Creating Sound Effects For Wrack

There may be some of you who would be interested in how to create your own sound effects for Wrack.  I’ll tell you how I’ve done it so far in hopes it will help you.

Brad has created a system that is a pleasure to work with. You’ll discover that it will be easy for you to plug your own sound effects into the game. The ease of doing this has made it even more fun to work on this project. It’s easy to try sounds out and see how they fit. Does the sound help the mood? Is the volume, treble, bass, etc. correct so it doesn’t cover up other effects that are important to hear? Those and other questions take a short amount of time to answer. All I have to do is give the effect the correct name, put it in the Sound directory, run the compile script (a batch file) and select that I want to compile Music and Sounds. Some seconds later I’m ready to run the game and see how everything is sounding. Great planning and programming on Brad’s part!

Back in the 90’s I came upon the audio editing software CoolEdit (by Robert Ellison and David Johnston, former Microsoft employees). I became a beta-tester and started using it most of the time. But I didn’t use it exclusively because I had gotten used to using other software that did what I needed to do. When CoolEdit became Audition, Adobe kept up the standards set by Ellison and Johnston and made the software even more powerful. Originally, Adobe bought CoolEdit Pro and sold it as it was, renaming it Audition. With Audition 2, they started adding features. After Audition 3, they came out with Soundbooth, a less powerful, consumer friendly version. It seemed they were going to forget Audition completely. I think they realized that was a mistake and now have Audition 4 (as of April, 2011).  But, from what I’ve read online, Audition 4 leaves out some powerful features of Audition 3 (tone/noise generation being an important one to me — good sounds to build effects from). So, I’m using Audition 3 for Wrack. Please understand, though, that almost any modern  multitrack audio software can work for sound effects creation. And this is not a recommendation for Audition. Audition 3 has some interface problems that make it not so fun to work with at times.

The first thing I did to start the creation process was to play the game as it stood when I first came on board. I didn’t have any temporary sound/music on so I could get into the mood of the action alone. I took notes of where I thought sounds should be used. After going over things with Brad and making some basic decisions, he created hooks (maybe not the technical term) for the individual sounds. We continue to do this same thing as new aspects of the game are developed.

For sounds that have to be synchronized with an animation, I play the game and record a video with screen capture software (but you could use a video camera and upload it to your computer). It doesn’t have to be a great video, but it should clearly show the action you are creating a sound effect for. If you’re going to replace existing sounds in Wrack, you won’t have to record a video since you can make your effects line up with the effect(s) being replaced.

I import the video into Audition. Then I open “raw material” sound effect files that I think can be layered to make a new sound for the action. Each raw material sound effect is put on a separate track. Audition has many effects that you can use “real time” in Multitrack mode — non-destructive effects that do not affect the original raw material. I can use most of the effects available in Audition this way (pitch shift, EQ,  reverb, modulation, echo/delay, amplitude/compression, etc.). This makes it easy to try different effect settings. The effects I use most often are pitch shift and EQ.

Next, I create markers for the start and end of the action needing a sound effect. If there are other things within the action that need a special sound, I create a marker for them, too.

Now I drag raw material sounds to the correct marker(s) and play them while watching the video. If they sound close to right and the timing is correct, I move to tweaking the sounds.

Before I talk about tweaking the sounds, let me explain where my raw materials come from. I’ll also talk a bit about income tax :-) Almost everywhere I go, I carry a solid state digital recording device (years ago it was a DAT — Digital Audio Tape recorder, and before that it was a cassette recorder). If I hear a sound that I think is different/unique/catchy/whatever, I record it. This helps me in at least two ways. I have lots of free sound effects to work from. And, since I am in the business of sound effects, for tax purposes I can write off the expenses of collecting them — meaning it helps pay for trips :-)

When I was working on Duke Nukem, I needed a servo sound effect. No raw material I had was close to what was needed. Then I remembered the soft drink machine (I was at Apogee/3D Realms at the time). I took the DAT recorder and some bills/change and ran that machine through it’s paces. The change return mechanism ended up being perfect with a little pitch shifting. Some of the other sounds worked into the game, too — the can coming down the chute, the whir of a defaced dollar being rejected and the coins dropping. Another time I needed sounds for when Duke was in the HVAC ducts. That was a square metal office trash can being flexed. And did you ever get Duke to relieve himself? That took drinking all the drinks I bought from the drink machine and a visit to the men’s room — oh, and a long time finding a short loop that allowed endless urination on Duke’s part :-)

Bugs! Bad for software, GREAT for raw sound material. Electronics can sound really weird when pitch shifted. Home appliances. Tools. Vehicles. Animals. The sky is the limit. And you don’t have to pay a lot for a recorder. Many of the inexpensive ones do a great job for sound effects — especially those sounds to be layered with other sounds.

And, yes, there are some fantastic sound effects CD’s out there. If you look around, you’ll find older CD’s full of sound effects of yesteryear. They can come in very handy and are not expensive at all. For personal use, you’ll have no problem using any of them, but if you’re going to use them in a commercial venture, make sure permission is given for that.

And, of course, there are literally tens of thousands of effects available on the web, some for free, some inexpensive and some not so inexpensive.

Tweaking sound effects is an art, but it requires familiarity with your audio editing software, too. I look at the video and somehow hear how I think that action would sound. My only task is to get that sound out of my head and into reality. This requires tinkering with settings on effects, trying out different combinations of sounds and such. Lots of times I give up getting the sound right and leave it for a day or so. When I come back to it, I’m usually able to get it the way I want it.

