Seeking Idiots Guide to multi-sub 2ch REW/Dirac Live calibration for miniDSP

[mps]

You are absolutely sounding entitled.

Imagine that the time of the actual experts here is worth a very high hourly rate.

You may not be "demanding", you may not "feel" entitled, but the way you approach asking for help will definitely have an impact on the quantity and quality of help you receive.

How To Ask Questions The Smart Way

Edit: Note that the CATB.ORG website is not itself a provider of help.

I thought @Smithg97 sounded perfectly reasonable. At no point did he imply that anyone was obligated to help him. I think there have been bad actors in the forum before, but I am comfortable assuming the best of OP.

 

[thcdru2k]

Haha yes I had this impression from other threads on similar topics

Keep it simple. I would focus first on proper subwoofer integration like Keith_W is describing and save that preset as something like “sub_integrated_noEQ”. Spend some time listening to your speakers without subs, then with the subs properly integrated before introducing any EQ or Dirac. That alone will teach you a lot about what good integration actually sounds like and is probably the majority of what you are trying to achieve.

After that, experiment with REW Auto EQ or Dirac Live if you want, but save those as separate presets and compare them directly against the integrated no-EQ version. Otherwise it becomes difficult to tell whether an improvement is coming from the actual sub integration or from the correction layer on top of it.

 

[Smithg97]

Keep it simple. I would focus first on proper subwoofer integration like Keith_W is describing and save that preset as something like “sub_integrated_noEQ”. Spend some time listening to your speakers without subs, then with the subs properly integrated before introducing any EQ or Dirac. That alone will teach you a lot about what good integration actually sounds like and is probably the majority of what you are trying to achieve.

After that, experiment with REW Auto EQ or Dirac Live if you want, but save those as separate presets and compare them directly against the integrated no-EQ version. Otherwise it becomes difficult to tell whether an improvement is coming from the actual sub integration or from the correction layer on top of it.

Thanks dru I think it all makes sense! My setup is a bit complex but at the front of the room I have a Lyngdorf TDAI-1120 running 2.2 with roomperfect as well as Denon X3700H running 7.2.4 with OCA's A1 acoustica and both sound phenomenal! It's just the desk setup i have had troubles with

 

[Keith_W]

By the way, you mention that MSO does not support your specific model of MiniDSP. I believe that it can be made to work.

But first, you need to understand the difference between PEQ's and biquads. A biquad is a set of coefficients that need to be generated for a specific hardware DSP model and at the appropriate sample rate. The DSP model then uses these biquad coefficients to calculate the PEQ's. Biquads are not portable, in that biquads generated for (say) a MiniDSP can not be used on (say) a Xilinx. However, PEQ's are.

A PEQ can be easily recognized, it will have frequency (f0), Q, and gain. A biquad will have up to 6 coefficients (sometimes more), labelled a0, a1, a2, b0, b1, b2. If you examine the text file, you will quickly understand what you are looking at.

I believe that MSO can be set to output raw PEQ's. I would not discount using MSO just yet, it is a very powerful tool. Since MSO calculates the delays for you, all you need to do is implement the crossover and take the measurements recommended in MSO's manual.

As a side note: all this back-and-forth about the OP's intentions needs to stop. ASR would be a better place if you directed your energy to answering his question.

 

[Smithg97]

By the way, you mention that MSO does not support your specific model of MiniDSP. I believe that it can be made to work.

But first, you need to understand the difference between PEQ's and biquads. A biquad is a set of coefficients that need to be generated for a specific hardware DSP model and at the appropriate sample rate. The DSP model then uses these biquad coefficients to calculate the PEQ's. Biquads are not portable, in that biquads generated for (say) a MiniDSP can not be used on (say) a Xilinx. However, PEQ's are.

A PEQ can be easily recognized, it will have frequency (f0), Q, and gain. A biquad will have up to 6 coefficients (sometimes more), labelled a0, a1, a2, b0, b1, b2. If you examine the text file, you will quickly understand what you are looking at.

