Spatial Audio: An Interview with Sound Designer Natalie “Nat” Houle

Spatial Audio: An Interview with Sound Designer Natalie “Nat” Houle.

In recent years, spatial audio has been the subject of frequent discussions in audio engineering. Whether it’s Meyer’s Spacemap Go, L-Acoustics’ L-ISA, or D&B’s Soundscape, spatial audio seems to be making a home in the production world. To most of us it may seem a little like black magic, so to better understand what spatial audio is and where it’s going this month Samantha Boone sat down for an interview with Natalie “Nat” Houle, sound designer and creator of nmhspatial.com to discuss what spatial audio is, its use cases, and where the technology is going.

Boone: What is spatial audio, and why do you feel it’s important to an audience experience?

Houle: To define what spatial audio is, we have to backtrack for a second. First, we need to acknowledge that our standard workflow in audio can be characterized as channel- or bus-based. This means the path and summing points that our inputs take on their way to the PA are based on predefined relationships of level and time. We carefully dial in our delays, front fills, subs, and other components to have a certain affiliation with one another. When we have the opportunity to employ techniques that involve adjusting delay or pan, it takes programming and snapshots to make it dynamic. This is cumbersome and time-consuming because our channel-based tools aren’t designed to accommodate that kind of processing workload or workflow; it is not the inherent nature of the system.

This is where object-based, or spatial audio, comes in: the fundamental design of a spatialized system is such that inputs (objects) play an active and user-modifiable role in their own delivery. Instead of, for example, an input going to a bus, then a matrix, then into a processor, and distributed out to the PA, each input preserves its integrity as an individual source with unique characteristics of how it behaves and occupies space. Additionally, a spatial audio system is designed with overlapping coverage. This contrasts our typical philosophies for overlapping left-right or distributed mono signals. This means that house right can localize something that is panned hard house left without a major drop in SPL. It means we are more connected to the location of sources on our stage, as opposed to everything arriving from the same arrays or point sources. 

This transformation of our established tradition represents a shift in the industry that, when implemented successfully, inarguably results in an overall better audience experience with less ear fatigue and an entirely other level of artistic potential. Spatial audio isn’t new, but it is now prevalent enough that we cannot ignore it. Due to its wide availability for all levels of implementation today, I believe we should all view it as important. We have the opportunity here to shift the live industry and improve everyone’s experience. Don’t scroll past it.

Boone: How did you discover spatial audio?

Houle: The first encounter was in the classroom during grad school. I had the opportunity to use SpaceMap with Dimitri and Spacemap Go using a Galaxy within a few weeks of one another. At that time, I understood its inherent value, but it was still an intimidating topic. Something hadn’t clicked yet in my designer brain; I did not consider the possibility that it would be anything more than another tool. A few months later, I was intellectually ready for the next level, which arrived in the form of L-ISA. Once I experienced it through loudspeakers, I was completely sold on the idea that I needed to start using spatial audio in my work. I had to have it, and that same passion for what is possible with object-based modalities has only grown stronger since.

Boone: In your opinion, what are the biggest limitations of a traditional stereo audio system?

Houle: There are many things we’ve universally accepted with left-right deployments since the beginning. To name a few: lack of actual localization, inputs “crowded together” in our boxes, and the resulting frequency masking. We have also accepted the channel processing burden on the console to “carve out” space for each element in the mix, the inconsistency of panned signals experienced across an audience area, and the listening fatigue that comes with even great stereo mixes. Even when we achieve consistent SPL and frequency response throughout a venue, these problems persist fundamentally. We can use advanced tools to try to mitigate them, but the format itself puts up a ceiling that prevents us from achieving a higher level of art. Spatial audio blows through that ceiling and enables us to go deeper into what people love about live shows in the first place: connection.

Boone: Where do you see spatial audio going in the next five years?

Houle: What is necessary in the next five years is enhancing the partnership between manufacturers and their end users. This relationship has to change if spatial audio deployments are going to become more prevalent, if not common. We need more educational material, user guides that are designed differently, more information about what’s happening in the algorithms, and more application examples that are available for public viewing; more videos, interactive tools, and opportunities for product training that aren’t behind a paywall. There are certain things that most people are still not convinced of when it comes to this topic, and manufacturers should be addressing those questions for us. Manufacturers should also be integrating accessibility features into their work to accommodate visual, motor, or cognitive differences and neurodiversity. I see that the names I know well are working on these educational materials in one form or another and to varying degrees of reinvention. I’m excited to see the improvement in consumer literacy when it gets into the hands of consumers. 

Secondly, we on the ground designing shows with those solutions need to be braver about pushing for the technology we want to use. We have to turn the Rubik’s cube over and over until we find what works. (We need to help each other in this, too.) On the “it’ll cost too much” page of my website, I talk about some of the ways we can help to rationalize our idea to others and convince people that obtaining the resources for spatial systems will be advantageous not only to “team sound” but to other departments as well. I hope that in the next five years we’ll see more designers, at every producing level, dipping their toes in the water. That may mean using a Soundscape 180 system instead of full 360, exclusively spatializing playback in L-ISA, or only using Spacemap Go for a few sequences. Before any of that becomes a reality, consumers must believe that the tool is accessible to them in the first place. Most designers do not believe that right now; the technology has gone further than the effectiveness of the pitch itself has.

There is a symbiotic relationship here, and until both parties become aware of that in a new way, the products won’t feel accessible, and most designers will not engage. I always encourage designers to talk to manufacturers and to remember that, yes, these are companies and corporations, but the folks we interact with and who help us troubleshoot when we’re in a pinch are human beings.

Natalie “Nat” Margaret Houle is an LA-based sound designer from the Hudson Valley, New York, with nearly fifteen years of experience in audio. She is most well-known for creating nmhspatial.com, a product-agnostic analysis of object-based audio specifically through the theatrical sound designer’s lens. Addressing both the technical and the creative sides of spatial audio, nmhspatial.com bridges the gap between manufacturer and end user by presenting questions that can be asked about spatial solutions and presenting philosophies to be considered in theatrical works.