Dr. AIX's POSTS — 02 August 2016


Continuing with the importance of having a proper listening room, I’d like to continue talking a little more about isolating an individual room. Last time, I talked about things that professional studio do to isolate adjacent rooms from leaking sound into each other. Having double walls, lots of soundboard and drywall layers makes a huge difference in the amount of information transmitted from one space to another. And remember that low frequencies are tougher to isolate than higher frequencies.

I remember visiting my dentist a couple of years ago and being seriously bothered by a very high frequency while I was having my teeth cleaned. I asked the hygienist whether the sound annoyed her. After all, I was only there for a short visit — she worked there all day. She responded that she didn’t hear anything. I mentioned the sound to the dentist and he acknowledged that they recently had to move the offending machine from an exterior location to a closet across the hall. That’s when the sound became obvious. So I told him to get some 3/8″ rubber weather stripping and attached it to the door jam and to attach an aluminum threshold with a rubber stopper under the door. He did and when I returned six months later, the sound was completely gone. High frequencies are fairly easy to attenuate. Low frequencies are something completely different.

That’s why the Astound Studio, which is located in the middle of the building and costs over $1,000,000 to construct, isolated their control room and iso booth on a separate layer of new concrete. The contractor placed a series of dense rubber cubes at equal intervals on the existing concrete floor and then laid 3/4-inch plywood on top. Once the ply was secure, they poured a new 3 inch layer of concrete on the plywood. The edges of the new floor do not touch the exterior walls. This strategy is called “floating” the floor and is very effective at removing low frequency leakage. But it’s very expensive. I isolated my main control room with rubber under the floor joists.

So what’s really practical for a home system? What are the costs vs. benefits to doing real construction in your space? Just how much work is required to adequately isolate your room from the outside world and keep the rest of the house from experiencing the sound coming from your system? If your listening room is in your basement or you live in a multistory house, you have to be concerned with noise coming through the ceiling. The same holds true for apartment dwellers — the noise coming from neighbors can be very troubling.

Obviously, pouring a new layer of concrete is out of the question. But attaching a new layer of soundboard and drywall to the interior surface of your walls is doable. The amount of isolation provided by placing a single layer of 1/2 soundboard and a layer of 5/8″ drywall is surprisingly good. And you don’t have to double up the wall thickness on all of the walls (or ceiling) of your listening room. Any leakage problems are going to come from the closest sound source. Simply attach a couple of new layers on the problematic walls and any leakage will be reduced.


The Sonic Blocks Indiegogo campaign launched last night at midnight New Jersey time. There was a flurry of activity leading up to the start of the 30-day campaign: creating an email campaign with custom graphics and making sure that the video and information were all, as we wanted. You can visit the page and check out the “perks” at Sonic Blocks Indiegogo Page We’ve already gotten a fair amount of positive attention from C|Net, Digital Trends, and Yahoo News. If you can help in any way, my friend Scott and I would appreciate it. There are some serious discounts available for early backers.


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About Author


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

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