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

dominikz

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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:
Revel M16 - Harman target (+6dB bass boost, 45-210Hz).PNG


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):
ARC3.PNG


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:
Sonarworks.PNG


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:
DRC filter comparison.png

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:
DRC filter comparison - IR.png


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:
Dirac Live for Studio - FR.png

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:
IK Multimedia ARC System 3 - FR.png

Notice no rising phase response, unlike Dirac Live.

ARC 3 with 'Linear' phase variant:
IK Multimedia ARC System 3 (Linear ph) - FR.png

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:
Sonarworks Reference 4 Studio edition - FR.png


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):
Revel M16 - in-room response with and without DRC.png

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:
20201220_193504.jpg


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.
 
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Nice comparison of features and a lot of work! Thanks for your effort.

I'm looking forward to trialing the new Dirac in the near future and have used Sonarworks Ref3 in the past. I tried ARC recently and didn't like the results I got initially - it seemed to sound processed no matter what I tried so gave up on it as I didn't really have the time to devote to figuring out the UI subtleties.
 
I’ve been using Dirac Live for over 5 years and it is excellent product.

It works great for bad speakers and bad rooms/ acoustics, well for ok speakers/rooms, and has minimal positive effects for excellent acoustics and excellent designed speakers.

I would say that’s it’s definitely a game changer and one of most significant developments in the last decade...
 
Excellent, Blackadder, excellent!
Inspiring. I have roughly the same prob with room (and building) resonances between 35 Hz and 140 Hz. Did initial measurements and the initial corrective file w Dirac. Glad to know, an improvement can be achieved.
 
So this raises a concern:

index.php


There is a ton of amplification of that "null" around 67 Hz. In my limited testing of the latest version of Dirac, I noticed the same. My Purifi ampifier ran out of amplification power and started to distort! Even my 1000 watt amplifier was struggling. Did you notice a problem like this? It only shows up if you turn up the volume.

I wanted to confirm this but have not had a chance.
 
I also don't really like boosts, not because of amplifier power, but rather hearing protection concerns - If there is an in-room dip here at this location it is possible to have a peak at the same frequency somewhere else in the room, so now you get double the boost.
 
Very interesting, well done!

you don’t mention what is the platform required for running the software. On IK’s site I see all photos assume Mac OS.

I am not an expert on this matter, of course I don’t want to dedicate a costly mac/pc for DRC for normal listening, so I wonder if you can “port” the curve once measured to a dedicated DSP like the one in the RME ADI-2 (knowing its built in DSP has only 5 parametric EQ) or the Behringer DEQ2496 I already own.
Thanks.
 
I am not an expert on this matter, of course I don’t want to dedicate a costly mac/pc for DRC for normal listening, so I wonder if you can “port” the curve once measured to a dedicated DSP like the one in the RME ADI-2 (knowing its built in DSP has only 5 parametric EQ) or the Behringer DEQ2496 I already own.
You cannot directly. These are "whole curve" correction systems, not individual filters like RME has. The latter is made for manual correction, not automatic like these systems are.
 
Thank you Amir. So question maybe compatibility with not too recent Mac/PC versions so it can be possible to build a reasonably cost effective system.

by looking at IK ARC3 tech specs, I see the following:

Mac® (64-bits)
  • Minimal: Intel® Core 2 Duo Processor, 4 GB of RAM, macOS® 10.10 or newer
  • Supported Plug-in formats: Audio Units, VST 2, VST 3, AAX
  • Works with any audio interface with a phantom powered XLR microphone input and a pair of outputs for monitoring
  • 48kHz sampling rate is required for the measurement process
Windows® (64-bits)
  • Minimal: Intel® Core 2 Duo or AMD Athlon 64 X2 Processor, 4 GB of RAM, Windows 7 (64 bit) or newer
  • Supported Plug-in formats: VST 2, VST 3, AAX
  • Works with any audio interface with ASIO drivers, a phantom powered XLR microphone input and a pair of outputs for monitoring
  • 48kHz sampling rate is required for the measurement process
so in both cases it is ensured compatibility with not too recent machines, even 8-10 year old ones. I own a Macbook Pro with MacOS 10.11 just requiring RAM upgrade for instance. A reasonably good 48KHz ADC must be also part of the game.

thank you.
 
