# MiniDSP / REW help for dummies ??



## cycleguy (Feb 12, 2013)

Hello... Yes I realize I am an idiot and my lack of understanding will perplex you audio engineer types but I still need some help! I have been looking at integrating a miniDSP / REW system to hopefully balance out my home theatre and maybe I need the idiots guide to miniDSP integration because for some reason I can not wrap my head around how to integrate the mini DSP in my home theatre / audio setup. I can't even figure out the best unit to use. I have read the entire miniDSP manual and then the entire REW manual referred to by the miniDSP, which only made my confusion worse as the REW manual doesn't even mention the DSP anywhere in the manual !!
My main goal is to balance out the frequency response of the main speakers and possibly the center. I have tried using the program built into the yamaha as well as the denon before it but it ends up sounding like someone threw a wet blanket over the sound. Kind of like it is forcing everything down to the least common denominator.

I would greatly appreciate it if you could tell me:
1. The best unit to use for my application
2. what other equipment I will need. mic, plug in, 3rd party like REW ?
3. Where in line to hook it up with the least negative effect effect on resolution/clarity.

Thank you for your input and if you are in the Houston area I will pay you for your time if you can offer some hands on assistance.

Here is a diagram of my equipment layout


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## Wayne A. Pflughaupt (Apr 13, 2006)

Do you have a link for the manual of the AX3020? I can’t turn up anything on it.

When you say your “looking at integrating a miniDSP / REW system,” you have to first understand that REW is a measurement platform. It is not a system component, whereas the miniDSP is.

The miniDSP would connect line-level between your receiver and amplifier. They have a unit with eight inputs and eight outputs; that’s probably the one you would want.

Regards, 
Wayne


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## cycleguy (Feb 12, 2013)

Hi Wayne,
I tried uploading the manual but at 17megs it wouldn't work. If you go to yamaha's website and look under the support tab you can download it there. It is listed as the aventage AX-3020.

I realize the REW measures and the DSP is a component. I saw on the miniDSP site where the 2 can work together to automatically calibrate a system. The parametric EQ on the yamaha leaves a lot to be desired and am looking for a way to tweak my speakers to my room.

thanks
Jerry


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## Wayne A. Pflughaupt (Apr 13, 2006)

Hey Jerry,

Is that the RX-A3020? If so, as I understand it has independent 1/3-octave parametric equalization for every channel? That’s pretty powerful stuff, I can’t imagine how it “leaves a lot to be desired.” I had great success with the same equalization the RX-V2500 in my bedroom system. Only a separate outboard equalizer for the sub was needed. If the RX-Z9 in my main system had that feature, I'd almost be inclined to retire my outboard main-channel equalizers.

If you weren’t happy with the receiver’s built-in calibration, I’d suggest equalizing manually. It’s not that hard, using REW’s RTA feature to tweak filters in real time. That’s how I did mine. As far as I know, the only auto-calibration REW does in conjunction with the miniDSP subwoofers, not full range.

Regards, 
Wayne


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## AudiocRaver (Jun 6, 2012)

Jerry,

Wayne P. Is extremely knowledgeable about these things. I will just throw out a couple other thoughts for your consideration.

If you decide to go with a MiniDSP unit, it would fit easily between the preamp outs of your Yamaha and the inputs to your B&K amplifier. The MiniDSP will interface with REW to accept its filter values. While REW can generate correction filter values for the entire frequency range, it is generally recommended that room treatment be the first and primary approach for mid and high frequency correction, and use REW's correction primarily for taming low-frequency problems that cannot be solved by sub positioning. And for tweaking the high-end if it is still needed after acoustical treatment efforts are exhausted. Of course, that is just a guideline, jumping straight into equalization for the whole spectrum is certainly an option, it is just not a cure-all when there are acoustical problems.

If you do go with MiniDSP, you'll want to choose one of their IIR solution, compatible with REW's filter generation approach. First, though, you should probably do some analysis with REW to determine how much correction you need, and decide if you're going to do any acoustical treatment. The more EQ correction you do, the more capable a MiniDSP plug-in will be required, which will determine what hardware platform is needed. REW will give you a pretty good you how much correction is really called for. That's how I would approach it.

