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How to Use Loops for Soundtrack Pre-production


Post-production is sometimes overlooked in the audio field. Record producers, music engineers and platinum records are more respected, popular and cool. Everyone wants to know how this record was made or how somebody got that sound on tape. Fewer people care about the subtle intricacies of building a soundtrack for a movie, recording foley or dubbing radio novels.

There is a lot of work in the post-production stage, and building a scene from scratch is no easy feat. It has to be subtle, yet effective. You can't go overboard in effects, otherwise it'll sound unrealistic. Yet at the same time you have to make sure the feel of the scene is right. The choice of music, atmosphere, object sounds and such have to be right.

Post-production is sometimes overlooked in the audio field. Record producers, music engineers and platinum records are more respected, popular and cool. Everyone wants to know how this record was made or how somebody got that sound on tape. Fewer people care about the subtle intricacies of building a soundtrack for a movie, recording foley or dubbing radio novels.

There is a lot of work in the post-production stage, and building a scene from scratch is no easy feat. It has to be subtle, yet effective. You can't go overboard in effects, otherwise it'll sound unrealistic. Yet at the same time you have to make sure the feel of the scene is right. The choice of music, atmosphere, object sounds and such have to be right.

A Few Post-production Terms

Room Tones

Room tones are the noises of the room. Basically how a room sounds. A big warehouse doesn't have the same characteristics of a small basement cellar. So by having room tones underneath it is easy to place your scene. Room tones are often captured after the scene, when all the actors have gone home and nobody is there. The post-production crew records the noise of the room to use afterwards.


Foley is the noise of objects, footsteps, doors slamming, etc. Sometimes this is dubbed in after, to enhance a scene. Sounds can be on image or off image, be related to a certain object, or related only to a situation. Object sounds can be recorded or taken from libraries, and sometimes are created completely from scratch, using other objects that have nothing to do with the original. This is closer to sound design, as sound designers create sounds for objects that don't really exist in the real world. Examples of this would be the sounds of light-sabers and laser guns in Star Wars. The sound of a light-saber is mostly a 100 Hz sine wave but that's another story.


Although I say a scene must be realistic, it also tends to have unreal qualities that are not in the world of the characters. Music sets a certain feel, and a good soundtrack gives the listener the mood to which the scene is set. The correct music is the perfect way to propel the listener into the character's world. Music can be of various types. It can be a soundtrack over the scene, not in the world of the characters. This type of music is called non-diegetic music as it doesn't come from within the characters world. Music that the characters are listening to on the radio of the car, or music coming through the window of an apartment, is another type of music—the music that's put into the world of the characters, or diegetic music. Sometimes these are linked—for example, when you have a soundtrack blasting as a car zooms by, then hear the same song out of the radio inside the car.

Examples of non-diegetic music are in the various film scores of movies such as Star Wars, Indiana Jones and The Dark Knight. These films all have scores that are not in contact with the world, but at the same time portray certain moods, characters and scenes. Everybody recognizes the Star Wars theme in the real world, but you won't hear it coming out of the radio on the Millennium Falcon.

No Need to Know Music—Use Loops

You don't have to be John Williams, or Danny Elfmann to write a good soundtrack. Sometimes you can make do with what you have, your huge loop library and some simple editing skills. Below I will show you how to make effective sound moods, using only loops and some editing. Given the quantity of loops Apple offers with their Jam Packs, it is easy to search through and mix and match until you find a good starting point.

There are many people making their own music without playing a single musical instrument—check out this article and the various comments you readers made about creating music without playing an instrument.

In the following examples I will be using Apple loops but there are a lot of resources out there for free sound effects, foley and room tones that you can grab for use in your projects. Granted, Apple loops work really well because you can easily mix and match different loops that stay in the key you want it to. But if you have a big enough loop library, you will be able to sculpt your soundtrack easily. If you don't have too many loops, but can dabble on the piano, you will be able to create a believable soundtrack using all the various synths on offer. Bear in mind that in the following examples I am using Logic, but you can use whatever DAW you want, if it has believable synths and you have enough loops.

