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Thread: Dirac Unison

  1. #1

    Dirac Unison

    The technology which has been previewed at January CES and tentatively named Unity has been finally trademarked as Dirac Unison.
    It is not a product as of now, the tuning is really complex to release to the public so if/when we make it a product it will probably be for manufacturers, installers and pro markets only for very high-end systems.

    Things are easier in a fixed environment (a predefined car model) with unlimited available measurements (i.e. 800 as you will see) so the first licensee to use Dirac Unison is the Volvo Car Group making the technology available in the all-new Volvo XC90 with a Bowers & Wilkins audio system.
    The announcement is here: http://www.dirac.se/en/news-events/l...imization.aspx

    I can add the following from Michael Adenauer, former music producer and audio expert at Volvo Cars:

    In the new XC90, the software has been used to re-create the exact acoustic qualities of Gothenburg Concert Hall, located in Volvo’s home town and home to the Gothenburg Symphony Orchestra, the National Orchestra of Sweden. A simple change in the centre touch screen that controls all the car’s features and the system will immediately alter its settings to mirror this concert hall, a recording studio or a stage.

    “It took some 800 individual measurements in the Gothenburg Concert Hall before we captured the true richness of the acoustics,” said Mr Adenauer. “When it comes to the Studio Mode, it offers a precise and dry listening environment, similar to that which a recording engineer experiences in a studio. The Individual Stage mode offers the opportunity to control your position in a virtual venue through the innovative use of two sliders called ‘envelope’ and ‘intensity’. With these sliders you can move close to the stage, be surrounded by the musicians or place yourself out in the audience.”

    Among the innovations in the new XC90 are the world’s first sub-woofer to be integrated into the body of the car rather than being a freestanding box that is simply bolted to it. Furthermore, this sub-woofer is also air ventilated – another world first – which means the air is expelled from an opening near the rear wheel-arch.
    “The sub-woofer design is integrated in our new Scalable Product Architecture and is a world first in the automotive industry,” said Mr Adenauer. “This increases the subwoofer’s capacity to pulse more air, which enables extremely low bass tones all the way down to 20 Hz. In principle it turns the whole interior space in the car into a giant subwoofer.”

    Ciao Flavio
    Last edited by Flak; 06-09-2014 at 03:46 AM.
    Warning: My posts may be biased even if in good faith, I work for Dirac Research :-)

  2. #2
    Hi Flavio,

    Unison must be amazing.

    I'm thinking - maybe take only one feature of it - "a completely new kind of bass management, which is automatically matched to the room and the loudspeakers" and make it into a consumer product?

    Could be a heck of an upgrade module to Dirac Live!

  3. #3
    Quote Originally Posted by Ron Kuper View Post
    Hi Flavio,

    Unison must be amazing.

    I'm thinking - maybe take only one feature of it - "a completely new kind of bass management, which is automatically matched to the room and the loudspeakers" and make it into a consumer product?

    Could be a heck of an upgrade module to Dirac Live!
    Yes Ron

    Flavio
    Warning: My posts may be biased even if in good faith, I work for Dirac Research :-)

  4. #4
    Quote Originally Posted by Flak View Post
    Yes Ron

    Flavio

    Where do I pay?

  5. #5
    With reference to Dirac's Unison a very recent paper has been published by the Audio Engineering Society... it is dated February 10, 2015 and is available in full here:
    http://www.aes.org/e-lib/browse.cfm?elib=17563

    The following is an excerpt with relevant references:

    "To obtain a specified target response in several measurement positions is a difficult task, particularly with individually designed filters.
    First, as nearly all loudspeaker–room impulse responses exhibit excess phase (non-minimum phase) behavior [17, 25] the pre-compensator must be of so-called mixed phase type to correct for the excess phase distortion, i.e., the distortion components that are non-minimum phase.
    Minimum phase filters, which are most commonly used, are generally insufficient for correcting such components.
    Second, if a loudspeaker impulse response varies significantly between different measurement positions, as is typically the case in a normal room, then a single individual filter design for each speaker would, in general, not be sufficient to obtain good performance in all measurement positions.
    A response may be attained that on average is close to the specifications, but there will always be remaining errors at each measurement position.
    Hence, single-channel methods are most effective for compensating distortions that are common, or nearly common, to all positions in the region of interest.
    Since audio systems of today generally include multiple loudspeaker channels, modern room correction methods propose the use of all, or at least a subset of, the available loudspeakers, see, e.g., [1, 2, 9, 12, 13, 18, 21, 23, 30–32].
    In a recent publication, a Multiple-Input Multiple-Output(MIMO) approach to room compensation by the use of support loudspeakers was proposed and evaluated for a varying number of support loudspeakers [9].
    It was shown that the effect of the room acoustics can be completely controlled up to a certain frequency, which is determined by factors such as, e.g., the number of loudspeakers, the size of the room and the sweet spot, and the granularity of the grid of measurement positions.
    In the present paper we shall investigate how the MIMO framework can be used to variably control the contribution of the listening room acoustics throughout a spatial region where the listener is located.
    By allowing the support loudspeakers to help the primary loudspeakers (e.g., the left and right speakers in a stereo system) to a higher or lesser degree, we can obtain a range of different equalizers that, to corresponding degrees, suppress the room acoustics while the direct sound of the primary loudspeakers is enhanced.
    Consequently we are able to decrease the influence of the room in all spatial positions simultaneously, to an extent that can be determined by the user.
    In the sequel we will refer to this concept as “Focus Control.”
    The motivation for this type of variable room equalization can be manifold and depends on the role of the listener, on the audio material, and on the practical situation.
    For example, a professional listener such as a mixing or mastering engineer can use it as a tool for carefully examining how various levels of listening room acoustics affect the perception of the material being produced.
    At the consumer end, the preferences and needs of listeners may vary depending on the material being listened to.
    If maximum intelligibility is desired for, e.g., a speech recording, then the maximum focus level (minimum level of listening room acoustics) is most likely preferable.
    On the other hand, if the recording is a musical performance in a studio, involving a voice or an acoustic solo instrument, then it may be better not to remove too much of the listening room’s response, since the performance may then appear overly dry or dull, lacking the natural acoustic space normally associated with such performances"

