Systems, methods, and apparatus to filter audio

1. An apparatus, comprising:

first and second audio speakers having same first audio characteristics in a mid-tweeter-mid configuration;

a third audio speaker having second audio characteristics, wherein the third speaker is positioned between the first and second audio speakers in the mid-tweeter-mid configuration;

a first audio filter to process an audio input signal to have a first frequency response including a first cutoff frequency, the first audio filter to output a first audio output signal having the first frequency response to the first audio speaker; and

a second audio filter to process the audio input signal to have a second frequency response different than the first frequency response, the second frequency response to compensate for interference between the first and second frequency responses caused by a position of the first audio speaker relative to the second audio speaker, and to output a second audio output signal having the second frequency response to the second audio speaker.

2. The apparatus as defined in claim 1 , wherein the second audio filter is to have a second cutoff frequency greater than the first cutoff frequency when the mid-tweeter-mid speaker arrangement is oriented horizontally.

3. The apparatus as defined in claim 1 , further comprising a digital audio processor including the first and second audio filters.

4. The apparatus as defined in claim 1 , wherein the first audio filter comprises a low-frequency shelf filter, a bandpass shelf filter, and a low-pass filter having the first cutoff frequency.

5. The apparatus as defined in claim 1 , wherein the second audio filter comprises a low-frequency shelf filter, a bandpass shelf filter, a low-pass filter having a second cutoff frequency, an allpass filter, and a high-frequency shelf filter.

6. The apparatus as defined in claim 5 , wherein the allpass filter applies a −360 degree phase shift to the audio input signal or to a filtered signal based on the audio input signal.

7. The apparatus as defined in claim 5 , further comprising an orientation detector to determine whether the first, second, and third speakers are in a first orientation or a second orientation, wherein the second audio filter is to apply the allpass filter and high-frequency shelf filter when the first, second, and third speakers are in the first orientation and is to omit the allpass filter and the high-frequency shelf filter when the first, second, and third speakers are in the second orientation.

8. The apparatus as defined in claim 1 , further comprising a network interface to receive at least one of the input audio signal, a synchronization signal associated with a multiple-device arrangement, or a configuration signal associated with a multiple-device arrangement.

9. The apparatus as defined in claim 1 , wherein the second speaker is to be positioned on the outside when in a multiple-device configuration.

10. An apparatus, comprising:

first and second audio speakers having same first audio characteristics;

a third audio speaker having second audio characteristics, wherein the first, second, and third speakers are arranged in a mid-tweeter-mid (MTM) configuration, the third audio speaker located between the first and second audio speakers; and

a digital audio processor to filter an audio signal to cause first audio output from the first audio speaker to have a different frequency response in a first frequency range relative to a second audio output from the second audio speaker so as to compensate for interference caused by a position of the first speaker relative to the second speaker in the mid-tweeter-mid configuration.

11. The apparatus as defined in claim 10 , wherein the digital audio processor is to filter the audio signal to cause the first audio output to have a −360 degree lag relative to the second audio output.

12. The apparatus as defined in claim 10 , wherein the first frequency range is between a cutoff frequency of the second audio output and a crossover frequency.

13. The apparatus as defined in claim 10 , wherein the first frequency range is based on a spacing between the first and second audio speakers.

14. The apparatus as defined in claim 10 , wherein the digital audio processor is to cause the first audio output and the second audio output to have a substantially equal frequency response when the first, second, and third speakers are in a second orientation.

15. The apparatus as defined in claim 10 , further comprising a network interface to synchronize the first and second audio output with another audio device.

16. The apparatus as defined in claim 15 , wherein the network interface is to receive at least one of the audio signal or a user input.

17. A method, comprising:

applying a first mid-range filter of a mid-tweeter-mid speaker arrangement to a first audio signal;

applying a second mid-range filter different from the first mid-range filter to a second audio signal to compensate for interference caused by a position of a first mid-range speaker in the mid-tweeter-mid arrangement relative to a second mid-range speaker in the mid-tweeter-mid arrangement, the second mid-range speaker having same audio characteristics as the first mid-range speaker;

outputting a first filtered audio signal from the first mid-range filter via the first mid-range speaker; and

outputting a second filtered audio signal from the second mid-range filter via the second mid-range speaker.

18. The method as defined in claim 17 , further comprising determining a configuration of the mid-tweeter-mid speaker arrangement in a multiple-device arrangement, wherein applying the second mid-range filter is based on the configuration.

19. The method as defined in claim 18 , wherein applying the second mid-range filter comprises providing an output audio signal filtered using the second mid-range filter to an outermost mid-range speaker of the mid-tweeter-mid speaker arrangement in the multiple-device arrangement.

20. A method, comprising:

applying a first mid-range filter of a mid-tweeter-mid speaker arrangement to a first audio signal;

applying a second mid-range filter different from the first mid-range filter to a second audio signal to compensate for interference caused by a position of a first mid-range speaker in the mid-tweeter-mid arrangement relative to a second mid-range speaker in the mid-tweeter-mid arrangement, wherein a second frequency response of the second mid-range filter has a higher cutoff frequency than a first frequency response of the first mid-range filter and wherein the first and second mid-range speakers have same audio characteristics in the mid-tweeter-mid arrangement;

outputting a first filtered audio signal from the first mid-range filter via the first mid-range speaker; and

outputting a second filtered audio signal from the second mid-range filter via the second mid-range speaker.