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More => Old Versions => JRiver Media Center 18 for Windows => Topic started by: Jamesey on June 27, 2013, 09:49:24 am

Title: Is the parametric equalizer minimum phase?
Post by: Jamesey on June 27, 2013, 09:49:24 am
From a search, I see that it's IIR, but I don't see a definitive response on whether it's minimum phase. Can we get a confirmation?

(Minimum phase filters are needed to correct typical room and driver distortions, which are minimum phase.)
Title: Re: Is the parametric equalizer minimum phase?
Post by: mwillems on June 27, 2013, 09:59:46 am
From a search, I see that it's IIR, but I don't see a definitive response on whether it's minimum phase. Can we get a confirmation?

(Minimum phase filters are needed to correct typical room and driver distortions, which are minimum phase.)

My understanding is that they are all minimum phase (IIR filters can't be linear phase).  I can confirm from personal measurements that the crossovers, shelving filters, and frequency EQ mimic exactly the expected behavior of the equivalent analog circuits (which are minimum phase), in both frequency and phase response.  I can't speak to any of the other filters, but, as I said, I believe them to be minimum phase.
Title: Re: Is the parametric equalizer minimum phase?
Post by: Jamesey on August 05, 2013, 08:37:43 pm
FIR filters need not be minimum phase, according to http://en.wikipedia.org/wiki/Finite_impulse_response (http://en.wikipedia.org/wiki/Finite_impulse_response).

There is a surprising lack of detail on JRiver's parametric eq, given it's such an important feature of the system.
Title: Re: Is the parametric equalizer minimum phase?
Post by: mwillems on August 06, 2013, 10:35:30 am
FIR filters need not be minimum phase, according to http://en.wikipedia.org/wiki/Finite_impulse_response (http://en.wikipedia.org/wiki/Finite_impulse_response).

There is a surprising lack of detail on JRiver's parametric eq, given it's such an important feature of the system.

You're right that FIR filters don't need to be minimum phase, but IIR filters are AFAIK necessarily minimum phase (except when deployed in certain dual pass arrangements).  I believe the PEQ filters are all IIR filters.  FIR filtering requires introducing some latency into the system, and the only part of the DSP studio that supports FIR filtering (to my knowledge) is the convolution module.