gain" for that particular dvd. And that analyzing might take some time.

The "midnight" mode on my particular dvd player/receiver doesn't seem to do the trick, but sometimes having the DSP set to "vocal" helps bring out the talking but not the crash scenes.

posted by escher to Technology (15 answers total)

you can't normalize on-the-fly, but you can do dynamic range compression which will effectively make the quiet things louder and the loud things quieter. some dvd players have this feature.
posted by sergeant sandwich at 11:09 AM on August 22, 2006 [1 favorite]

Here's the thing - you probably actually want to compress it.

Normalization takes the entire piece of audio and makes the loudest part of that audio approximately equal to digital zero. I'd guess that if you're watching action movies, there are already parts that are that loud - the explosions, the music, etc, during the action scenes. Were you to normalize such a piece of audio, it would probably remain unchanged, or only be marginally louder.

Compression, on the other hand, is designed to make the quiet parts louder, and the loud parts softer. After that parity of levels is achieved, the whole signal gets "turned up." The signal is loud enough to listen to, and there's less difference between the loud and quiet parts.

As for how to go about compressing your signal, I'm not so sure. There are probably DVD players that offer such a feature, somewhere. Whether it sounds good (on all your DVDs, for that matter), is another question entirely.

You could buy a rack device, and run the output of your DVD player through it, but that'd probably require all sorts of balancing/unbalancing of cables. However, it would be really hard to set a compressor to sound good on all movies, or throughout a single movie, really. It would also be a pretty inelegant solution.

And then, of course, there's the whole concept of how true you want to stay to the original intent of the movie - the fellow that mixed the movie probably meant for the dialogue to be audible, and for the explosions to blow you out of your seat. If that's not so much your thing, I understand. Realistically, however, I think your options (besides riding the volume button on your remote) are pretty limited. There's nothing that doesn't have a downside.

I'd love for someone to prove me wrong, though. Even as an audio guy, I get a little peeved at the EXTREME DYNAMIC RANGE that's present in most films.
posted by god hates math at 11:17 AM on August 22, 2006

The free option (provided you have a movable/spare computer) would be to run the audio through the computer, get a free vst host (or use an audiounit if you are on a mac, I suppose garageband could do this), and download a free compressor plugin such as the mda plugin called "dynamics". I don't know about the resulting sound quality, though (I've never used that particular plugin).
posted by advil at 11:27 AM on August 22, 2006

Compressing DVDs for most setups is hard because you're dealing with anywhere between 6 to 8 discrete channels. If you were using stereo compressors you'd need 3-4 of them and getting all the settings to work in concert could be heard. This is a feature that some DVD players have but I'd expect to see it on a theater processor more than I'd expect to see it on a dvd player (that is, whatever device is taking your digital signal and turning it into 6-8 audio signals). A lot of good theater processors offer these kinds of features.

Something that might work decently is if you can adjust the gain on your center channel - this is where most of the dialogue is.
posted by RustyBrooks at 11:31 AM on August 22, 2006

It would be HARD to get the settings to work together. Not HEARD.
posted by RustyBrooks at 11:32 AM on August 22, 2006

Yeah I didn't think of that -- my solution would basically require the DVD's audio to be stereo at some point (not 5.1 for instance), unless you have a fancier sound card than you probably do.
posted by advil at 11:35 AM on August 22, 2006

Previous posters are correct -- you're actually trying to compress the audio.

My DVD player (a Panasonic that cost maybe $125 three or so years ago) has a setting called "Dialogue Enhancer" that processes the audio somehow towards the ends you describe. You'd probably be best off looking for something like that.
posted by YoungAmerican at 12:27 PM on August 22, 2006

My cheap Onkyo home theater receiver has a "Late Night Off/Low/High" setting that compresses the audio exactly how you want. Since we live in an apartment with thinnish walls, we tend to use that setting all the time, especially when watching action DVD's (Lord of the Rings Trilogy, I'm looking at you).
posted by empyrean at 12:54 PM on August 22, 2006

I have this problem when I plug my DVD player into my stereo - what I do to get around it is to turn the treble knob all the way up, and the bass all the way down. Since the quiet parts are people talking (relatively high pitch) and the loud parts are stuff blowing up (bass), it kind of works itself out.
posted by ny_scotsman at 1:38 PM on August 22, 2006

Close relative to the 'loud commercial' PITA.
The Audiovox AV-1 might help.
posted by Fins at 2:25 PM on August 22, 2006

I would not expect that gadget to work well. The site seems a bit... shifty.

How do you know that's an audiovox AV-1? The name, manufacturer, etc, is not listed on that page anywhere. The front of the box says "Terk TV Volume Regulator" I've never really heard of smart home but I guess that doesn't mean they're a disreputable dealer.

The customer reviews look like they're written by kindergartners.

You can buy it from SmartHome. Or, you can bid on it via auction... from SmartHome. That's kind of weird.

There's no view of the rear so I have no idea what kind of inputs/outputs it has, and all it says is that it comes with a
6 foot audio cable" which could mean just about anything, but probably does not mean s-link, digital coax, etc, which is what you usually need for dvd audio, unless you just have a stereo setup.

They sell a lot of X-10 stuff, some of which is OK, but much of which is useless junk.
posted by RustyBrooks at 3:07 PM on August 22, 2006

Actually now that I look closer it says that it uses RCA cables for hookup, so that would work (if the device works well) as long as you have a plain stereo hookup and you use RCA and not digital outs.
posted by RustyBrooks at 3:09 PM on August 22, 2006

Audiovox website which includes the Terk by Audiovox AV-1 owners manual.

A similar device is the Radio Design Labs FP-ALC2

There are discussions and mixed reviews of both online (commonly associated with loud commercials)
posted by Fins at 4:39 PM on August 22, 2006

I third (?) the recommendation for a compressing DVD player or receiver. My DVD player doesn't do it, but my 5-year-old Sony receiver has "Dynamic Compression" which basically just boosts the dialogue and quiets the explosions a bit.
posted by cebailey at 6:40 AM on August 23, 2006

Coincidentally, my girlfriend just got a DVD player that has a built in "dynamic compression" options also -- this is a Samsung DVD-V9650. Probably other models have it too if you don't want the combined DVD/VCR player. I haven't tried it yet, so I don't know whether it works.
posted by advil at 4:45 PM on August 23, 2006