Phase graph
- Thread starter giocapy
- Start date
WiiM EQ uses IIR filters, so the phase response is 100% determined by the amplitude response. There's also no way to change this dependency. What would you do with the additional information (and the added visual clutter)?
Admittedly, the combined phase response of multiple filters is certainly not all that easy to imagine. But again, I don't see what to make out of this extra information.
Admittedly, the combined phase response of multiple filters is certainly not all that easy to imagine. But again, I don't see what to make out of this extra information.
And it would not matter very much given what the loudspeakers add to the total system phase behaviour.
(I don't think adding a phase correcting FIR filter to each EQ setting should be of high priority for WiiM.)
(I don't think adding a phase correcting FIR filter to each EQ setting should be of high priority for WiiM.)
Each filter introduces additional distortion to the signal phase. For PEQ this information can be useful in choosing the number, type, and parameters of the filters. A few well calibrated filters may produce a less precise freq. response, but can reduce the phase distortion. In room calibration, you will have infomation about the overall phase distortion introduced in the pursuit of a flattened response
IIR minimum-phase filters are just the right way to counteract the defects (amplitude and phase) in other minimum-phase systems.
Single speaker drivers (within their limits of power linearity) are pretty much minimum-phase systems. If you correct the amplitude response of a full range driver to be flat then the combination of IIR filters achieving this goal automatically corrects its phase response, as amplitude and phase are exactly related.
Similar things can be said about correcting room modes below the Schrödinger frequency, albeit with some additional boundary conditions. Dips caused by room modes cannot be corrected for. Precise correction is only possible for a distinct position.
Correcting for speaker boundary interference is less strict forward due to the sheer number of reflecting surfaces and objects and their different and frequency depending absorption properties. Also multi-way loudspeakers are typically no longer minimum-phase systems. In this case IIR minimum-phase filters can introduce unwanted phase shifts, indeed. But I don't see how just looking at the filter chain's phase response is of any help here unless you know the amount of phase shift that does need correction. You will have to use external measuring tools for this job anyway. And if you already have them you can also assess the correction filters phase response of have an external tool calculate the best filter setup anyway.
Single speaker drivers (within their limits of power linearity) are pretty much minimum-phase systems. If you correct the amplitude response of a full range driver to be flat then the combination of IIR filters achieving this goal automatically corrects its phase response, as amplitude and phase are exactly related.
Similar things can be said about correcting room modes below the Schrödinger frequency, albeit with some additional boundary conditions. Dips caused by room modes cannot be corrected for. Precise correction is only possible for a distinct position.
Correcting for speaker boundary interference is less strict forward due to the sheer number of reflecting surfaces and objects and their different and frequency depending absorption properties. Also multi-way loudspeakers are typically no longer minimum-phase systems. In this case IIR minimum-phase filters can introduce unwanted phase shifts, indeed. But I don't see how just looking at the filter chain's phase response is of any help here unless you know the amount of phase shift that does need correction. You will have to use external measuring tools for this job anyway. And if you already have them you can also assess the correction filters phase response of have an external tool calculate the best filter setup anyway.
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