Quick question on audio levels for mixing an event DVD

[Dave Largent]

Hi, I make event DVDs for playing on
all types of home TV sets.
There's spoken word and music.

I've been having my levels average about -9dB
and keeping in the range of going up 6dB (to -3) and
and down 6dB to -15.

I'm tired of the effects of heavy compression and
limiting and was considering shooting for an average
of -12dB, and keeping in the range of up 9 and down 9,
so keeping levels between -3db and -21dB.

Do you think the levels would end up being too low.
Someone here menioned that TV programming is
usually kept in the area of 3dB up and 3dB down.

[Don Bloom]

Dave,
Peaks on DV should be around -12db (equals 0db in analoge)- I try to keep my average around -15 or so but most importantly I work at keeping peak at-12. At most of the seminars I do that's generally fairly easy to do it's the DJs and bands at receptions that play havoc.
Sometimes with the camera set to peak at -12 the average drops to about
-20 and then I have to boost it a bit but I'd rather do that than have to play with compression to try to save a clipped piece. But that's just me!

Don

[Douglas Spotted Eagle]

Originally Posted by Don Bloom

Dave,
Peaks on DV should be around -12db (equals 0db in analoge)- I try to keep my average around -15 or so but most importantly I work at keeping peak at-12.
Don

Actually, this number is dependent on the gear's calibration, not any baseline spec. This is why the ATSC determined a few years back, that -20dBFS is the equivalent of 0 dBVU.
Content dependent and calibration dependent, -12dB is a reasonable averaging point, but if you've got more than 12dB of dynamic range, this means you're hitting 0dBFS, and unlike analog, you can't go past that point. it truncates/blows up/shatters/brickwalls/whatever you want to call it. Keeping your PEAK at -12dB means you're throwing away a lot of bits.

[Emre Safak]

What constitutes a 12dB dynamic range?

[Douglas Spotted Eagle]

Measuring from the most quiet point to the loudest point is how dynamic range is determined.

[Don Bloom]

Hey Spot,
Thanks for the info-I've always looked at -12 as my peak level and try to stay around -15 to -20 for average but now I need to look at that again. But maybe not-you know I've got it going pretty much where I want it now using those levels (took me some time to get them figured out-about 5 years ;-0) so maybe I shouldn't mess with it.

BTW, I don't remember if you were the one who recommended the AKGSE300/C93 hypercaroid - if you were thaks a milion-great sound for indoor run and gun and receptions and such-sounds so much better than the ME66 and the AT897. (if you didn't reco it thanks for all the audio help anyway)

Don

[David Ennis]

Originally Posted by Douglas Spotted Eagle

... -12dB is a reasonable averaging point, but if you've got more than 12dB of dynamic range, this means you're hitting 0dBFS...

I think you must have meant 24dB dynamic range?

[Douglas Spotted Eagle]

I could have said that better, sorry.
If your quietest point is at -12dB, and you have say...14dB of dynamic range, you're screwed.
If your average is -12dB, then you have 12dB of dynamic range. Thanks for catching me on that, Fred.

[Emre Safak]

Originally Posted by Douglas Spotted Eagle

Measuring from the most quiet point to the loudest point is how dynamic range is determined.

I understand that, but I was looking for a real-life example of a situation where you would encounter such dynamic range. Basically I am trying to get a feel for the numbers.

[Douglas Spotted Eagle]

depending on the person's speaking voice, you *could* encounter a dynamic of 20dB, if they were passionate or pulpit pounders, and the spoken word contains a lot less dynamic than the singing voice, which is why compressors are all but required in most singing-voice situations and many spoken word situations.
Additionally, you might have two actors with a wide range from the most quiet point of one actor and loudest point of another.
Television has a dynamic range of around 8-10dB, which is better than it was just a few years ago, and getting wider bit by bit (no pun intended). Technology has the ability to provide a lot more range than that, but at the same time...you gotta be careful about how much range you put into something. Walter Murch says he's squeezing 25dB of dynamic into some motion pictures. That's a lotta range! I'd like to be that good and still leave the audience without bleeding ears. :-)
Anyway...recording normal, average dialog expecting around 12dB of dynamic range should be plenty, but as a side tour, this also explains why you need compression, and good compression, for most projects. I'd be seriously in trouble without my UA100 or WAVES tools on the software side, and various compressors on the hardware side.
Somewhat related... This is a great read

[Barry Werger]

For the record -

Classical music usually has much more dynamic range than that. And it's rarely compressed. Requires good equipment for playback, and a lot of skill for recording - and good sound-checking! A soprano has a tremendous range, and a peak can easily jump 30db above averge for lots of pieces!

Percussion, applause, etc. have lots of big peaks, too, but are often forgivable in a way that other sounds aren't; you can sometimes let those go. But listening is the only way to know!

[Patricia Lamm]

Sorry, audio newcomer here. How do you impose DVD-appropriate levels on your audio using something like Sound Forge 8.0? Using Normalize (peak or RMS?)? or Dynamics (which settings?).

[Steve House]

Originally Posted by Patricia Lamm

Sorry, audio newcomer here. How do you impose DVD-appropriate levels on your audio using something like Sound Forge 8.0? Using Normalize (peak or RMS?)? or Dynamics (which settings?).

Normalizing raises the overall gain of the track so the peaks are just below clipping. It's like turning up the volume control. Compressors such as Sound Forge's Dynamics plugin, OTOH, selectively change the gain, raising quiet passages while leaving the loud ones as is. There's no single set of settings that would be universal. It depends on the type of music, etc, and personal taste.

I discovered some "tips and tricks" documentation in the product information section of the Waves web site - www.waves.com - that can help you with starting points for settings to try. Even though they are discussing their own products (which will work with Sound Forge, BTW) those pages can help you understand the principals.

[Patricia Lamm]

Hi Steve, thanks for your answer. I've gone through some books and videos and have a general idea of how to play with normalization and dynamics/compression. I think my confusion at this point is more one of terminology and how to find certain quantities using something like sound forge. When someone says they keep their average levels at -15 dB, are they referring to an RMS of -15 dB over the entire sample? (I know they don't really mean 'average' because that should be -Inf, right?)

[Douglas Spotted Eagle]

Originally Posted by Barry Werger

For the record -

Classical music usually has much more dynamic range than that. And it's rarely compressed. Requires good equipment for playback, and a lot of skill for recording - and good sound-checking! A soprano has a tremendous range, and a peak can easily jump 30db above averge for lots of pieces!

Percussion, applause, etc. have lots of big peaks, too, but are often forgivable in a way that other sounds aren't; you can sometimes let those go. But listening is the only way to know!

Of course it does. But you cannot put uncompressed classical music into a broadcast or into a DVD stream, for the most part. Audiophiles *hate* this, of course, but when mixing/mastering, you've got to consider John Q. Public and not the guy that has top end Martin-Logan, tube or super high end amp/preamp, etc.
I would shudder to think anyone might use a DV camera or HDV camera for primary audio source from an orchestra or symphony....Yuk.