I believe that MSO can be set to output raw PEQ's. I would not discount using MSO just yet, it is a very powerful tool. Since MSO calculates the delays for you, all you need to do is implement the crossover and take the measurements recommended in MSO's manual.

As a side note: all this back-and-forth about the OP's intentions needs to stop. ASR would be a better place if you directed your energy to answering his question.

Thanks Keith, I did try MSO before after reviewing some of the guides on YouTube and thought I got the hang of it but I saw a post on here from the SW developer AndyC who attached a link stating that the miniDSP is incompatible when Dirac is being used with the device so are you saying that this hurdle can be circumnavigated? I think perhaps where i went wrong before was in the time and/or phase alignment part of the process as you can appreciate there is quite a steep learning curve with this stuff which was what triggered my request for an idiots guide here.

But yes for the record I'm not entitled, I do not expect people to give me something for nothing but I needed help and I know there are people on this and other forums who like sharing their knowledge to help people and hold the specific knowledge i want to tap into (i.e. Keith_w) and I also reciprocate when I can if it's an area I'm knowledgeable in....this is the benefit of forums like this if you ask me

 

[john61ct]

My understanding is with miniDSP you either run it in Dirac mode, or use its (limited) compatibility with outside tools.

Can't do both at the same time.

 

[thcdru2k]

In general, you do not want two correction systems operating on the same problem domain unless they are intentionally complementary

 

[Smithg97]

I see, I think I'll avoid MSO for the time being then and attempt to follow the steps outlined by Keith to see what results it yields as I do want to get the most out of the hardware I paid good money for but not if it means a 40 hour trial & error exercise where i end up pulling my hair out and make no progress on improving the sound so will aim to not add complexity to an already complex process lol

 

[Keith_W]

Thanks Keith, I did try MSO before after reviewing some of the guides on YouTube and thought I got the hang of it but I saw a post on here from the SW developer AndyC who attached a link stating that the miniDSP is incompatible when Dirac is being used with the device so are you saying that this hurdle can be circumnavigated? I think perhaps where i went wrong before was in the time and/or phase alignment part of the process as you can appreciate there is quite a steep learning curve with this stuff which was what triggered my request for an idiots guide here.

My understanding is that Dirac-enabled MiniDSP's have the FIR filters locked out by Dirac. This was certainly true of the MiniDSP I had on loan for a while (SHD Studio), but I don't know if it's true for other models. The biquads are still available for programming using any software you choose, including MSO.

MiniDSP models which are not Dirac enabled do not have the FIR filters locked out and are thus available for programming. IMO this is a scummy move by MiniDSP and Dirac. You pay more for crippled hardware with locked out FIR filters. It would have cost them exactly $0 to make the FIR filters available to you. The ONLY reason for doing this is to force you to buy a Dirac license if you want to use the FIR filters. Another reason for me to dislike Dirac, as if I don't dislike them enough already.

Since MSO does not use any FIR filters, you should be able to use MSO with your MiniDSP.

You are worried about a 40 hour trial and error process? It took me YEARS to learn what I know about DSP. Enjoy the process, it's fun and educational! MiniDSP's are pretty basic. Yes it's possible to screw it up, but since you have fewer options, you have fewer opportunities to screw it up.

 

[Smithg97]

H

My understanding is that Dirac-enabled MiniDSP's have the FIR filters locked out by Dirac. This was certainly true of the MiniDSP I had on loan for a while (SHD Studio), but I don't know if it's true for other models. The biquads are still available for programming using any software you choose, including MSO.

MiniDSP models which are not Dirac enabled do not have the FIR filters locked out and are thus available for programming. IMO this is a scummy move by MiniDSP and Dirac. You pay more for crippled hardware with locked out FIR filters. It would have cost them exactly $0 to make the FIR filters available to you. Another reason for me to dislike Dirac, as if I don't dislike them enough already.

Since MSO does not use any FIR filters, you should be able to use MSO with your MiniDSP.

