Audio levels for cinema

[timrabrown]

Hi,

My short documentary is playing at a film festival next month and I'm not sure if I'm able to test it in the cinema beforehand. This is the first DCP I've created and was wondering if the audio levels look about right? Or should there be more separation between the C and L/R channels? The film is mostly underwater so L/R is ambient sounds (notched at1kHz to reduce frequency overlap with dialogue) with music slowly coming in from around 1:20. L/R surround is just the ambient sounds and I kept them a bit lower to be safe.

I know I should be monitoring this in a calibrated 5.1 environment but I don't have the ability/budget to. Would it be safer to drop the L/R channels to make sure the dialogue isn't hard to hear or it looks OK from the graph? It sounds OK when listening through headphones but I assume this isn't a good test.

Thanks

[Carsten]

This is just an educated guess:

Overall loudness looks okay for me at around -20 LUFS. It may be that dialog on center would need more boost to separate better from the ambient sound on L/R. At least when I assume that the center carries dialog that is meant be understood clearly. You could raise center by nearly 3dB (actually, 2.6dB) before it clips. Overall LUFS would increase slightly as well that way, but should still stay reasonable.

Given that your dialog is already hovering close to -20dB (good), I guess it would be better to lower L and R. So, your own assumptions are correct, I guess.

[jdent02]

Do you have any idea where the volume knob will be at during playback? That would influence your decision between boosting center or dropping L/R.

[Carsten]

Hard to tell. From my experience with festivals, they will either always have a hand on the volume knob during presentations, or, they will listen through every piece beforehand and will create a dedicated volume cue.

It depends a bit on wether you want your piece to sound 'soft' or 'loud'. I would imagine, an underwater scene with some ambient sounds and music would be on the softer or 'medium' side (compared e.g. to a car chase). I would probably raise center to max (+2.6), and lower L/R by (-)3dB. That probably keeps the overall LUFS more or less the same, I guess.

In my opinion, you can't go wrong around -18 to -20 LUFS.

[timrabrown]

Thank you for the replies. I'm not sure where the volume knob will be so I think dropping the L/R might be a good approach. As Carsten suggested, ambient sounds are definitely better on the softer side for this and while I want to give the sound an 'immersive' quality, dialogue clarity is the priority.

Out of interest, do you think the ambient sounds in L/R surround channels will create a more immersive quality or would it potentially be distracting / risk making the dialogue less clear?

[Carsten]

The most important thing for dialog intelligibility is to have dialog coming from a single source only (center). As long as it has a higher level than L/R and surround, and is coming from a single speaker, it should be fine. One can only guess to a certain extent. If you're interested, you could upload JUST the audio MXF for me to download it, and I could give it a try in our cinema.

[timrabrown]

Thanks Carsten, that would be very helpful. You should be able to access the audio here: https://drive.google.com/file/d/16BIWnV ... sp=sharing

That version is a new one with the C boosted slightly and L/R reduced (graph below). Dialogue is just in center channel.

[Carsten]

Okay, I converted this audio mxf into an all black DCP and listened to it in our dark auditorium. All levels went through unaltered as you set them.

To me it sounds perfect. The voice is dominant, but not hurting. The surrounds/ambient work very nicely and are not distracting. I think you will be very pleased with them.

I played it at our standard feature level (which is 5.5 on our Datasat processor). The listening situation and level thus is exactly the same as every night here, and from my exchange with colleagues, comparable with other cinemas of similar profile.

We're a mixed mainstream and arthouse venue with a large 460 seats auditorium. Our sound system thus uses large speaker systems. Certainly not a current state-of-the-art sound system, but a slightly outdated large auditorium JBL system. But dedicated JBL cinema series speakers.
When I compare it with modern, but mostly smaller auditoriums, I usually like the richness of our system more, especially dialog.
You can hear our systems are big without seeing them.

I took some extra time to check L/C/R balance and surround levels before I listened, and found them to be correct. I sat in the sweet spot, that is the middle of a 3/4 back row.


I'd say, leave it like this.


- Carsten

[timrabrown]

Thank you so much Carsten. That's incredibly helpful and takes a lot of stress out of a first-time cinema screening.