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Comparison of DRCs: Dirac Live for Studio, IK Multimedia ARC System 3 and Sonarworks Reference 4 Studio edition

Flak

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GREAT thread!

Regarding how to position microphones for room analysis, it isn't quite clear. Traditionally, for room analysis it was always said to use a 90 degree position, pointing at the ceiling and 0 for loudpseaker analysis. But I remember Sonarworks and I'm seeing ARC 3 now demonstrating to point it in the direction of the speakers. Can somebody clarify this?
We suggest using a vertical mic orientation in all cases when running a Dirac room calibration (speaker design can be different)... provided that the appropriate cal file is available of course.
If omnidirectional mics were perfect the mic orientation would make no difference.
They are not... so a calibration file is used in order to take into account the deviation (at high frequencies only) between a 90° vertical position and a 0° horizontal one.
However, since the magnitude response of the microphone is different for every angle, such a curve is only 100% valid for a single angle only.
Now you can point the mic horizontally towards the center between the speakers using the 0° file, you will get good results but there be will an angle because the mic is not exactly in the front... or you can use the 90° file with a vertical mic orientation pointing it towards the ceiling, in which case all direct waves and reflections in the same plane will get the same "coloration" that will be corrected by the cal file (provided that it's perfect).
Anyhow even assuming that the cal file does what it is supposed to do different angles cannot be treated differently, nor is that information even available.
 

andivax

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GREAT thread!

Regarding how to position microphones for room analysis, it isn't quite clear. Traditionally, for room analysis it was always said to use a 90 degree position, pointing at the ceiling and 0 for loudpseaker analysis. But I remember Sonarworks and I'm seeing ARC 3 now demonstrating to point it in the direction of the speakers. Can somebody clarify this?

It's all different. Just read the manual carefully and use the "proper" technique which is recommended by developer.
 
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dominikz

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GREAT thread!

Regarding how to position microphones for room analysis, it isn't quite clear. Traditionally, for room analysis it was always said to use a 90 degree position, pointing at the ceiling and 0 for loudpseaker analysis. But I remember Sonarworks and I'm seeing ARC 3 now demonstrating to point it in the direction of the speakers. Can somebody clarify this?
Thanks! :)

You should of course first consult the manual of the room EQ SW you are using to see what is recommended by the manufacturer.

That being said, for in-room response measurements the method giving the most accurate results is when measuring with the microphone in vertical orientation (aiming at the floor or ceiling) and with the 90° calibration curve applied.
This gives the most natural representation of the spectrum of both direct sound and the main horizontal reflections in the measured response. See also a short explanation here.

However note that the difference between vertical and horizontal orientation of an omni measurement mic will mostly be in the high frequencies - i.e. largely irelevant if you only aim to correct the response in the low frequencies (which is what I'd typically recommend if you have loudspeakers with a neutral anechoic response).

Hope this helps! :)
 

dasdoing

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GREAT thread!

Regarding how to position microphones for room analysis, it isn't quite clear. Traditionally, for room analysis it was always said to use a 90 degree position, pointing at the ceiling and 0 for loudpseaker analysis. But I remember Sonarworks and I'm seeing ARC 3 now demonstrating to point it in the direction of the speakers. Can somebody clarify this?

you should use what the mic is calibrared for, but it is actualy more complicated than this: https://mnaganov.github.io/2019/12/understanding-microphone-calibration.html
 

dasdoing

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in the case of having both calibration files I would choose 0 degrees. in a normal living room the direct sound should always be louder than the reflections, so that is the axis that should be the most accourate in a measurement.
 

audio4life

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You guys are tremendously knowledgeable and the more I learn from here the more indecisive I become haha The more you know the more hesitant you are, at least for me.

In my case, I will be using a Dayton emm-6 and of course it has its own cal files. And @dominikz that was a really great and straightforward explanation which made sense. Then there is the simple logic of following the manufacturer's advice (ARC 3), which is at the speakers. Correct me if I'm wrong, they did not state however the best positioning for 3rd party mics like the Dayton while using ARC 3.
 

dasdoing

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audio4life

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How interesting! A few years ago I noticed something odd in the high end, maybe it was indeed due to this. But I'm just wondering is it something they can correct and reupload for the user to use or maybe it's just better not to use the cal file altogether like the link suggested. Wow, thanks for bringing this to my attention!
 
