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Digital  Audio  Forensics

The main area of our work is to process very, very poor quality audio files and enhance them to produce pristine, clean and tidy post processed digital audio tracks that conform to any specific need of our clients.

(If you are not satisfied with your current digital audio forensics provider, why not contact us, we would love to hear from you and demonstrate the work we do).


Årsundavägen  46                     
81161  Sandviken

Phone: +46 (0)26  21  80  22 
Mobile: +46 (0)733 14  44  04


Defining our suite of services and areas of expertise:


What we do:

Our work mainly involves the extraction of inaudible dialogue from poor quality recordings, so that what is being said can be heard correctly. (However we can process audio in many other ways depending on the client's requirement).
We go much further that just running ‘Denoisers’ and 'EQing' to correct poor audio recordings…
The areas that we focus on when improving audio quality means we are dealing with the elimination of many types of sound artifacts that occur naturally and can damage the quality of any recording, (both in and out of the studio).
Such as:
-Wind and other types of extreme weather.
-Sneezing / coughing / unwanted breathing noises / popping the microphone.
-Hum and Hiss removal or reduction from badly grounded recording equipment.
-Isolation of vital source audio artifacts.
-Removal of unwanted small random sonic events, that get in the way of vocal intelligibility.
-Preserve harmonics - if needed.
-Elimination of all unwanted static interference and other ambient background noise such as traffic and crowd chatter. 

Legal Work

Digital Audio Forensics:

Time-stamped task histories, which we normally submit as XML files with screenshots, are important when we are tasked with legal work.
The modern courtroom requires specific types of audit trail to confirm the validity of any audio evidence in question. As audio technologies advance, the same tools that improve the clarity of audio evidence can also be used to obscure the truth, either through counterfeiting or concealing source file manipulation. The documentation provided by our teams prove that no audio files have been wrongfully tampered with, once the recordings have been released to us for processing.
Sometimes the courts request us to authenticate the re-processed audio files, which require hard proof of discontinuity, location analysis, voice and equipment identification... We then always provide spectral profiles for future comparison – therefore, preserving legal integrity and ensuring a verifiable chain of custody.
Time-stamped task histories, which we normally submit as XML files with screenshots, are important when we are tasked with legal work.

We also can assist in the clean-up of undercover or concealed microphone/ hidden camera audio recordings. 



- All analogue audio playback devices. Tape, Vinyl,       Cartridge, Vintage.
- All optical audio playback devices. MiniDisc, CD, DVD, Blu-ray, Magneto-optical.
- All digital format playback devices.
- All known digital audio file formats - RAW and Compressed.

A vast array of audio rack hardware, channel strip and software post processing tools.
And we can usually source any other obscure playback hardware, for the rare cases when we get obsolete archived media from long term storage facilities.

We employ many different approaches to the work we do and the job flow is usually different for every job. Depending on the type of result required, some of the methods we typically use are: heuristic analysis, spectral analysis and mathematical algorithms.

A digital or analogue audio signal can be decomposed into a number of discrete frequencies, or a spectrum of frequencies. The statistical average of a certain signal, (or collection or signals), as analyzed in terms of its frequency content, is known as a spectrum analysis. 



Law firms.
Insurance claims disputes. 
Civil cases - Private customers.
Employment law. 
Music producers.
Police / Security Forces.
Contract law. 
Private Investigators. 
Other legal activities. 



Very low level audio manipulation.
Audio Restoration. 
Compressed or encrypted audio data.
CCTV evidence used in court. Where
vocal quality must be pristine. 
Sound FX processing for TV / Film.
Jingles for Radio Production.
Vocal auditions mastering.
Voice over demo reels.



All digital audio file types and formats.
All analogue source recordings. 
Tape (all formats). 
Video media tracks. 
Any other audio media.



Our core activities are to extract, separate AND isolate vocals, (or any other specified audio artifact), from any audio track with any of the following:
- Background noise, interference, corruption, distortion.
- Poorly recorded audio that is either too quiet, loud or echo removal.
- Eliminating unwanted sonic artifacts.

Costs and Fees



For repeat work, or ongoing services, then we set our pricing at 460:- SEK per billable hour, with a minimum term of 6 hours. We initially do a free evaluation to asses the work involved.


                      Fixed Fee

Some clients prefer to agree a fixed fee for the work upfront. This can be achieved by previous agreement or pre-assessment and is offered on a job-by-job basis.


               Free Evaluation

We will pre-analyse your recording free of charge. Engineers asses the work involved, give you a price estimate and explain what sort of result would be expected.


Raw files and all other 'non-digital' media must be physically shipped to us.
If recordings are from analogue sources, then the recording must be in its original condition AND
on its original media - not a 'copy of a copy'.

Digital source files can be emailed or uploaded direct to our servers, contact us for upload details.
Of course, you can always ship digital audio files to us on a USB memory stick or similar.

