What's the difference between diffusion and absorption?
Love Music More · hosted by Luke F. Walton (Scoobert Doobert) · Solo episode
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Topics discussed
Host note
Flutter echo is one of the first things you notice in an untreated room and the last thing people think to fix. It's that metallic slap between two parallel walls, the thing that makes a raw recording sound like it was captured in a bathroom. It doesn't have vibe. It's very difficult to manipulate after the fact.
I break down the two tools for dealing with it: absorption, which soaks up the sound wave and converts it to heat, and diffusion, which scatters reflections in multiple directions so you keep a sense of space without the harsh slap. They're complementary, not interchangeable, a fully absorbed "dead room" sounds wrong too.
Drawing on building my own home studios, I get into the practical end: why really controlling a room's acoustics means building a room inside another room (and why that gets expensive fast), and where affordable shortcuts actually work, including the bookshelf trick, which is a tried-and-true diffuser that costs nothing if you already own books.
Selected moments
- Introduction to acoustic treatment 0:51 I introduce the topic and my personal experience with building studios.
- Understanding flutter echo 2:18 A definition and explanation of flutter echo in acoustics.
- The concept of a dead room 3:49 I explain what a dead room is and its significance in recording.
- The role of absorption 6:47 An explanation of absorption and its importance in recording environments.
- The need for diffusion 14:19 Discussing the role of diffusion in maintaining a sense of space in recordings.
- Practical tips for home studios 18:48 I offer suggestions for cost-effective acoustic treatment solutions.
Selected excerpts
So I've covered this in some other episodes because I've built my own home studio... What are these things? What are they trying to do?
When we're recording stuff, you want to avoid that most of all because that is just kind of death. It doesn't sound good, doesn't have vibe and it's very difficult to manipulate.
Absorption is soaking up the sound... Diffusion is sending the sound waves in a bunch of different directions.
To combat that, that's where studios get really, really expensive because... it's about building a room inside of another room.
The bookshelf thing is a tried and true method of diffusion. It's not perfect but it helps.
FAQ
What is absorption in sound treatment?
Absorption is the process of soaking up sound waves, effectively deadening the room to minimize reflections.
How does diffusion work in a recording studio?
Diffusion scatters sound reflections to minimize harsh echoes and maintain a sense of space.
Why do recording studios need acoustic treatment?
Acoustic treatment is essential to control sound reflections, reduce flutter echoes, and produce high-quality audio recordings.
Curated notes only — no public transcript. Listen on the links above.