My first successful speaker and room correction using REW and MacOS system-wide EQ

[f1shb0n3]

Acknowledgement
Thanks @3125b for the suggestion to use a measurement microphone for room correction EQ at my first noob question on the forum and everyone else's comments - without your advice I would have spent $1000+ on stuff without getting any actual improvement, where now I got a massive bump in sound quality for $70 and got to spend some quality time learning about room measurement and EQ correction.

About me
I'm still a noob in the audio world - have been listening happily to my KRK Rokit 8 G2 studio monitors with KRK 10s subwoofer connected to Motu M2 in my home office and enjoying it a lot. Little I knew how bad my speakers actually sounded..

My EQ story
Few days ago I bought Dayton Audio EMM-6 mic and measured speakers and sub from my listening position using Room EQ Wizard. These Rokit 8 G2s measured exactly as they sound - pretty much a V-shaped curve in relation to the target. Applying some EQ to correct it to loosely match the Harman target using only 5 bands of parametric EQ (to minimize loss of quality from over EQ-ing) I got an incredible improvement in sound quality. I can't believe I was listening to the non-EQ'd version of my speakers and thought they sound fine - A/B testing of no EQ vs EQ is a night and day difference! I can definitely say I enjoy my music so much more now.

Here's the original frequency response (red), the target (blue) and the EQ'd (green) frequency response:

Note that the graph is for a predicted frequency response, but the actual measured one matches it almost perfectly. This actually surprised me - I expected a laborious back and forth trying to get the perfect EQ settings that translates well to measurements, but in fact REW's suggested EQ made the speakers frequency response exactly as expected.

Measurement process using REW

• Using Room EQ Wizard I measured with mic pointed from listening position to left and right speaker separately while both speakers + the sub are playing and averaged the curve. My reasoning for that is it will reflect what my left and right ears hear most accurately.
• Generated parametric EQ settings with 5 bands only using a house curve based on Harman target from Julian Krause's video, without a room curve. For anyone starting out in this Julian Krause's video is the easiest and shortest explanation of the basic process to to follow.

System-wide EQ in MacOS
There aren't many options on the market for software to apply a system-wide EQ in MacOS. The best one I found is SoundSource which costs $39 - it can apply Audio Units plugins system-wide to the output. I know free alternatives exist (Hosting AU with BlackHole or Soundflower), but it required using two separate programs with cryptic UIs, where for $39 I could get something that does the job with one click, thus my preference for SoundSource.

MacOS includes a great AUNBandEQ plugin that can be used in SoundSource and in it I could add the parametric EQ settings from REW.
Note that AUNBandEQ uses a "Width" parameter (also known as "bandwidth") instead of "Q" which is given by REW's EQ. Conversion from Q to bandwidth can be done at this website.

Another good EQ plugin I found is FabFilter Pro-Q 3 which costs $179. I'm using the trial now and definitely appreciate the ability to save/load EQ presets and the one-click A/B test for different EQ settings. It has it's own quirks btw - the "Q" there is defined differently than REW (see their forum post) - the REW "Q" value has to be multiplied by square root of 2 (1.414213562373095) before putting in its EQ configuration. If this plugin could load REW EQ settings from a file it would have been a great value even for the steep price.

Questions
Of course as an audio noob I have a million questions that I would like to ask. I will list the most important ones I have and will appreciate if you can help me answer them!

• A dip bottoming around 80Hz is visible on the graph - when playing a sine wave with that frequency I can hear the dip at my listening position, but 2 ft on the right it's much louder. What is the best approach to fixing this - experiment with sub placement, bass traps, what else?
• Does "excessive" EQ'ing actually degrade sound quality? With 5 bands of parametric EQ I got a significant improvement, wondering if it would be worth it to try to flatten the frequency response even further?
• Do you know any good system-wide EQ solution for MacOS that can import REW EQ settings similar to Equalizer APO for Windows? SoundSource + FabFilter Pro-Q 3 is the best I found but it costs a lot and does not import from REW. There's an open-source software for Windows - REWEQ2EQPreset that should be able to do a conversion from REW EQ settings to Pro-Q preset but I haven't tried it. If if works I would consider porting it myself to MacOS. It's a market opportunity for sure to create a good system-wide parametric EQ with ability to import from REW and AutoEq.

Thanks!

 

[Dimifoot]

A dip bottoming around 80Hz is visible on the graph - when playing a sine wave with that frequency I can hear the dip at my listening position, but 2 ft on the right it's much louder. What is the best approach to fixing this - experiment with sub placement, bass traps, what else?

Get a second sub

 

[AnalogSteph]

Said dip still is high enough for it to potentially be a phase issue between sub and mains as well. Getting it in phase with both mains may not be feasible without repositioning, and even then results across the room are likely to be all over the place. At least things can easily be measured.

I actually don't think it's all the speakers' fault, but rather the room and placement of speakers and listening position is likely to have a lot to do with it.

Let me have a guess:
Speakers and/or listening position are near a wall or even in corners?
Possible acoustic panels or other absorptive materials at the wall behind the RP8 G2s?
The periodic "wiggles" could be prominent side wall or ceiling reflections.

BTW: Microphones are not ears and may not give accurate results when off-axis response is not well-behaved. Checking known problem areas e.g. just below woofer/tweeter crossover by ear with pink noise may be advisable.

 

[Eetu]

The ~80hz dip is probably a null caused by surfaces/boundaries ~110cm (desk, side walls, rear wall, floor) from the speakers. You can add your room dimensions and speaker positions here to see what's causing the dip http://tripp.com.au/sbir.htm
edit: fixed distance

 

[Willem]

Thanks for posting this. As was said already, dealing with that big dip is a different story. Dips cannot really be equalized. Moving the sub around may help. Your best bet is indeed a second sub. Archimago recently posted some measurements on this.

 

[Slyman]

OP didn't you find any good EQ solution for Mac that can import from REW?

 

[wacomme]

I'm in the same predicament as the OP. I'm seeking a plugin to use with SoundSource on my Mac that directly imports REW files. Is there anything available?

 

[f1shb0n3]

I was able to find some old code which can convert REW EQ to FabFilter Pro-Q presets. It didn't work right out of the box, so some code changes were necessary. Overall, I would not recommend as an option given FabFilter Pro-Q is commercial and not cheap. Here's the code if anyone wants to play with it: https://github.com/perivar/REWEQ2EQPreset

What I ended up using for room correction on my desk setup is Dirac Live on MiniDSP SHD. Picture and diagram of my setup is available at this thread post. Since then I've only upgraded speakers to KEF R3.

What I'd recommend for most people is getting a trial of Dirac Live for PC/Mac and check out the amazing improvement Dirac Live can deliver. Easily beats any manual REW calibration I can do myself. Very important - don't use Dirac's default target curve - it's very bass-lean. Something closer to Harman would be best, attaching my personal favorite developed and tuned over the last couple of years. Remove .txt extension so Dirac can load it.