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

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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 0
slartibartfast said:
I compared my USB UMIK-1 to an iMM6 both connected to a Pixel 3A. The UMIK-1 is the green curve, iMM6 is the red curve. I will try the iMM6 with an old Samsung S5 to compare later but the iMM6 is unusable when plugged into the headphone socket of the Pixel 3A.

View attachment 15880
Click to expand...
Here is another comparison with the iMM6 plugged into the headphone socket of an old Samsung S5. You can see it is nowhere near as bad as the Pixel 3A but has a severe roll off below 60Hz.

imm6s5_vs_umik1.jpg
 
MCG555 said:
No, it is not happening a lot at all. Not in bass - not with iphone.
So I wonder what else it might be in your system.
Click to expand...
Well, I already prof my case, so please prof your case🙂 Its not enough to say ”not” show your findings.
 
Dako said:
Well, I already prof my case, so please prof your case🙂 Its not enough to say ”not” show your findings.
Click to expand...

I am sorry. I do not have to proof anything.
I have posted so many things on this topic in the past x months.
It is all there in the various RC threads in this forum.
😊
 
Follow-Up with Umik-1 Measurements

I revisited the Wiim RC measurements using a iPad Mini (borrowed from a friend) in combination with an Umik-1 microphone The measurement procedure remained the same as before, relying on the REW MMM (Moving Microphone Method) to capture averaged in-room responses.
  • Purple = Wiim RC (20–300 Hz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve
Screenshot 2025-01-11 at 13.45.26.png

From Figure 1, it is clear that Wiim RC (20–300 Hz) (purple) closely aligns with REW MMM (20–300 Hz) (orange) when using the Umik-1. This suggests that the Wiim RC algorithm is highly effective for low-frequency correction without calibration file.

By contrast, in Figure 2, the Wiim RC (20–20 kHz) (blue) introduces significant discrepancies at higher frequencies—most likely because the Wiim software cannot apply a calibration file for the Umik-1, leading to less accurate results above the midrange.
  • Green = Uncorrected
  • Purple = Wiim RC (20–300 Hz)
  • Blue = Wiim RC (20–20 kHz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve

Screenshot 2025-01-11 at 13.45.14.png

Conclusion: When Wiim RC is limited to 20–300 Hz and measured with a Umik-1, the outcome is very similar to REW MMM. This indicates Wiim’s room correction can be excellent, as long as the software has accurate measurement data and is restricted to the problem frequencies below ~300 Hz. When Wiim adds support for custom calibration file, the RC solution could become even more robust across the entire bandwidth.

One additional point worth noting is how consistently both Wiim RC (20–300 Hz) and REW MMM (20–300 Hz)maintain a smoother transition between sub-bass and mid-bass. If you look at the 70–150 Hz region, both curves follow a very similar contour, suggesting the algorithms effectively target the same modal peaks without producing any abrupt dips. By contrast, the full-range Wiim RC (20–20 kHz) shows more variability above 300 Hz, which highlights the importance of limiting correction to where it’s really needed—primarily below about 300 Hz in most rooms.

Another interesting observation is how the uncorrected response (green) may already be fairly balanced in parts of the midrange and treble, indicating that the LS60’s native design is solid beyond the low-frequency room interactions. The upshot is that if your speaker is already well-engineered (like the LS60), you usually won’t need significant mid or high-frequency adjustment, reinforcing the idea that limiting the correction range can yield the best overall result.
 
Dako said:
Follow-Up with Umik-1 Measurements

I revisited the Wiim RC measurements using a iPad Mini (borrowed from a friend) in combination with an Umik-1 microphone The measurement procedure remained the same as before, relying on the REW MMM (Moving Microphone Method) to capture averaged in-room responses.
  • Purple = Wiim RC (20–300 Hz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve
View attachment 16096

From Figure 1, it is clear that Wiim RC (20–300 Hz) (purple) closely aligns with REW MMM (20–300 Hz) (orange) when using the Umik-1. This suggests that the Wiim RC algorithm is highly effective for low-frequency correction without calibration file.

By contrast, in Figure 2, the Wiim RC (20–20 kHz) (blue) introduces significant discrepancies at higher frequencies—most likely because the Wiim software cannot apply a calibration file for the Umik-1, leading to less accurate results above the midrange.
  • Green = Uncorrected
  • Purple = Wiim RC (20–300 Hz)
  • Blue = Wiim RC (20–20 kHz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve

View attachment 16097

Conclusion: When Wiim RC is limited to 20–300 Hz and measured with a Umik-1, the outcome is very similar to REW MMM. This indicates Wiim’s room correction can be excellent, as long as the software has accurate measurement data and is restricted to the problem frequencies below ~300 Hz. When Wiim adds support for custom calibration file, the RC solution could become even more robust across the entire bandwidth.