I also notice that you are running the LFE outputs to your mains as well as to your sub. That can sometimes work fine, but having multiple low frequency units working together takes some special care, they can end up fighting each other and giving you unpleasant low-frequency results. The most common advice here would be to try having the one sub do the low-frequency work, and play with the placement of the sub, see if that cleans up your low-end.

I hope that doesn't muddy the waters. Just my two cents worth. Best of luck.:sn:


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## sKiZo (Feb 9, 2013)

Accepting membership in the dummy society? <G>

I've got REW and the MiniDSP (2x4 balanced w/2 way advanced plugin) and am getting ready to give it a go. Also read the books but haven't found anything definite on what exactly I'm testing for.

Should I be doing a mono test with both speakers firing at the mike? Or individual left/right tests, then averaging the results? Multiple sets of tests on each channel, averaging those and hopefully loading each channel into the MiniDSP? Haven't quite figured out how I'd go about that.

Does the MiniDSP even accept dual sets of filters, one for each channel?

Reason I ask is there's major inconsistencies side to side, and no amount of room treatments is gonna help - hence the digital eq attempt. The answer is probably somewhere in the docs but I did notice myself going crosseyed a few times reading thru them ...

EDIT >> Ah. Maybe I answered my own question here. Looks like I'd analyze and create a filter set for each channel individually in REW, then select either INPUT 1 or INPUT 2 in the MiniDSP plugin before transferring the settings to hardware one channel at a time?


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## AudiocRaver (Jun 6, 2012)

sKiZo said:


> Should I be doing a mono test with both speakers firing at the mike?


Never.



> Multiple sets of tests on each channel, averaging those and hopefully loading each channel into the MiniDSP?


Something like that. You will get a lot of different advice here. My approach is fairly simple. For each channel, 1) take one measurement at the center listening position, 2) take two more measurements a foot or so side to side if you are only concerned about the center listening position, or measurements at each of the other listening positions if you're concerned about a bigger listening area. 3) If the later measurements only vary a small amount from the first measurement, go with first measurement. If you do see a lot of variation, then you have to decide: do you sacrifice the prime listening position and make it worse so that the other listening positions are better, or favor the prime listening position and other positions are just out of luck? If you decide to do some kind of averaging, then 4) choose the alternate curve that looks best to you as a "happy medium" target across a broader listening area, but never one that is very much different from the center listening position curve, because that is where you will be sitting most of the time, why make that position worse for the sake of other listening positions that will only sometimes the occupied? It is okay to be a little selfish here, it is your system.



> Looks like I'd analyze and create a filter set for each channel individually in REW, then select either INPUT 1 or INPUT 2 in the MiniDSP plugin before transferring the settings to hardware one channel at a time?


Correct.


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## sKiZo (Feb 9, 2013)

Now THAT's what I'm talkin'bout ... Anyone can manage to work something like that into the manual, I for one would think it'd be a good thing ... unless I just missed it in the docs, then ... never mind ...

As far as mike setup goes ... pivoting a foot or so will be easy and it'll also be easy to return to the original position. 










And bigger listening areas certainly isn't a problem. My system's in a closet ... brings new meaning to the term "near field" ... <G>










Big room behind it which allows the big boxes to breathe, but as you can imagine, I have some "interesting times" when it comes to room treatment and eq. Only real hardscaping is at the upper rear to deaden out the arch header. The speaker/seating relationship actually works quite well with the equipment. I'm a Carver holographic fan, and the sweet spot is a lot smaller than most. The chair is screwed down to the floor, but it can swivel for fine tuning the image. I get that foot or so good, I'm gonna be a happy camper.

PS ... that's my RTA setup outside the room next to the stove. Keeps me out of the "room" when running tests. Unless I'm running for the switch on the amp when it goes into a feedback loop. <G>

And ya ... I installed the MiniDSP plug in, and poked around in there a bit. That's when I got the brainfart on loading individual curves for the channels. Good to see I was on the right track. Surprised REW doesn't allow you to integrate left and right tests into one download though, unless I'm missing something there. 

