A new paradigm

in room correction.









BACCH-ORC is the most advanced room correction technology today. Unlike any other commercially available room correction system, BACCH-ORC relies on quick in-ear (binaural) acoustic measurements, millimeter-resolution head tracking, and cutting-edge algorithms derived from years of psychoacoustic research, to produce and apply individualized optimal room correction (ORC) filters that elevate any stereo loudspeaker playback system to its ultimate level of transparency.

Not only does BACCH-ORC correct for the spectral coloration of the loudspeakers and the listening room, it also neutralizes the spatial signature of the loudspeakers, which interferes with the spatial cues of the sources in the recording, leading to significantly enhanced spatial imaging.

Binaural, Quick & Individualized

BACCH-ORC relies on quick binaural acoustic measurements using Theoretica's BACCH-BM in-ear microphone (a scientific-tool-grade individually-calibrated microphone with ultra-linear response) worn by the listener sitting in the desired sweet spot. Such a binaural measurement not only contains the acoustic information about the loudspeakers and the listening environment needed to equalize the sound, but also captures how the sound interacts with the torso, head, and pinna

(outer ears) of the individual listener.

This individualized acoustic information allows BACCH-ORC to identify the particular spatial cues contained in the measured frequency spectrum that cause the listener to locate the loudspeakers in space. Such loudspeaker localization spectral coloration, which interferes with the source localization cues in the recording, is then neutralized by BACCH-ORC's advanced algorithms. The resulting tonal and
spatial transparency of the ORC filter (which acts in the frequency domain), when combined with the lauded 3D imaging capability of a BACCH (crosstalk cancellation) filter (which acts in the time domain), amounts to a true and complete disappearance of the loudspeakers in favor of a stunningly accurate reproduction of the recorded sound image.


Other room correction systems rely on a set of time-consuming measurements done with a microphone in free field (i.e. with no listener present), which are then averaged. Such an averaged room correction filter is always compromised to a certain degree, especially if the listener's head moves. With BACCH-ORC the listener's head is tracked with a compact optical sensor (or, optionally, an infrared sensor for head tracking in pitch darkness) and the ORC filter is updated in real time as a function of the precise location of the listener's ears. This ensures seamless room correction that is robust against head movements.
The same head tracking data is used to update the BACCH (crosstalk cancellation) filter so that 3D imaging and spectral correction are always perfectly matched, and synced to head movements. (Head tracking can be optionally defeated if the listener does not intend to move outside the main sweet spot.)

Optimal & Transformative

BACCH-ORC produces an optimal room correction filter. There is no need to "dial a target curve" as in other room correction systems because there is only a single optimum for a given listener, room and loudspeaker playback system. While the user has access to the parameters controlling the optimizer, the default settings are pre-chosen to yield the ideal room correction for critical listening.
To arrive at this optimal filter, the BACCH-ORC patent-pending method, aside from treating the early and late components of the sound differently, splits the measured response into three bands:
1) The quasi-free field response (encompassing the room and body of the listener), 2) the low-order pinna response (associated with the listener's head and ears) and 3) the high-order pinna response (due to the finer structure of the pinna). Each of these bands is then processed and equalized separately based on the value of its spectral entropy (a measure of the randomness of the distribution of spectral energy) and the whole is assembled into a composite spectrum from which the ORC filter is derived.
BACCH-ORC is available for $1000 as an optional module of BACCH-dSP 14 (Audiophile Edition and above), the application at the heart of Theoretica's BACCH4Mac products.