# More filters for MiniDSP? (Save predicted as measurement?)



## Nemesis.ie (Feb 10, 2010)

Hi John,

I was thinking it would be useful if a predicted trace could be saved as if it were a measurement, from the EQ screen.

The idea would be that for example with a MiniDSP where you have "banks" of EQ (6 filters each) you could set the match range for e.g. 15 to 50Hz, create a predicted graph, output the filters, save it, then run another match range from e.g. 50 to 100 and then output that. You now would have up to 12 filters and not have them overlapping negatively. With some loop-back, one MiniDSP could have up to 4 sets of 6 filters.

Another idea might be to have an option to tell REW "I have 12 (or 18 or 24) filters available" and have it create 2, 3 or 4 MiniDSP files that you can load into the different sections and have them work together. 

I believe the MiniDSP folks are thinking about a plug-in that combines the filters available to give e.g. a mono 12 filter or whatever, so it might also be worth having a chat with them as I think this could be really nice.

Thoughts?

Thanks!


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## JohnM (Apr 11, 2006)

Nemesis.ie said:


> I was thinking it would be useful if a predicted trace could be saved as if it were a measurement, from the EQ screen.


Agreed, it is already on the list.



> I believe the MiniDSP folks are thinking about a plug-in that combines the filters available to give e.g. a mono 12 filter or whatever, so it might also be worth having a chat with them as I think this could be really nice.


The MiniDSP folks and I have been conversing for a while, there is plenty to come on the MiniDSP front.


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## Nemesis.ie (Feb 10, 2010)

Excellent stuff!


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## HionHiFi (Feb 18, 2007)

I'm contemplating a REW miniDSP setup to equalize the entire frequency range, think Audyssey or YPAO or MACCAC from Pioneer. Can REW and miniDSP provide similar results?


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## Nemesis.ie (Feb 10, 2010)

HionHiFi said:


> I'm contemplating a REW miniDSP setup to equalize the entire frequency range, think Audyssey or YPAO or MACCAC from Pioneer. Can REW and miniDSP provide similar results?


I don't think you will get any time-domain processing like Audyssey XT32 does, maybe something like that can be added in conjunction with REW, that would be really nice, but you will get a PEQ result.

Also, the MiniDSP runs at 48KHz sampling, so for higher frequencies, if you are playing e.g. 96KHz or higher sources you would be reducing the sampling frequency (not a problem at sub woofer frequencies).

Additionally, either more MiniDSPs or the update to do more bands may be needed as 6 is probably not enough.

There is a 30 band or so GEQ plugin too which might be of use.


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## HionHiFi (Feb 18, 2007)

Nemesis.ie said:


> I don't think you will get any time-domain processing like Audyssey XT32 does, maybe something like that can be added in conjunction with REW, that would be really nice, but you will get a PEQ result.


Ok, no time domain processing. I can live without this for now. I've revised my goals downward. Instead of doing the whole frequency range, I decided to get focus on the subwoofer. After I dial this in I'll move to the rest of the system. 

Focusing on the subwoofer serves two purposes: 
Allows me to dial in the 3 subwoofers in my system.
Gives me valuable experience working with REW v5 & accompanying equipment.



Nemesis.ie said:


> Also, the MiniDSP runs at 48KHz sampling, so for higher frequencies, if you are playing e.g. 96KHz or higher sources you would be reducing the sampling frequency (not a problem at sub woofer frequencies).


None of my sources are above 48KHz. I don't have any high rez files on my computer played through my PS3 or Directv. Those are the 2 sources I'll be using. 



Nemesis.ie said:


> Additionally, either more MiniDSPs or the update to do more bands may be needed as 6 is probably not enough.


Now that I have revised my goals, I believe 6 filters will be enough. 

The system I have mapped out thus far is: 
MiniDSP​Behringer UCA202​RS Analog SPL​REW v5​Necessary Cables​


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## JohnM (Apr 11, 2006)

MiniDSP gives you more than 6 filters, but they are set up as blocks of 6. There are 6 on the input side, 6 on each output and another 8 that are usually used for crossovers.


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## HionHiFi (Feb 18, 2007)

JohnM said:


> MiniDSP gives you more than 6 filters, but they are set up as blocks of 6. There are 6 on the input side, 6 on each output and another 8 that are usually used for crossovers.


Thanks for the clarification John. For what I'm doing I'm sure the 6 will be fine. However, I do have 3 subwoofers in my system. I have a pair of Definitive Technology powered towers BP7006's plus a SuperCube II. The BP7006's are wired using the LFE line level out of the receiver along w/the SuperCube II. I have to figure out a way to equalize all these monsters.