One additional point worth noting is how consistently both Wiim RC (20–300 Hz) and REW MMM (20–300 Hz)maintain a smoother transition between sub-bass and mid-bass. If you look at the 70–150 Hz region, both curves follow a very similar contour, suggesting the algorithms effectively target the same modal peaks without producing any abrupt dips. By contrast, the full-range Wiim RC (20–20 kHz) shows more variability above 300 Hz, which highlights the importance of limiting correction to where it’s really needed—primarily below about 300 Hz in most rooms.

Another interesting observation is how the uncorrected response (green) may already be fairly balanced in parts of the midrange and treble, indicating that the LS60’s native design is solid beyond the low-frequency room interactions. The upshot is that if your speaker is already well-engineered (like the LS60), you usually won’t need significant mid or high-frequency adjustment, reinforcing the idea that limiting the correction range can yield the best overall result.
Click to expand...
Well observed! 👍🏻 Thank you for the thorough analyses and comparisons. It underlines my subjective impressions and experiences…
 
well done ....and thank you.... ;-)
(but there is nothing so surprising about sticking to corrections below 300hz in any case unless there are serious problems with the speakers... ;-) )
 
Last edited:
canard said:
well done ....and thank you.... ;-)
(but there is nothing so surprising about sticking to corrections below 300hz in any case unless there are serious problems with the speakers... ;-) )
Click to expand...
Thanks! I agree in principle—correcting only below 300 Hz is standard practice. However, if you look at the earlier measurements, you’ll see that the iPhone microphone did a poor job even in that range. I’m fairly certain most WiiM users aren’t using a Umik-1, so this comparison was aimed at the average user relying on a built-in phone mic.
 
Dako said:
Thanks! I agree in principle—correcting only below 300 Hz is standard practice. However, if you look at the earlier measurements, you’ll see that the iPhone microphone did a poor job even in that range. I’m fairly certain most WiiM users aren’t using a Umik-1, so this comparison was aimed at the average user relying on a built-in phone mic.
Click to expand...
This is why the use of the Dayton imm6 USB with its ADC (or non-USB) has been pointed out for a long time so that the "cal" provided can be used etc....
an affordable solution that is consistent with wiim consumer products...
 
Last edited:
Dako said:
Thanks! I agree in principle—correcting only below 300 Hz is standard practice. However, if you look at the earlier measurements, you’ll see that the iPhone microphone did a poor job even in that range. I’m fairly certain most WiiM users aren’t using a Umik-1, so this comparison was aimed at the average user relying on a built-in phone mic.
Click to expand...

That the iphone does a poor job is slighty exaggerated! 😉 It‘s in my case certainly much better than nothing!
 
Dako said:
Thanks! I agree in principle—correcting only below 300 Hz is standard practice. However, if you look at the earlier measurements, you’ll see that the iPhone microphone did a poor job even in that range. I’m fairly certain most WiiM users aren’t using a Umik-1, so this comparison was aimed at the average user relying on a built-in phone mic.
Click to expand...
But can’t you just adjust the frequencies manually that the iPhone exaggerates?
 
Well done!

Dako said:
Conclusion: When Wiim RC is limited to 20–300 Hz and measured with a Umik-1, the outcome is very similar to REW MMM. This indicates Wiim’s room correction can be excellent, as long as the software has accurate measurement data and is restricted to the problem frequencies below ~300 Hz. When Wiim adds support for custom calibration file, the RC solution could become even more robust across the entire bandwidth.
Click to expand...
This is pretty much what I had expected. The main drawback of WiiM RC is currently the lack of calibration file support, support for averaging over multiple mic positions should be the next thing to add.

Dako said:
By contrast, the full-range Wiim RC (20–20 kHz) shows more variability above 300 Hz, which highlights the importance of limiting correction to where it’s really needed—primarily below about 300 Hz in most rooms.
Click to expand...
If you import the calibration file of your UMIK-1 into REW as a frequency response (not as a cal file) you may find that quite some of the anomalies in the blue line, figure 2, above are reflected there (in inverted form). Sticking to the frequency range where room effects exist might not be a big surprise, but this is a fine proof why it makes sense.

