Room (Correction) With A View/Dirac Room Correction software

Room Correction? Is that not the advanced sort of the good old days´ Bass and Treble controllers on every Hifi set that I remember from the 1970´and 80´s ?

Sort of, I tell you, but it´s got a very, very long way since those days; now computers rule the world, and thus there are new fantastic possibilities for some real advanced Room Correction.

Swedish audio specialist Dirac knows how to. So they not only adjust the bumps (to much energy) and decreases (a suck out in the frequencies), but even more importantly they also do work with the parameters of the time domain.

But why is that important you might ask. Now take a normal domestic living environment. As todays modern listening rooms are hardly filled with furniture, often a naked hard wood floor with no carpets and lots of windows is quite often seen here in Scandinavia or around the world. All these hard surfaces are highly reflective. And that means, quite simple, that any sound will bounce (loud or not, but it will be reflected), and arrives milliseconds later at the listeners ears. But that´s not only goes for your loudspeakers output, but for all the sound in the room. Your wife´s voice (Honey, what ARE you saying, I cannot hear you, you want to buy me gold and diamonds?) or the TV sets narrator will be difficult to understand. Reflections are BAD for music and speech recognition. Many a good listening rooms are filled with sofa´s, thick carpets and heavy curtains. All this stuff is called damping materials, because they DAMPEN the first of those early reflections. And the reflections are the ones that do the trick to your ear, so you can define minut details in the sound stage, depth in the music, cues to where your wife or kids are standing. Being right behind you? Or has she now moved 2 cm to your right? The kids turning their head while they sing? All this is only possible due to spatial cues in the sound and the room you are in. So the room, whether it is a domestic living room or your beloved listening room (or both) is, together with your loudspeakers, actually the biggest factor if the sound of your HiFi system is good or bad. And your ears are some of the worlds finest measurement tools available, so please trust them when you judge your music gear (or anything else).

LP´s and bookshelves also help a lot to make your listening room as good as it gets. Also the dimensions of your room make a huge impact on the sound. If you have ever visited a house where you´d found yourself immediately at home, maybe the acoustics where just about right. Remember that bad acoustics aren´t often found in nature, they are mostly men made and artificial.

Zero Room

The guys from Dirac have found a way to actually diminish the influence of your room to something like nada, nill. Zero. I know that can be a big pill to swallow, but I really mean this. And I know there are other big players in the game of Room Correction, Tact/Lyngdorf is one and I have used it for many years too. The main reason I switched to Dirac is that a) it is very easy to set up and b) very professional to use, c) it works perfect with my music computer and d) just does wonders to my room acoustics.

So how easy is Dirac to get to work you might ask?

Obviously you need the software, you can download a demo mode that works for two weeks for free from www.dirac.com But you also need a measurement microphone. I got myself this one: link. Without the Mic there is no way that you can use Dirac.

When you got both, then you load the Dirac Live Calibration Tool. This is the software that does all the measurements. I´ll guide you through this in a minute. After you finished the measurements and calibration, you just load the: Dirac Audio Processor which is what you need on a day to day basis.

With the Dirac Live Calibration Tool loaded you choose if you have a stereo or surround system, you then choose your playback device (that´s the one that outputs the sound to your speakers, aka soundcard, DAC or whatever you use). 

Then you choose your sample rate that Dirac has to work with. Then you click: Proceed at couple of times, and choose your recording device. In my case this is the:
USB Advanced Audio Device that comes with my XTZ microphone. Again you hit:

Proceed and adjust the level of the pink noise coming through, so the software can get enough information to work with:

Thereafter you choose if you have a:

“Chair”, a “Sofa” or an “Auditorium” to be seated in.

After you hit Proceed the measurements will start, a sine sweep will be output to your speakers, and I dearly suggest you to put fingers into your ears for the 10-12 seconds the noise will last. After that you move the microphone to the new place that Dirac suggests and the next measurement will take place. After nine in a row you are finished and you get something like this:

Don´t worry, most listening rooms look like this. The impuls respons looks maybe something like this:

And it also shows that the loudspeaker, in this case the digital input of Dynaudio´s Focus 200XD, output is with reversed polarity - the spike goes down!

Then you highlight the Target button (above, in the middle) and now you can see the RED target curve, suggested by Dirac:

You can actually now play with the Target curve, and adjust it to your taste. You simply double click on the RED line and make some cross-points, and can then drag them to your taste. A straight line is only good in theory, in nature a straight line does not exist, so we would suggest something like this:

You see we did emphasis the bass around 60 Hz for maybe 6 dB´s, and cut 2 db`s around 1 kHz and also made a tiny raise around 7 kHz.

When finished you hit Optimize, save the Filter and save the Target response, whereafter you go to the Dirac Audio Processor. You remember, the DAP is the one you use on a daily basis.

So just quit the Dirac Live Calibration Tool. You only use it for measurements and for changing your Target curves. But if you want to use it again, you MUST connect the Mic, otherwise it won´t show you your measurements or the changes you will make.

All this will take maybe 20-30 minutes the first time, after this you can do it within 10-12 minutes is my guess.

In the Dirac Audio Processor you choose your output device (DAC or whatever you use), and you also choose your corrected Filters, in this case QRT+10dB in position 3 and so on. I think you get the point. (The filter “QRT Weird” I made for a quick test with some middle frequencies exaggerated by 12-14 db so I can easily judge if the whole chain is working and sound is output the right way)

While you are in your favorite music player (ROON, iTunes etc) you choose Dirac as your output device also. So in this case ROON outputs the sound to Dirac Audio Processor, which then sends the music to your DAC/active loudspeakers/Amp.