You are worried about a 40 hour trial and error process? It took me YEARS to learn what I know about DSP. Enjoy the process, it's fun and educational! MiniDSP's are pretty basic. Yes it's possible to screw it up, but since you have fewer options, you have fewer opportunities to screw it up.

Haha what i mean is *another 40 hours*, I've spent so many hours trying to get this setup dialled in, when I had it at the front of the room I did get 1 really good calibration done (more by luck than design I think) then decided to get the Lyngdorf and move the minidsp to the desk, the Lyngdorf roomperfect proved to be insanely easy to setup and the results blew me away, it's an easy way out if I throw more money at it but before doing that I want to attempt one more time to get the minidsp firing on all cylinders either that or how much £ would you want to do the calibration for me? Lol

I'm being slightly facetious but I will set aside an afternoon this weekend to have another crack at it and report back

 

[Satanica]

As the title suggests I'm really hoping someone can provide a step-by-step idiots guide as to how to, once and for all, properly calibrate my miniDSP Flex Dirac Live version for a 2.2 music setup.

I've tried numerous times and either miss something or do something which later transpires is wrong (e.g. using MSO as I see now that Dirac enable miniDSP Flex is listed as incompatible) or follow a rigid process that I believe is correct and when it comes to the listening test sounds awful so therefore must have done something incorrectly!

I have the following hardware in my setup;
miniDSP Flex unbalanced with Dirac Live
Nord acoustics MP NC252 2ch power amp
Arendal 1723S THX bookshelf speakers (desk setup so quite near field)
SVS PB1000 Pro x2 subwoofers (placed about 9ft behind me close to the backwall with no option to relocate)
UMIK-1
I'd like to understand a full end-to-end process if someone is kind enough to draft one as i've seen high level bits and pieces online, or guides which become dated or don't account for nuance....etc what I'd really appreciate is full end-to-end process;

• Which mic cal file to use (given i have speakers in front, subs behind)
• Do i set XO first or later in the process? Should i high pass speakers or just low pass subs?
• For the routing matrix do i sent L+R channel both L+R subs or keep them separate?....etc
• Do i use REW to gain match & time and phase align subs and speakers, if so how and in what order? What options do i need to activate in REW.....etc - my current calibration sounds awful i think due to time alignment with subs being wrong so always hear a distracting boominess that sounds completely out of sync
• For the acoustic timing reference what is the correct way to use this feature to ensure time alignment is correct
• What stage in the process do i run Dirac Live calibration and how to ensure it improves sound rather than destroying any pre-calibration i've already done on subs....etc?

Sorry if this has been asked or answered, do you want to run your two subs stereo or mono?

 

[andyc56]

Just as a reminder, the incompatibility of this device with MSO is mentioned on the MSO homepage. This incompatibility is mentioned, not because it's theoretically impossible to use it, but that a user who wants to do so and have the final measured results agree with MSO's predictions would need to go through extraordinary effort to get correct results, including acquiring a deep understanding of the technical details of the topic. But the OP, in his own words, is looking for an "Idiot's Guide". Telling the OP that he needs to acquire such a deep understanding is completely at odds with what he's looking for, and does him a disservice.

I have not tried to figure out how to use this device, and would have to rack my brain to do so. Doing this on account of a vendor that's boneheaded enough to put equalization upstream of bass management is not my idea of a productive pursuit, and writing it up would add insult to injury. Then here comes a guy who has admitted in the past that he's never even used MSO saying in effect, "Yeah, go ahead and use it" just leaves me shaking my head.

The only thing I can offer, assuming the OP will by using the subs in mono, is to recommend Jeff Mery's instruction video for using the REW alignment tool to determine relative sub delays.

 

[john61ct]

Well the request for cookbook handholding is pretty much moot

But OP is apparently offering to pay for help (having it "done for them") so perhaps reco's on other people who do that professionally via remote would be appropriate?

I do think otherwise it is perfectly appropriate for us to reinforce "keep climbing that learning curve" in the normal way, by trial and error, reading up on collected resources, posting specific questions, posting REW MDATs to see who's willing and able to help at that time.