Allow me to ask: By emphasizing that Sonarworks DRC works "system-wide", are you implying that Dirac does not and only applies to a so a specific application? Thus not to games, movies, browser streams or the like?
 
Allow me to ask: By emphasizing that Sonarworks DRC works "system-wide", are you implying that Dirac does not and only applies to a so a specific application?
That's correct. It only comes as a "VST" plug-in which your player must support or you can't use it. My roon player does not so I am out of business. No game supports VST either.

The older version I am still running installs as a new sound driver so worked with every application. Sadly they moved away from that which is a big miss.
 
Dirac does not and only applies to a so a specific application? Thus not to games, movies, browser streams or the like?
one of the options to utilize it system wide would be to use wdm driver from say jriver acting as vst host
 
Nice write up and a lot of work! Promoting to home page. :)

Wow - thanks a lot! :)

I would say that’s it’s definitely a game changer and one of most significant developments in the last decade...

I'd definitely agree that limited room EQ is a game changer - much more improvement to be had in many rooms vs swapping almost any component (save poor speakers perhaps). :)

So this raises a concern:

index.php


There is a ton of amplification of that "null" around 67 Hz. In my limited testing of the latest version of Dirac, I noticed the same. My Purifi ampifier ran out of amplification power and started to distort! Even my 1000 watt amplifier was struggling. Did you notice a problem like this? It only shows up if you turn up the volume.

I wanted to confirm this but have not had a chance.

To be honest I didn't notice any audible issue with it - could be due to any of the following factors:
  • The SW trims the overall gain so to compensate for the boosts - in my case around 10dB trim. This reduces the SNR of course and overall loudness you can get before clipping. However with my very modest amp (65 W @ 4 Ω/ohms, 1 kHz, THD+N 0.7 %) I didn't come close to clipping at the levels I used.
  • Which ties in to the fact that normally I don't listen very loud - 75-80 dB(C) at the listening spot that I used to record the clips was quite a bit louder that what I usually listen to (life in a residential apartment building and all that:))
  • I only listened to music for these tests - meaning limited dynamic range content. Didn't try to watch movies, which would probably be a lot more challenging.
I also couldn't detect any audible ringing artefacts from the sharp boosts either, but I admit I don't really know what to listen to. I'll see if anything sketchy is visible in impulse responses and report back!

In summary, it looks like the ARC3 is the best one?
Personally I thought Dirac was best overall, followed by ARC3.

I also don't really like boosts, not because of amplifier power, but rather hearing protection concerns - If there is an in-room dip here at this location it is possible to have a peak at the same frequency somewhere else in the room, so now you get double the boost.
Fully agree in principle, and I typically tend to avoid boosts when doing manual EQ. But in my experience there are still cases where boosts can help quite a bit. Note that these automatic room correction plugins take a lot of measurement points spread across the space to determine the overall filter coefficients and they seem to take spatial distribution of room modes into account too. I thought at least Dirac and ARC3 gave quite convincing results, to be honest!

I am not an expert on this matter, of course I don’t want to dedicate a costly mac/pc for DRC for normal listening, so I wonder if you can “port” the curve once measured to a dedicated DSP like the one in the RME ADI-2 (knowing its built in DSP has only 5 parametric EQ) or the Behringer DEQ2496 I already own.
That's a good question and one I asked myself too :) So one of the first things I tried was to measure the filter response of a DRC with REW and use the match target curve option in REW EQ section to try and manually create a similar type of correction.
However I gave up quite quickly - it was complicated to do and the initial results didn't sound very convincing to me. There's a lot of convenience to these products, and I'd say it's worth going for them if you have the need for room EQ but don't want the hassle of figuring it all out manually with EQ.

Allow me to ask: By emphasizing that Sonarworks DRC works "system-wide", are you implying that Dirac does not and only applies to a so a specific application? Thus not to games, movies, browser streams or the like?
Dirac Live and ARC3 are plugins only, that's correct - but you can run both of them them systemwide with a few 3PP applications and by following this guide from IK Multimedia.
 
Great review, thank you. Any reasons why you did not consider Audiolense or Acourate?
 
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