By the way the now corrected Impulse Response in Dirac looks something like this below, and please notice that Dirac has reversed the now correct output (the impulse goes up, the green spike).

Now you are finished and ready to enjoy.

And what do you now hear and is it that obvious? Let me tell you, changes to a new loudspeaker or a new amp is way smaller then the change WITH or WITHOUT Dirac. 

The Dirac Audio Processor has a simple Filter ON/OFF switch. Here you can bypass and hear what Dirac does! And that is not a small change, I´ll tell you.
Immediately you hear the difference, even in rooms that are good to start with and with lots of damping materials. Dirac also adjusts for subtle differences between your left and right speakers, and compensates for this level as well as for the (even more important) changes in delay between the speakers. 

Test tracks for using Dirac:

And when you hear tracks like Tori Amos version of “I´m Not In Love”, just listen to the electronic bass rumbling through your listening room, but now it´s just without standing waves. Bypassing Dirac will probably leave you in a state of chock, now you know how standing waves sound like.

It´s also very easy for you to discern if your listening room has some major disadvantages. Most of us use the triangel listening room solution, where you and your speakers make a triangular setup, you sitting exactly in the middle - aka the sweet spot. Sometimes though this is not possible, moving to a new house, or an open path to the nearby kitchen, or a glass door on the left (or right) side of your speakers. Or (as here) arrival of a baby, so most of the ideal acoustic solution had to be banned, and the speakers to be put quite awkward with the left speaker 0.5m closer and 10cm higher to the listener then before. But you know what? With a new set of measurements and Dirac doing it´s great job, I cannot even here the slightest difference before the “perfect” setup some months ago or this new one. When I hit the Bypass switch on Diracs DAP though, I am definitely in audio hell. Nothing is good anymore, it sounds as if someone put a blanket on the one speaker, and reversed the phase on the others middle diaphragm as well as the right speakers sounds as it plays right into the backwall, and not towards me.

The artist Rumer just released the album “This Girl´s In Love” where she performs Bacharach´s song “The Look Of Love”. With and without Dirac is worlds apart, her lovely voice just stands exactly where I want it to be: in front of my speakers, and not somewhere “behind” or to much “to the right/left”. And also the beautiful acoustic guitar solo, surround by the strings stands solid as a rock. Have I tried to bypass this track with Dirac? Yes, I have, and never will do again.

Or take the Danish heavy act Pretty Maids new (yes it´s possible to listen to other stuff then a two track acoustic female voice recorded during a full moon session surrounded by blond virgins) track:  “When God Took A Day Off”. Impossible to listen to with Dirac on bypass! Singer Ronnie Atkin´s great voice again stands in front of the band when I switch the room correction system back on. Guitars, bass and drums are just one hell of a mess without Dirac. Not one note to follow your ears, it could be also like a vision of a rainy day seen through a bus drivers window, just to many small fragments and bits and pieces, but not the whole beautiful picture. Which is what we get with Dirac!

Standing waves:

This means that some notes are way to loud. If you ever have listened to music with standing waves, you are in no doubt what it is. It really is like a big tsunami (sound) wave coming at you. And thereafter there is silence in the bass, just until the next tsunami comes rolling in. Some bass-notes are like hitting you in the face and filling your room, others are barely audible.

But the rest is getting even better. It´s not only the bass, i.e. the low frequencies that gets better. The timing in the most important midrange, where your ears are the most sensitive, gets way better too. Small details, like the reverb on the snare drum, or delays on the guitar, backing-vocals that otherwise are smeared in the sound picture suddenly stands clearly as on a spring morning. Strings that sometimes can drift between the left and right speakers now stand solid as in concrete where the sound engineer has placed them in the first place. Minute details in the music are now not just felt, but heard and the depth of the music is reaching new levels. 

The drummers hi-hat now is placed exactly where it´s supposed to be. Vocals, violins, trumpets… you name it - they all stand out crisp, sharp and live-like. And right in front of you - if recorded that way of course. Bas lines are way easier to follow, and don´t have that “too loud” or “where is that note NOW” thing.

And just before my deadline I had the privilege to do a review of the new software player AudirvanaPlus with MQA, so the sound now took new levels to say the least. Try to compare “The Look Of Love” with Rumer in a MQA and a non-MQA version. Add to this recipe the Dirac magic and a very big smile on your face should appear within seconds. The new Audirvana makes the music sing, the MQA makes the digital music sounding analogue to your ears, and Dirac makes your listening room vanish. To goo to be true? So my dear friend, try Audirvana and Dirac for absolutely free for the trial period, and listen to what it does to your beloved HiFi system, and to your ears and your wellbeing.

Very, very heartily recommended!

Words © Kurt Lassen 2017


389 EUR

Dirac has written this piece of paper about the why and how´s: link.


Dirac works with companies like BMW, Rolls Royce, Oppo, Volvo amongst others.

It works on 24 bit and 192 kHz and the full version (30 days free trial) works with 8 channel audio with a one year free support and updates include costs 650 Euro. The two channel version has the price tag of 389 Euro.


Head Office:
Dirac Research AB
Vaksalagatan 16
753 20 Uppsala