I found with my UMIK-1 and UMIK-2 that the 90° calibration file (which equals the frequency response) is flatter than the 0° calibration (but does not extend much above 4 kHz, of course). So, if you decide to use WiiM RC into a slightly broader frequency range, pointing the UMIK-1 to the ceiling instead of the speakers can be beneficial. Having said that, the 90° calibrations are not directly measured, but calculated from the 0° calibration files, so there is an additional uncertainty.

But even if we get the ability to import calibration files into the WiiM Home app, I'm not convinced that doing a full range correction following a given target curve is the best thing to do. And this ...
Dako said:
Another interesting observation is how the uncorrected response (green) may already be fairly balanced in parts of the midrange and treble, indicating that the LS60’s native design is solid beyond the low-frequency room interactions. The upshot is that if your speaker is already well-engineered (like the LS60), you usually won’t need significant mid or high-frequency adjustment, reinforcing the idea that limiting the correction range can yield the best overall result.
Click to expand...
... is a good example why. Measuring a set of stereo speakers in a living room up to 20 kHz is relatively tricky and not absolutely necessary. Measuring (and optimising, using DSP) the anechoic response of a speaker is really easier to do. And as we see, a speaker that performs well under anechoic conditions will usually also perform well in room (except for the frequency range where the room dominates the response).

The LS60 Wireless is certainly a prime example for a perfectly engineered active speaker.
 
Dako said:
Follow-Up with Umik-1 Measurements

I revisited the Wiim RC measurements using a iPad Mini (borrowed from a friend) in combination with an Umik-1 microphone The measurement procedure remained the same as before, relying on the REW MMM (Moving Microphone Method) to capture averaged in-room responses.
  • Purple = Wiim RC (20–300 Hz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve
View attachment 16096

From Figure 1, it is clear that Wiim RC (20–300 Hz) (purple) closely aligns with REW MMM (20–300 Hz) (orange) when using the Umik-1. This suggests that the Wiim RC algorithm is highly effective for low-frequency correction without calibration file.

By contrast, in Figure 2, the Wiim RC (20–20 kHz) (blue) introduces significant discrepancies at higher frequencies—most likely because the Wiim software cannot apply a calibration file for the Umik-1, leading to less accurate results above the midrange.
  • Green = Uncorrected
  • Purple = Wiim RC (20–300 Hz)
  • Blue = Wiim RC (20–20 kHz)
  • Orange = REW MMM (20–300 Hz)
  • Red = Harman target curve

View attachment 16097

Conclusion: When Wiim RC is limited to 20–300 Hz and measured with a Umik-1, the outcome is very similar to REW MMM. This indicates Wiim’s room correction can be excellent, as long as the software has accurate measurement data and is restricted to the problem frequencies below ~300 Hz. When Wiim adds support for custom calibration file, the RC solution could become even more robust across the entire bandwidth.

One additional point worth noting is how consistently both Wiim RC (20–300 Hz) and REW MMM (20–300 Hz)maintain a smoother transition between sub-bass and mid-bass. If you look at the 70–150 Hz region, both curves follow a very similar contour, suggesting the algorithms effectively target the same modal peaks without producing any abrupt dips. By contrast, the full-range Wiim RC (20–20 kHz) shows more variability above 300 Hz, which highlights the importance of limiting correction to where it’s really needed—primarily below about 300 Hz in most rooms.

Another interesting observation is how the uncorrected response (green) may already be fairly balanced in parts of the midrange and treble, indicating that the LS60’s native design is solid beyond the low-frequency room interactions. The upshot is that if your speaker is already well-engineered (like the LS60), you usually won’t need significant mid or high-frequency adjustment, reinforcing the idea that limiting the correction range can yield the best overall result.
Click to expand...
I did a similar comparison to yours, comparing REW 25-300Hz Var smoothing to WiiM 25-300Hz 1/12 octave smoothing with a B&K target curve. A UMIK-1 was used for both measurements. While similar the WiiM results deviate more from the target.

Blue - WiiM RC
Green - REW MMM
Red - B&K target

REW vs WiiM.jpg
 

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slartibartfast said:
I did a similar comparison to yours, comparing REW 25-300Hz Var smoothing to WiiM 25-300Hz 1/12 octave smoothing with a B&K target curve. A UMIK-1 was used for both measurements. While similar the WiiM results deviate more from the target.

Blue - WiiM RC
Green - REW MMM
Red - B&K target

View attachment 16845
Click to expand...

Thank you!
Was the microphone fixed on a stand?
Have you been yourself at exactly the same position?
 
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