ABOUT CAMDEN LABS

Dr Gilbert Soulodre, FAES
Founder and CEO - Camden Labs

SUMMARY BIO

Dr. Gilbert Soulodre has more than four decades of experience in the field of audio as a research scientist, a product developer, an educator, and a mixing engineer. He has written more than 60 scientific papers in the areas of loudness metering, subjective testing, concert hall acoustics, psychoacoustics and spatial perception, digital signal processing, and multi-channel audio. As the founder and CEO of Camden Labs, he has invented a variety of signal processing algorithms and has authored numerous patents. His product development work stretches across a wide range of areas including; automotive audio, consumer electronics, immersive cinema surround sound, virtual reality, microphone array processing, the music recording industry, audio restoration, mobile phones and tablets, speech processing, and audio compression.

Gil was the head of the Audio Perception Lab at the CRC in Ottawa where he developed the subjective testing methods that are used in the ITU-R BS.1116 and BS.1534 (MUSHRA) standards. During that time he also conducted numerous subjective tests to evaluate the performance of various perceptual audio codecs. He was formerly a professor in the Sound Recording program at McGill University and also in the Department of Psychology at Carleton University. He served as a reviewer for the Journal of the Audio Engineering Society (AES) for many years.

Gil is a Fellow of the AES and has received recognition and awards from the Acoustical Society of America, the American Institute of Physics, the IEEE, and the Canadian Government. He received the AES Publications Award for his work on spatial perception in immersive sound environments. In 2022, he presented the Richard C. Heyser Memorial Lecture at the 153rd AES Convention in NYC.

In the early 2000’s, Gil developed a method for accurately measuring and predicting the perceived loudness of audio signals. This technology was adopted as an international standard (ITU-R BS. 1770, EBU R-128, CALM Act) and is now used extensively around the world. In 2012, Gil received a Technology and Engineering Emmy Award from the National Academy of Television Arts and Sciences for his work developing the loudness meter.

In 2024, Gil was awarded the AES Gold Medal (the Society’s highest honor), “for extraordinary contributions to audio, including the creation of the loudness meter that helped address loudness issues in music and broadcast”. It is fair to say that a large portion of the people on the planet have (unknowingly) benefited in some way from his work.

LOUDNESS
During the late 1990’s and early 2000’s the so-called loudness war was in full force, wherein content creators and broadcasters were battling to be louder than their competitors. In the music world, this resulted in excessive amounts of dynamic range compression and clipping which destroyed the fidelity of the music and greatly lessened the listening experience. In TV and radio broadcast, this was experienced as very disturbing jumps in loudness during commercial ads, as well as large variations in loudness when switching between stations. At the time, the ITU-R (International Telecommunication Union) set out to address and resolve the loudness war problem by standardizing a suitable loudness meters. A total of ten different loudness meters developed by professional audio companies and research institutes were submitted as candidates for the standard. In parallel to this, Gil developed his own loudness meter. The ITU-R conducted a series of formal subjective tests at five tests sites around the world to evaluate the performance of these meters. Ultimately, the loudness meter developed by Dr Soulodre was found to outperform all other meters and was unanimously adopted as the standard by the ITU-R as Recommendation BS. 1770. The EBU (European Broadcasting Union) subsequently adopted Gil’s loudness meter for the R-128 standard. Gil’s loudness meter is also the foundation of the CALM Act in the USA (A85-2013). The loudness meter has been integrated into a vast array of software and hardware products, and has been universally adopted in the various audio communities around the world. This includes music recording and mastering, radio and television broadcast, as well as streaming services for music, podcasts, movies, and television series. Gil’s loudness meter is often credited with helping to end the loudness wars. At the time that the loudness meter was adopted as the international standard, Dr Soulodre chose to forgo any financial rewards, and to make it open source and royalty-free. He did this to help ensure its widespread use and to make it fully accessible to users in all parts of the world. Note: The history of events leading up to the adoption of Gil’s loudness meter are chronicled in an October 2004 article written by Daphne Lavers and published in Broadcast Dialogue Magazine
SPATIAL PERCEPTION OF SOUND
Gil conducted pioneering research work on the spatial perception of sound. He identified that spatial impression is made up of two components – apparent source width (ASW), and the perception of sound enveloping the listener. In 1994, he introduced the term Listener Envelopment (LEV) to describe the latter component. His research revealed that ASW is determined by the relative strength of early reflections arriving from lateral angles, whereas LEV is determined by the relative strength of the later arriving lateral energy. He went on to develop objective measures of LEV that accurately predict this parameter both in rooms (concert halls) and in multi-channel surround systems. This work was recognized by the Acoustical Society of America and the American Institute of Physics as one of the most newsworthy advances in the field of acoustics in 1995.
PRODUCT DEVELOPMENT

Dr Soulodre has invented numerous audio technologies that are found in scores of audio products from numerous manufacturers, including several award-winning products. Some of these technologies/products are described below.

• QuantumLogic Surround; QuantumLogic 3D; QuantumLogic Immersion
The QuantumLogic family of technologies are advanced real-time multichannel upmixers that can include height channels to create a truly immersive playback experience from stereo source content. QuantumLogic uses several signal extraction technologies invented by Gil to decompose the original stereo signal into individual sound sources (objects). It also uses the reverb extraction (dereverberation) algorithms invented by Gil. QuantumLogic can create independent output channels for traditional 5.1 and 7.1 formats, but can create up to 32 independent unique channels from any audio source.

• Clari-Fi audio restoration. Real-time processing to restore the perceived quality of audio signals that have been compressed by lossy perceptual audio codecs (eg MP3).

• AutoVolume (A real-time process to automatically control and balance the loudness of audio signals coming from multiple sources).

• The loudness meter (ITU-R 1770 and EBU R128) invented by Gil is found in a wide range of products offered by numerous manufacturers of professional and consumer audio products.

• BackDrop Noise Reduction BackDrop is TC Electronic’s flagship noise reduction algorithm available on their System 6000 platform. It has found widespread use in mastering of music and film.

• Real-time noise reduction algorithm for hearing aids (used by multiple manufacturers).

• Digital artificial reverberation algorithms embedded in products from several manufacturers

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