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dominikz

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How interesting! A few years ago I noticed something odd in the high end, maybe it was indeed due to this. But I'm just wondering is it something they can correct and reupload for the user to use or maybe it's just better not to use the cal file altogether like the link suggested. Wow, thanks for bringing this to my attention!
Personally I wouldn't put much faith in calibration files provided by Dayton Audio. I also own a Dayton EMM-6, but I bought mine from Cross-Spectrum Labs with their Basic+ individual microphone calibration service.
Here's how the manufacturer 0° calibration file compares to the one provided by Cross-Spectrum labs:
Dayton EMM-6 - 0° calibration file comparison - Manufacturer vs 3rd party (Cross-Spectrum) labs.png

As you can see the curves are very different, and personally I put more faith in the one independently provided by a third party. Note however that the scale is zoomed-in so the overall imprecision is relatively low, all things considered. Since the microphone is relatively 'flat' out of the box, it is debatable if the calibration file is needed at all when measuring on-axis (0°). Note that the manufacturer unfortunately doesn't provide a 90° calibration file.

In EU a similar 3rd party calibration service seems to be provided by hifi-selbstbau.de (though I'm not sure if they provide any reference to standards or methodologies they use).

With the MMM method, Cross-Spectrum Labs 90° calibration curve, and EMM-6 in vertical orientation I get in-room response measurements that pretty closely track the predicted in-room responses calculated from 3rd party anechoic polar measurements, example:
Neumann KH 120H - in-room MMM (vertical mic + 90° cal file) vs Klippel PIR.png


Finally, regarding mic orientation with various DRCs, I found the difference is not so big if you apply the appropriate calibration file and (in some cases) adapt the target curve accordingly - e.g. see this post with examples done with Dirac Live and MathAudio EQ.

Once again, I'd in general recommend going with the instructions provided by the room EQ SW manufacturer, as typically we don't know how the SW does its calculations and consequently if the microphone orientation is impacting the results (or by how much).

Hope this helps!
 

audio4life

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Personally I wouldn't put much faith in calibration files provided by Dayton Audio. I also own a Dayton EMM-6, but I bought mine from Cross-Spectrum Labs with their Basic+ individual microphone calibration service.
Here's how the manufacturer 0° calibration file compares to the one provided by Cross-Spectrum labs:
View attachment 216159
As you can see the curves are very different, and personally I put more faith in the one independently provided by a third party. Note however that the scale is zoomed-in so the overall imprecision is relatively low, all things considered. Since the microphone is relatively 'flat' out of the box, it is debatable if the calibration file is needed at all when measuring on-axis (0°). Note that the manufacturer unfortunately doesn't provide a 90° calibration file.

In EU a similar 3rd party calibration service seems to be provided by hifi-selbstbau.de (though I'm not sure if they provide any reference to standards or methodologies they use).

With the MMM method, Cross-Spectrum Labs 90° calibration curve, and EMM-6 in vertical orientation I get in-room response measurements that pretty closely track the predicted in-room responses calculated from 3rd party anechoic polar measurements, example:
View attachment 216162

Finally, regarding mic orientation with various DRCs, I found the difference is not so big if you apply the appropriate calibration file and (in some cases) adapt the target curve accordingly - e.g. see this post with examples done with Dirac Live and MathAudio EQ.

Once again, I'd in general recommend going with the instructions provided by the room EQ SW manufacturer, as typically we don't know how the SW does its calculations and consequently if the microphone orientation is impacting the results (or by how much).

Hope this helps!
Thanks a lot!
Yes, not huge discrepancies but nonetheless SO fascinating the manufacturer of said mic actually has the least reliable cal file!
I suppose short of simply going ahead and using the Dayton at 0, pointing in the direction of the speakers without a cal, I could consider the actual provided mic by IK for my ARC 3 measurements. I will mull it over. Not sure it justifies purchasing it vs. the Dayton sans cal file in light of all info here.
 
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dominikz

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Thanks a lot!
Yes, not huge discrepancies but nonetheless SO fascinating the manufacturer of said mic actually has the least reliable cal file!
I suppose short of simply going ahead and using the Dayton at 0, pointing in the direction of the speakers without a cal, I could consider the actual provided mic by IK for my ARC 3 measurements. I will mull it over. Not sure it justifies purchasing it vs. the Dayton sans cal file in light of all info here.
Perhaps you might find this post useful as well - where I show that a Rode NT2A large diaphragm condenser microphone (in omni mode) gives pretty comparable in-room measurement results to the Cross-Spectrum Labs calibrated EMM-6.

