A guide how to do room correction and use it in Roon

(Magnus) #201

Yea, speaker isolation is nice, mine costed 10$ and made a noticeable difference. I also believe that better cables and USB purifiers makes a difference, but those changes are very small and should only be considered once you have a good room with DRC, good speakers, amp and dac.

I think there are several reasons why some people don’t like digital room correction:

  1. They did it wrong (as did I first time), usually by only doing one measurement/channel, which will make the music at higher frequencies sound false and mess up stereo imaging. The reason for this is the short waves at higher frequencies, so moving your head/ear just an inch from the measurement spot will give a different sound.
  2. They did it right, but is so used to the old sound that the improvements sounds worse. For example, if your room gives a peak at around 100 Hz, many instruments like acoustic guitars will sound thinner when corrected.
  3. They believe that bit perfect is the way to go, and that whatever they hear when using bit perfect and expensive audio equipment equals what the artist intended (that reasoning is only valid in a perfectly acoustic treated room like a mastering studio).
  4. It feels expensive to spend money on a software like Dirac (better to spend them on cables right? :slight_smile: )

I listened to some expensive stuff in an HiFi stora a while back, but in a mildly treated room with no digital room correction, and despite that the speakers, amps and dac used was about 10 times as expensive compared to what I have, it sounded much worse (some parts in higher frequencies did sound better though).

(Steve) #202

Not a silly question.

I didn’t, because I haven’t had time and I’ve been experimenting (they’re on loan). But yes I will have to. I don’t think the 2-3 cm height increase is the predominant factor to be honest. The isolation works so well I’ve got completely new depths to the bass, depth I’ve never heard before in this house, and based on that I assume that other peaks and troughs caused by speaker/floor interaction have changed too.

I plan to measure with and without and see what the deal is. Another Gaia/Devialet user has done this and shown some bass peaks have been reduced. But it’s obviously a bit of a PITA to swap the feet over.

Frankly, I kind of like what I hear but I want to re-do it anyway as I want to maximise their potential. I also plan to try the homedidelityaudio service so I get full convolution with phase and reverb, rather than the basic REW one.

But I need to buy the footers first! Then I need time. So scarce to have the house to myself with time to mess around with microphones. Sadly.

Anyway the footers by themselves make a big difference. Consider me a sceptic that’s been won over - and isoacoustics are pro audio and there was no trace of foo in our email exchanges.


@magnus thanks for this brilliant guide! I realise this is probably a really silly question from a newbie here but when you do the measurements do you pause recording as you transition to each location (left ear, right ear, face) or just record continuously when moving to these positions? Thanks!

(Rémi) #204

Position mike at starting position, hit “record”, then start moving slowly following the suggested patterns, then stop record, save. Then do it again for the other speaker.


Great, thanks for clarifying - will give it a try!

(Magnus) #206

Record continuously, I move the microphone in 2 spirals outside each ear, one spiral is on the left-right plane and one is on the front-back plane, and with increasing radius. About 10 seconds/spiral, and 5 spirals in total so 50 seconds of continuously measurement for each speaker (in some cases its enough to to do one measurements with both speakers, so experiment and compare whats best in your case).

You can try other patterns as well, the important thing is to get a good average outside each ear, and to do it the same for both channel and for left/right side of head. Getting a good average is the main improvement over spot-sweep measurements, and can make a fairly big difference.


Thanks @magnus, all clear now and rest of the guide was very easy to follow too.


Sigh. This gives me a headache.

(Magnus) #209

One tricky part of doing room correction is to know where its safe or not to apply a boost. Applying a boost to a dead node just leads to increased distortion. For example, my 48 Hz is stone dead, and if I try to boost it I don’t get any more 48 Hz, but I get very audible distortion, and increased ear pressure (very easily noticed on some tunes).

Here is how you can use REW to find out where its safe to boost. Its called excess phase, and where the excess phase is spiky and far from zero, you should not try to boost. To get the excess phase, do this:

  1. Do sweep measurements, one on each side of the head, right outside the ear
  2. Generate minimum phase in REW (its in the controls section, button to the right).
  3. Select the GD tab (Group Delay), and check the excess phase

More information here: https://www.roomeqwizard.com/help/help_en-GB/html/minimumphase.html

Don’t bother about excess phase on higher frequencies though, they will be so very localized and besides if you use variable averaging you will average them out. But below 500 and especially below 100 is very important to not try and boost excess phase areas.

