My desktop 2.2 system was a pair of the Neumann KH120 and a pair of JBL LSR310S subwoofers. I purchased the Neumann KH310s right before Amir tested his unit. The KH310s were not cheap. In order to prove that I could indeed an improvement, I decided to blind test myself and find out whether I truly prefer the more expensive speakers.
The Setup
My signal path was MacBook->Motu M2->JBL LSR301S->KH310 or KH120. I connected the M2 with two TRS splitters so that the signal fed into both the LSR310S was stereo. The LSR310S is a typical studio subwoofer that has a built-in high pass filter and balanced in/out to the main speakers. This means when the sub is turned off, the main speakers are silent. I bought two remote controls and connected the receivers to the end of the subs’ power cords, allowing me to switch between the two subs within a few seconds. I tested and verified that one remote only worked with one receiver. I scrambled the identical remotes and marked them A and B using stickers. I piled the stickers off after finishing a set of listening tests, and repeated the process before testing the next set of samples.
The LSR310S extends to 27Hz, just barely covers the whole piano range. I could make it extend to 20Hz using Dirac but I did not do that during this test. Adding a sub to each pair of speakers gave them equal bass extension but not equal room resonance. However, the bass quality was not my focus. The point of adding a sub was to see which pair of speakers sound better when only playing above 80Hz.
The KH120s were placed on the outer side and KH310s on the inner side. I eliminated some visual and audio cues that could give it away. I put duct tapes on the subs’ indicator lights so that I wouldn’t know which sub is turned on. The subs would make a popping sound when powered on, therefore, I had to walk outside the room and then use the remotes. This way I couldn’t tell which sub was on, nor could I saw the Neumann indicator lights changing colors.
I was unable to randomize my samples because it was impossible for me to be unaware of which one of the remotes I just pressed. This means my samples had to be ABABABAB and couldn’t be scrambled in to something like ABBABAAB. I verified which speakers that A and B represented after I listened to a group of samples. I know this was imperfect.
I used only classical solo piano pieces as my test tracks for two reasons. A) When playing solo piano music, KH120 often sounded a little shrill, and I couldn’t fix that no matter how I change the placement or use Dirac to add a steep high-frequency tile. B) I needed the music to be as simple as possible. Having multiple instruments in a piece means more spatial information. The more complex the music was, the easier I could identify the speakers by their placements. I did not try to identify which speakers were playing from samples A and B. Rather, I simply put a check next to the samples that I found more pleasing.
The Measurements
@amirm has measured the KH310 a few weeks ago. Guy Layfield from Neumann has posted KH120’s measurements done at Kippel in Germany. Neumann’s website also provides detailed official measurements.
The responses below are my in-room measurements. Both were using Dirac full-range correction. These were taken when the KH120s and KH310s were placed individually before and after the test, not when they placed next to each other, and not when the responses I listened in my blind test.
Can you guess which pair of responses is the KH310+sub, and which pair is the KH120+subs?
The Result
I call a single A or B a sample, a pair of A B a trial, and 8 samples or 4 trials a set.
Set One: Nocturne Op. 9/1
B A B A B A B A
X√ X√ X√ √X
A is better on 3 trials, B is better on 1 trial.
A=KH120
B=KH310
Set Two: Prelude Op. 28/1
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Set Three: Prelude Op. 8/24
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Set Four: Etude Op. 10/1, Etude S. 144/3
A B A B A B A B
√X √X √X √X
A is better.
A=KH310
B=KH120
Set Five: Ballade Op. 2, Kavierstucke Op. 76/1, Glasswork, Etude No. 9
B A B A B A B A
X√ X√ X√ X√
A is better.
A=KH310
B=KH120
Set Six: Jeux d'eau, M. 30, Nocturne Op. 9/1, Ballade No. 1, Prelude Op. 28/1
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Total Preference of the KH310:
42/48 samples
21/24 trials
5.25/6 sets
Basically, except for the first 3 trials, I always preferred the sound of the KH310+sub over the KH120+sub in the following 21 trials.
Keep in mind that I couldn’t randomize the samples, I could only randomize the first 2 samples of each set. I think 5/6 is the best number to describe my sccuss rate, i.e., I preferred the KH310 five times out of the six first trials after the two remotes were scrambled.
