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Multi-Channel Sound for Your Home Haunt

by Hauntmaster, 10-1-2005

The key to a really great haunt is an immersive environment. An environment that stimulates as many senses as possible not just the sight. We've all been in haunts where a chainsaw wielding maniac jumps out at us, his chainsaw roaring, causing all before him to flee. However, it's not our seeing the spinning blade that makes this realistic for us. It is the guttural sound of the saw that makes us certain our end is near. This is but one of many uses of sound.

Imagine your guests enter a darkened room. They hear whispers coming from all around them warning them of some unknown horror that awaits them before a loud voice screams "run!" directly behind them. Or perhaps they walk into your dungeon, the screams of the damned echo from not-so-distant torture chambers. You could have a large number of actors concealed in your display but it's often easier and more practical to create a multi-channel sound track and leave the important scares to the actors.

What I'm going to describe is just one method of creating multi-channel sound in your haunt using equipment you most likely already have and some free tools from Microsoft. There are many ways of creating multi-channel sound. Many are easier and/or more elegant but require you to buy a product before you can get started. More important than the tools you use is the creativity with which you apply them.

What's Required

Just a few bits of hardware and software are required to produce the sound files needed for our project. You most likely have most of these items as they come with the majority of computers. The linked sound file and Microsoft software can be downloaded for free.

Creating the Individual Channels

First thing you'll want to do is create sound files for each channel. Each file must be in uncompressed PCM format, must have the same length, and must have the same sample rate and bit depth. For a 7.1 surround sound effect there are eight channels as detailed in the image.

7.1 surround sound layout

Creating the individual channel sound files is easily accomplished with the Windows Sound Recorder. Sound Recorder is usually installed by default and can be found under Start > Programs (or All Programs on XP) > Accessories > Entertainment > Sound Recorder.

One limitation of the Sound Recorder is that by default it only records 60 seconds of sound. There are two workarounds to this issue. The first is to start a recording and before reaching the 60 seconds, stop the recorder, and start again. Every time you start you will again be able to record 60 seconds of sound thus you can make a very long recording. The second workaround is much less of a pain and requires you to start Sound Recorder and insert a blank sound file. In the What's Required section above I've included a zipped, blank 5 minute wav file (44.1 kHz, 16 bit, Mono, PCM). If you want to record longer than five minutes simply insert the file multiple times. Each time you insert the file it will add 5 minutes to your recording.

Record over this file for each channel and use the "save as" command to save the file. It's helpful to name each file according to its intended position. For example fl.wav for the front left channel, br.wav for the back right channel, etc.

Single Channel WAV to Multi-Channel AVI

Now we will combine these files into a single multi-channel AVI file with Windows Media Mono to Multi-channel Wave Combiner 9 Series. If you haven't already downloaded and installed the combiner do it now. Copy the eight sound files from where you previously saved them to the directory where you installed the combiner.

Open a command prompt, Start > Programs (or All Programs on XP) > Accessories > Command Prompt, and change to the directory in which the Multi-channel Wave Combiner (WavAviMux.exe) was installed. The default installation directory is %systemdrive%\Programs Files\Windows Media Components\Tools\WAVAVIMUX. Type the following, without quotes and on a single line, at the command prompt, and then press enter: "wavavimux –o [Output file] –iwav 8 [Input files] –mask 255". Substitute [Output file] for the name of the AVI you want to create, for example, halloween.avi. Substitute [Input files] for the eight WAV files you previously created. If you've taken my file naming advice your command may look like this:

WavAviMux -o halloween.avi -iwav 8 fl.wav fr.wav fc.wav w.wav bl.wav br.wav sl.wav sr.wav -mask 255

Command entered at command prompt

Once you hit enter, the program will take some time to combine the files. It will not give you a status update, the cursor will just blink. This is normal, relax and let the program run to completion.

Compress the AVI

After the program finishes, you will have a fairly large AVI file. You can use this file as is but you may want a more easily portable format. Using the Microsoft Windows Media Encoder 9 Series software we can convert the AVI file to a more compact WMA file.

Start the Microsoft Windows Media Encoder 9 Series software. In the New Session dialog, double click Convert a File. Select your source file, in our example it was halloween.avi. The output location will automatically be filled in but you can change this if you like. Click next. Select how you are going to use your file and click next. On the Display Information screen you can add optional information to your file. It's helpful to have a short description of what is in the file and what you intended to use it for. Clicking next brings up a review of the information you've provided. Finally, click finish and the encoder will convert your file to a WMA file.

If you get any error messages about codecs not being installed you can download a package of codecs from Microsoft.

Setup at the Haunt

Whew, that seemed like a lot of work, right? Well, the first time can be confusing and a little frustrating. The more you work with the procedure the quicker and easier it becomes.

Once you've created your sound file you can either play it through surround sound speakers connected to your personal computer or burn to disk and play from your home audio system. You can also connect your computer to your home audio system with a mini-plug to RCA adapter (RadioShack catalog# 15-2473).

So in conclusion, let your imagination guide you and I'm sure you'll find creating multi-channel audio for your home haunt to be both fun and rewarding for you as well as experience enhancing for your guests.


Update 10-16-2006: I always like to hear about people who've taken information or an idea from Haunted Bay and done something interesting with it. Bryan Davis told us about how he modified and expanded upon this to get sound for seven different props. He even wrote a small GUI front end to make the process easier. Read his article on his website, Encoding Multi Channel Audio.

 
   

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