Btw, no amount of phase/time alignment trickery in software is going to fix this, you will have the exact same type of problems in Dirac, HomeAudioFidelity, Acourate etc. The only way to solve this is to do room related stuff like moving the subvoofer, moving the listening position or acoustic treatment in the room (bass traps), and even then it might be very hard to fix.

(Magnus) #210

The notch filters (Roon calls them band stop) turned out to work very well, not even Lorde - Royals present any problem (the part at 25 secs is especially difficult). Just pure bass, despite that I sit in a concrete bunker :slight_smile:

Here is my EQ, applied to a flat response (if you follow the guide, then set LF Raise slope and HF fall slope to 0 to get a flat target):

Of course, the placement of the notch filters depends on the room, so don’t copy this. Follow my previous post to find out where you need them.


why do you have a 1dB Peak added at 75Hz?

(Magnus) #212

To get a little extra warmth, not that it matters much. It has nothing to do with notch filters or dead nodes.

(Douglas Maurer) #213

I finally tried doing some room connection last night using REW and it went perfectly according to the guide until I got to the step to “export to WAV” files. I am using the REW program on a Mac mini. Nowhere in the version of that program do I see the tool bar that is in the screenshots above as part of the guide. The mac version doesnt have a “file save as WAV” option that I can find. I see nowhere to select “export to WAV” or anything similar. I can save filter files in the text or save all in the MDAT formats only. What am I doing wrong?

(Rémi) #214

Can you check your REW version number ? The latest is V 5.19 Beta 7. I have a Mac and can export impulse responses (incl. filters) in WAV.

(Magnus) #215

Its from menu File -> Export -> Export filter impulse response to WAV
At least its there for the Windows version.

(Douglas Maurer) #216

Thats the issue…the mac version doesnt look like the screenshots of the windows version and lacks the bar across the top that has “File”, “Tools”, “Preferences”,etc…I cant find where it hides on the Mac version? Any Mac REW users out there know?


What happens if you press ctrl-alt-F ?

(Douglas Maurer) #218

I figured it out. I went to my other Mac which is on a typical computer monitor downloaded the program and then I could see the bar across the top. On my Mac connected to my OPPO the top bar on the television wasn’t showing —just barely cut off. Once I knew it was there I was able to start clicking on it and was able to finish the process. Definitely impressed with the sound difference particularly in the high-end and mid bass region. Seems to take a bit out of my subs but that’s easy enough to put back in. Thanks to all for making this guide and helping the community.

(Noel) #219

Hi @Magnus - thanks so much for the guide, I wouldn’t even know where to start with REW otherwise! :slight_smile:

So, I’ve gone though your guide today with UMIK-1, but strangely my system won’t allow me to choose which speakers i want to run the Pink PN noise from, by default it send the sound to my right speaker only, so i have had to swap the cable (L–>R) to do one measurement over the other. Logically I think the result should be the same.

What I’m still not so sure of, is how to read the measurement and also the adjustment that REW made. If you don’t mind, can you please look at the EQ graphs below and let me know what else can I try, and also if I want to make some boost on certain frequency, how should I do that. If there’s one thing that I noticed that i miss when compared to how it sounds without the adjustment is that I seem to be missing some ‘oomph!’ from my bass, but I also noticed that the higher range sounds better especially guitar sounds. Is there a way to adjust to keep the higher range but bring back more bass?

First graph is from my LEFT speaker, while the 2nd one is from my RIGHT. If it required, my speakers’ frequency is from 42Hz to 100kHz - at least that’s what the website says.

Appreciate your advise on this, thanks in advance.

Regards, Noel

(Magnus) #220


I think the best for you would be to correct to a flat target, and then add a house curve after. So remove the slopes in REW, set target at 70 dB and generate filter, export to wav and use that with a house curve in Roon, something like this:

Then you can modify the house curve until you find what suits you, maybe add a little +gain on 5k and higher to compensate the dip you have there,