KEF LS60 Room Correction Showdown: REW MMM vs. Wiim Ultra—A Data-Driven Analysis

Dako

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1. Introduction and Background​

Room acoustics play a pivotal role in perceived audio quality in home listening environments. Of particular importance are resonant frequencies—or room modes—that commonly arise in rectangular rooms. These modes often lead to significant boosts or cuts in specific frequency bands, especially in the low-frequency region. Effective room correction aims to minimize the impact of these modal peaks and dips to provide a flatter, more accurate frequency response.

The following equipment was used:

  • Speakers: KEF LS60
  • Streamer: Wiim Ultra (with coaxial output to KEF LS60)
  • Subwoofer: KEF KF92 (crossover at 60 Hz)
  • Microphone: Umik-1 (USB measurement microphone)
The listening room is rectangular, and based on previous tests and known theoretical properties of such rooms, primary room modes appear at approximately 25 Hz and 60 Hz. In practice, a strong peak of about +8 dB occurs around 60 Hz, primarily from subwoofer excitation. Since subwoofer placement options are limited, employing parametric equalization (PEQ) or an effective room correction system is essential for reducing excessive bass buildup.


2. Methods​

2.1 Measurement Protocol (REW MMM)​

Measurements were performed using the Moving Microphone Method (MMM) in REW (Room EQ Wizard). MMM involves continuously moving the microphone within the listening area while generating test signals to capture an averaged response that accounts for spatial variations in the room. This approach is known to provide more robust correction data, particularly at lower frequencies where room modes dominate. For details on the MMM technique, see AudioScienceReview Forum reference. Smoothing VAR.

2.2 Correction Strategies​

  1. Uncorrected (Blue Curve)
    Represents the baseline measurement of the KEF LS60 and KF92 subwoofer without any equalization or room correction.
  2. REW MMM Correction (Green Curve)
    A correction filter was derived in REW, targeting frequencies below 300 Hz to address major room modes. This filter was then applied to the system to tame peaks at ~24 Hz, ~60 Hz, and between 100–200 Hz.
  3. Wiim Room Correction (Purple Curve)
    Wiim Ultra’s built-in room correction was used with an iPhone 13 as the measurement device. For testing purpose I selected a correction range of 20–20,000 Hz. This contrasts with the more typical approach of only correcting frequencies below ~300–400 Hz.

2.3 Target Curve and Subwoofer Integration​

Harman target curve was adopted, which slightly boosts low frequencies while remaining relatively flat through the midrange and treble. The subwoofer crossover was set at 60 Hz to integrate with the KEF LS60 main speakers.


3. Results and Discussion​

3.1 Uncorrected Response (Blue Curve)​

The blue curve (Figure 1) reveals substantial peaks near 24 Hz and 60 Hz, along with additional irregularities between 100 and 200 Hz. Subjectively, these peaks produce a “boomy” or “heavy” bass characteristic. The 60 Hz peak is particularly problematic, causing bass overhang and masking details in the upper bass region.
Screenshot 2025-01-04 at 15.40.53.png

3.2 REW MMM Correction (Green Curve)​

The green curve (Figure 2) demonstrates a significantly more even response below 300 Hz once corrections are applied. By attenuating the 24 Hz, 60 Hz and around 100 to 200 hz peaks, the overall bass character improves. Subjective listening confirmed a reduction in boominess and an increased sense of clarity, allowing the KEF LS60’s inherent qualities to come through.
Screenshot 2025-01-04 at 15.42.00.png

3.3 Wiim Room Correction (Purple Curve)​

The purple curve (Figure 3) shows the outcome of Wiim Ultra’s auto-correction feature. Contrary to expectation, the system boosted frequencies between 20 and 70 Hz rather than attenuating them, exacerbating the existing room modes. It also introduced noticeable changes around 1 kHz and a high-frequency lift of approximately +4 dB. Subjectively, this yielded an overly bass-heavy and excessively bright tonality, diverging considerably from standard room correction targets. It appears that Wiim’s current algorithm attempts a full-range correction but may lack sufficient resolution or measurement precision to accurately handle complex room interactions.
Screenshot 2025-01-04 at 15.43.00.png

4. Conclusions​

4.1 Effectiveness of Methods​

  • REW MMM-based Correction: Offers a more controlled low-frequency response, aligning closely with recognized best practices for room correction (targeting problematic modes below ~300 Hz).
  • Wiim Ultra Correction: Full-range correction in its current form seems suboptimal, particularly in challenging low-frequency environments. The resulting boosts and treble enhancements suggest it is neither designed nor optimized for precise sub-300 Hz corrections in typical rooms.

