Active monitoring headphone and a binaural method for the same
AssigneeGenelec Oy
InventorsJavier Gómez-Bolaños, Aki Mäkivirta, Ville Pulkki
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Abstract
According to an example aspect of the present invention, there is provided a method for forming a binaural filter for a stereo headphone in order to preserve the sound quality of the headphone, whereby the sum of the direct and crosstalk paths from loudspeakers to each ear have flat magnitude responses.
Claims12
A method for forming a binaural filter for a stereo headphone, wherein a sum of a direct path and a crosstalk path from loudspeakers to each ear are formed such that amplitude is essentially unchanged as a function of frequency and wherein the binaural filter is formed such that binaural time responses of a dummy-head are measured for a stereo loudspeaker setup inside a listening room with a predefined reverberation time, advantageously 340 ms, the measuring resulting in measured responses, and using said measured responses to calculate a set of binaural filters
- Hbin=F{hij(t)w(t)},i∈{L,R},j∈{l,r},
- wherein Hbin is the set of binaural filters, denotes Fourier transform, and w(t) is a predefined long time window, advantageously 42 milliseconds, hij(t) are binaural time responses of a dummy-head, L and R are left and right loudspeakers, respectively, and l and r are left and right ears, respectively.
A non-transitory computer readable medium configured to cause a method for forming a binaural filter for a stereo headphone to be performed, the method comprising the steps for forming a binaural filter for a stereo headphone, wherein a sum of a direct path and a crosstalk path from loudspeakers to each ear are formed such that amplitude is essentially unchanged as a function of frequency and wherein the binaural filter is formed such that binaural time responses of a dummy-head are measured for a stereo loudspeaker setup inside a listening room with a predefined reverberation time, advantageously 340 ms, the measuring resulting in measured responses, and using said measured responses to calculate a set of binaural filters Hbin=F{hij(t)w(t)},i∈{L,R},j∈{l,r}, wherein Hbin is the set of binaural filters, denotes Fourier transform, and w(t) is a predefined long time window, advantageously 42 milliseconds, hij(t) are binaural time responses of a dummy-head, L and R are left and right loudspeakers, respectively, and l and r are left and right ears, respectively.
A method for forming a binaural filter for a stereo headphone, wherein a sum of a direct path and a crosstalk path from loudspeakers to each ear are formed such that amplitude is essentially unchanged as a function of frequency and wherein the binaural filter HbinEQ is formed via the following steps:
- binaural time responses of a dummy-head, are measured for a stereo loudspeaker setup inside a listening room with a predefined reverberation time, advantageously 340 ms, the measuring resulting in measured responses, and using said measured responses to design a set of binaural filters, by windowing the first predetermined time, advantageously 42 ms, of the responses,
- Hbin=F{hij(t)w(t)},i∈{L,R},j∈{l,r},
- wherein Hbin is the set of binaural filters, F{⋅} denotes Fourier transform, and w(t) is a predefined long time window, advantageously 42 ms, hij(t) are binaural time responses of a dummy-head, L and R are left and right loudspeakers, respectively, and 1 and r are left and right ears, respectively
- using binaural networks of both ears, obtaining a average filter HSM
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- H
- SM
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- =
-
- H
- R
-
-
- 1
-
- +
- ^
-
- H
- L
-
-
- 1
-
- +
-
- H
- Rr
-
- +
- ^
-
- H
- Lr
-
- 2
- ,
- wherein {circumflex over ( )} denotes one octave smoothing process after the sum of direct and crosstalk filters,
- and wherein a magnitude of the filter HEQ is obtained as the inverse of |HSM| between frequencies 50 Hz and 20 kHz and wherein the binaural filters Hbin were convolved with HEQ to obtain the equalized binaural filter HbinEQ HbinEQ=HbinHEQ, wherein
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- H
- EQ
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- =
- 1
-
- H
- d
- +
- H
- x
-
- ≈
- 1
-
- H
- SM
-
- and wherein Hd is a direct path from a loudspeaker to an ear on the same side of the head as the loudspeaker and Hx is the crosstalk path from said loudspeaker on to the ear on the other side of said head.
Dependencies are inferred from the claim text.