In short, if you're measuring in-room response for the typical purpose of EQ-ing low-frequencies only (<500Hz) I wouldn't worry too much about your microphone's absolute precision.
Though I can definitely understand the appeal of having more confidence in your measurements that better measurement equipment may bring! :)
 

audio4life

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Perhaps you might find this post useful as well - where I show that a Rode NT2A large diaphragm condenser microphone (in omni mode) gives pretty comparable in-room measurement results to the Cross-Spectrum Labs calibrated EMM-6.

In short, if you're measuring in-room response for the typical purpose of EQ-ing low-frequencies only (<500Hz) I wouldn't worry too much about your microphone's absolute precision.
Though I can definitely understand the appeal of having more confidence in your measurements that better measurement equipment may bring! :)
:cool: Exactly, bolded, underlined for emphasis
 

JoachimStrobel

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Very interesting reading. Did anybody extend these comparisons to a Multichannel setup?
 

dasdoing

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One thing about the 0 axis that some seam to be misunderstanding. it is not the axis vertical forward. If you only have this cal you need to aim at the speaker
 

audio4life

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Just wanted to update you guys (if anyone cares lol) I decided to order the specific IK mic for the ARC measurements! :cool:
 

napilopez

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[MOD EDIT: This is a member contribution]
Hi all,

Lately I was playing a bit with digital room correction (DRC) SW to see if I can tame the bass in our living room with a pair of Revel M16 (no subs) so I thought it could be useful to share my findings. Some of my in-room measurements are available already in this post, and here are the quasi-anechoic measurements of our pair of speakers. As you can see, we get a bit of bloom under ~200Hz, which should be right around the Schroeder frequency of this room.

The three DRCs I tested were:
All of them offer free trial versions, which is what I used to test them out and compare.

Measurements were done with a Cross-Spectrum Labs calibrated Dayton EMM-6 measurement microphone and RME Babyface Silver edition soundcard.

Here's some of my quick thoughts on each one of them:

Dirac Live for Studio
Usability and UI is very nice in general - though I was having some issues with logging-in to the user account on the Processor component (VST plugin) and was also getting some errors when loading saved projects. I don't like the fact that you can't edit (or even see) the target curve in the plugin (Processor component), and due to issue with loading saved projects it can be tricky to edit saved curves.
The measurement process was relatively straightforward and quick (actually the quickest of these three), and the resulting responses seem in line with what I was getting with REW.
I'd say there's really a lot of power in Dirac - it sounds great, and is really flexible in target curve customization (you can load target curves, edit them, add many break points, freely set range for the correction...).
Here's the correction curve I liked the most:View attachment 100557

IK Multimedia ARC System 3
Not bad UI and usability, though there are a few things I didn't like: e.g. when you load the mic calibration curve, there's no indication that it loaded correctly, and due to this one of my measurement attempt turned out incorrect. Another thing I don't like is that there are only 6 target curve break-points, and the SW applies some correction to FR even outside of the configured range (unlike Dirac) - so you should be careful how you set the breakpoints if you limit the range, as you will need a few of them out of the range set at 0dB to really limit the correction. This means you get really limited with how you can set the target. You can also only set the break points in between the +/-6dB of the reference the SW selected - which can also be limiting when we consider downward-sloping in-room response curves that we get when listening in far field.
However, there's some nice additional features to play with, like two types of filter phase (natural and linear) and 'virtual monitoring' target curves that attempt to mimic other speaker system's FR.
Measurement process was relatively simple, but requires more measuring points (21 in total, with 8 sweeps per point).
Sounds quite good to me too, but the target curve configuration is a bit limiting.
This is the curve I ended-up with (range a bit wider that Dirac, and maybe a bit less bass boost):
View attachment 100558

Sonarworks Reference 4 Studio edition
Maybe the best UI, stability and usability of the three. I enjoyed the gamified concept of the measurement process, but in practice it is quite tedious to do as it takes something like 37 measurement positions to do the calibration - so it's quite a lot of loud sweeping and chirping noises to endure :D
This is also probably the most complete SW package of the three - it offers systemwide application and plugin version, and on top of offering loudspeaker calibration it also provides a pretty large database of headphone equalization configs. They were obviously aiming for user-friendliness :)
What I don't like is that target curve customization is very limited (including almost non-existent range limiting). Because of this, most of the result sounded over-processed to me and I couldn't really find any that sounded close to what I thought was natural (and which I could get with the other two).
Here's the best I got:
View attachment 100559

