CONVERTIBLE AUTOMOBILE SOUND SYSTEM EQUALIZING
The invention relates in general to convertible automobile sound system equalizing, and more particularly concerns novel apparatus and techniques for adjusting the convertible automobile sound system equalization in response to the state of the convertible top.
BACKGROUND OF THE INVENTION For background, reference is made to U.S. Patent No. 5,023,914 disclosing nonminimum phase equalization of a vehicle sound system, and U.S. Application Serial No. 10/290,989, filed on November 8, 2002, disclosing a dual-mode sound system having optimized modes corresponding to different configurational states of an automobile, the entire content of which are incorporated herein by reference.
SUMMARY OF THE INVENTION
In a convertible automobile, there is a sound system with equalization circuitry. A sensor provides a top state signal representative of the state of the convertible top. The equalization circuitry responds to the top state signal to provide equalization representative of the state of the top. In a specific form of the invention, the convertible automobile includes left and right dash speakers, and the equalization circuitry includes left and right equalization circuitry responsive to the top state signal for providing top up equalization when the top is up and top down equalization when the top is down. The sovmd system may also include door speakers with door speaker equalization circuitry responsive to the top state signal for providing top up equalization when the top is up and top down equalization when the top is down. The sound system may also include seat speakers in the seats and seat speaker equalization circuitry responsive to the top state signal for providing top up equalization when the top is up and top down equalization when the top is down. The sound system may also include a center dash speaker and center dash speaker equalization circuitry responsive to the top state signal for providing top up equalization when the top is up and top down equalization when the top is down.
EquaUzation circuitry as used herein means circuitry that coacts with other elements of the sound system so that the radiated acoustic power into the convertible automobile listening area varies as a fimction of fi-equency in a predetermined fashion over a substantial portion of the range of audible frequencies.
Other features, objects and advantages of the invention will become apparent from the following detailed description when read in connection with the accompanying drawing in which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG 1 is a top pictorial view of a convertible automobile sound system according to the invention in a convertible automobile in an exemplary embodiment;
FIG 2 is a block diagram of a system for providing an audio signal to energize the sound system of FIG 1
FIG 3 is a graphical representation of the top up and top down equalization furnished by the left and right dash speaker equalization circuitry;
FIG 4 is a graphical representation of the top up and top down equalization furnished by the center dash speaker equalization circuitry;
FIG 5 is a graphical representation of the top up and top down equalization furnished by the door speaker equalization circuitry; and
FIG 6 is a graphical representation of the top up and top down equalization furnished by the seat speaker equalization circuitry.
DETAILED DESCRIPTION
With reference now to the drawings, and more particularly FIG 1, there is shown a pictorial representation of a convertible automobile sound system according to the invention seated in convertible automobile 11. There are left, right and center dash speakers 12,13 and 14, respectively, seated on the convertible automobile dash. There are left and right door speakers 15 and 16, respectively, mounted to the front doors. There are rear speakers including left seat, left channel speaker 21, left seat, right channel speaker 22, right seat, left channel speaker 23, right seat, right channel speaker 24 mounted in or adjacent to the left and right seats 25 and 26. A seven-channel amplifier 31 including the equalization circuitry may be mounted vmder the passenger floor mat. A soimd system control panel 32 may be mounted on the dash above the center console 33.
Referring to FIG. 2, there is shown a block diagram illustrating the logical arrangement of the system for energizing the different speakers with seven channels in the exemplary embodiment. There is a signal source 41 that furnishes soimd signals to channels 1-7,
respectively. Each channel also receives a signal from top state signal source 42 representative of the state of the convertible top. Channel 1 energizes left dash speaker 12 with a front left input signal. Channel 2 energizes right dash speaker 13 with front right input signal. Channel 3 energizes left door speaker 15 with front left input signal. Channel 4 energizes left channel rear speakers 21 and 23 with left rear input signal. Channel 5 energizes right channel rear speakers 22 and 24 with rear right input signal. In one embodiment, channels 4 and 5 are left and right surround channels. Channel 6 energizes right door speaker 16 with front right input signal. Channel 7 energizes center dash speaker 14 with a mono signal that is half the sum of the left and right front input signals.
