Posts Tagged ‘Audio restoration’

Post JFK Assassination Air Force One Flight Deck Enhancement Process

Friday, November 15th, 2013

Air Force OneA lot of people have been asking how I restored the Air Force One radio transmissions from November 22 1963, right after JFK was shot. Below I have outlined my process with brief explanations about each.

I used a software program from Adobe Audition for this entire process.

I identified the points in each version of the tape recordings, the LBJ version and the General Clifton version, for edit points before altering the recordings for enhancement.

I began the restoration process by sampling the tape hiss present on the entire recording and reducing with Adobe noise reduction. Next I went section by section and reduced the radio transmission noise which varied from conversation to conversation.

Then I applied equalization and compression filtering to help bring out the conversations. This was also done section by section since each conversation varied in speaking frequencies.  Adobe CS6 has a great tool, the FFT equalization which is very easy to use.

Audio restoration and enhancement is a process. I refer to it as peeling an onion; one layer at a time. If something does not sound right, I go back a step and try a different process. That’s the beauty of digital audio restoration and enhancement.

I am still working on the restoration as time permits and will update the videos posted here. I am hearing more and more of the conversations using critical listening and additional enhancement. Considering how primitive the technology was back then I am very impressed with the sound quality of these recordings. By the way, the General Clifton version is much better sounding and longer then the LBJ version.

Below, you can watch the story on “The Lead” with Jake Tapper on CNN:.

Post JFK Assassination Air Force One Flight Deck Enhanced Recordings

Tuesday, October 8th, 2013

Post JFK Assassination Air Force One Flight Deck Enhanced Recordings

Primeau Forensics was originally contacted by Bill Kelly, a researcher for the JFK Assassination in connection with Duquesne University. He asked Audio Forensic Expert Ed Primeau to assemble and enhance the original Air Force One radio transmissions. It was at that time that Ed Primeau realized just how special this case would be, examining the events that were recorded the day JFK was assassinated 50 years ago.

Audio Enhancement

At the end of this post is a fully enhanced digital audio file available for listening and downloading of the government conversation that occurred at the time of the assassination of President John F. Kennedy. However, the Announcer at the beginning of the recording  is the poorest quality of the entire 2:01:59.

The enhanced work products are a combination merged from two physical copies in existence. The first copy was released by the government and referred to as the ‘LBJ tapes’ in the early 1970’s. In addition, another longer copy surfaced in a private auction in Philadelphia  2011. This longer copy was found in the belongings of the late General Clifton. Thanks to Bill Kelly, a veteran JFK researcher, Primeau Forensics has combined the contents of both recordings and fully restored them.

In this enhanced recording, you will hear conversations from Air Force One over the Pacific Ocean as they abort a trip to Japan and turn around, mid-air, to return to the mainland after learning about the assassination of the President of the United States. In addition, these recorded conversations between Ground Command, the White House and Air Force One include code names such as ‘Duplex,’ ‘Digest,’ ‘Volunteer,’ ‘Liberty,’ ‘Witness,’ ‘Crown,’ ‘Baker,’ ‘Watchman,’ and ‘Tiger.’

During the call they make arrangements to transport John F. Kennedy’s body, his widow, President Johnson and the other 40 people safely back to Washington DC. The carefully coordinated and strategically executed planning is heard in this recording. The decisions about media coordination on the ground at the White House, the postmortem autopsy to be performed by law and President Johnson’s conversation with JFK’s mother, Rose Kennedy can also be heard.

To learn more about the enhancement processes Ed Primeau applied, please Click HERE.

Video Exhibit

The quality of technology back then was very poor which weighs heavy on understanding the dialogue of the radio transmissions even after audio enhancement. It was at this time that Primeau had an idea. He decided to create a video which displays the transcript on screen while the dialogue from the radio transmission plays.

After that, Primeau recorded authentic footage from a private jet cockpit via a pilot who is a good friend of Primeau’s. This footage enhances the experience of listening to the flight deck recordings with a closed caption type text add on.

For instance, this perspective is often applied to audio evidence that doesn’t have video content to immerse the viewer into the experience in which the recordings were originally created. The videos are available for viewing through the links below:

Part One

Part Two

Part Three

Part Four

It may take a while to get your ears acclimated to this early, mobile technology. Primeau Forensics has carefully removed unnecessary radio static and squeals to accommodate better listening. Above all, it is recommended that you use a combination of speakers and headphones to best listen to these recordings.

Listen to the Clarified Audio Track HERE:

Download Recordings Here!

Download Transcript Here!

50th Anniversary Symposium

Passing the Torch-An International Symposium on the 50th Anniversary of the Assassination of President John F. Kennedy will be happening October 17-19 2013 in Pittsburgh.

For more information on the conference contact:

Deborah G. Jozwiak

320 Fisher Hall
600 Forbes Avenue
Pittsburgh, PA 15282
Phone: 412-396-1330
Fax: 412-396-1331

Digital Audio Enhancement and Authentication/Audio and Sound Restoration

Tuesday, January 1st, 2013

audio restorationDuring the last quarter of 2012 I saw an increasing demand from litigators requesting the audio portion of video recordings, as well as concealed audio recordings, to be enhanced – or, as I prefer to designate it, clarified and authenticated- in order to better hear the series of events that have been recorded digitally.

Since just about every case that I have worked on over the past several years has been recorded on digital media, the process for authentication and clarification using digital forensic software programs is extremely beneficial for litigators.