A good sound effect library is invaluable if you are doing a lot of post-pro work. Also, it can be fun to add various ambience noises and sound effects to songs. Just like in creating atmosphere in a fictional scene, it can also create atmosphere in your music tracks. Envato's AudioJungle has a lot to offer for this. Everything from music loops to sound effects can be found there and it's definitely worth a browse to see if you can find something to your liking. Also, if you want some free stuff to fool around with, a quick search on Google will get you some good results. I found these two websites in five minutes, when I was searching for sound effects.

Creation of a Scene

There are two distinct scenes I want to show you how to do. It is easy to edit together a sound track from loops, and by putting a little bit of foley and ambient noise you will have an instant scene. Although I've been talking about doing sound for picture, we won't be using video in these examples. These examples are just pure audio tracks. We'll be using audio to trick the mind that we're somewhere else and by accomplishing a convincing scene with only audio, half the battle is won.

I was leafing through pages of a comic when I stumbled upon a scene I thought would be great to put sound to. I wanted it to have a certain film noir type quality so I searched the sound banks for the type of loops I could use to accomplish this. I found some jazzy piano loops and some double bass I could use together. Editing the loops together I was able to create a believable backdrop soundtrack, and in conjunction with an alley at night I got an instant film and soundtrack. I am using four different loops to make this soundtrack, two of the piano and two for the bass. When I fade this part into another I will be adding a new part to segue this part into a new scene.

The second scene I am creating is an interrogation room at a jail. In this scene you are following the main character, as he walks down a hallway into a room. By using foley (footsteps and door noises), changing room tones (open jail noise, small room hum) with moody music you create a believable scene, and all without actually seeing a thing.

Scene 1: Crime Alley

Let's take a look at the first scene. I am using two piano loops to create the backdrop scene. A two chord vamp that repeats itself and with adding the second loop the chord progression resolves itself. I recommend reading Ryan Leach's article on The Basic Functions of Harmony for a little understanding on this. At the end of the scene I am using a piano solo loop to close the scene.

Listen to the three different piano loops here

Since the double bass loop is in the same category of the Apple loop library (viz. Jazzy Bass) it fits together perfectly. If you are using loops from other libraries it might not be equally easy to make them fit together. Timing issues and tonality play a big factor, so choose your loops wisely when structuring your track.

Listen to the three bass loops I'm using underneath the piano track.

As you can see in the screenshot below the first loop is used as an introduction to the scene. When things start happening, e.g. dialog, I've cut the bassloop, making it only play the first two notes. This, added with the piano playing chords that don't resolve themselves makes for a nice tense soundtrack. Only after eight bars does the piano resolve itself to the fundamental chord, which then leads the outro piano solo.

So, this soundtrack is basically arranged as follows. A few bars of intro, then a continuing chord vamp underneath the dialog which then finally resolves and flows into an outro. This outro then mixes with the next scene, but I'll get to that later.

Listen to the soundtrak here. We've yet to add atmosphere and such to it so it has only the elements of the piano and bass.

Now, we are making a realistic scene where stuff is happening. To give a scene it's certain mood you will have to put in the ambience of the scene. Where does it take place? Music on it's own will just sound like you're listening to music, but when you put background noise, you put the music inside the scene. Are we in a dark alley? Are we outside on a sunny day? Or maybe we're inside a small room? Whatever the scene is, there has to be an ambience engulfing the music so we feel like we're somewhere. You need to be able to feel where this is taking place.

This scene in particular takes place at night. So by searching by loop library I found something called City Alley Night. Listening to the background play against the music I liked where it was going, but I thought it was too quiet. I found another loop called City Traffic which had more car noise etc. By playing with the faders I was able to get a nice balance between the two. The alley is loud in the mix, but the traffic complements it nicely underneath. I get the nighttime feel that I want, but also a little bit more traffic and such happening in the background.

Here are both variations, only with the alley scene, and the other with both. Notice how the traffic in the background gives it more depth.

It's time we put the last things into the scene. I'm putting in a few foley effects, footsteps, money thrown on a surface and someone leafing through a wad of money. And lastly, the overdub of the actor, his grim Spanish setting up the scene. Now you have the sense of the scene, it's dark and jazzy portrayed by the soundtrack. The ambient noise places the scene at night time, and the foley effects set up the scene by hearing someone walk up. For a radio novel like this one, I don't think you need a lot more. This scene works quite nicely as minimalist as it seems.

