# REW-generated Biquad EQ vs PEQ for minidsp



## mclab (Feb 28, 2009)

Hi,

I used REW to measure my room and then generate the PEQ filters for minidsp. There are two ways to enter the PEQ settings into minidsp: (a) using the auto-generated biquad filters; or (b) manually enter the {Freq, Boost/Cut, Q} for each PEQ filter into minidsp.

My question is: are the two approaches result in the exact same filters and produce the same effects?

The reason I asked is because I normally setup the minidsp PEQ using the biquad coefficients but sometimes I want to tweak the settings a bit, e.g., changing the boost/cut, but it is not possible with the biquad coefficients unless the PEQ is changed to the non-biquad version.

Thanks.
Jack


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## fusseli (May 1, 2007)

Welcome to HTS!

I would imagine that you should get nearly identical performance if you were able to recreate all of the same filters as individual PEQ bands. I would suspect that the biquad filters themselves are probably a convenient choice having something to do with the algorithm used to calculate the filter parameters. I don't see why there would be a performance difference, but I could be wrong.


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## mclab (Feb 28, 2009)

Thanks. I also posted the same question at the minidsp forum:

http://www.minidsp.com/forum/software-support/9649-rew-generated-biquad-eq#11597

and one member (author of rephase) noted that the two approaches can be quite different. Thus I'd like to confirm with the REW community about this.


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## JohnM (Apr 11, 2006)

Yes, they are identical ways of representing the same filter.


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## mclab (Feb 28, 2009)

Thanks John for the confirmation.

I also verified it by comparing the REW-generated biquad filters and manually entered the EQ settings. The measured differences are very small, most likely due to round-off errors in entering the EQ settings into minidsp.


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## StanDingwave (Feb 25, 2012)

I don't know if this will help you, but I've used both MiniDSP 2x4 'advanced' PEQ and REW's calculators to do extreme EQ with the MiniDSP. By that, I mean boosts or cuts greater than you can enter with the plugin's controls. For example, if you want to notch out resonances, you need very narrow filters. You can hunt for, and model these, using REW. But you have certain limitations using the MiniDSP plugin. You have far fewer limitations if you use the advanced biquads. My before and after REW sweeps seem to prove they work as expected.

My application was a custom Bose 901 equallization. I think MiniDSP put the tutorial on their web site, but here is my own copy of it:

http://bmmoser.myweb.usf.edu/shared/MiniDSP 2x4 as Bose 901 EQ/Custom EQ with the MiniDSP.doc


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