The curse of a large dynamic range.

[Guy Rowland]

Yes, unintelligible dialogue again. Great article here on Production Expert, with a possible tech solution.

https://www.production-expert.com/produ ... om-in-2026

I dubbed an indie comedy earlier this year, and last week was the cast and crew screening at a cinema in London. It was great seeing on the big screen, but it sounded bloody awful.

All the filmmakers kept saying to me before I started work is "we need to hear the words". Guess what - I agreed! The mix was engineered to hear everything super-clear, and then the music and effects have their moments around it. A friend of mine did the 5.1 mix, and we were all rather chuffed.

At the screening, pretty much ALL you could hear clearly was the dialogue. I mean, rather that way than the other, but the music was so weak. Very quickly I guessed what had happened - everyone at the cinema complains the dialogue isn't clear so they push up the centre speaker. For a badly mixed film where the dialogue is buried, it works quite well - it's how I have things set up at home in fact. But for a (ahem) well mixed film, it sounds awful.

Anyway. As an industry, we are still in thrall to the wonders of a wide dynamic range, believing it to be a purer and "better" sound experience. BS. People need to hear the words - keep the dynamic range more limited and keep the dialogue front and centre. And that can be cinematic too - Hot Fuzz was on the other day and I swear it's the greatest sound mix of any movie. EVERYTHING has impact where it should, there are moments of quiet so its not fatiguing and I can hear every single word effortlessly.

[wst3]

The myth of dynamic range continues to frustrate audio professionals and consumers alike.

A 120 dB dynamic range is just plain ridiculous!

It is generally agreed that the minimum signal to noise ration for acceptable speech intelligibilty ss 10, but many studies put that threshold at 15dB. In some settings the number can go as high as 30dB, although that figure seems to have lost favor.

Oddly enough, the generally accepted S/N ratio for music is 60dB to as high as 70dB.

Which is not nearly as counterintuitive as it might seem, but that's the subject for a different post.

From these statistics we can assume that our music should be 60dB above the ambient noise, which is actually pretty low in a well designed theatre. And the speech should be 70dB above ambient noise, or 10dB above the rest of the soundtrack.

• The target noise floor for a theatre is NC25 to NC30 (which is roughtly 25dB ro 30dB A-weighted.

• The threshold of pain is 120dB.

• The threshold for damage to the ears is 85dB.

These numbers are from notes for a class I taught a long time ago, they may have changed a little bit, but not enough to throw off the rest of the argument. And these are single measurement numbers, which it turns out are not all that useful, except for argument's sake

Anyway... let's assume a noise floor of 25dB, that means the music needs to be 85dB, and the speech needs to be 95dB. Pretty daunting eh?

Take another case - a moving car interior - the noise floor can be as high as 75dB or more. That leaves very little room beneath the level at which hearing damage can occur.

So if the loudest part of a track is 85dB and there are parts that are more than 20dB below that they will be swamped by the noise.

All of this is further complicated by the fact that average dynamic range for the human ear approaches 120dB (hence all the chip manufacturers shooting for that). But there really is no setting where music with a 120dB, or even half that, would be terribly enjoyable.

Re-reading this I realize I may have further muddied the waters...

so TL;DR - dynamic range needs to match the environment in which is it played. In a theatre, with a noise floor of 30dB A-weighted, a useful dynamic range might be on the order of 55dB, and in practice it is actually lower than that. Complicating factors include the condition of the listeners ears, the spectral distribution of the noise, and the spectal distribution of the program material.

It is a very deep, and very tricky topic!

[Luke]

Great post, Guy. Definitely worth discussing.

Bill, wonderful info! Fascinating. You really put levels and context into perspective. I don’t do sound mixing but will definitely make a note of all this.