Today I am going to write about my thoughts regarding how I approach a Trailer for Sound edit and Mix. What role does sound play in it and what is its purpose?

First off, remember that a trailer and teaser are different. The purpose of a teaser is just that. Tease. Show a bit of the movie so much that nothing is revealed in detail yet creates an interest. A trailer on the other hand also generates interest but also gives a bit more exciting scenes and a bit of the context of the movie. Usually teasers are more musical in India. Rarely are they based on effects although that trend is changing now. Also, a teaser is under a minute in most cases.

Approaching a Trailer

There are 2 common ways to approach a trailer. They can break down into sub-divisions for ideas later. The ways are:

1. What is the Trailer trying to say in looks and edit?
2. What is the flow?

Both of these are very useful methods to approach a trailer and something that I frequently do. Lets face it, not all trailers are well edited. There are some that are not upto the mark or may feel difficult. Even so, when doing the sound edit, try and see what the Editor /  Director has to say with the trailer.

Every good trailer has a rhythm to it. Try and get that in first. Because the only way you are going to make it impressive and sustain the audience is by following that. Because that makes most of the effects flow with the narrative. Every trailer has a narrative, even it it looks like a mish mash of visuals.

Choosing Sounds

These are some tips that I use when doing sound edit for a trailer:

1. Choose sounds that sit well with the Music. Always try and have the reference score for the trailer. Remember, the purpose is not to show off sound design, it is to show the trailer.

2. Choose sounds that dont have to much in the 2k-8k frequency range as that would immediately shoot up the LEQ and loudness and would be very difficult to get it under control. That being said, dont try to make too many EQ decisions during the sound edit as it would be difficult once the music comes in to the mix.

3. Don’t layer too many sounds for one aspect.The idea is to fit it in the narrative and the flow. So, it wont help having too many tracks that clash at the same frequency range. As usually music will take prominence when considering the flow. That doesnt mean that you dont give FX importance. It is critical to choose the right one.

4. If at doubt with some effects, have an option muted underneath for the mix. This will help the mixer if there is something else that is needed.

5. Ambience should be minimal unless it is a scene that is depicted as real without score. The reason is that there is no time nor the aural space to establish the ambience. In a film, one has all the time to get the audience in. Not so in a trailer. This requires that it is there to support what is before and after the scene.

6. If doing it for a 5.1 or other surround format, make sure you have atleast 2-3 layers of sound for ambience if used or crowds etc. The reason is that it will sound more full when they are placed in the surround space rather than panning just a single stereo track.

There are much more, but most of them stem from these points above. These are just general pointers that will help you to start off.

Mixing the Trailer

One of the very important things in a mix is controlling the levels. Not just levels, the loudness is the most important factor. This is where the idea of having the session as i outlined above comes to play. But another very important factor is how the LEQ(m) calculates the levels.

The LEQ is an averaging loudness measurement based on the Fletcher Munson Principle. The Dolby LEQ uses a variation of it with the peak calculation ranging from 4kHz to 8kHz. Dolby calls this the Annoyance Frequency. The measurement is based around this. So the more peaks you have around this, the faster your LEQ meter will rise. And you need to keep it within 85 for an approved trailer.

The Trick with the LEQ is always averaging. If you need something loud, you need an equal amount of signals soft before it. Else, it just becomes loud and the whole trailer will have to be pulled down. Imagine this, If there are 10 students in a class and the average pass mark is 50, if 5 students get 100 and 5 get zero, the average becomes 50. Basically it is the sum divided by the total number of students. In the case of the LEQ, it is the sum averaged over time. But the sum based on frequency. The values approved by TASA are based on these values:

Frequency in Hz Response in dB Tolerance in dB
31 -35.5 ± 2.0
63 -29.5 ± 1.4
100 -25.4 ± 1.0
200 -19.4 ± 0.85
400 -13.4 ±0.7
800 -7.5 ± 0.55
1000 -5.6 ± 0.5
2000 0.0 ± 0.5
3150 3.4 ± 0.5
4000 4.9 ± 0.5
5000 6.1 ± 0.5
6300 6.6 ± 0.0
7100 6.4 ± 0.2
8000 5.8 ± 0.4
9000 4.5 ± 0.6
10000 2.5 ± 0.8
12500 -5.6 ± 1.2
14000 -10.9 ± 1.4
16000 -17.3 ± 1.65
20000 -27.8 ± 2.0
31500 -48.3 + 2.8, – ∞

If this was plotted, you would see a bump at the 4k to 8 k range. (For those who really want to know the formula is:


and L(i) is given by


Dont ask me for an explanation!)

But what we need to understand is one more thing apart from this bump. The values for the low frequency are really not calculated much into the meter that Dolby has because it has a high pass filter on all channels at around 80 Hz. The second fact is it also has a 3dB less calculation in the surround channels for these values. This means that we need 3dB louder signals in terms of frequency to achieve the same LEQ in the front. Confusing? Dont worry. It only means that we have an ability to mix the surrounds louder than a conventional mix and use that as an advantage to get bigger mixes that dont affect the LEQ much and help us stay in the designated range.

So the tip to to get a bigger sounding trailer mix, you can have more low frequency elements, less mids, more sounds in the surrounds. But in all of this, make sure the mix sounds balanced and not tilted towards the rear. You can get some techniques that I use in some of my earlier blog posts on how I achieve this. It only has to do with coherent and non coherent signals, Once this is clear, the mix part becomes very easy and trust me it wont take years. What takes years is aesthetics. But you can shorten the technique and path to this because I just told you how! 🙂

Now how do you control all of this? That is where the basics of using an EQ, a multiband Compressor and proper panning techniques come into play. The reason I have the trailer video above is to show how the mix and balance was done. (the high frequencies on the youtube version were boosted to get it through laptop speakers as that was the primary way this was being heard.) I have done the sound edit and the mix with the sound designer being Stephen Gomes and Dialogues by Lochan Kanvinde. If you notice, to create the link I have a reverse drop whoosh from the title of Dharma to the opening duduk of the trailer. This establishes the fact that we have started it from the title and it is not a separate entity. Everything from the rain to thunder and even the reverb tails were based on that tempo. The idea is that is sounds musical although it is an event. The percussive elements gave me an opportunity to establish tempo and energy already. This also gave me the idea to drop elements rather then the score for dialogues. Our mind wont notice this and will fill the gaps in this.

For the mix, I used a lot of multiband compression rather than EQ as that gave me an even tone while holding on the LEQ too. The LFE and Surrounds were also as I described above

Digital Trailers

A lot of times I have heard trailers for the digital version just loud and boosted by 3-5 dBs in many cases. There is absolutely no need for this and in my personal opinion will cause the trailers to be lowered even more in the theaters. It is perfectly possible to get a good sounding trailer at 85 too. Ofcourse it depends on the way the trailer is edited. There is no point in having all the loudest portion in the movie in one trailer. It just causes the Dynamic Range to drop and thereby increases the LEQ.

The whole point being that the better dynamic range we have in level, frequency and pans, the more impact we can get for a trailer mix. Hope it was useful!

Have fun mixing more interesting stuff guys!