@jussi_laako, do you use digital room correction only for say the <300Hz region, or all the way up to 20kHz?
I have two sets of filters, one that is bass-only (roughly up to 500 Hz) and one full-band to 20 kHz. Most of the time I use the “bass-only” filter. Response above that is reasonably flat with averaging and I want to avoid sharp “high-Q” corrections because those have too much potential to sound strange. In any case, correctable room errors are mostly in low frequency area. Higher corrections become more like loudspeaker corrections. If a speaker has radiation (polar pattern) problems, those cannot be corrected this way. Phase response / group delay corrections stemming from cross-over design are still within doable range and different from frequency amplitude corrections.
So starting with good speakers is essential, and then the speaker-room interactions can be gently helped with digital room correction. Possibly with some phase corrections.
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Cool, I am of the same thought.
When I bought an Anthem MRX 710 many years ago I was discussing room correction quite a bit with them and they also recommended correcting only lower frequencies, <300Hz, whether using their ARC product or any other digital room correction products.
I’ve used Meridian Room Correction (<250Hz) + Dirac Live with great results. If you know what you are doing, you can transcribe the MRC notch filters into Roon’s parametric eq, but it’s a bit of a pain.
Cool, that ~ <300Hz range (give or take) seems to be the recommendation by the room correction experts out there.
I was going to buy Acourate but then I thought I’ll hold off, after seeing this from Brian a while ago:
He’s a clever Engineer and pretty good at maths, so I’m happy to wait for Roon to make it easier with an integrated elegant solution, even if it takes time to do it well, whether in house or integrate a 3rd party solution 
Whoops, I glossed over this.
So you do digital room correction >250Hz with Dirac Live? All the way up to 20kHz, where found applicable by the software?
Whenever I’ve heard room correction done for >500Hz at friends or at a high end speaker shop , it always sounded a little funny to me (a little like Jussi’s comment). But it probably wasn’t done properly.
Yes. I’ve actually had three layers of room correction 
- The boundary settings in my Meridian DSP speakers.
- MRC
- Dirac
At the moment, I’m running without MRC. It doesn’t sound as good to me as with MRC, but I only have two non-apples-for-apples data points which make drawing conclusions meaningless.
- 1 + 2 + 3
- Move speakers + 1 + 3
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Haha I joke of course - it’s all good.
I look forward to this digital room correction game.
I’m just on headphones for the moment.
I tried Sonarworks True-Fi with my HD800S cans, but didn’t like the result at all.
I wonder if the time domain measurements are out of whack, even if the resultant freq response is (apparently) flat.
This is well and truely out of my area of expertise though.
All I can say with absolute certainty is it subjectively sounded extra weird, not natural sounding at all. But some love it.
@dabassgoesboomboom if you have a very large room or an acoustically very good or treated room RC below 250-300Hz may be enough. Other vice full range RC is the way to go. After using RC for over 10 years this is my experience. I’ve tried low-range only correction, but this was never optimal for my systems and rooms. Jussi has it all covered in his post!
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I’m using Acourate to create filters for HQPlayer. Before that I used RoomEqWizard which works well too, a bit simpler approach.
Regarding Brian’s comment; yeah, there’s no magic in DSP, but a lot of hard work. For example HQPlayer is this year 20 years old, and my company 10 years old. No magic, just lot of hard work. Just like designing good upsampling filters, there’s quite a bit of fine detail going on in digital room correction filter design, lot of scientific work done around that at universities etc. It, like many other things, may look seemingly simple on surface, but devil is in the details. It may be simple to design some filter that does something roughly what is wanted. It is much less simple to design good filter because first you need to design the design algorithm (if you want to do something original, instead of copying some else’s thing).
It is not so hard to make a “car” either, four wheels and moves from place A to place B. Making a good car is totally different thing. Same goes to any other technology area. Doing GUI design for music player is not magic either, but making a good one is lot of hard work too.
Recreating what Acourate and other similar software does is not first thing on my agenda. Those work fine with HQPlayer, I don’t need to. I have other things to work on, things that are not as commonly available in this context…
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To support Jussi’s analogy, I don’t know how to design a car, I buy them from people who do. And generally, I find you get what you pay for.
Similarly, I tried some free tools and then bought Acourate. Great results.
I run full range.
One commonly expressed concern is that upper range results are extremely position sensitive, because of the short wavelength. I didn’t find that. I measured in several seating positions and the curves were squiggly but with a few dB. No audible gremlins.
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I use Meridian’s MRC for the sub 250hz region (built into my processor).
I do use additional Roon filtering, but deliberately only a very simple smoothing of treble (almost like a treble control) to cater for my slightly “hot” tweeters on my speakers.
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