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Here’s the how to Multichannel tune with an 8x12 or 88bm 1 month 1 week ago #57412

  • denver8me4dinner
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Hey guys I was tuning a car and tried this approach with the new 3.1.1 and an 8x12 for a multi-way tune in Dirac.... this is an exciting time for a lot of us car guys, I figured I would spread it to the home people and minidsp forum. as far as a multi-way and tuning in Dirac this method is only good for 1 seat....  what we’re going to do is get good crossover behavior for one seat. And super fine tune that multi-way.... having the crossovers work properly is more important then flattering the sum of all phase in a 2ch Dirac tune... the end result gives better results.  If you can get your crossovers to behave properly without doing this method, then knock yourself out. Most ppl I know can’t achieve crossover that behave as close to textbook and all pass as possible. With Dirac , your crossovers will sound better then ever before. At one position.  Here we go 
 1. Setup you sub in bass management. setup your matrix and mixer for 7ch Dirac for a 4 way.  set all output CROSSOVERS AND EQs to DISABLE  them. And I mean all of them.
  2. go to “Dirac channels” in the 8x12 app and setup for a multi-way. Tweeters to tweeters, mids to mids , woofer to woofers and sub to sub channels.
 3. Disable ALL crossovers in the dsp... bypassing all crossovers so every speaker gets a full range signal.  the tweeter you might want to install a 400v polypropylene 50mfd cap on the tweeter to protect it and leave it on permanently, even after your measurements as it will become part of the measurements.  protection to tweeter is on you.... I’ll tell you how to get it to have a good crossover, it’s up to u to figure out how to properly protect it. Maybe someone can chime in  if you use an active filter on the tweeter before this process, let’s say two octaves down from desired crossover as a tweeter protection. The phase change will be added after the correction when you change the crossover. So maybe for the tweeter just use the desired crossover and use peq after to get it to behave properly.  ​​
​​​​4. Start Dirac 3.1.1  Run your set up and run all your master outputs at each channel at maximum. If you have a pair of speakers that are substantially quieter than other ones you might want to go to the output and lower it to match as much as possible.  You’ll want to exit Dirac and do this from the minidsp app, that will allow your configurations to be reloadable without a bunch of weird sounding affects when you disengage Dirac or change configurations as the levels won’t be tied to the Dirac filter..... although Dirac will still adjust levels on its own. I’m speaking of how the configurations behave with the app. It just work better like this, to have all the masters in the Dirac app maxed out.  
  1. In the Dirac app, with all speaker masters at max , set the main master to the proper range for measurements and the mic gain properly. Get all speakers to be between -7db and -12db with the noise generator. 
  2. Take measurements, 
  3. In filters creation tab after measurements are done , You’ll need to ungroup and regroup all of your outputs into pairs for your multi-way.  Make your sub have its own target, and group your midbass together then your midrange together and your tweets together. So you have 4 groups, each group containing 2 stereo channels per multi-way outputs. 
  4. Draw your targets to be perfectly flat. DRAW them to extend ALL OF THE RESPONSE. Knee to knee! Curtain off the knees... your way out of band of your desired crossovers, so don’t worry. Get the target flat through all of the usable response on the screen.  You will not achieve good crossover summation with a tilt it won’t work we will add that a different way later on. For the crossovers to behave textbook they must be on a flat target curve. (Just trust me) I would set all targets to be like -5db down. Wherever you decide to put your targets make them all the same exact “dB” in the Dirac scale. It’s normalized view is showing what you see. Just make sure that all outputs are the same dB in Dirac. -5db down sounds good. Do this for all speakers.
  5. Send filters to your configuration 
  6. Save and turn back up master output to 0db then exit Dirac app 
  7. Go to minidsp app, make sure not to play any music yet because you don’t have any filters. Now go in and turn on all your desired Crossovers in your outputs. And then take a listen and you will be astonished how well your crossovers are behaving. Make the adjustments needed. Reverse polarity the low pass on any 2nd orders, etc etc . 
  8. Using shelving filters now you can build the tilt that you want. You won’t need very much tilt because you will notice with the crossovers summing properly, you will be noticing much much less crossover cancellations. So a flat response will sound more like a tilted response it will sound more fuller and more accurate and many times most people prefer just a listen to it flat and not add tilt at this point
  9. If you do decide to do the tilt use your PEQ outputs and make shelving filters but that seems shelving filter Has be applied to every single output so that The phase changes from the shelving filter are inherent on every channel. Cannot hear inherit phase changes. So make sure all outputs get the same shelving, same frequencies, same Qs. THAT is important. 
  10. If you have to use a PEQ or two to make the tweeter a little better, apply those PEQs to all outputs as well. 
  11. Your bass management will also allow you to use a different shelving on sub then other drivers. Just make sure your shelf doesn’t affect your crossovers dB down point. 
  12. Enjoy your system and be astounded how much better it sounds now. 
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Last edit: by denver8me4dinner.

Here’s the how to Multichannel tune with an 8x12 or 88bm 1 month 1 week ago #57453

  • rccotroneo
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I had recently thought about trying this method but hadn't set aside time to do so.  Then I saw Andy (the guy denver ate for dinner) post about it on another forum and it gave me the nudge to get'r done.

I've performed 3 tunes using a variation of this method and have had very good results.  The main advantage over other methods is repeatable excellent cohesion resulting in textbook summing in the xover regions particularly important in the transition area between the sub & both midbass.
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