When you are listening to your favorite record through your home Hi-Fi system, you would sit nowhere else but in the “sweet spot” to perceive the unbiased stereo stage right in front of you. You expect the same listening pleasure from the same track while you are driving to work as well. However, none of the seats in a car are positioned within the sweet spot. Accordingly, the virtual soundstage that you are supposed to experience ahead of you is instead shifted to the loudspeaker closest to you. Dirac Virtual Center technology has been developed to address this problem to ensure you have the same listening experience in a car that you have at home. 

 

 

Key Features

  • Corrects near-side bias
  • Creates a stable and distinct phantom centre
  • Based on the measurements of specific car audio systems
  • Ideal for car sound systems with or without a center speaker
  • Fast and consistent tuning results
  • Can be combined with other Dirac technologies

The non-optimal seating positions

 

To enjoy music from loudspeakers as you would at a concert, sitting in the right place is critical for the stereo soundstage and imaging. The best place is located on a stereo axis equidistant to the two loudspeakers, which is called the “sweet spot”. At home, you can simply put your sofa in the sweet spot to enjoy the virtual stage taking shape through the sound in front of you.

However, this is impossible in cars, because all of the seats are located in off-axis positions – outside of the sweet spot. Passengers sitting on the left-hand side of a car therefore perceive the center image from the left side and vice versa and the entire soundstage is shifted to the closest loudspeaker: as if you were sitting at the side at a concert. 

 
 
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Stable and distinct phantom center

 
 

Dirac Virtual Center technology processes the audio signals to ensure that you are listening to the music as if you were within the sweet spot, regardless of your actual position in the car. The technology adjusts the phase between two loudspeakers or input signals in each seat via digital all-pass filters. These filters equalize the sound system, so that the properties of the phase responses in the sweet spot are reached. As a result, wherever you sit, you can simply enjoy the music as you would at home or at a concert: with the virtual soundstage right in front of you.

Dirac Virtual Center can be applied even when a physical center speaker is mounted. Depending on the input mix to the center speaker, the soundstage tends to be rather narrow, in particular when the center speaker is fed with a left + right signal. Dirac Virtual Center allows for a tuning process where the physical center speaker is used to stabilize the center image rather than creating it. This results in a more stable and wider soundstage and a more distinct phantom center compared to when only a physical center speaker is used.

 
 
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Accurate, consistent and flexible

 

Different from technologies with similar objective on the market, the Dirac Virtual Center tuning process is based on the measurements of specific car audio system. This ensures accurate phase adjustments that preserve the music fidelity and create a stable, distinct phantom center. For each car model, the optimal filter is calculated carefully. Accordingly, a high level of consistency with stable results across car models is obtained.

 Moreover, the technology can be implemented by FIR filters or a number of all-pass IIR Biquads, which ensures the required flexibility for different DSP platforms. The Dirac Virtual Center technology can even be combined with other Dirac cutting-edging technologies to produce an in-car listening experience that exceeds expectations. 

 

 

Other Dirac technologies for automotive audio systems