Jerry (Aka AustinJerry) from AVSForum is a long time member of the AVSForum community. He's well known for his writting skills along with providing his support countless times for a wide range of questions. From the 2x4 to the DDRC-88A + BM, Jerry has kept himself busy with a wide range of step by step tutorials. His constant feedback and support means a lot to us. Here are few links worth reading. Make sure to Thank him next time you interact with him on the community! :-) 

miniDSP 2x4



As for a great resource of DDRC-88A end users, make sure to check out the AVSForum thread on the DDRC-88A.

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Here is again to a great tutorial from the AVSForum crew! Keith (Aka kbarnes70) has been a DDRC-88A early adopter who's been providing countless advice on the AVSForum along with other core community members. With his dual DDRC-88A setup, he's now set for 16ch of Dirac Live processing for ATMOS. We're very gratefull he took the time to clarify his setup in this great tutorial!

Atmos set up with DDRC-88A



Writing a clear and concise technical application isn't easy but for long time AVSForum member AustinJerry, it seems second nature! We're certainly very impressed by the amount of details and work that was documented in this very nice application note. It's by far the most complete of our Community Tutorial series and we'd like to extend our big Thanks to Jerry! Make sure you do the same. :-) 


The purpose of this procedure is to outline the approach to use the MiniDSP 2x4 to time-align multiple subwoofers when using an AVR with Audyssey room correction.
The benefits of using the MiniDSP, rather than relying on Audyssey's sub correction alone are:

1.Allows time-alignment of multiple subs for AVR's with Audyssey MultEQ or MultEQ XT, which do not have two sub channels with unique level and delay settings.
2.Allows more control for time-aligning more than two subs on AVR's with Audyssey MultEQ XT32.
3.Allows experimentation with EQ'ing the sub channel prior to running Audyssey, potentially improving the final frequency response.
4.Allows implementation of the MiniDSP DDRC-88A Dirac Live, which (as of this writing) lacks support of multiple sub channels.

Read more here.

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 Jerry strikes back! Once again Veteran AVSForum member "AustinJerry" comes up with a great tutorial. Resulting from a true community effort from the AVSForum community including the expertise of Markus, it's once again a nice effort as they squeeze out every inch of Dirac Live. Advanced users, get ready to master building custom target curves!

A live copy of the tutorial can be downloaded directly from here.

Custom target curve

All Credits goes to the AVSForum DDRC-88A owners who were involved in this nice tutorial.



Credits: Community member "Soldermizer"

In this tutorial I will show you how to use the 2x4 to use custom biquads to enter EQ values that the user interface would not otherwise allow.

Room Equalization Wizard (REW) is a great utility to set up a sound system. Explaining how to use it is beyond the scope of this tutorial.

Quoting from REW's help file: "An advantage of [miniDSP's advanced biquad programming] is the very high filter frequency and Q resolution it allows, permitting exact targeting of modal resonances."

I will use the 2x4 to do one thing that REW is very useful for: to find room modes (or resonances) in the bass region and create very narrow "notch" filters to attenuate them. This is the first example of using a filter that is most likely too narrow for the GUI (of the Plug-In).

A second use is to create the extreme EQ curve that the Bose 901 needs. Of course you could emulate the EQ curve of the standard 901 active EQ. However, that is so "1970s." Why not use modern technology to make a custom EQ curve? If you have a measurement tool like REW, many people choose a "flat" (or "house curve") for their system. In my case, I use what I call "1/3 octave pink noise subjective EQ" -- I listened over a long period of time, adjusting each band of noise until it sounds nearly the same level as the others. In either case, and for any kind of speaker, you are EQ-ing the speakers and the room as a system, so you only need one curve.

I only use the "advanced" cryptic biquad formulae when I have a very narrow and/or deep filter that I cannot input using the Plug-In user interface. Of course, you can just use the GUI to enter values that are within its range.

Tools used

  • MiniDSP 2x4
  • Plug-In: PEQ 2 way advanced (need to use custom biquads)
  • Room Equalization Wizard (REW) from (free, registration required)
  • Testing mic + preamp for the above
  • Biquad calculators (free, see below) -- to calculate the numbers that MiniDSP wants. I used an Excel spreadsheet named "All-digital-coefs v1.2.xls" I do not have a link but you can Google it or look on the web sites minidsp or diyaudio.