Filter response comparisons
First thing I'd like to show is soundcard loopback frequency response with each DRC after calibration to compare the filter responses:
View attachment 100550
As we can see, Dirac Live and ARC 3 filters were limited to our problem area (45-210Hz) and I was surprised to see that the filters between them end up looking fairly similar. Reference 4 cannot be limited in the same way so here I'm showing 'Reduced' LF limit and 'Normal' HF limit. We can see right away that filters used by Reference 4 are less sharp in the LF range and I couldn't find a way to get a better match to the other two.
Note: the above is with 'Natural' phase and 'Sharp' filter type set in ARC3 - other settings resulted in worse match to Dirac Live (i.e. less sharp filters). For Reference 4 I used 100 Wet config to get most sharpness (although I used it with 60% as that sounded more natural).

Edit: adding the impulse response comparison from post #24 for completeness:
View attachment 100628

Here's full phase and magnitude diagrams (please disregard the 'hairiness' above ~4k for Dirac and ARC - it is an artefact of the way I did loopback testing of these two plugins and not something they do normally):

Dirac Live:
View attachment 100552
What I found interesting was the gradually rising phase response after the filter. Is this due to impulse-response and delay correction/optimization Dirac does?

ARC 3 with 'Natural' phase variant:
View attachment 100553
Notice no rising phase response, unlike Dirac Live.

ARC 3 with 'Linear' phase variant:
View attachment 100555
Notice that filters are less sharp, but phase response is smooth (P.S - this was range limited to ~900Hz and with a different target - here just used to illustrate phase behaviour).

Reference 4:
View attachment 100554

In-room response measurement example
Next here's an in-room loudspeaker response comparison of no DRC (averaged across 9 positions) vs ARC3 correction (averaged across 5 positions):
View attachment 100563
Note that the curves don't overlap very well in the mid and higher frequencies - they were done on separate occasions and the measurement positions and mic height naturally weren't the same between the two measurement runs - but they are roughly close.
Still, we can see how much the bass response got evened out by DRC - peaks got flattened and the dips got filled in, as we could only have hoped for :)

Sample in-room recordings

Lastly, I thought how to illustrate the audible differences, and decided it might be interesting to do in-room stereo recordings of playback without any DRC as well as with the three DRCs reviewed above.

In-room sample recordings were done with the classic mid-side stereo recording technique, using a combination of Dayton EMM-6 as 'mid' and Rode NT2a in figure-of-eight mode as 'side' at the listening position in our acoustically untreated living-room. I chose mid-side technique for two reasons:
  1. Use of omni mic for 'mid' should be good to record realistic low-end response in the far-field
  2. It is not critical to have a closely matched pair of microphones :)
Edit: Listening position is ~2,2m from each speaker and SPL was between 75-80 dB(C) (measured with a cheap SPL meter close to mics) for each clip.

The recordings were not post-processed, except summed for stereo listening and (LUFS) loudness matched.
Here's a picture of the mic setup:
View attachment 100560

The song/recording I used was one of the vary few I have distribution rights for as it was made and recorded by my band - so I guess what follows could also be considered shameless self-promotion. :D Anyway the source track can be found on most streaming services via this link.

The resulting in-room recordings in FLAC (44,1kHz/16bit) are uploaded here - I suggest to listen on headphones to avoid adding additional room effects to an already quite live recording. :) These recordings definitely don't convey the full in-room listening experience, but I still thought it was an interesting project and may provide some insight.

Conclusion
All in all, this was quite an interesting little project for me. My takeaway is that there are definitely some really good options on the market for DRC - out of these three my preference would be:
  1. Dirac Live 3 - sounds the best to me and offers most flexible target curve config. Natural sounding and with reasonable target configs I thought it was not destructive in any way. Not cheap, though.
  2. IK Multimedia ARC system 3 - in my opinion it can be configured to sound close to Dirac, but required a bit more fiddling. It may not be able to satisfy every requirement as far as target curves go though - this is my main gripe with it. However it is quite a cheaper option than the other two.
  3. Sonarworks Reference 4 Studio edition - I couldn't make myself agree with this one :) Sure, there are some nice features there (plus great systemwide version and some extensive headphone EQ options) so I'm sure it works great for many - but lack of filter sharpness, true correction range limiting and detailed target curve editing are for now deal-breakers for me.
There it is - hope some will enjoy the read and maybe even find bits of it useful! :)

EDIT: Some thoughts and measurements related to nearfield use (in my case with JBL LSR305) can be found in post #55.

