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Hello all,
This will be a summary of (many
) measurements I did with the Neumann KH 120A that I recently purchased.
The pair were manufactured in 2013 and sport the older, IMO slightly industrial looking finish:
A few notes on measurement methodology:
The stand itself is 85cm tall, but I can extend it to about 115cm by putting my desktop monitor stand on top - which puts the speaker at more-or-less ideal height for measuring in my room (midpoint between floor and ceiling) - which is how I measured.
Basic measurements
Anyway, here's the spinorama for one of the units:
Preference rating as calculated by VituixCAD is:
We can see port resonances are well attenuated, but there is a visible, though low-in-level, resonance (~1,6kHz) around the crossover.
Horizontal directivity to 90 degrees:
Again we can see a bit of resonance coming up around 1,6kHz at very off-axis angles. Overall it looks really good, as off-axis response is very similar to on-axis in shape, with just the slope changing as we move more off-axis.
Horizontal directivity (normalized to on-axis response):
Vertical directivity (normalized to on-axis response; we can see here that crossover and acoustic response is indeed optimized for the specified acoustic axis):
Comparisons
Here's how the spin compares to a Klippel NFS spin published by Neumann here:
As mentioned, the nearfield measurement below 350Hz is not fully reliable and is only qualitative, and resolution until ~1kHz is relatively low due to the 6ms gate - but we still have a pretty good match.
Above 1kHz, where I expect a close match of the two methods, we also see a few small deviations, namely:
However, since I collected the data, here's a couple more comparisons:
As you can see, unit-to-unit variance is pretty low, most of it being in the crossover area (but still within less than 1dB)!
Here's how the same unit measured at two different microphone distances compares:
The differences are marginal. There's a bit more difference in the 300-900Hz range - but this is mostly due to use of different temporal gates, mandated by the measurement distance. Resolution in this range is pretty low anyway.
Distortion
These THD measurements were done in-room at 50cm distance from tweeter, while SPL on the graphs is scaled for 1m distance (i.e. reduced by 6dB due to distance doubling).
I'm only showing 2nd, 3rdand 5th harmonic to make the graphs less busy (as these dominate the THD anyway) and total THD (2-9th harmonic).
[EDIT 2021-10-02] Additional distortion measurements added in post #14.
Unfortunately I didn't really measure any high-SPL, but up until ~84 dB SPL that I did measure the distortion seems pretty low!
Let's see how THD of both my units matches:
Seems pretty close - again showing very good unit-to-unit matching - better than my previous (though much cheaper) JBL LSR305s.
In-room measurements
I use these on my desktop at about 70cm listening distance - so very nearfield. Therefore I'd expect the in-room response to track the LW pretty well in HF.
As we can see the match to quasi-anechoic LW is pretty impressive above ~1,2kHz! You can also see I have a very severe resonance at my listening position around 130Hz - this I'm normally compensating with the EQ within RME TotalMix SW - however all EQ was disabled for the above measurement.
Equalization
Next I designed a flat-LW-target EQ in REW based on the average of both unit's LW:
The preference score also rises to 6,6 (8,6 with sub).
If I now apply LW-based EQ above 300 Hz and MMM-based in-room EQ below 300 Hz, I get the following in-room response (the two pairs of responses are scaled for better visibility):
The peak around 430Hz and the dips before and after look problematic on paper, but I can't hear them with music - or even when trying to pin-point them with a slow-moving sine sweep. On the other hand the narrow (but deep null) around 206Hz is very audible with a sine sweep (but not with music).
Also, in the uncorrected response, the huge room resonance around 130Hz is very audible (with both music and sweeps).
Interesting thing is that there is 0,7dB difference in level between my channels when uncorrected - but this could be aligned with the input gain pot on the monitors or the RME balance control.
The EQ-ed response sounds pretty good to me - all in all! Though I have to say that normally I just use the 3-band RME TotalMix EQ to correct the few larger resonances below ~300Hz and call it a day - I wouldn't say heavy DSP correction we see in graphs above is really needed to enjoy speakers as good as these.
Conclusion
I'm pretty impressed by these speakers - technically they are a clear step-up from the budget monitors I had before. Unit-to-unit consistency is amazing, and match to vendor-provided data is very good - both huge pluses for Neumann in my book!
They of course also sound great, but as I said before, IMHO diminishing returns set-in pretty early in audio these days and one can get pretty similar sound with nice-measuring budget monitors (at least at lower SPLs). Still, there is something to said for owning something as well made and engineered as the KH120As - I'm definitely enjoying mine
In case @MZKM and/or @pierre (or others) might be interested to do their magic, CTA-2034-A exports from VCAD are attached as well.
[EDIT 2021-10-05] Added step response plot comparison in post #15.
This will be a summary of (many
) measurements I did with the Neumann KH 120A that I recently purchased.The pair were manufactured in 2013 and sport the older, IMO slightly industrial looking finish:
A few notes on measurement methodology:
- The loudspeaker has been measured at ~130cm distance from any reflective surfaces, with the microphone at 50cm distance from the speaker (I also remeasured at 1m to confirm the results, as you will see below), so the first reflection was around 6ms after the main impulse.
- The reflections were removed by temporal gating at ~6ms in REW to get some (low) resolution of quasi-anechoic measurement down to about 200-300Hz range (resolution is much better above ~1kHz).
- LF response (<350Hz) is spliced from nearfield measurement and therefore not absolutely accurate (especially since one cannot directly access the woofer due to the non-removable grille). Take the absolute shape of the response there with a few grains of salt.