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## Nemesis.ie (Feb 10, 2010)

HionHiFi said:


> Thanks for the clarification John. For what I'm doing I'm sure the 6 will be fine. However, I do have 3 subwoofers in my system. I have a pair of Definitive Technology powered towers BP7006's plus a SuperCube II. The BP7006's are wired using the LFE line level out of the receiver along w/the SuperCube II. I have to figure out a way to equalize all these monsters.


For subs, the MiniDSP with current advanced plugins is very good. Generally EQing all subs (on the LFE output) together is the simplest and seems to be best. If you EQ each on its own you still need to EQ them as a whole as they will interact.


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## TAMUmpower (Dec 27, 2010)

I use 2 MiniDSPs in my car. 1 for the active front stage and the other for the sub. It's not so bad the way the banks of 6peq filters are setup. I can measure each speaker and apply 6 Banda of correction to each driver. Then I am left with 6 bands for each side of the car so if you did need to dial down some smaller peaks you have that ability. I am using the 2 way advanced for the record. 

It would be cool for REW to recognize the ability for it to use some of the extra filters on the inputs though. Can't wait to see whats coming in the future.


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## sKiZo (Feb 9, 2013)

JohnM said:


> MiniDSP gives you more than 6 filters, but they are set up as blocks of 6. There are 6 on the input side, 6 on each output and another 8 that are usually used for crossovers.


Huh?

So, you're saying I could import more than two REW measurements (left and right) into MiniDSP? If I'm following you right, I could create two filter sets and load one into the "Parametric EQ" section and another into the "PEQ Output" section and double the number of filters per channel? Maybe a third set to "Imported Frequency Response" on the System Settings panel? 

Sort of like run measurement sets in REW for the lows, mids, and upper mids, then import all three sets of filters to the MiniDSP ... that'd be slick!

I don't see any way to load an REW export, or even raw filter data, into the crossover section. Only thing I see there is bandpass filters. I've been ignoring that and leaving the defaults as I'm only using the MiniDSP as an eq ... I have a "complex" room and it'd be nice to be able to access those filter blocks also.

Last measurements, I set the range to 20hz to 8kHz and REW seemed to be ignoring anything higher than around 200hz ... yet when I target 1kHz to 3kHz, it builds six filters ... apparently you have to work with narrow spectrums to make it do anything?

PS ... I'm currently using REW V5 and the 2 way crossover advanced plugin ...


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## Nemesis.ie (Feb 10, 2010)

sKiZo said:


> Huh?
> 
> So, you're saying I could import more than two REW measurements (left and right) into MiniDSP? If I'm following you right, I could create two filter sets and load one into the "Parametric EQ" section and another into the "PEQ Output" section and double the number of filters per channel? Maybe a third set to "Imported Frequency Response" on the System Settings panel?
> 
> ...


Yes, you can do exactly that, I've been doing it with mine since I got them a couple of years ago.

You can use the crossover to shape (to some extent) the low-end roll off - so I kind of think of it as "one" filter.

If you need more than 12 you may have other problems.  A technique I use is splitting the response curve, e.g. applying the first set of filters to e.g. half the area, run a sweep with those in place and then apply the next 6 to the other half. Depending on your response, that or an overlay may be better. Another method is to apply the first set to only the most troublesome area and the second as a final tweak to the overall response.

You can also cascade a 2nd (or more) unit but that may introduce issues, especially if you are not just doing subwoofer bass which is all I use them for.


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## sKiZo (Feb 9, 2013)

What I wanted to hear! :clap:

The curves did look a bit busy on my last attempt, but I did no smoothing. I was planning to do two ranges - attack the low-mid bass using the default REW range, but I also want to do something in the low mids or vocals. 

Just to make sure I'm following you here ... run sweeps (e.g. low range), apply filters to the PEQ section in the plugin, download those to the MiniDSP, plug that into the audio chain ... set a new target range, run a new set of measurements. Apply the second set of filters to the PEQ output section, download both sets of filters to the MiniDSP, and run another set of REW measurements to verify the results.

Also, I figure if anything catches my eye after that AND if I have any leftover slots for filters, I can run yet another measurement targeting that area specifically and manually enter that in the plugin. Can't see wasting a slot, eh. That's AFTER I manually add a conservative low pass filter to each channel to compensate for a somewhat shrill top end - hard room, lots of reflective surfaces, and no tone controls ...

If I decide not to do a low pass in the the crossover section of the plugin, anything I need to do there other than leave it at the default settings?


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## Nemesis.ie (Feb 10, 2010)

sKiZo said:


> What I wanted to hear! :clap:
> 
> Just to make sure I'm following you here ...


