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Manual room correction for stereo - best practice ?

ZolaIII

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I don't know even how to do proper calibration with Emotiva XMC-2 in equations as it won't be good one or other way (for stereo or multichannel) and you can forget about equal loudness normalisation. Only thing that can in both cases is Denon AVR's with newer Audyssey with loudness function but even they have their flaws.
Sorry I can't help you with something I don't fully understand. Give up on advance multichannel formats or multichannel setup long ago. It whose to much of the fuss for me making properly bullshit's work properly. For more basic formats JRiver and other players do a quiet good decoding and downmix and retain abilities to insert it's DSP chain which is more than enough for me.
I can walk you up for stereo and that's it from me. JRiver has pressets so you can use it like that for stereo and what ever you cook for multichannel.
 
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Baku

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XMC-2 offers different setup slots for the inputs and for the speakers as well. I will run the 7.2.4 HC correction with Dirac Live. It does a good enough job for me for this tasks.
As mentioned I may run the Dirac Live correction for the 2.2 setup as well, but this time I want to try to deal with it manually for the stereo.
The piece of the puzzle that I can't wrap my head around is the subs with mains manual time alignment o_O
What are the preferred tool(s?), order, goal, verification... As far as my knowledge goes it should be approximately:
* Measure 1, 2, 3...
* Calculate 1, 2, 3...
* Apply x' delay
* Remeasure, recalculate, apply y' delay
...
My toolbox is full, but I feel empty handed...
 
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OCA

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Hi Everyone !

I need an advice for the my stereo setup.
I am using a 7.2.4 system that is used for HC and music in a dedicated room. Rough dimentions : 520 cm x 320 cm. Ceiling 260 cm.

The stereo path of my system :
DAC: Denafrips ARES 12TH
Pre/Pro: Emotiva XMC-2
Power: Emotiva XPA-2
Speakers : KEF R3
Subwoofers : 2 x SVS SB-2000 Pro combined with MiniDSP 2x4HD
HTPC with local lossless collection streamed to the DAC exclusively through JRiver with USB connection.

In the past I was using the automatic room correction for both the music and the HC with some tweaks here and there. Audyssey (Denon), ARC (Anthem) and Dirac since Emotiva XMC-1.

Recently I have added the second sub with minidsp and some pressure acoustic treatment.
I understand that nowadays with the available tools (hardware and knowledge) one may achieve pretty good results manually measuring and building the RC filters.
Following the outstanding guides of Serkan ( OCA ) I would like to try to make a best possible digital filters correction manually instead of the Dirac for the music listening.
I have some knowledge and experience with REW over the years and the calibrated Umik-1 mic I have purchased in the past from the Cross Spectrum.
The MLP for the music is a static single position ( focused ).
I can of course make my measurements, time align and create the IIR filers with REW and upload it to the XMC-2. This part is what I am familiar with. And maybe I will achive even better customized resule in FEQ that Dirac, I am convinced that Dirac will do a better job treating the phase.
The OCA guides include several ways to create both the IIR and the FIR filters.
The FIR filters are a learning curve for me. I am trying to get my head over the Virtual Bass Array, Phase inversion, Convolution filters among other interesting phase related tools.

Since the guides are not structured between each other, please advice what would be the best practice for me to go with in order to combine the FIR with IIR filters ?

1. Should I measure and EQ with IIR filters first applying in XMC-2 ( full range - subs + L / subs + R ) and afterwards measure & create the convolution filter for the JRiver ? - probably not the optimal order.

2. Should I first create the convolution filter for full range - subs + L / subs + R, apply it in JRiver and then run the measurements with the pink noise/sweeps files generated by REW through the JRiver for the IIR filters EQ in order to apply them into the XMC-2 ? - probably better result.

3. Or should I split the FIR and IIR filters between the subs and the speakers ?

In other words - first create the FIR filters for each of the subwoofers and apply in the minidsp ? Then create the convolution filter for the speakers response only (no subs) for JRiver ? Then IIR EQ for the subs only to apply in minidsp and different IIR EQ for the L and R speakers only, applied in the XMC-2 DSP ? With both EQed responses crossed properly according to the Harman curve ?

As you may understand I am a bit lost. As a matter of fact I love what Dirac does to the room correction, but I do not like the black box implementation with no details of the changes made besides the impulse delay. Dirac treats the phase pretty nice though. Yet I want to try the manual path for thee stereo I never did before for the enthusiasm or maybe for even a better result than Dirac...

What do you think ?
As @RayDunzl mentioned above you're limited to 1024 taps/channel and a total of 4096 taps for all channels with a MiniDSP 2x4 HD which could be enough for HF phase correction with some windowing tricks but will not suffice for the LF. However, since you're using Jriver on a PC as your source, you don't need anything else for digital correction. You can comfortably create unlimited tap FIR filters and adapt them in JRiver's DSP engine.

You're right about the structure of the tutorials but the channel grew erratically over a couple of months with both REW and my methods continiously improving.

Basically, get your subwoofer integration with the stereo speaker pair right with proper time alignment and crossover selection and then you can treat the combined system as one while creating your correction filters. The simplest efficient method is explained in this one. It is also supplemented with a pdf guide which covers all basics:


Later on you can improve your sound further by adding virtual bass array filter, speaker crossover phase correction and excess phase inversion in decreasing order of acoustic effect. Usually the later the video, the better the method but all methods will result in audible improvements.
 
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