Virtual surround

Virtual surround sound for simulated surround sound or English Virtual Surround Sound, is the reproduction of a surround sound audio signal ( ie, a multi-channel signal with at least four channels ) over stereo speakers or headphones. This procedure simulates a plurality of sound sources are referred to as virtual sound sources.

Basics

The method is based on the outer ear transfer functions ( HRTF ). These functions describe how the ear changes a signal depending on its direction. This change can be replicated and count on an audio signal. This creates the sensation as if the signal from the corresponding direction comes, even if in that direction no real sound source is located (eg, a speaker).

Method

The simulation of the outer ear transfer function by means of convolution or by using notch filters. The starting point for a virtual surround mix is a true multi-channel recording. First of all simulated channels are separately. Then you generate per channel two separate outer ear transfer functions (each for the right and left ear ). For the center channel and the LFE channel, there is only one transfer function.

Applications

Proprietary applications include:

  • Dolby Virtual Speaker Dolby
  • SRS TruSurround by SRS Labs
  • DTS Surround Sensation of DTS

Especially for headphones:

  • Dolby Headphone Dolby
  • Silent Cinema, Yamaha
  • DTS Headphone: X DTS
  • Ensonido for MP3 files from Fraunhofer IIS
Quadraphonic sound Low-frequency effects Dolby Laboratories Sound Retrieval System
806171
de