Yes, I think you have it.


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## sKiZo (Feb 9, 2013)

And just to clarify, as in crystal, approaching pure and pristine transparency ...

Still not sure about the "Imported Frequency Response" on the Systems Settings tab in the plugin. That does allow you to load an REW export file ... but no idea what it does with it. Ever play with that? 

Having a spot of trouble trying to wrap my brain around the screen info for that:

"The graph will be shown on corresponding graphs"

Er. Uh. ?

Didn't even know the plugin did graphs. If it does, they're VERY well hidden! <G>

Anyway ... I'd think that would be a "secret spot" to load yet a third set of filters, but without the bling of listing them separately. Seems as if there should be at least a temp file somewhere that I could poke about in for hints and clues. Sort of a "Where's Waldo?" thing.

PS ... just did a goooooogle on "where's waldo" and it points to a cemetery in Ohio. Well, that's just ... disturbing. Waldo's dead? Say it ain't so!! 

EDIT > > Brainfart ... have to check and see if REW will allow me to IMPORT settings from the MiniDSP plugin. Maybe that's the graphs they speak of?
ANSWER > > No. Did some digging and the only filter file I can find written by MiniDSP is in XML format, which isn't on the REW import list.


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## Nemesis.ie (Feb 10, 2010)

When you upload the filter output from REW into the MiniDSP it shows you a graph of the "correction" it will use in each of the stages. That might be what they are referring to.

I've only imported the REW created filters, never messed with manually making them.


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## sKiZo (Feb 9, 2013)

OK then ... this is getting a bit off topic, but ... hey, that's what we do. <G>

Went thru all the calibrations again just to be sure. Soundcard turned out the same, using the same mike file, and reset the SPL to a 75db range as suggested. Did a final tweak on the system volume to get the recommended ranges in dynamic and headroom levels, and here's the results. Just as single test pass, no averaging or smoothing applied.










My question is ... normal to have the actual measurement so far away from the base level - in this case 75db? I get what looks like good results by clicking "Set Target Level" prior to running the EQ filter wizard ... maybe not an issue, as I have to think this sort of thing is why that button is there in the first place? I do notice that now the filters are centered better than they were before, and expect that should help alleviate the lower system volume issues I was having.










That's targeting 20-200hz ... I also plan to get another set of filters at around 250-1500hz as that looks like I'll get the most bang for the buck. 

Thoughts?

PS ... one nice thing about lowering the SPL calibration from my original 90db ... don't have to wear the ear protectors when testing anymore, and I didna blow even one tweeter fuse this time! :T

** If I'm reading it right, those XR16's are doing McIntosh proud 30 years later. Looks like good usable SPLs down to around 14db. Not bad!


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## Nemesis.ie (Feb 10, 2010)

I would think you should start my having your average measured SPL within 5db or so of the target. It looks like either you are playing the tone too loud or the SPL level is not calibrated? Personally I think calibrating at either reference or near where you listen when you play loud(ish) is useful. I usually play the sweeps at about 82 db and try to cut the peaks.

I would also suggest you set your graph to start at e.g. 9db so you don't have all the empty space on the left. 

If you are planning to target 20 to 200Hz fro example, set the graph to just a bit wider than that range, you'll get a better idea of what is going on.


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## sKiZo (Feb 9, 2013)

Yup on the targeting. Right now just trying to make sure it's all set up properly.

Come to find out, the internal SPL meter in REW wasn't calibrated to match my BSR analog meter. Took care of that, and all is well. 










I know I did that ... I've had a few settings disappear that I just KNOW I've done. 

I'll just blame it on the dog ... bad dog! :unbelievable:

What I'll do next is run some real measurements with four sweeps and load those into the MiniDSP and see if that takes care of my volume issues. If not, I'll try readjusting the input levels to around 82db and see wot hoppens. I don't suppose there's some master boost/cut control on the MiniDSP that would make that easy other than the internal switches (I've verified those are both set to 0.9db). I've also seen mention of manually "smoothing" the filters by limiting the excursions a bit if they're too radical. Already did some of that in software by changing the defaults in the FILTER TASK settings:

- Individual Max Boost - 7db
- Overall Max Boost - 7db
- Flatness Target - 3db

What I SHOULD do next is some more room-scaping. Looks like I got a whole lotta flutter at the top. Reflections, right?

PS ... thanx for all the help.


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## Nemesis.ie (Feb 10, 2010)

You're welcome.

And yes, there is a level control in the MiniDSP units.


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## sKiZo (Feb 9, 2013)

Only level controls I see are all set to -0- (unity) in the plugin. I see where the 2x4 mini has provisions to add a volume pot, but pot I ain't got ...