I did figure out a little problem I had right up front trying to calibrate the soundcard. For anyone having issues with the Behringer UCA202 ... turn the monitor switch off dummy! :bigsmile:

*ONE OTHER QUESTION*

Should I be testing with all post processing disabled? I'd think I'd at least want to keep stuff that affects the sound stage and spatial imaging on when getting eq curves as those would affect the relationship to the mike? Or is that all psycho-acoustic and something the mike will ignore? I know the room gets a whole lot bigger with the holographic engaged.


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## Wayne A. Pflughaupt (Apr 13, 2006)

FYI skizo – you don’t need the wind screen for taking measurements. :T

Regards, 
Wayne


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## AudiocRaver (Jun 6, 2012)

Near Field, indeed!

A couple more thoughts.

Make sure the measurement mic is right where the head position ends up, with near-field monitoring little differences in position can make a big difference in measurement results. In your photo it looks like the mic could be a little forward of the head position. When you sit down the chair probably leans some, too.

More discussion on listening position mic placement in this older thread might be of interest.

Are your monitors on the floor? If so, you will get better results by elevating them so the midrange driver is on axis with your ears. Conventional wisdom says to put the tweeter on axis with the ear, but I have found over and over that the best imaging occurs with the midrange driver at ear level, haven't figured out why yet. A good approach is: position for imaging, then correct eq as needed. You will probably have 20 people tell you ways that doesn't make sense, I'm just saying what I have experienced.

Always run REW analysis with effects turned off. Acoustics get weird enough on their own without adding electronic effects. It sounds like fun to add them in to see their affect on your final results when completed, but definitely do analysis & correction without.

And continue to have fun with it! Hope some of this is helpful, feel free to ignore anything that does not apply or sounds too outlandish. Good luck!


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## sKiZo (Feb 9, 2013)

Near field indeed ... did I mention it's a quad system also?










I do plan to turn off the rear channels also when measuring the room. Somewhere down the road, I expect I'll end up getting another MiniDSP to handle those, but I only use them for ambience anyway ... you can tell by the way the shade's pointing in the pic. <G>

*******


> feel free to ignore anything that does not apply or sounds too outlandish.


I'm too new here to ignore anything ...

And your point on speaker height is well taken. I do notice I have a tendency to have to slouch into the window, so I have been planning to elevate the Big Macs some. I was figuring to split the difference between center tweet and high mid.










Not a lot of difference, but better alignment to the upper mids might not be a bad thing anyway as that's where your vocals succeed or fail. The XR16s have a history of losing a db or two on those particular drivers over time anyway, so that's where I expect to see the best bang after eq. Around five inches higher should do the job, so a simple stand out of 2x6 pine should do if I inset the top just a bit. The speakers should drop right in, and that should keep them from wandering about, as horizontal placement is also extremely critical with holography. Add a bottom plate, screw the stands to the floor, and add some sand for damping. Little trick I learned. The boxes don't have to be pretty - once I get them built, just spray them with a couple coats of black gravel guard paint available from the local auto parts. Gives a nice pebble grain matte finish. 

And ya ... the mike setup is just a trial thing to see if it'd work. The stand is for a guitar mike and real easy to adjust. Bonus, I can just pivot it up out of the way when checking the results. I will take the windscreen off prior to getting like ... to it. Still scratching my head a bit about the horizontal vs vertical alignment on the mike itself ... it does make more sense leaving it horizontal, but ... the debate rages on. Maybe I'll compromise and just point the head straight at the upper mids also. Wouldn't hertz to run a couple test curves with different alignments to see if it makes any difference.


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## AudiocRaver (Jun 6, 2012)

sKiZo said:


> ... did I mention it's a quad system also?


Alright! Pure fun!



> ... you can tell by the way the shade's pointing in the pic.


Hard on lamps, isn't it?:hsd:



> ...horizontal placement is also extremely critical with holography...


Sounds like you You are kind of a nut for super laser holographic imaging like I am. Not as big a priority in home theater, but with two channel/music it becomes a holy Grail after you have experienced it.



> Still scratching my head a bit about the horizontal vs vertical alignment on the mike itself ... it does make more sense leaving it horizontal, but ... the debate rages on


Some people make a big deal about that. An omni mic becomes slightly directional at high frequencies, but it is hard to see mic angle making much of a difference with room measurements, more than a fraction of a dB in final results.

Love your posts. Carry on.


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