Referring to FIG. 3, there is shown the top up equalization 51 and top down equalization 52 furnished by channels 1 and 2 to left and right dash speakers 12 and 13, respectively.
Referring to FIG. 4, there is shown top up equalization 53 and top down equalization 54 furnished by channels 3 and 6 to left and right door speakers 15 and 16, respectively.
Referring to FIG. 5, there is shown top up equahzation 55 and top down equahzation 56 furnished by channels 4 and 5 to left channel rear speakers 21,23 and right channel rear speakers 22,24, respectively.
Referring to FIG. 6, there is shown top up equahzation 61 and top down equalization 62 furnished by channel 7 to center dash speaker 14.
Preferably, the system is constructed and arranged to furnish minimum phase magnitude equalization for all amplifier/speaker channels, phase alignment equalization using all pass filter stages and/or delays for coherent and/or intentional incoherent acoustic energy addition and delay acoustic energy of rear speakers with respect to front speakers to create a front dominant sound stage with an enhanced sense of spaciousness.
In practicing the invention, the associated top up mode is generally tuned for determining minimum phase magnitude equalization, phase alignment equalization and delay. The top down mode may be estabhshed by adjusting the magnitude equalization by using the difference in the speaker raw acoustics between the top down and top up case. Preferably, there are different delay and polarity relationships between the front and rear channels in the top down mode to create similar spatial and spectral impressions to those obtained in the top up mode. In the top up mode in this example, signals to the rear speakers were delayed 5 ms with respect to signals to the front speakers, and the polarity of signals to the rear speakers was reversed with respect to
signals to the front speakers. In the top down mode, the rear signals to the rear speakers were delayed 6 ms with respect to signals to the front speakers, and the polarity of signals to the rear speakers with respect to signals to the front speakers was not reversed.
This approach can be applied to more complex systems, and is not limited with respect to which signal processing channel nonminimum phase property is varied with respect to which other channel. In this specific example, signals to rear speakers were delayed with respect to signals to front speakers, but other systems may relatively delay signals to other sets of speakers.
There has been described novel apparatus and techniques for a convertible automobile sound system. It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific apparatus and techniques herein disclosed without departing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques herein disclosed and limited only by the spirit and scope of the appended claims.
What is claimed is:

CLAIMS
1. A convertible automobile sound system comprising,
a plurality of loudspeakers,
a source of a top state signal representative of the state of the convertible automobile top,
equalization circuitry coupled to said loudspeakers and responsive to said top state signal for providing equalization related to the state of the convertible top.
2. A convertible automobile sound system in accordance with claim 1 wherein said source of a top state signal provides a top up signal when the convertible automobile top is up and a top down signal when the convertible automobile top is down so that the radiated power by said plurality of loudspeakers as a function of frequency is substantially the same when the top is up as when the top is down.
3. A convertible automobile sound system in accordance with claim 2 wherein said plurality of loudspeakers comprise left, right and center dash speakers seated on the convertible automobile dash, left and right door speakers mounted in left and right front doors respectively of the convertible automobile,
left outside, left inside, right inside and right outside seat speakers respectively mounted in left and right seats of said convertible automobile,
a seven-channel amplifier including said equalization circuitry,
a signal source constructed and arranged to furnish sound signals to the seven channels of said seven-channel amplifier,
the first of said channels constructed and arranged to energize said left dash speaker with a front left input signal,
the second of said channels constructed and arranged to energize said right dash speaker with a front right input signal,
the third of said channels constructed and arranged to energize said left door speaker with a front left input signal,
the fourth of said channels constructed and arranged to energize said left seat speakers with rear left input signal.
the fifth of said channels constructed and arranged to energize said right seat speakers with rear right input signal,
the sixth of said channels constructed and arranged to energize said right door speaker with front right input signal,
and the seventh of said channels constructed and arranged to energize said center dash signal with a monaural signal that is half the sum of the left and right front input signals.
4 A convertible automobile sound system substantially as hereinbefore
described with reference to the accompanying drawings.