Doing that process in public IS contributing, a paper trail other learners (relative noobs) can follow and learn from in future.

Taking MSO-produced filters and trying to (as close as possible) replicate the results in miniDSP would likely be a FANTASTIC process for us to follow if guided by one of the gurus here.

Of course if OP decides to spend lotsa money on a different "more automated" solution, that is their decision to make too.

I personally would hate to see it go toward more proprietary hardware solutions, but that's my own cross / bugbear

 

[john61ct]

Personally I would get (speaker EQ plus) crossovers all set, both time and FR domain without trying to do any DRC at all.

IOW collocate the two subs to emulate a pair of big full range Stereo towers.

THEN try Gsonic reference, other tools (maybe trial Acourate with Keith's help) but working the DRC part in "simple stereo" rather than MSO or rePhase+REW

Slightly shifting placements may help as well

Still use REW if needed for measurements ofc

 

[Keith_W]

Then here comes a guy who has admitted in the past that he's never even used MSO saying in effect, "Yeah, go ahead and use it" just leaves me shaking my head.

I do recall seeing MiniDSP's note on how to use MSO with their device in the past. And I have used MSO, I seem to recall there is an option to save MiniDSP biquads as a .TXT file. On some MiniDSP models, the FIR filters are implemented on the analog inputs, upstream of the matrix, as you said. But I was under the impression that MSO does not use any FIR filters at all, only biquads. At least that's what I see when I examined the output. This is why I thought that MSO could be made to work if Dirac processing was disabled. If I am wrong, then I apologize.

 

[john61ct]

OMG can't believe that you of all people were the referent to a "some guy" comment – the cheek!

Yes MSO does IIR via biquad text format filters, so is PERFECTLY compatible with miniDSP

so long as the user disables DL plugin(s?)

and sample rates are matched.

...

FIR filters?

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Gathering Filter Information

After optimization is run, you can show a filter report. This page describes how to use it.

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MSO- Multi Sub Optimizer Beginners Thread

Found out about this reading a app note on the mini DSP website. I searched here to see if there were any dedicated threads, to no avail. It looks really promising- and might make my purchase of Dirac Live a waste of money (I wonder if I could transfer the user license to someone else if I don't...

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[john61ct]

In general, you do not want two correction systems operating on the same problem domain unless they are intentionally complementary

...
I completely agree, within the context of my hobby horse "Modularised DSP" ™

FXRoute, browser-controlled Linux audio player and DSP control surface for mini PCs

Love this! Probably not for me atm I agree that old PC's are better than Rasp Pi in a lot of cases. But I went with a rasp pi for my specific need - which is to playback to a USB Audio Interface. Pi in a case is smaller than the USB interface so practically invisible Nothing wrong with the...

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[Keith_W]

OMG can't believe that you of all people were the referent to a "some guy" comment – the cheek!

There is no need for that. This is the author of MSO we are talking about, if anybody knows his product it will be him. If there is a disagreement between us, it is more than likely that I am the one who is in the wrong. I don't have a problem admitting that I am wrong, or even being publicly shamed for being wrong. I see it as a learning opportunity. Don't worry, I am very robust Maybe he does have a point that asking someone who wants an "idiots guide" to do so much work is too much. We'll just stick to the facts and wait and see what he says.

 

[ZolaIII]

@Keith_W & @OCA to my understanding MiniDSP's are 1024 taps per bank (lower/uper but still same limited) same can be combined the other way around. 10 PEQ's and 1024 taps per chenel. Use first bank's to do XO, room fundamental and too XO bass correction and shaping filters for ELC. Use secund banks to mix everything else (convolution kernel) including MMO to dead if you wish (more importantly time/impulse alignment and so on) keeping it linear phase. That are limits to Mini's actual DSP's. I don't own one, I do it a my way (JRiver, bunch of VTS even direct show filters for videos). I appreciate the effort to try to write comprehensive setup manuals.

 

[john61ct]

There is no need for that. This is the author of MSO we are talking about

Oh wow egg on my face, it was me I thought "some guy" LOL

apologies to the board, no the whole world