Audio restoration

What Can Restoration Achieve?

Enhancing problem audio in the analogue domain has always been difficult, and every method employed had unwanted side-effects.  Modern specialist digital processing can now achieve remarkable, sometimes magical improvements with many problems that used to be regarded as ‘something you just have to live with’.  However, heavy-handed or inappropriate use can still make matters worse, so an experienced engineer and accurate monitoring are essential to judge the balance between perceived improvement and unwanted side-effects.

We have the Cedar range of hardware processors, plus the best of the more surgical plug-ins and stand alone software applications (iZotope, Waves , Kush Audio and Slate Digital), and the experience to know which will work best for the multitude of issues that can now be successfully addressed.

Tape Hiss Removal

A particular problem with analogue tape, but hiss can also be an issue on digital recordings: for example a low-cost mic used to record a very quiet sound source, incorrect use of a ‘pad’ switch or with vintage equipment.  Significant improvements can usually be achieved, but over-processing produces very undesirable side-effects; better to leave just a little hiss as it sounds more ‘natural’.

We can reduce hiss in stereo mixes considerably by careful processing, but if a multi-track tape is available much better results are achieved by de-hissing each individual track separately before remixing.  Settings can then be tailored to each instrument for maximum hiss reduction and minimum side effects.

Clicks & Crackles Removal

We can remove short duration clicks perfectly by careful ‘surgical’ processing.  The most serious (like a badly scratched record) need more careful treatment but can usually be successfully disguised using a variety of techniques.  Editing around such loud clicks may be a better option.

Crackles are more difficult, but significant improvement can usually be achieved with careful adjustments.  ‘Spectral’ repairs can also yield excellent results.

Hum, Buzz & Other Intrusive Sounds Removal

Mains hum or buzz is a common problem when working with analogue equipment and frequently goes unnoticed until the recording is played on headphones or full-range speakers.  We can usually remove hum very successfully with modern specialist software, and with minimal side effects.  Great care is taken to ensure no wanted bass is lost in the process.

The Cedar ‘De-crackler’ unit is also exceptionally good at removing low-level high-frequency buzzes like those resulting from thyristor lighting dimmers, frequently encountered on live recordings.

Extraneous noises, such as a ‘P’ blast on a vocal mic, feedback on live recordings, a knocked mic stand and similar unwanted sounds, can be very effectively removed by ‘spectral repair’ software.  We use iZotope RX4 Advanced for such ‘surgical’ noise removal.

As with any form of audio restoration, all of these repairs are best effected on the specific track of the multitrack recording where the noise occurs rather than the stereo mix, but improvements to both are usually possible.

Forensic audio enhancement


Audio Enhancement

Using professional tools, our associates can enhance the quality of many recordings.

In a computer based environment, generally called a DAW (Digital Audio Workstation), the file can be played back and also observed as a graphical waveform.

Any point of the file can be immediately accessed, and any time section of the file can be viewed.

Tools for enhancement such as Noise reduction, Compression, Equalization and Hum Removal, can be applied to the file to bring out details, reduce unwanted noise, and level out soft and loud sounds.

Essentially these tools allow us to clean up the file, making the recording more audible.

Audio from Video Enhancement

Surveillance cameras, cell phone cameras, camcorders, police body cameras and police in-car cameras are capturing events all the time.

Often these videos are used to assist in investigations that may be used in a court of law or other official proceedings. Private citizens may simply want to have documentation for their own purposes.

But sometimes the audio from video is of poor quality due to movement, weather, traffic,  mechanical noise, etc. Dependent on the nature and quality of the recording, it may be necessary to use only the auditory file from a video for evidence, other times it is essential to combine enhanced file with video.

We separate audio from video and use our professional tools to enhance the audio . After this process we then combine enhanced audio back to video.