It was all eq issues anyway. Reset the system to test at 82db per your suggestion, and ran TWO sets of measurements per channel. First set targeted 20-200hz, and the second 250-2500hz. Built two sets of filters from those, and loaded them into the EQ Advanced plugin. Not to get too much into the fiddlybits, here's the results with the raw curve at the top of each pic ...

LEFT









RIGHT









Now that's more like it. Sounds good with very little variance in overall volume in or out, and the settings are close enough to what I had in my Technics SH9010 parametric that it's instant smiles. Too radical a difference, and it's always a good idea to let your brain get used to it before giving it a thumbs up or down. You can also see how the room curve is affecting the mids, giving a close approximation of the infamous "smiley face" that's ever so popular. Only real issue I see is the radical dip at 300hz on the right side could use a tweak to bring it up a few db, but ... too much of a change can sound worse than just leaving it be. That looks like a good candidate for room treatment.

Here's a pic that shows why I was looking for a way to add more filters ...










I just stitched the two pics together from the two filter sets. Yet again, a macro view without the details, but enough to show the need. The wizard left a couple slots open, so that leaves me room to manually enter a shelf or band pass if I've a mind to. So far - maybe won't need it. The filters in the low mids seem to have eliminated all the ringing and flutter that I would have thought were happening higher in the range. 

And ... just to show what horrible things can happen when you don't read the book ...










First time I loaded the filter sets to the MiniDSP, I forgot to turn off one of the bypass buttons on channel two input in the crossover section. Or was that forgot to turn on the bypass button which turns off the bypass. Or vice versa ... that part of the interface needs some work. Confused me anyway. But ... all's well that ends well.

Gonna leave it go as is for now and just enjoy for a while. I'll probably get into playing about with the FILTER TASK settings again later and see if I can smooth things out a bit more. I also had a brainfart - I'm using a room curve (X-small) and that's a simple text file. I see no reason why I couldn't tweak that to raise or lower specific frequencies. Here's a small sample from the room curve I'm using ...

50 -0.5
51.874	-0.435
53.394	-0.361
54.958	-0.2555
56.57 -0.25
58.226	-0.1055
59.932	-0.0585

As you can see, it allows you to get real finicky on output levels and runs in REW independent of the filters.

Enough for now ... thanx for the help. I'm gonna go listen to some music!


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## Nemesis.ie (Feb 10, 2010)

It looks like you are getting there alright.

It doesn't look like you have any really bad nulls so you might want to try being a little more agressive with the filter settings. Save what you have first of course.

Regarding the level control at 0 in the MiniDSP, yes, it's a trim, so it will only allow you to lower the level, but at least it will give you some control.

I think the room curve (house curve) just adjusts the target that you want, so the auto-filter will try to change your current measurement to match it. It is very useful though, I use it to add a small boost to the lower end. There are some (long) threads here on the topic. 

Enjoy the music.


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## sKiZo (Feb 9, 2013)

_I think the room curve (house curve) just adjusts the target that you want, so the auto-filter will try to change your current measurement to match it._

My thought exactly - so for example if I do a bit of a bump DOWN at 300 in the room curve file, the wizard should give me a bit more boost in that area ... theoretically of course. Only way to know for certain is to run the wizard, check the filters, and then do it again with a modded house curve and see what (if anything) changes. I also plan to run the filter wizard using the same measurement set without the house curve and see what that sounds like. I may find I don't really need it after all.

When I first started listening to the current filter set, it seemed a bit ... dull ... for want of a better word. A/B between the MiniDSP and the analog SH9010 parametric, and the SH9010 sounded "better". A couple short sessions later, I noticed I was hearing a lot more detail with the MiniDSP, it was coming to life, and the SH9010 was fast losing the lead with no other changes to the system. Important lesson to learn - Can't forget to include "psycho-acoustics" in the equation when doing eq, as it may take some time to retrain the ear. Always give yourself time to acclimate to any macro adjustments to the sound before trying to fine tune the fiddlybits. I still think that SH9010 will be handy down the road for on-the-fly tweaks - just a bit here and there if I feel the need without having to modify the filter program. 

Next step I suppose would be to add another MiniDSP for the rear channel speakers - being a quad kinda guy and all. That could get interesting, as I'm really running "sexophonic" sound by running the rear channel outputs into a Dynaco Quadrapter and having two sets of rears - one directly behind the listening chair, and another around 10 feet back, all balanced to hit the ear about the same. That makes for all sorts of interesting effects and one moo baby moo deep sound stage, but does complicate eq a bit. Then again, I just use those for ambiance and I haven't noticed any real issues from the back that need to be addressed.


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