Just wondering about something...I've had customer whine about how much the sound levels changing dramatically when watching a dvd. For example, they may be watching a quite scene with just talking, and then suddenly an action sequence starts and it seems really loud. I've alway just told them it's the way the movie is recorded. Any thoughts anyone?

I would HOPE so!

Have you thought about explaining to them that a cannon, or missile, or gunshot, or helicopter IS louder than the human voice in a sex scene?

Okie Dokie then!

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avdude
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You could always have them enable "dynamic compression" on their DVD player.

I always wondered this too. In the Home Acoustics Alliance/Sencore training we learned why this sometimes happens.

It is not because it was recorded that way. If the ambiant (background) noise level of the room itself is too high, it will obscure low level details like soft sound effects and some dialog. If you have certain loud bass modes, they will be relativly much louder than the recorded bass level, even if all the levels were set correctly overall.

The answer is in taming these problems. Most good soundtracks should not cause this problem.

What?

Okay, if all you say is true, then the same thing should happen in a theater because that is how the sound track is recorded.

I just wrote a long paragraph that was too hard for me to understand. Let me rewrite it with numbers.

Let's say you have a room with an ambient level of 65 dB. If the quiet portion of a movie is at 60 dB, then the overall sound level will be about 66 dB and it will be hard to hear the quiet parts. If a 95 dB scene comes on, the overall sound level will be about 95 dB, maybe 95.5. The sound will have increased from 66 dB to 95 dB, an increase of 29 dB.

In a totally silent room, the quiet part at 60 dB will come out at 60 dB; the 95 dB part will come out at 95 dB; the difference will be 35 dB.

Thus there will be an actual greater difference in volume between loud and soft parts when the ambient volume in the room is lower. There is one thing that offsets this psychoacoustically, though -- in the room with the louder ambient level, you are likely to be leaning forward, concentrating on the quiet parts, so when the loud part comes on, you will be blown away. But with 6 dB less of a volume difference than in a quiet room!

Right, it would happen, but commercial theaters are designed to be very quiet rooms. You are able to hear all of the softest sounds and the loud sounds are dynamic but not overweming. In a good, properly calibrated theater of coarse.


In a totally silent room, you would not have to turn up the overall volume higher just to hear the low level sounds. With the overall volume down a bit (it could still be quite loud, i.e 80 dB reference level) the loud parts would not be so loud as to be uncomfortable.


The dynamic range (difference between the lowest and highest parts) is recorded into the soundtrack just the way it is supposed to be. On a well recorded soundtrack of course.

This can all be verified easily with an audio analyser and by using the SMPTE Noise Criteria (NC) chart. The soundtracks are meant to be played in a very quite room to be reproduced correctly.

This was all a complete mystery to me before I took the HAA training. It has really improved the sound quality of my projects since.

Right. I missed that. This is not as big a factor as you might think, though, since we tend to get accustomed to whatever volume we are listening at. The thing to note is that higher background noise will lessen the dynamic range of the playback by raising the noise floor, while also making it hard to hear the quiet parts. This is similar to the difference in specs between analog tape recorders and any digital method -- the dynamic range is greater with the technology that has the quieter noise floor, which we call ambient noise when it is in a room.

Everyone did great at explaining to Andrew why his customer is hearing what he's hearing. But does anyone have a solution?

I was thinking about this problem just the other night, probably the same day the thread started, as I was watching a movie with the volume control in my hand, trying to adjust on the fly so as to hear all the dialog clearly, but not wake my kids up during explosions. Daniel's suggestion of enabling compression within the DVD player would help, but this movie was in my TiVo.

My TV set has a setting called "sound level" which is supposed to even out volume levels, but it doesn't seem to do much, if anything. I don't think anyone makes a 6-channel programmable compressor with presets you can recall by remote. Some components I've come across have a feature similar to "sound level", but it's always an on-off thing that never seems to do enough.

Virtually all my watching is done while the rest of the house is asleep. I'm sure some of our customers have a similar problem, and telling them "that's just how it's recorded" never satisfies them, as we all know. It's an example of how our quest for perfection needs to be compromised to fit the customer's lifestyle, something we're used to doing whenever an interior designer is involved. But this issue just involves sound, not appearance.

There's not much gear out there that addresses this problem. I'd be interested to know what products anyone has come across that does.

Doug @ HomeWorks

Any other responses?

How about a dynamic range compressor?

Edit: Sorry, my link wasn't working, but it is now.

Larry
www.fineelectricco.com

This message was edited by Larry Fine on 06/17/04 09:49.

How about putting Butt Kickers in your couch for the low end and wearing a nice pair of Sony headphones when everyone else goes to bed. Just turn off the speakers and sub and enjoy. I have done this for a few customers and they were very happy with the results.

Yamaha has a "Silent Cinema" mode on their receivers to handle such concerns.

Larry, how would we get that to work with digital multi-channel audio?

I have used the compressors in the presentation industry a couple of times, but never in a home situation. Sounds kinda funky, literally.

Roddy

This message was edited by roddymcg on 06/19/04 17:34.

Post production editing for a movie is extremely tedious involving a lot of people that scrutinize every choice in every aspect of the sound mix before it is released. Dynamic elements of a mix are designed to provide impact to a flick. The classic "dip" where all sound is removed millisecionds prior to a huge explosion creates the illusion of the explosion being much louder than it is. So, maybe one of a variety of things could be occuring here. perhaps the woman doesn't have her system in the correct mode for listening, or two, she needs to teak the speaker levels, or she just doesn't appreciate punchy movie soundscapes. You could adda compressor limiter on the output of the DVD player or sat receiver and set it up to limit the dynamic range,