With standards, specifications and room correction all big subjects right now, Mathias Johansson, Co-Founder and Chief Product Officer at audio experts Dirac, answers a few key questions.
What were your key takeaways from CEDIA’s RP22?
RP22 is a really great step forward for audio. Those in our industry all have their own notions of what makes good sound. Yet, there’s never been a single source of truth that people could go to and use as a reference point when organising their systems.
CEDIA did a nice job remedying that by aggregating the collective wisdom of the industry and producing recommendations and guidelines for how a good-sounding system should behave. Although RP22 doesn’t provide you with a cookbook solution, it explains what to aim for and the different compromises involved in creating good sound. For us at Dirac, it also serves as a proof point for problems our award-winning software is solving.
Are you in general agreement with the outlined standards/recommendations?
Overall, I think it’s very applicable regardless of if you’re working on an immersive or stereo audio system. Whether building a system from scratch or enhancing an existing system, it’s a solid starting point.
Importantly, RP22 emphasised what we’ve long preached at Dirac. It’s not just about your speaker selection, the room itself has a significant impact on audio performance. In fact, a plot of an anechoic subwoofer frequency response will actually tell you nothing about how the system will sound. The room is part of the speaker. There is no separating one from the other.
It also reinforced the importance of bass to the overall sound of an audio system. In particular, seat-to-seat variation came up quite often, which can be a huge detriment. If you’re in the sweet spot, the bass will sound smooth, rich and tight, but the minute you move away, the uneven bass is extremely noticeable.
Recognising this reality, RP22 advocates for the use of multiple subwoofers, which I fully agree with. The high-end Hi-Fi community has not always embraced the use of subwoofers, but once integrated with care, they provide huge value. You really cannot talk about high-end sound performance unless you have great bass, and multiple subs are a great way to enhance any audio system in this critical area.
Why is there so much bass variation throughout a room?
Think of it as waves in the ocean. Sound waves are literally making waves in your room. When a wave is emitted through a subwoofer, it travels through the room and bounces back, just as the tides move in and out.
These wavelengths are very long and we’re asking a little room, which is sometimes shorter than the wavelength itself, to accurately reproduce it. As these waves move in and out, they begin clashing with each other to produce a muddy and varied response.
What are the factors driving the multiple subwoofer trend?
The main factor is the recognition that high-end sound requires good bass, and in order to achieve that consistently for every position in a room, multiple subwoofers are the only way to go. Multiple subwoofer setups are popular because they help even out seat-to-seat variation.
Multiple subs can allow the user to shape how sound waves interact with each other. If you manage the phase interactions of the subwoofers with the room correctly, the waves will sum up coherently rather than crashing into each other randomly. Because the bass is originating from different positions in the room, you’re decreasing the chances of having these big clashes.
Also, more equipment than ever is designed to support multi-sub setups, which of course broadens the possibilities for using it.
What are the unintended consequences? Why can’t new equipment alone assist in these scenarios?
This all sounds nice in theory, but it’s often not as easy as it sounds. Without the proper technique and technology support, users can get themselves into trouble with multi-sub.
For example, I was just recently measuring our sound lab here at Dirac HQ. We have three subwoofers in a relatively well-treated room. I calibrated each subwoofer individually as part of the process and measured the result. The unfortunate reality was I experienced more variation, and even less bass in the sweet spot than I had with just one subwoofer.
This isn’t uncommon. Even with multiple subwoofers, variation can still occur across seats and even cancel each other out in the sweet spot, ultimately producing less bass than with one sub.
The good news is that it’s possible to remedy this if you properly co-optimise the subwoofers by measuring their interaction in the room and adjusting their response so that they sum up coherently throughout the listening area. That’s precisely what our technology Dirac Live Bass Control does by working only with phase adjustments, timing and gain.
What’s a better alternative to multiple subwoofers and why?
Dirac Live Bass Control ensures that users get the most bass possible from the sweet spot and times the subwoofers for reduced variation. We want everyone in the room to have the same rich, full bass experience.
For example, someone seated near a wall will often hear the results of a bass buildup where the bass may be too prominent and then someone in front of them may experience much less. Dirac Live Bass Control, combined with multiple subwoofers, can even that out so everyone is hearing the same thing.
How do you see the role of room correction evolving with bass management specifically?
Room correction will continue to grow in importance as a means to keep up with ever-evolving listening spaces. We used to more commonly see dedicated, purpose-built rooms – either a home theatre or stereo listening room – specifically designed to optimise the system’s performance.
The room was rectangular; furniture was placed to align with the sweet spot; and speakers were situated in the appropriate locations to achieve peak performance.
Today’s listening room is much different (and more complex) than that of the past – for example, an open floor plan downstairs or an entire basement entertainment area.
The room’s dimensions, furniture placement and speaker locations, create an environment that works against, rather than optimises, audio performance – regardless of system quality.
The output of every speaker, whether high-end or budget-friendly, relies on how it interacts with the room, especially in the bass region. Because today’s listening spaces are very often a detriment to speaker quality, room correction is becoming a prerequisite for achieving premium bass performance.
Using subwoofers in conjunction with small or big main speakers provides significant potential performance enhancements at a good value point. But that potential is only realised through measurement-based optimisation of the bass management and the interaction of the subwoofers, the other speakers and the room itself. So room correction and bass management will evolve into a seamless measurement-based optimisation of the overall sound system.
Do you want to preview anything related to Dirac Live Bass Control? Any recent or upcoming product integrations we should be aware of?
We’re very excited about our recent announcement that seven mid-range and high-end Denon and Marantz units will be able to run Dirac Live Bass Control.
This is a significant step toward our goal of making high-quality bass accessible to everyone from professional integrators and audiophiles to the broader consumer market. Look out for more partnership announcements in 2024 that put professional-level acoustical room control within reach of all listeners.