4.2 Recommendations​

  1. Limited Frequency Range Correction: Focus correction efforts between roughly 40 Hz and 300–400 Hz to mitigate the most problematic modes without over-processing mid and high frequencies.
  2. Refinement of Wiim Algorithm: Future firmware updates or user-selectable target curves could improve Wiim’s utility as a room correction solution. Until then, using a dedicated EQ tool (like REW-generated filters) may yield more accurate and predictable results.
  3. Verification Through Multiple Measurements: Continue using techniques such as MMM to capture representative spatial responses. This approach helps prevent over-correction or erroneous boosts in response to single-point measurements.
 

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Upvote 1
Thank you!
Was the microphone fixed on a stand?
Have you been yourself at exactly the same position?
This time I left the mic lying on top of the sofa with the capsule end in free space. I could try it again using the stand included with the UMIK-1. The REW measurement was using the moving microphone method so exact same position doesn't apply. It is encouraging to see that the moving microphone method with REW is fairly close to the single point sweep measurement.
 
Hello! Thanks for the author, really helpful information, especially for newbies like me.)

I have finally received a Dayton Audio USB iMM-6C mic. Now planning to do some deep dive into RC. According to the above mentioned observations it is best to make RC inside the Wiim Ultra with the following settings?

Frequency range: 20-300hz
Max gain: 4db
Octave: 1/12
Target curve: BK

By the way, I was able to download the calibration file for the mic in the following official Dayton Audio website:

 
According to the above mentioned observations it is best to make RC inside the Wiim Ultra with the following settings?

Frequency range: 20-300hz
Max gain: 4db
Octave: 1/12
Target curve: BK
I don't think you can say universally that this is true.
 
How about Max Q, which is the preferred level?
Also difficult to tell as it defines how broad or narrow the correction can/should occure at a certain spot. I limit it to „4“. It also correlates with the smoothing factor…
 
Hello! Thanks for the author, really helpful information, especially for newbies like me.)

I have finally received a Dayton Audio USB iMM-6C mic. Now planning to do some deep dive into RC. According to the above mentioned observations it is best to make RC inside the Wiim Ultra with the following settings?

Frequency range: 20-300hz
Max gain: 4db
Octave: 1/12
Target curve: BK

By the way, I was able to download the calibration file for the mic in the following official Dayton Audio website:

20-300 Hz will be fine measuring from listening position.
300-20000 Hz has to be measured from a short distance of 70cm-1m from each L and R speaker to not give false measurement results, because of the precedence effect. Use a microphone stand for the measurements.

One can just use 20-300 Hz and after that, play around by ear with shelving filtering from listening position above 300 Hz. Sometimes its good enough.

Personal opinion: A Q value above 7 is not very useful. 1/12 octave is more exact than the ear, 1/6 is more the way we hear.
 
20-300 Hz will be fine measuring from listening position.
300-20000 Hz has to be measured from a short distance of 70cm-1m from each L and R speaker to not give false measurement results, because of the precedence effect. Use a microphone stand for the measurements.

One can just use 20-300 Hz and after that, play around by ear with shelving filtering from listening position above 300 Hz. Sometimes its good enough.

Personal opinion: A Q value above 7 is not very useful. 1/12 octave is more exact than the ear, 1/6 is more the way we hear.
there is a certain contradiction with the approach (which I also think of trying), of making a strong ls in the bass, event etc, in particular on a library... and this measurement at 20hz will have the effect of probably inflating the extreme bass... so you can try to observe the ls that you want to achieve and make a chirp above this and then add your "ls"...in the idea
;-)
 
You will have to describe in detail the capture mode and on what etc. :cool:
 
You will have to describe in detail the capture mode and on what etc. :cool:
Well, yes, but no matter how these curves for Rød and Blå were captured, the channel balance and overall response are quite impressive. :)
 
@canard These are a couple of years old, and I haven’t used the equipment since, so bear with me: It’s a Umik-1 and REW measurement in my listening position (140 cm spreaker-ear), sliding window, 1/6 oct smoothing. I have distortion, waterfall and RT60 plots too.
 
@canard These are a couple of years old, and I haven’t used the equipment since, so bear with me: It’s a Umik-1 and REW measurement in my listening position (140 cm spreaker-ear), sliding window, 1/6 oct smoothing. I have distortion, waterfall and RT60 plots too.
Is sliding window the Frequency Dependent Window feature of REW?
 
@canard These are a couple of years old, and I haven’t used the equipment since, so bear with me: It’s a Umik-1 and REW measurement in my listening position (140 cm spreaker-ear), sliding window, 1/6 oct smoothing. I have distortion, waterfall and RT60 plots too.
I don't really understand how you obtained such measurements in domestic conditions, and with a simple method, especially below 300Hz (sealed speakers
and "truncated" measures ?)...
but I learn something new every day...

if you remember?
;-)
 
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