    REFERENCES
    [1] P. Antsalo, M. Karjalainen, A. Makivirta, and V. Valimaki, “Comparison of Modal Equalizer Design Methods,” presented at the 114th Convention of the Audio Engineering Society (2003 Mar.), convention paper 5844.
    [2] J. Backman, “Subwoofers in Rooms: Modal Analysis for Loudspeaker Placement,” presented at the 130th Convention of the Audio Engineering Society (2011 May), convention paper 8323.
    [9] L.-J. Brannmark, A. Bahne, and A. Ahlen, “Compensation of Loudspeaker–Room Responses in a Robust MIMO Control Framework,” IEEE Transactions on Audio, Speech, and Language Processing, vol. 21, no. 6, pp. 1201–1216 (2013 June).
    [12] A. Celestinos and S. Birkedal Nielsen, “Time Based Room Correction System for Low Frequencies Using Multiple Loudspeakers,” AES 32nd International Conference: DSP for Loudspeakers (2007 Sep.), conference paper 19.
    [13] A. Celestinos and S. Birkedal Nielsen, “Controlled Acoustic Bass System (CABS)—A Method to Achieve Uniform Sound Field Distribution at Low Frequencies in Rectangular Rooms,” J. Audio Eng. Soc., vol. 56, pp. 915– 931 (2008 Nov.).
    [17] M. O. Hawksford, “Digital Signal Processing Tools for Loudspeaker Evaluation and Discrete-Time Crossover Design,” J. Audio Eng. Soc., vol. 45, pp. 37–54 (1997 Jan./Feb.).
    [18] M. O. Hawksford and A. J. Hill, “Wide-Area Psychoacoustic Correction for Problematic Room Modes Using Non-Linear Bass Synthesis,” presented at the 129th Convention of the Audio Engineering Society (2010 Nov.), convention paper 8313.
    [21] M. Kolundzija, C. Faller, and M. Vetterli, “Multi- Channel Low-Frequency Room Equalization Using Perceptually Motivated Constrained Optimization,” in IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP’12, Proceedings, pp. 533–536, Kyoto(2012 Mar.).
    [23] A. Makivirta, P. Antsalo, M. Karjalainen, and V. Valimaki, “Modal Equalization of Loudspeaker–Room Responses at Low Frequencies,” J. Audio Eng. Soc., vol. 51, pp. 324–343 (2003 May).
    [25] S. T. Neely and J. B. Allen, “Invertibility of a Room Impulse Response,” J. Acous. Soc. Am., vol. 66, no. 1, pp. 165–169 (1979 July).
    [30] J. Vanderkooy, “Multi-Source Room Equalization: Reducing Room Resonances,” presented at the 123rd Convention of the Audio Engineering Society (2007 Oct.), convention paper 7262.
    [31] J. Vanderkooy, “New Thoughts on Active Acoustic Absorbers,” presented at the 131st Convention of the Audio Engineering Society (2011 Oct.), convention paper 8458.
    [32] T. Welti and A. Devantier, “Low-Frequency Optimization Using Multiple Subwoofers,” J. Audio Eng. Soc., vol. 54, pp. 347–364(2006 May).
    Warning: My posts may be biased even if in good faith, I work for Dirac Research :-)

  6. #6
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    Ah yes. By chance I ran into that paper when I was researching something else and brought back good memories of seeing it work at CES last year. is this still aimed at automobile OEM business as opposed to consumer?

  7. #7
    Quote Originally Posted by amirm View Post
    Ah yes. By chance I ran into that paper when I was researching something else and brought back good memories of seeing it work at CES last year. is this still aimed at automobile OEM business as opposed to consumer?
    Thanks Amirm,

    I'm pleased to read that your memories of Unison are good, as is your question... what has changed since last year's CES and the most recent one is that Dirac Unison is now definitely aimed at consumers also (but no release date has been established yet)

    Flavio
    Warning: My posts may be biased even if in good faith, I work for Dirac Research :-)

  8. #8
    Member Sponsor Addicted to Best! dallasjustice's Avatar
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    The new Volvo XC90 looks great. It looks like it's a great value compared to Range Rover. Is unison tech in the upgraded B&W system?
    MUSIC IS GOOD

  9. #9
    Quote Originally Posted by dallasjustice View Post
    The new Volvo XC90 looks great. It looks like it's a great value compared to Range Rover. Is unison tech in the upgraded B&W system?
    I cannot double check because it's sunday but as far as I know BMW is using Dirac Live.

    Flavio
    Warning: My posts may be biased even if in good faith, I work for Dirac Research :-)

  10. #10
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    Quote Originally Posted by Flak View Post
    Thanks Amirm,

    I'm pleased to read that your memories of Unison are good, as is your question... what has changed since last year's CES and the most recent one is that Dirac Unison is now definitely aimed at consumers also (but no release date has been established yet)

    Flavio
    Excellent!

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