EDIT (2020-12-28): Some thoughts and measurements using MathAudio Room EQ in a nearfield listening setup can be found in post #96, and measurement and comments on use of MathAudio Room EQ in my main system can be seen in post #104.

EDIT (2020-12-30): Some of my thoughts on using JuiceHiFi Audiolense XO trial in a nearfield setup can be found in post #109, and some measurements in post #114.

EDIT (2021-01-12): More measurements with JuiceHiFi Audiolense XO trial in my living room setup, including comparisons with Dirac Live and MathAudio Room EQ as well as some blind listening tests can be found in post #125.

EDIT (2021-04-18): Measurements and my thoughts about REW-generated EQ filters for room correction can be found in post #205.
@dominikz Just wanted to say thanks for this very useful thread!

I recently bought the iLoud MTMs for my digital piano/newbie composer setup, so I can get ARC 3 for quite cheap. I know how to REW+EQ, but thought it would be nice to get something more automated and not have to bust out the CSL Umik from my basement. I know from review experience that Dirac works excellently, but given its claim-to-fame FIR filters add about 23ms latency it's a no-go for piano. I usually play using VSTs in the DAW, but sometimes the piano's internal sounds too. So it seems that using the ARC3's natural phase mode (lower latency) might be the way to go.

I was a bit thrown off by the fact that it seems their default curve is just a straight line, but given that I'm listening from about 2-3 feet away that shouldn't really be an issue.

I just wish IK Multimedia would allow me to load the calibration files directly onto the speakers, since they already feature at least a rudimentary form of ARC. I currently route my audio through the piano as sometimes I just want to sit and play without hooking up my laptop. Now that I think of it, I wonder if the internal calibration files are somehow accessible via the speakers' USB service port, even though that isn't officially supported...
 
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dominikz

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@dominikz Just wanted to say thanks for this very useful thread!

I recently bought the iLoud MTMs for my digital piano/newbie composer setup, so I can get ARC 3 for quite cheap. I know how to REW+EQ, but thought it would be nice to get something more automated and not have to bust out the CSL Umik from my basement. I know from review experience that Dirac works excellently, but given its claim-to-fame FIR filters add about 23ms latency it's a no-go for piano. I usually play using VSTs in the DAW, but sometimes the piano's internal sounds too. So it seems that using the ARC3's natural phase mode (lower latency) might be the way to go.

I was a bit thrown off by the fact that it seems their default curve is just a straight line, but given that I'm listening from about 2-3 feet away that shouldn't really be an issue.

I just wish IK Multimedia would allow me to load the calibration files directly onto the speakers, since they already feature at least a rudimentary form of ARC. I currently route my audio through the piano as sometimes I just want to sit and play without hooking up my laptop. Now that I think of it, I wonder if the internal calibration files are somehow accessible via the speakers' USB service port, even though that isn't officially supported...
Thanks, I'm very glad you found it helpful! :)

I can definitely understand the reluctance to use FIR-based filters for real-time audio applications - and especially non-causal FIR filters used to correct crossover phase delays (e.g. such as in Dirac Live)!
Actually, it is one of the reasons why I just use the built-in 3-band IIR PEQ from my RME audio interface for room EQ on my audio workstation. Just 3-bands of PEQ is not a lot for room EQ (though usually enough to solve main issues), but a large benefit is that RME TotalMix DSP adds only a few samples of latency; i.e. virtually zero!

With this in mind, I sometimes wonder what is the input-output passthrough latency of various DSP-enabled studio monitors (e.g. Neumann KH80, IK Multimedia MTM and similar) - I don't usually see this specified. My experience measuring input-output passthrough latency of various digital guitar processors and amplifiers resulted in an unpleasant surprise a couple of times! That makes me wonder if most DSP-enabled studio monitors would be suitable for real-time audio applications - especially since latency can add-up fairly quickly in a complex digital system!
 

audio4life

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Quick update guys...thanks so much for this thread! The ARC 3 and the mic have been stellar for me. One thing I noticed is how natural it sounds. I directly compared it with Sonarworks and after 6 years or so with SW I'm sticking with arc.
 

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Can I use umik-1 as the IK Multimedia ARC System 3 test microphone? Because I only have the umik-1 test microphone, without an external sound card.
 
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