One of the techniques that I use that I would like to share in this blog post is to create several filters to apply to the audio file which in turn result in several enhanced or clarified ‘revised’ audio files. In other words, I listen to an audio file and create filters to apply to better hear the desired conversation. Each filter applied results in a separate audio file of the recording or version one, two, three and so on.

I go back to the raw ‘original’ file a second, third, fourth … up to ten times, creating different filters each time to apply to the original audio file in order to hear different parts of the conversation that may be masked or covered by different background sounds.

Because I have a ‘trained ear’ and have been working with spoken word recordings for nearly thirty years, as a practicing audio forensic expert I have a critical listening skill. This keen sense of hearing that most people don’t have is very important for understanding poorly recorded conversation.

I use this listening skill and create a forensic transcript. The forensic transcript helps the litigators better understand the conversation or poorly recorded audio. The multiple filters and variations of that audio file allow me to hear the conversation in various sections much better in order to create the forensic transcript.

As an example, if I’m conducting a forensic investigation and trying to determine what is being said in a busy restaurant where there are other voices talking, dishes clanking, and even music playing I will apply filters to the recording and then listen to the recording and write down the words that I can hear from that first filter application.

Then I will go back to the original file and create different filters to help remove different parts of the background noise to allow me to hear additional words that I may not have been able to hear from the first filtering pass. The combination of creating multiple restored files and a forensic transcript has been very successful. I see this forensic application being very successful and necessary in the future.

The need for a forensic expert to enhance, or clarify, audio recordings will increase due to the number of conversations that are being recorded in public places. Forensic processes similar to this will be extremely important as technology changes and more and more clarification becomes necessary.

photo credit: 24/96 via photopin (license)

The Art and Science of Removing and Restoring Audio From Video

Friday, November 16th, 2012

5570870656_81ed95b87c_oWe receive video recordings as evidence that have recorded audio as well. The audio portion of the recording may aid in an investigation but is often difficult to comprehend.

Even though the video presents clues and truth about the events as they occurred, the audio track also provides an opportunity of clues and events. As audio and video forensic experts, we are asked to perform forensic audio enhancement on CCTV surveillance recordings.

Clarified vs enhanced

The process of removing the audio track from a CCTV recording for enhancement and clarification is crucial to the success of presenting the enhanced or clarified audio recording in court as evidence.

First of all, most people search for audio enhancement when they come to us. We like to begin a conversation about the words used to explain this process. We explain that some of the time it’s better to use the word ‘clarify’, because judges do not approve of enhancement because of their perception of the word. Enhancement means to change. When we testify, we help the courts understand the semantics and the difference between the words ‘enhanced’ and ‘clarified’.

Clarified has less harmful impact than enhanced. If you’re in court and tell a judge that you enhanced an audio recording, one of the first things the judge thinks is that something has been done to it to take it or change it from its original state, and that’s not the case. But, most people are educated and search for audio enhancement when they’re looking for an expert to help solve their problem or clarify of their evidence.

Remove the audio for forensic enhancement

Removing an audio track from a CCTV video recording is a three step process. First, the recording must be loaded into a software program capable of removing the audio portion. The audio portion is exported in a full quality high resolution file creating a sub file. This is an audio only file.

Step two, that exported audio file is loaded into an audio program capable of forensically enhancing that audio so the dialogue is easier heard. Forensic audio enhancement is removing the unwanted sounds and increase the wanted sounds including speech, gun sounds and other extraneous noises to the environment which could be crucial to the understanding of the events as they occurred.

The tools that we apply to the audio portion of the recording are used in accordance with accepted standards in the scientific community. If this case were to go court we could explain, by our work product and notes, the filters and tools that were applied for the speech to be better understood.

Step three, once the audio enhancement process is completed, the exact file, in it’s enhanced state – which is easier to understand – is re-imported and connected back to the original video recording. At that point it is re-synched with the video evidence and exported to create the clarified version of that or enhanced version of that recording.

There may be video enhancements to be made in addition to the audio enhancement. Enhancements like sharpening of the image, zooming or cropping is also done before exporting the new clarified evidence to be used in court.

Our audio and video enhancement processes are accepted in the scientific community. These processes are an important part of the forensic expert’s day to day activity. We also keep great notes of all applications in case we draft a report or testify in court.

Let us know if you have any questions about enhancing the audio portion of your CCTV surveillance video recording.

photo credit: J·K·L (87/365) via photopin (license)

A Three Part Process for Audio Restoration

Wednesday, July 13th, 2011

audio restorationIn the following blog post, I will help you understand a basic three part process for audio restoration. In the embedded video, I exhibit an audio file that was lifted from a video which is in need of some audio restoration. The video walks you through the process which varied from video to video in this video training set.

The first step is to either compress the audio increasing the gain during the process or removing any unwanted distortion; whichever you feel is best to lead with. You can try one process first then the second. Worse case you can apply the processes in opposite order if your initial results are not up to your expectation.

Varying the order which filters and noise reduction are applied is how a forensic examiner will proceed when restoring an audio file. Audio restoration takes time, patience and good critical listening skills.

The three filters I will demonstrate in this video are wave hammer, equalization and noise reduction. I use Sony Sound Forge software 9.0 for this example. Other audio software programs can be used and more than likely include similar filters to those found in Sound Forge.


 photo credit: Mixer Controls: Sliders Faders Buttons Switches Knobs via photopin (license)

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