Dirac Live Bass Control
In the past, room-correction solutions focused on optimizing magnitude response, with little help to correct phase response crucial for consistent performance throughout a room. However, with advancements in artificial intelligence and machine learning, combined with the development of all-pass filters, Dirac Live can now deliver spatially consistent bass response to make the most of your subwoofer setup.
Sound frequency basics and subwoofers
Modern full-range speakers, such as left, center, and right (LCR) speakers in a surround-sound system, combine a woofer and tweeter to reproduce the full range of audible frequencies. Subwoofers are often added to enhance the low bass. The subwoofers will only produce sounds lower than the frequency set by the system’s onboard low-pass filter – typically offering selectable cutoff points from 30Hz to 120Hz.
These low-frequency wavelengths are many meters long and must be treated different from higher frequencies with respect to interference and room resonances.
Why do we need bass control?
Why do we need bass management? Bass tones communicate feeling and physical power in music and film. Carefully controlling each speaker’s magnitude and phase is necessary to create a space where each participant fully experiences a song or a film score. This solution will provide a consistently excellent listening environment regardless of listener location.
Optimizing a sound system’s magnitude and phase response is especially crucial in the range of frequencies near the subwoofers’ upper limit. This “crossover point” is where the output of different speaker types overlap and can result in wide variations in magnitude and phase at various locations in space. Any solution to correct these issues must consider variables such as the shape of the room, location and direction of each speaker, reflective or obstructive surfaces, and multiple observation points to ensure consistent performance throughout the space.
While equalization (EQ) solutions can improve an audio system’s tone, they don’t correct for phase. A 100 percent phase linear system delivers sound from every speaker in every frequency to the listener at the same time. An out-of-phase system will have reduced clarity and accuracy, resulting in a sub-optimal experience. The difference is typically experienced a less tight and boomy bass.
The more speakers a sound system has, the more reflections and interferences are likely to occur. High-end home theater systems often have multiple subwoofers. Aligning all speakers optimally for each listener location can be complicated.
Traditional challenges with bass management
Historically, room correction tools have been developed to optimize full-range speakers. They have offered little support for subwoofers and bass control other than equalization, which mitigates but doesn’t solve the problem.
For optimized bass performance, a system’s phase response, combined from multiple sources and room reflections, must be corrected – and that can be tricky. Determining the ideal phase response for each subwoofer is almost impossible with traditional tools. This procedure requires significant setup time – a significant downside to most room correction solutions – because no two rooms or two sounds systems are the same.
Overcoming challenges to bass management
One of the keys to solving the bass optimization problem is introducing an all-pass filter that allows for precise control of a speaker’s phase response. Unlike high-pass and low-pass filters, an all-pass filter allows every signal through and adjusts the phase response (timing). With this type of filter, it’s possible to fine-tune the phase of each speaker so that the sound waves don’t cancel each other out and create dead zones in a room if you use multiple speakers.
Dirac Live Bass Control leverages all-pass filters, plus machine learning and artificial intelligence, to calculate gains, delays, and all-pass filters for each subwoofer. In this way, the Dirac solution ensures that low frequencies add up so that not only the average is controlled, but most importantly, seat-to-seat variation is minimized as we can now achieve a level of control in multiple locations at once.
A New Solution: Dirac Live Bass
Building on the strengths of the existing Dirac Live room correction solution, Dirac Live Bass Control introduces an automated method for controlling the bass characteristics of a sound system at multiple listening locations. The solution comes in two versions:
1. Dirac Live Bass Control Single Subwoofer adds automatic calibration and filter adjustments for a single subwoofer towards the full-range speakers it supports.
2. Dirac Live Bass Control Multi Subwoofer is designed for multiple subwoofer management. This version uses machine learning and AI to quickly determine the ideal settings for multiple subwoofers and automatically apply filters. This technique dramatically simplifies a procedure that could otherwise take several days to complete to the same standard.
Dirac Live Bass Control is available on a limited number of products. Check our Online Store to find out if your sound system can be upgraded with Dirac Live.
What is the time-domain, and why is it important?
At Dirac, we believe that the reproduction of transients is critical for a truly natural and transparent sound. For example, the stereo image is critically dependent on the time-domain differences and similarities between the sound at the left ear and the right ear. As such, Dirac’s impulse response correction improves the depth, the positioning and distinction of individual voices and instruments.
Mixed-phase room correction technology
Using a look-ahead buffer enables impulse response correction Minimum-phase and linear-phase room correction filters can’t physically optimize the acoustic impulse response in a room. At best, they can minimize problems caused by the application of a filter. Room-acoustic responses are non-minimum-phase, which is why Dirac Live® uses mixed-phase correction. Dirac Live® is unique in that it improves the impulse response throughout the listening area, not just in a particular zone.