Scene 2: Prison Interrogation

The second scene is a completely different affair. I'm using a different loop for background, even easier to do this time around, two different ambient noises, a jail tone and a room tone for the interrogation room. The beginning jail tone is spacious and is contrasted by the claustrophobic hum of the fluorescent lights in the interrogation room. I wanted to portray a little movement in this scene, so I am trying to get the feel that you are following the main character. His footsteps down the hall, opening the door to the room and then closing himself with you inside.

Listen to the scene here :

The music loop is the first four bars of some rock song in the Apple loop library. But I liked the delay guitars for atmosphere so I cut it at the end of the intro and looped it. So this scene has even less work as I don't need to edit any loops together. The only thing musically that's left is the end, where an outro song fades up and closes the scene.

Here is the intro loop. A simple delay guitar, taken from the jam pack library. You can hear the different room tones soloed here. First one is the the jail tone. Big and echoey. Second one is the small room, an almost overbearing hum.

There is a lot of difference between the two, one being a sort of hallway to a big open space, and the other being a closed room. There are various resources for finding room tones on the internet. As before, this is from the Apple Loops library, where you can find an assortment of room tones to create a credible space. I did a quick search on the Internet and found a site called Soundsnap that had room tones to download.

Notice how easy it is to place a scene by just using the room tone. By having that hum constantly in the background, your subconscious seems to make up the scene in it's head instantly. By listening to the whole scene, we only have a couple of elements. Moody music in the background for atmosphere, room tone to place the scene and various effects. I use the door sound to change between the different room tones, as it's obvious that the sound of a room would change when you enter and exit a different area. As you can see in the screenshot, the jail sound quickly fades out when the door is opened and we introduce a new location with a new room tone.

Moody Music Change

Let's listen to the whole jail scene. Non-Spanish speakers can disregard the dialog—we are making the sound around the dialog so let's concentrate on that instead. We've just been having a tiny atmospheric guitar loop over and over in the background, but at the end of the scene I'm introducing a new music loop. Like the piano solo in the first scene this soundtrack is used to close the scene, but also to add a cool effect. When the narrator says “Lo voy a averigüar/I'm going to find out!” I fade in the music (aptly named Macho) to accentuate his words. Then as the music gets to full strength we hear a door opening bringing back the jail area room tone from before. And to end the scene a door slams in the distance. Which I think adds a nice touch to the scene.

Fading the Scenes Together

These two scenes directly follow each other in the comic book/radio novel format I am making, so it needs to seamlessly merge into each other in a smooth way. By having the piano interlude close the alley scene I fade it out and slowly fade in the delay guitar track. This way I get a cool smooth transition. Of course, the switch between scenes is a bit longer than if you were reading a comic book and flipped the page, but it adds suspense and atmosphere.

You can see in the screenshot that the scene change is done with pure automation. I am simply fading out the piano, bass and city ambiance to be replaced by the guitar soundtrack, footsteps and room tones. Not much to it.

Listen to the scene change here.

Putting Your Soundtrack Inside the Character's World

You have all seen the typical scene of a car zooming down a highway, camera following behind at great speed while a thundering soundtrack blasts in the background. Suddenly the scene switches to inside the car, and now the soundtrack is coming out of the radio. It's a pretty cool way to change the non-diegetic soundtrack of the movie to the world of the characters. Let's try to do something similar, using the scenes we've created.

Carrying on with the alley at night and a small room, we'll be making two distinct scenes. Using a little EQ and Logic's Space Designer we'll project regular song files into the world of the characters. First a pop songs that sounds like it's coming out of the radio, and then like we're standing outside a club blasting beats inside.

Enclosed Radio

In the scene we'll be listening to a part of a song, regular volume, regular mix. Then we introduce a few footsteps, an open door and then instantly change the music like it's coming from the radio inside the door we just opened.

Listen to the scene here before we continue.

Step 1 – Volume Change

In the picture above you can see the layout of the scene. It's simple, only has the song file, the room tone, a door opening and the footsteps leading up to that. You can see the automation of the song file, it's quickly reduced in volume as the door is opened. It's supposed be sounding only in the background and thus, is cut in volume. The room tone is loud in the
mix for demonstration purposes, and adds to the atmosphere of the scene.

