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Poor sound diffusion is so common, that I wish everyone could have a first time QDA experience. Poor diffusion is one of four room acoustic distortions that must be dealt with in today’s small rooms. There are room modes, comb filtering, SBIE or speaker boundary interference effect and poor diffusion. All of these issues must be dealt with if you are going to make your room acoustically disappear. Room modes mask certain frequencies and exaggerate others.

SBIE is when your speaker and nearest boundary like a side wall or front wall are to close to each other producing an area where comb filtering can occur. Comb filtering is the back and forth reflection pattern of higher frequencies that occur between the room walls ans the speaker cabinet. All of these room acoustic distortions add their own sonic stink to the total sound in our room which is the sum of room sound (reflections) and direct sound from our speakers.

In this video, you will see and hear Bruce, an audiophile of over 40 years, explain his first time hearing quadratic diffusion set up on the rear walls and front walls of his listening room. You will hear Bruce discuss all of the cool things he heard and how this new clarity and separation contributed to his new found emotional connection to his music.

Audiophile – 40 Years

Bruce started where he should, with the management of low frequency energy in his listening room. He purchased 3 ACDA-10 and 3 ACDA-12 units which are low frequency absorbing, diaphragmatic, activated carbon units. Since his room is 15′ wide, he had low frequency pressure issues between those walls and with the introduction of these 6 units, he was able to minimize their impact on his listening position.

With low frequency issues and the room modes that they represent under proper management, he went to the next logical step. He bought new speakers. He bought new speakers because he heard how his existing speakers really sounded in a room where low frequency energy was properly managed. His next approach with his new speakers and new room was to introduce sound diffusion.

Sound Diffusion

Sound diffusion adds many dimensions to your listening experience. It adds separation to each instrument and vocal. Remember when you are listening to a lead vocal and can not hear the background singers doing the harmony. The only time you hear the harmony from the background singers is when the lead vocal is not singing. Diffusion puts a stop to that. There is a separation with diffusion that can not be achieved with any other form of room treatment.

Sound diffusion technology adds a definition to every vocal and instrument. Through the use of sound diffusion technology you can now have the same resolution in your room as the transition from digital from analog only without the harsher artifacts of digital. Sound diffusion technologies also add “air” to the presentation which is really not a separate and distinct element. Air in our audio presentations is the summation of separation and definition that creates what we call “air”. We call it air because that is what we have all been gasping for.

In Summary
If you would like to go on a similar acoustical journey as Bruce and learn more about room acoustics please sign up for my free videos and ebook by joining the mailing list here. I send room tuning tips and things for you to test in your room every Wednesday. They are easy to follow and will really help you enjoy more of your music.

Alternatively feel free to contact me directly at: 520 – 392 – 9486 MST or You can see more of my research and development story and why I started Acoustic Fields at:

Thanks and speak soon

Dennis Foley

I am an acoustic engineer with over 30 years’ experience in the business. My technology has been used in Electric Lady Land Studios, Sony Music of New York, Cello Music and Films founded by Mark Levinson, and Saltmines Studios in Mesa, Arizona, along with hundreds of others.

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