Evidence Review

The Evidence Review Process: Audio

By Jason Stroming | E-Mail

So the EPIC team has just finished a long night of investigating your house, into the wee hours of the morning. We pack up our cameras, audio recorders, flashlights, and all our other gear, and head off, telling you we'll let you know what we find. But what exactly happens in the next week or so? In this article, I'll go into a bit of detail regarding how we review the audio evidence.

The Equipment

We use a few different pieces of equipment to capture audio evidence. The main recorders that we use are digital audio recorders, Olympus WS-100 brand recorders. These are little handheld recorders usually used to record lectures, or to take audio notes. They have an average recording time of 8 hours, and you can save many different sound files to them. You can also set them to "voice activation," meaning that they will automatically start recording when voices or sounds are detected..

The second piece of equipment we use is the wireless audio microphone. This consists of a transmitter and a receiver. The transmitter is placed in a location where we want to capture audio, and the receiver is usually hooked up to our laptop computer. This allows us to monitor the audio in real time, as the investigation is under way.

The third tool we use is a software package called Cool Edit (also called Adobe Audition). This is an audio software package that has many uses, but we mainly use it for audio playback and cleanup. We can eliminate background noise and hiss, amplify the whole file or certain sections, and actually see a visual representation of the sound file.

The Process

For the digital audio recorders, we have to download the audio files onto our computer. They have integrated USB plugs, so all we have to do is plug them into our PC, and copy and paste them into our client folder. Each file is appropriately labeled, and then backed up on our backup hard drive, for safety reasons. Then, we use a software program called Cool Edit to listen back to the audio. Since the wireless audio is actually recorded via Cool Edit in real time, the file is already loaded onto the computer.

Once the files are ready, they are opened in Cool Edit, and we begin listening back to them, from start to finish. It should be noted that we do not enhance, modify, or make any changes to the raw audio at this point. We are simply listening to see if anything anomalous was captured on audio. If we do hear something, we may try to eliminate the background noise, or to amplify it, but we do not make any other modifications to the audio. We do not believe in manipulating the audio until we hear something, like some groups do. We hear something, and only then do we try to clean it up, to hear it better.

It is important to remember that if our investigation lasts 6 hours, there is not simply six hours of audio to listen to. We have to listen to 6 hours of audio for each piece of equipment. Therefore, if we have a wireless mic and 2 digital recorders all running for 6 hours each, that is 18 hours of audio that has to be reviewed! Throw in extra digital and analog recorders that are usually used for more specific EVP work, and we can easily go over 20 hours of audio to review for a 6-hour investigation.

Each piece of suspected evidence is isolated and saved to it's on distinct file. This way, we have the small section of audio that we can share with our team members and the client. Once the entire team has listened to the small sections of evidence, we as a group decide whether it is significant and impressive enough to be considered "anomalous." If it is, it is then submitted to the client for their review and analysis.

Conclusion

Hopefully this article has shed a little light on our audio review process. This is just a basic summary of what we do, but hopefully it has shown a little bit of the science that goes into analyzing the evidence. You may only see us for 5 or 6 hours as we investigate your home, but there's an additional 20 or so hours that goes into evidence review for your particular case. And that's not including the video review!