Dirac Live

Dirac Live Room Correction combines cutting edge technology with a focus on usability.

• Impulse response correction: Where other room correction solutions deal only with the magnitude, Dirac Live will improve the entire impulse response of the system through our patented mixed-phase technology.
• New Auto Target Curve: The new Auto Target Curve replaces our old one-size-fits-all model and is automatically generated based on your speakers’ performance. It more faithfully reflects the inherent character of the measured system, minus the adverse acoustic effects of the room. You can now enjoy drastically improved sound without having to make a single adjustment.
• Multiple filter profiles: You can create different settings depending on where you sit, the content you’re listening to, or even one for each family member.

Dirac Live adds value to any sound system, be it an entry-level soundbar, a high-end home theater system, or a professional recording studio. To offer our business partners flexibility for licensing Dirac Live, we’ve developed three tiers.

• Ready: The system is prepared for Dirac Live Room Correction. Just purchase an end-user license to activate it.
• Limited bandwidth: The system can perform room correction up to 500 Hz, and the target curve can be tailored within this range. This correction is sufficient to deal with the bass and voice areas but not the entire audible spectrum. Upgrade Limited bandwidth to full bandwidth.
• Full bandwidth: This is the top tier of the room correction feature. It allows the system to be corrected across the entire frequency range while giving you full control of the target curve.

You can choose between the stereo and the multi-channel version if you purchase a Dirac Live Room Correction Suite license that runs on your PC.

• Correction of areas with sound gaps (bass decline)
• Smoother bass reproduction in the crossover area
• Bass Management on multiple subwoofers
• Flexible subwoofer placement in the listening space
• Visual representation of the predicted bass performance (subwoofer and speaker summation)

Dirac Live Bass Control is offered to our partners in different tiers to allow business flexibility.

• Ready: Standard bass management, but you see the predicted in-room response in our room correction software.
• Single Subwoofer: Measurement-based filter design seamlessly blends your single subwoofer with the full-range speakers that need bass management.
• Multi Subwoofer: Measurement-based filter design seamlessly blends all your subwoofers with the full-range speakers that need bass management. It also has a unique AI-based algorithm that co-optimizes all your subwoofers so that variations in the bass between the different measurement points are minimized.

All room correction systems try to even out the amount of energy present in each frequency band, usually referred to as equalization. Measuring the system supplies the information needed to understand how a specific audio system alters the tonal balance. It’s well known how to calculate a filter to restore the balance. So far, so good, but this isn’t enough to make sure the system sounds good. Here are a few examples, some silly, but revealing nonetheless, as to what tonal balance means, and doesn’t mean, for perceived audio quality:

• Your system plays all music in reverse. The music is the same, and the instruments are the same, so the tonal balance must be the same. But it sure doesn’t sound right.
• You’ve connected one of your front speakers out of phase. The out-of-phase speaker will have the same tonal balance, but the combination of two speakers playing stereo content will have a horrible sound stage. This conflict occurs because everything is spatially
• Your bass is booming all over the place and has no detail at all. Again, the system’s tonal balance doesn’t take into account when a sound is played, only that it’s reproduced somehow. Therefore, it’s often recommended to have sealed subwoofers for music listening. They tend to have better phase behavior (basically faster response). On the other hand, ported subwoofers tend to give you much more bass for their size but aren’t as well controlled as a sealed box.

The list could go on, but the message is clear. Phase and timing may be tricky to understand, and interpreting phase plots can be confusing. Still, they play a vital role in making sure we can enjoy good audio.

White Paper — Room correction and equalization of sound systems

In English       In Chinese 

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. Dirac’s impulse response correction improves the depth, 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 perfect 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.

Multiple measurements

Dirac Live® uses several measurement positions (typically 9) in the listening room, making it possible to find and correct acoustic problems accurately. In terms of the impulse response, this means optimization of the direct wave and early reflections. Generally, at higher frequencies, there’s less consistent time-domain behavior. Dirac Live® room correction automatically finds consistent problems in a frequency-dependent way and corrects for them. However, after addressing consistent time-domain behavior, there may still be some late reverberation in the room that causes subtle coloration. Dirac Live® corrects these in the frequency domain to achieve just the right resolution.

Impulse response correction

A loudspeaker’s impulse response affects clarity, detail, and all spatial aspects of the sound. Dirac Live® is unique in that it corrects the impulse response throughout the listening area, not just at a single point. By focusing on consistent problems across the measurement positions and correcting only these anomalies, Dirac Live® can achieve a faster decay time. Typically, the power ratio between the direct wave and the tail (later-arriving echoes) is improved by 6 dB or more, resulting in a vastly improved overall sound.

Frequency response correction

Why is it that the same frequency response can sound so different from room to room? To a great extent, the answer lies in the time-domain aspects of the measured frequency response and with critical differences in the spatial (angular) domain. Frequency response correction becomes more effective by addressing time-domain problems as such and not as minimum-phase spectral problems. After having conducted time-domain correction, we then treat the spectral colorations in a room. By paying particular attention to the variations across different measurement positions – not just the average – we can make sure not to overcompensate.

Implementation for best accuracy

Traditional EQ uses IIR filters for the lowest processor usage. Many room correction filters use FIR filters for ease of implementation and sound optimization. IIR and FIR filters both have their pros and cons. At Dirac, we use a proprietary filter structure that achieves maximum performance at much less processor usage than regular FIR filters. This filter structure also has great numerical properties and thus doesn’t produce any digital noise – thereby achieving enhanced sound optimization.

Choosing a target response

A flat frequency response does not necessarily sound neutral due to the ratio between direct and reverberant sound and the frequency-variable propagation loss. Dirac Live® can’t remove late reflections because they change too much between various positions. Therefore, a slight roll-off is often appropriate when listening at a distance. The Dirac Live® algorithm suggests a target response right for your listening environment and speakers. You can, of course, adjust to your taste using our simple graphical interface.