Data Recovery Sweden
Årsundavägen 46                     
81161 Sandviken
Phone: +46 (0)26 21 80 22 
Mobile: +46 (0)733 14 44 04


All digital audio files and formats

All digital media sources
All analogue recordings
If its sound, we can restore it


Easy and Simple to Use

Send us your audio recordings for
a swift assessment and totally
free evaluation


Quick turnaround

After your media has been assessed we can usually estimate how long the process will take and give you regular updates


Audio Restore

All digital audio data file types and formats.
All analogue source recordings.
Tape / Vinyl / Optical 
CD / DVD/ Blu-ray / Minidisc
Any audio media


Case Study 1

MINIDISC - Multiple failed sectors.
Stored for years in direct sunlight and humidity.
The Minidisc had alignment and tracking problems, so while the disc would play normally, it would often skip audio sectors, causing the error correction system to trigger constantly. This lowered the overall quality of the output. The normal working frequency response range of a regular optical audio minidiscs is 44.1khz, but with the error correction algorithm activating every time, this frequency response dropped to below 8khz. Thus making a noticeable reduction in the overall sound quality during regular playback.
Our engineers’ job flow was to re-image the original minidisc and read off most of the bad sectors that were being skipped. This process reduced the amount of unreadable areas on the disk from 16.01% to 00.09%. The playback of the new re-imaged disc was now 99.91% complete and the recording now sounded perfect.
But our engineers wanted to go even further. They were able to go into the actual raw audio data of each individual remaining bad sector on the re-imaged disc and using the audio information contained on the previous and next ‘good’ audio sectors they were able to fill in the missing audio data to a very high degree of accuracy. Resulting in a final pristine restoration of the original damaged track. 

Case Study 2

Vocals extracted from CCTV tape.
We had a CCTV security tape submitted showing an assault between 2 people in a public car park.
The video and audio on the tape showed the 2 people arguing, however the audio was extremely bad and also the recording possessed loud ambient background noise, traffic, extreme weather, other people’s voices. Furthermore, the overall recording quality was poor due to the basic microphone that was attached to the original security camera.
We were tasked with extracting the voice data of the 2 suspects, from the rest of the audio, so that we could show who was saying what to whom and (more importantly), what exactly was being said between the 2 people.
We extracted an audio track which contained ONLY the dialogue between the 2 people in question. We were able to remove almost all the other sound without losing any vocal integrity.
Once the exposed conversation was neatly isolated, distortion from the clipped audio required further cleanup for unmistakable intelligibility—a distinction that is key in a courtroom. These heavily distorted vocals also needed some de-crackle to really bring the audio up to unmistakable quality and final audio clarity.
We also produced a full transcript of the conversation between the 2 people. Both the transcript and the enhanced audio file of the extracted vocal track were submitted to our client for further action. 


About Us

Data Recovery Sweden launched in June 1999. It was originally called Venture Data Recovery and was based in England. The digital audio data recovery facility within Data Recovery Sweden consists of over 23 years 'cross-platform' audio data recovery knowledge and experience that is drawn upon to deliver tailor made data loss/restoration solutions and digital evidence gathering.

Our data engineers have low-level training on specific digital audio compression and audio data structures, which enhances the process of evaluating the processes in order to form an optimal digital restoration plan.

Our aim is to provide diagnostic assessments of poor quality audio recordings, (or similar), inaccessible audio files and analyze logical data structure integrity. Engineers rebuild audio format structures at sector and byte level before extracting, or isolating, the lost data or audio.

We stand behind our commitment to audio preservation with free diagnostic evaluations and exercise a "No Fix, No Charge" policy. By using unique intelligent hardware audio processing and recovery methods, we are able to offer our clients excellent service and value for the recovery/extraction of all damaged, (or poor quality), audio media recordings.

Please contact us, we would love to hear from you.

Data Recovery Sweden
Årsundavägen 46
81161 Sandviken
Phone: +46 (0)26 21 80 22
Mobile: +46 (0)733 14 44 04

Customer service
If you want to know more please contact us for further information and how to arrange a media submission for the next step. We will ask you to detail your requirements, so we can generate a specification which will be forwarded to our engineers, so they understand fully what their objective is for your specific case.

Many aspects of real-world audio forensic work require specialized tools and a professional approach. We apply our expertise to complete the tasks at hand to produce a best in class result, that we hope will not only meet, but exceed the expectations of our clients. There are many steps to the work that we do, but we have a very specific job and that job is to ensure that our resulting post-processed target audio can meet the extremely specific and unique needs of the client.
For example in legal situations if an action is ongoing where slander is involved, we need to ask ourselves:
- Can the audio be heard clearly and cleanly in a courtroom?
- Can we provide documentation of our methods that are accepted in a court of law?
Sometimes we take raw, undercover audio recordings and use our techniques to uncover and identify the voices layer by layer, working solely with the remit to increase intelligibility, so what is actually being spoken within the audio is unmistakable.


Årsundavägen 46                     
81161  Sandviken

Phone: +46 (0)26 21 80 22
Mobile: +46 (0)733 14 44 04


For PC Data Recovery
For Mac Data Recovery 


Feel free to send us your ideas and suggestions. Any feedback is always appreciated!