Room correction is a big subject currently as installers look to use anything at their disposal to get the best performance possible.

Dirac is a provider of digital sound optimisation solutions and here the company’s General Manager of High-Performance Audio, Niklas Thorin, underlines why he believes installers need to engage.

Recent advances pioneered by leading technology companies are changing how audiophiles and general home theater enthusiasts approach audio performance in their homes. While frequency equalisation provides a degree of control over sound characteristics, and room EQ solves some issues with reverberations and frequency response, a far more robust and effective solution is penetrating the market and delivering truly optimised listening experiences for any listening environment: room correction.

What’s wrong with the room?

Before diving into the key differences between room EQ software and room correction software, let’s discuss the role played by room acoustics software, in general, in optimising a home theater audio system.

Every room has unique acoustics, and they introduce a variety of distortions regardless of the audio equipment being used. Room acoustics software – like room EQ and room correction – can be used to reduce these distortions and improve audio clarity by altering the output of speakers to perform optimally based on precise measurements of a room’s shape, size, furnishings, reflective surfaces and listener locations. The major sources of distortion that affect the listening experience and can be addressed by room acoustics software are:

●             Frequency response, which describes a given speaker’s frequency range (i.e. 20Hz – 20kHz) and how the speaker increases or decreases the loudness of certain frequencies. For most situations, the ideal frequency response is ‘neutral’ or ‘flat’, where the speaker does not affect loudness of individual frequencies.

●             Impulse response, which is the output produced by a brief input signal, such as a single note of music. Poor impulse response can result in a muddy sound, where notes linger too long and blend together.

●             Phase alignment, which determines whether multiple speakers play the same sounds at precisely the same time. Proper phase alignment lines up the peaks and troughs of the crossing sound waves so they don’t cancel each other out.

●             Room resonances, which are standing waves that primarily affect bass performance, resulting in pronounced or ‘boomy’ bass notes due to a room’s architecture and geometry. 

●             Speaker driver alignment, which affects the timing of sounds from an individual speaker’s woofer and tweeter.

●             Cabinet diffraction, which occurs in a narrow field around the speakers, and can cause a perceived change of location for instruments and voices. It’s also called “early reflections”.

●             Room reverberation, which introduces spectral change and spaciousness to sound. It’s also called ‘late reflections’.

A more detailed analysis of these distortion sources can be found here.

How does room correction improve on room EQ?

Now that we’ve an understanding of the necessity of room acoustics software in creating an optimised listening environment, let’s get into the key differences between room correction software and traditional room EQ.

Many popular manufacturers offer room EQ that can adjust for reverberation and frequency response, but generally offer no solutions to improve impulse response, phase alignment, room resonance, speaker driver alignment or cabinet diffraction – the other room-related sources of distortion that impact the listening experience.

However, several high-end manufacturers have begun offering room correction, including our Dirac Live product, that adequately addresses all sources of distortion and imperfection through advanced algorithms.

A key differentiator of room correction solutions is their highly accurate impulse response optimisation, which results in a clearer, more accurate sound since each note lasts precisely the intended amount of time. Some room EQ solutions attempt to correct for impulse response by cutting off notes prematurely or starting notes early, but the result is often unnatural-sounding audio that doesn’t line up as intended – ultimately diminishing the listening experience.

But doesn’t room correction affect the warmth of analogue sources?

Certain members of the audiophile and Hi-Fi community still view any degree of digital processing as an intrusion on the warmth of analogue sources, such as LPs. The truth, however, is that virtually no modern audio is recorded using analogue equipment, and is therefore digital from the outset, regardless of what medium a consumer purchases. In fact, if room correction has any effect on the perceived warmth of a system, it’s likely to be heard as a positive effect, not negative, because all of the room-based distortions are eliminated.

What innovations does the latest in room correction offer?

Room correction has traditionally required a fairly technical process, but new solutions are making it much simpler and faster for integrators, and even end-user customers, to complete. For example, thanks to Dirac Live’s advanced algorithms and a redesigned, intuitive user interface that guides users through the process, what used to take a full day or more can now be completed in as little as 10 minutes. This enormous savings in time, not to mention frustration, helps integrators save money and increase the profitability of installations.

What’s the future of room correction?

Currently, room correction’s available on a number of mid-level home audio products and is most effective in environments with basic dimensions and standard seating positions, like living rooms or home theaters.

Looking forward, we’re exploring ways to apply its leading room correction technology to more dynamic and complex spaces, such as kitchens, where there’re more reflection points and more widely varied seating positions than a home theater. When mass-market consumer products begin integrating room correction, an entire home could be blanketed with acoustically perfect sound. We also hope to see room correction solutions for tube amplifiers in the next few years, which will offer audiophiles complete optimization of their high-end two-channel music systems.

Furthermore, although the industry’s made significant progress with room correction in the last 20 years, there’re still acoustical challenges that’ve yet to be solved. Solutions for standing wave cancellation, multi-sweet spot creation, and true bass management throughout an entire listening space are on the horizon. As a research-driven company dedicated to inventing the future of sound, Dirac’s actively exploring the edge of the market and developing breakthrough solutions, like the recently introduced Dirac Live Bass Management module, that create increasingly refined and perfected home theatre listening environments.

Learn more about Dirac here

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