- The loudspeaker front baffle was vertically aligned with center of speaker stand/turntable rotation
- Loudspeaker stand has been covered with a blanket to reduce potential reflections and care was taken to angle the microphone boom to minimize boom reflections
- Microphone was pointed to the manual specified acoustic axis (17cm from bottom and 9,1cm from side of loudspeaker), confirmed with laser level
- REW, Cross-Spectrum labs calibrated Dayton EMM-6 microphone and RME Babyface interface was used to measure, and VituixCAD to generate the spin (and exported with 1/24 octave resolution)
The stand itself is 85cm tall, but I can extend it to about 115cm by putting my desktop monitor stand on top - which puts the speaker at more-or-less ideal height for measuring in my room (midpoint between floor and ceiling) - which is how I measured.
Basic measurements
Anyway, here's the spinorama for one of the units:
Preference rating as calculated by VituixCAD is:
- Speaker alone: 6.1
- Speaker with sub: 8.1
We can see port resonances are well attenuated, but there is a visible, though low-in-level, resonance (~1,6kHz) around the crossover.
Horizontal directivity to 90 degrees:
Again we can see a bit of resonance coming up around 1,6kHz at very off-axis angles. Overall it looks really good, as off-axis response is very similar to on-axis in shape, with just the slope changing as we move more off-axis.
Horizontal directivity (normalized to on-axis response):
Vertical directivity (normalized to on-axis response; we can see here that crossover and acoustic response is indeed optimized for the specified acoustic axis):
Comparisons
Here's how the spin compares to a Klippel NFS spin published by Neumann here:
As mentioned, the nearfield measurement below 350Hz is not fully reliable and is only qualitative, and resolution until ~1kHz is relatively low due to the 6ms gate - but we still have a pretty good match.
Above 1kHz, where I expect a close match of the two methods, we also see a few small deviations, namely:
- In my measurement there is a bump in most curves around 1,6kHz. The bump is especially visible in off-axis responses but also in the port NF measurement (see graphs above).
- My measurements show a slightly larger directivity error around 2kHz
- My ER curve has an ~1dB dip 2-6kHz
[EDIT 2021-09-27]: The source of the ER difference has been identified as a calculation error in older Klippel SW by @napilopez in post #6 (fixed since then by Klippel), supported by the comparison graph of ER calculations vs Klippel in post #8.
However, since I collected the data, here's a couple more comparisons:
As you can see, unit-to-unit variance is pretty low, most of it being in the crossover area (but still within less than 1dB)!
Here's how the same unit measured at two different microphone distances compares:
The differences are marginal. There's a bit more difference in the 300-900Hz range - but this is mostly due to use of different temporal gates, mandated by the measurement distance. Resolution in this range is pretty low anyway.
Distortion
These THD measurements were done in-room at 50cm distance from tweeter, while SPL on the graphs is scaled for 1m distance (i.e. reduced by 6dB due to distance doubling).
I'm only showing 2nd, 3rd
[EDIT 2021-10-02] Additional distortion measurements added in post #14.
Unfortunately I didn't really measure any high-SPL, but up until ~84 dB SPL that I did measure the distortion seems pretty low!
Let's see how THD of both my units matches:
Seems pretty close - again showing very good unit-to-unit matching - better than my previous (though much cheaper) JBL LSR305s.
In-room measurements
I use these on my desktop at about 70cm listening distance - so very nearfield. Therefore I'd expect the in-room response to track the LW pretty well in HF.
As we can see the match to quasi-anechoic LW is pretty impressive above ~1,2kHz! You can also see I have a very severe resonance at my listening position around 130Hz - this I'm normally compensating with the EQ within RME TotalMix SW - however all EQ was disabled for the above measurement.
Equalization
Next I designed a flat-LW-target EQ in REW based on the average of both unit's LW:
This EQ improves the spin further (simulated in VituixCAD):
The preference score also rises to 6,6 (8,6 with sub).
If I now apply LW-based EQ above 300 Hz and MMM-based in-room EQ below 300 Hz, I get the following in-room response (the two pairs of responses are scaled for better visibility):
The peak around 430Hz and the dips before and after look problematic on paper, but I can't hear them with music - or even when trying to pin-point them with a slow-moving sine sweep. On the other hand the narrow (but deep null) around 206Hz is very audible with a sine sweep (but not with music).
Also, in the uncorrected response, the huge room resonance around 130Hz is very audible (with both music and sweeps).
Interesting thing is that there is 0,7dB difference in level between my channels when uncorrected - but this could be aligned with the input gain pot on the monitors or the RME balance control.
The EQ-ed response sounds pretty good to me - all in all! Though I have to say that normally I just use the 3-band RME TotalMix EQ to correct the few larger resonances below ~300Hz and call it a day - I wouldn't say heavy DSP correction we see in graphs above is really needed to enjoy speakers as good as these.
Conclusion
I'm pretty impressed by these speakers - technically they are a clear step-up from the budget monitors I had before. Unit-to-unit consistency is amazing, and match to vendor-provided data is very good - both huge pluses for Neumann in my book!
They of course also sound great, but as I said before, IMHO diminishing returns set-in pretty early in audio these days and one can get pretty similar sound with nice-measuring budget monitors (at least at lower SPLs). Still, there is something to said for owning something as well made and engineered as the KH120As - I'm definitely enjoying mine
In case @MZKM and/or @pierre (or others) might be interested to do their magic, CTA-2034-A exports from VCAD are attached as well.
[EDIT 2021-10-05] Added step response plot comparison in post #15.
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