Step 2 – EQ

Since the song is supposed to come out of a cheap transistor radio, we have to emulate the frequency range of it, and exaggerating it a little bit in the process. I'm filtering out all the low frequencies up until 800 Hz, which is a lot of filtering. I'm also cutting the high frequencies a little. Fooling around with one of the mid bands I decided to boost a little bit in the high mid range, which worked out nicely. Now the song file is sounding absolutely horrible, but perfect for what we

Step 3 – Reverb

Since the song is supposed to be heard inside a room, it needs a little reverb to glue it to the room tone. Logic's Space Designer is a great tool for all your reverb needs. It works on Impulse Responses from whatever room you need so the possibilities are endless if you have the correct Impulse Response. I wrote an in-depth Plus! article on Space Designer a while back that you Plus! subscribers have access to. So if the Space Designer looks scary to you, take a quick look at that tutorial before continuing.

To make things easy, I'm just using the preset Impulse Responses that come with Logic. In this case I'm using an office response. I don't want any of the dry sound, that would just sound like a badly EQed song. Instead I put it on 100% wet to engulf the soundtrack in the reverb of the office. Now we have a great radio like sound that we can use, and just need to fit the change into the scene itself.

Step 4 – Automation

We have to have an abrupt change of the song file so that it immediately changes form into the character's world. Which is really easy with automation. Putting your automation button on Logic to Latch and changing a parameter while in playback, the parameter stays that way instead of returning back to it's old value like you have in Touch mode. This is useful if you have minor changes throughout instead of just a little boost or cut in certain phrases.

Let's put both plugins, EQ and Reverb, into standby mode before anything. Put your automation mode into Latch. Let's start the song and listen to the sound of footsteps and a door opening. As soon as the door opens hold down the ALT button while clicking both plugins. This activates them and gives our song the radio feel we want.

By clicking A on the keyboard Logic goes into Automation View. Now you can see at what specific time you click the bypass button to activate your plugins. In the screenshot below I have activated the Insert #1 Bypass to see the specific automation I am doing. By moving the node on the orange line I can move the change to wherever I want, in this at exactly the same point as the room tone starts. Repeating the same thing with Insert #2 I align them perfectly with the room tone.

Now we have a believable scene. Soundtrack setting up a scene, then merges into the environment. Song selection depends on the scene, the direction you're going with the atmosphere and such. I am just using one of my own productions as an example.

The Alley

Now let's look at placing ourselves outside in the alley, with an underground club playing music that leaks to the outside.

Step 1 – Placing the Scene

So if we're standing outside in the street, or in an alley outside a club we have to have some ambience of the street. Below you can hear the same ambience sound as in the first scene. I have removed the music so you're just hearing the street.

Step 2 – Placing Music

Picture yourself standing on the street. If you were outside a club you would be hearing faint music coming from inside. I'm using a ambience techno track. Not something you'd maybe hear at the club but it'll do.

Listen to the unprocessed track here:

Step 3 – EQ

To make things sound like they're coming from inside somewhere is easy. You just need to filter out all the frequencies that are eaten by the walls, air and spaces before they reach you. Without going into a lot of acoustic theory, higher frequencies are generally absorbed easier than the low ones. So by taking a low pass filter to your audio track like you see below, you are filtering out the same frequencies as the walls and building of the club would.

Step 4- Reverb

Doing the same steps as in the other example, I'm using the Space Designer to put an “city street” reverb on the track. Like before, I'm using the preset Impulse Responses in Logic but if you have a convolution reverb engine and some IRs, you can achieve the same results. I'm taking all the dry sound out, and this time I'm only putting the wet to 50%. Adding more distorted and overloaded the sound.

And that's all there is to it. Listen to the finished result below. Pretty believable, no? Feels like the music is coming from inside somewhere, but can't quite put your finger on where.


I really enjoy doing post-production work like this, and hope I have shown you the possibilities of what it has to offer. Doing post-production work is creative and fun. Some people might view it as a boring job recording stupid sounds and then having to sync it to a track, but there is more to it than that.

Professional post-production workers use tools far more advanced than the examples I've shown above, with libraries upon libraries of sound effects to choose from. Then you have the sound designers that create interesting sounds from scratch using every synth known to man. But if you're doing basic post-production work, you can easily get great results using your chosen DAW, some sound-effects and a little bit of creativity.

So start experimenting, use your own songs, download some street noise and room tones and make soundscapes for your project. It'll widen your horizons and make you look at your audio production program a different way.

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