Causes of distorted DVD audio?

Maybe the problem is coming from your TV or set top? Can you run the set tp audio through your computer audio monitors?

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What did you set the dialog normalisation to be when you encoded to Dolby Digital? Does your set top have any specific settings for audio in it?

My guess is that you have normalised the audio at quite a high level (try to aim for -8 and see the difference) and then encoded it using a DNV of -27 (the default setting), and probably left the film standard compression in place as well. All of this needs to be set differently.

Try setting DNV to -31, and change the compression to 'None', then encode to AC3.

the -31 setting is one that causes debate. The DNV setting is designed to account for the differences between loud parts (such as explosions) and softly spoken parts. It is part of a formula which attenuates the audio. Leaving it at -31 means there is no change to the audio levels when you encode. Compressor, however, defaults to -27 which will cause some attenuation -you need to manually change it to -31 and go from there.

You are right about film standard compression - set compression to none.

Obviously, if you know the compression profile you have to use, and you need to use dialog normalisation then you would ignore the advice I am giving, which will basically ensure that you don't alter the audio levels from what you put in to what you get out.

There are books written abut this stuff, and we can't hope to get all of that info into a single thread, but when you create the audio track in Hollywood, there is a shed load more stuff happening to it than when you edit on FCP.

We can get close. Make sure your audio doesn't peak above around -8db in your FCP timeline (it can go higher, say -5 or -4Db but only occasionally. Aim for -8 and you should be pretty good for most things), and averages somewhere around -12Db (this is important - the average is a bit of a guess, you'll need to use some common sense on this bit). This should then be more than loud enough for TV playback. When you have the sound as you want it, export it as .aiff from FCP and go through Compressor to create AC3 using -31 as DNV and no compression profile. Make a DVD and test it out on your TV to see how it sounds. It should sound pretty reasonable (in terms of volume) and shouldn't distort within comfortable listening volumes.

For sure you can try the compression profiles, and these will alter the dynamic range of your audio. However, if you have fully balanced the sound and taken time to get the range within reasonable limits, applying another profile is counter-productive for many people. The governing factor should be where the disc is to be played, or intended to be played, and work to that. If you are sure your audio is heading towards a film theatre, then apply the appropriate profile. If it is a set top box in John Doe's front room, use the settings we have discussed above as a starting point and go on from there. The biggest thing to remember with the compression profiles is that they *DO NOT WORK WELL* unless you have taken the time to understand and apply the *CORRECT DNV* setting. You can only do this if you have understood what DNV is all about. The -31 setting is NOT a perfect setting. It prevents any attenuation, but may not be exactly right for every project. You really should work out the correct DNV to use by looking at your audio files with a tool that shows you the average levels. FCP is OK, but there are far better tools to use.

Experiment with the settings - there is nothing lost except the time to do so - and everything to be gained. If you end up understanding this stuff better then it is time well spent, IMO.

Most, if not all, Hollywood DVDs aren't made with DVDSP. There's high level Sonic products and proprietary ones studios use.

I stand by the -31 comments made. I always use that setting and things sound great. Stick to Dolby/AC3... no need to use PCM. Also, never mix audio formats. It can cause normilzation problems if you have something as an aif and something else as ac3.