Some of the sounds in Wrack are layered from dozens of sounds. I may use several sounds just for the start and end of the action. A click, followed by a whir, followed by several layered sounds that are remindful of air whooshing in a pipe. When I’m working on such sounds, I try to slow down the final effect in my mind and decide what will build up to creating that effect.

So, let’s say you’re replacing a lift (elevator) sound in Wrack. You’ll have three sound files to create. The first will be the start sound (Sound #1). The second is a looping “movement” sound (Sound #2). Some lifts in the game travel further than others. Rather than having to time all of them and create multiple files with the same sound in different lengths, a loop is used. The third sound would be the stopping sound (Sound #3).

The starting and ending sounds cannot be too long or they may last longer than the travel time of the lift. They probably need to have a switching sound followed by a mechanism start/end sound. And, most importantly, they will need the looping sound (Sound #2) layered in so that there’s not an abrupt change in sounds from starting sound to loop to ending sound.

In the early days of game production, sounds had to be short and sweet — limited RAM, disk space, etc. Looping sounds were required. A looping sound is one that can be played over and over, and the listener will never know it’s not an endless sound. Simple sounds (sounds that do not change over time) are easy to loop. Complex sounds (which change over time) are time consuming to loop. Some are virtually impossible to loop. There is no magic formula for complex sound looping. It takes a good ear and luck. It also helps to be able to look at a waveform and see where the looping possibilities are.

The important thing is to always loop at zero points and make sure the waveform continues in the same direction it was going. If the waveform is moving in a positive direction at the end of the loop, the start of that loop should move from zero in a positive direction. Otherwise, you get the dreaded CLICK that says another iteration of the loop just started.

So, here’s what you’d do:

  1. Decide on your looping sound and create it (Sound #2). If it’s layered (multitrack) sounds, mix it down to a single file (but keep your multitrack version for possible later use).
  2. Turn on zero crossing in your audio editing software so you will always be looping at a zero crossing point.
  3. Select part of the waveform.
  4. Play your selection.
  5. If it loops seamlessly, YIPEE! Go to step 7.
  6. If the loop isn’t seamless, change either the start or the end of the loop. Editing just one end of the loop seems to get faster results for me rather than reselecting both ends. Always move that one end of the selection to a zero crossing point. Go to step 4.
  7. Decide on your starting sound (Sound #1).
  8. If you’re using layered sounds, put each sound on a different track.
  9. Make sure you put your mixed down loop sound (Sound #2) on one of the tracks.
    1. If the loop (Sound #2) is shorter than the starting sound, use multiple copies of the loop (Sound #2).
    2. Most importantly, you want to make sure that you have the end of your loop (Sound #2) aligned with the end of the starting sound. Remember that the loop sound (Sound #2) follows the starting sound. You always want the end of the loop to play before the start of the same loop.
    3. The best way to do this is to work backwards. Put a copy of the loop (Sound #2) with its end aligned with the end of the starting sound. Then add copies of the loop to the left of that loop. If there’s not room for a full copy of the loop (Sound #2), trim the start of the loop so your partial loop fits the space. Again, you’re making sure the end of the loop always matches up with the next start of that same loop.
    4. Create a volume envelope for the track with this looping sound. Have the track volume increase as the starting sound plays (a fade in). This way the looping sound (Sound #2) will play smoothly after the starting sound (Sound #1).
  10. Do the same thing with the ending sound. This is when you’ll want to trim the end of the loop sound (since the ending sound follows the loop sound — Sound #2).
  11. Give your sounds the proper file name and make sure they’re in the Sounds directory of the game. Compile the sounds and play the game to hear your sounds.

These days, if you want to see some interesting waveforms in your audio editing software, you’ll have to look somewhere other than recent music recordings and many game sound effects. That’s because in recent years the music and audio industry have gone with extreme compression. Compression can be set to amplify low volume sounds without amplifying those that are already at maximum volume.

Here’s an example of a typical rock song where heavy compression has been used:

The green part is the waveform. If you play this file at regular volume and try to play a sound effect at that same volume, you’ll hear neither clearly. It would be the same thing as having each musician in a band play at the absolute maximum volume, disregarding that others were doing the same thing. If you were watching a sound level meter, it would be in the red all the time. You’d get digital splatter if you were recording.

So, when you create your replacement sound effects, remember that they will be playing with other sound effects in the game. For that reason, it’s best not to compress your sound effect unless it is compressed at lower than the maximum volume.

I hope this is helpful to some of you when the game comes out, and I hope you like the sounds I come up with for Wrack. I will look forward to sounds you all come up with, too :-)

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7 Responses to Creating Sound Effects For Wrack

  1. Jroc says:

    Awesome, I used to use cool edit too, it was amazingly simple yet amazingly powerful at the same time.

  2. Lunick says:

    Lots of interesting information. I bet the guys at Duke4 would like to know more about how you made the Duke sounds.

  3. Zaranell says:

    Interesting read. I always enjoy seeing what goes into making games and what the developer has to consider. On a side note, “Crusher” sounds pretty damn good! I look forward to seeing the rest of what you’ve come up with for Wrack!

  4. Tomer Feiner says:

    I think it’d be interesting to hear about other sound work of yours. For example, Doom, Wolfenstein 3D, Rise of the Triad (you know it’s getting a remake now, right?), etc. I think the sound you made that the story behind it is the most interesting is the chant of the Icon of Sin from Doom II (a.k.a. “oremoR nhoJ ,em llik tsum uoy emag eth niw ot.”).

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