50

50

Customer Support

50

50

Customer Support

50

50

50

50

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!

50

50

Customer Support

50

50

Customer Support

50

50

50

50

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 hometheatershack.com (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.

Read more ...

50

50

Customer Support

50

50

Customer Support

50

50

50

50

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. :-) 

Overview

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.