The Impression
Blind Testing: As I mentioned before, KH120 often had a tiny bit of shrillness when playing classical solo piano pieces. The shrillness of KH120 was inaudible to me when playing symphonies, concertos, black metal, or pop songs, but it irritated me in a very subtle way when playing simple piano notes. KH310 simply does not sound shrill, and that was the main reason I prefer the KH310 in my test.
Sighted Listening: When listening to other genres of music, the gap between these speakers was painfully obvious. Even when the shrillness of the KH120 is not presented, the KH310 had more depth, clarity, authority, smoothness… you name it. Any subjective rhetoric that you are familiar with when switching to a bigger speaker can be used to describe what I heard.
I am not sure what causes the shrillness of the KH120. According to my measurements at my normal listening volume, Both the KH310 and the KH120 produced distortion below the noise floor of my room, so it probably wasn’t due to the distortion. Their frequency responses and directivity are similar, the smaller KH120 might even be better, so it probably wasn’t that either.
The shrillness is probably not caused by the tweeter but the woofer. I found one particularly shrill piano note from the sheet music of a piano piece. The fundamental of that note is at only 349Hz, meaning this note does not activate the tweeter until its sixth harmonic. My theory is that, when holding the tweeter and sub constant, the combination of a dome and a big woofer is better than a small woofer. Quite an obvious explanation, isn’t it? But it isn’t so obvious in the CEA2034 data.
The Afterthought
Neumann studio monitors are known for their near-flat on-axis frequency responses and well-controlled directivity behaviors. According to Harman’s research, these two merits, along with the bass extension, are the dominating factors for predicting the preference ratings of the listeners. The KH310 scored 6.2 standalone and 7.6 with sub. We don’t have the data to calculate a score for the KH120, but given its similarity to other Neumann and even Genelec speakers tested by the NFS, I assume the KH120 would score at least 6 standalone and 8 with sub. That should mean the KH120 is as good as the KH310, and the KH120+sub is as good as the KH310+sub, right?
Well, not from my experience.
If I remember correctly, @MZKM posted that the preference rating formula starts to underpredict the actual preference when the rating goes above 6. I believe this is the case here. From what I heard, If the KH120 was rated 6 standalone and 8 with sub, then the KH310 would be 10+. I have yet to find any piece of music that sounds better on the KH120+sub than on the KH310+sub. Even when the shrillness of the KH120 is not present, the KH310 still sounded much fuller and heavier, like if the sound was solid. The KH310 makes the KH120 sound like gas.
I am not throwing shade on Harman’s research. I chose these Neumann studio monitors mainly because their CEA2034 data and presumed preference ratings are quite good. The CEA2034 data available on ASR and other sites have helped me avoid many unworthy options. These measurements allowed me to purchase the KH120 and KH310 without audition and have no regrets. Nonetheless, they have limitations, and it is beyond my understanding of acoustics and speaker design to identify what these limitations are.
The Setup
My signal path was MacBook->Motu M2->JBL LSR301S->KH310 or KH120. I connected the M2 with two TRS splitters so that the signal fed into both the LSR310S was stereo. The LSR310S is a typical studio subwoofer that has a built-in high pass filter and balanced in/out to the main speakers. This means when the sub is turned off, the main speakers are silent. I bought two remote controls and connected the receivers to the end of the subs’ power cords, allowing me to switch between the two subs within a few seconds. I tested and verified that one remote only worked with one receiver. I scrambled the identical remotes and marked them A and B using stickers. I piled the stickers off after finishing a set of listening tests, and repeated the process before testing the next set of samples.
The LSR310S extends to 27Hz, just barely covers the whole piano range. I could make it extend to 20Hz using Dirac but I did not do that during this test. Adding a sub to each pair of speakers gave them equal bass extension but not equal room resonance. However, the bass quality was not my focus. The point of adding a sub was to see which pair of speakers sound better when only playing above 80Hz.
The KH120s were placed on the outer side and KH310s on the inner side. I eliminated some visual and audio cues that could give it away. I put duct tapes on the subs’ indicator lights so that I wouldn’t know which sub is turned on. The subs would make a popping sound when powered on, therefore, I had to walk outside the room and then use the remotes. This way I couldn’t tell which sub was on, nor could I saw the Neumann indicator lights changing colors.
I was unable to randomize my samples because it was impossible for me to be unaware of which one of the remotes I just pressed. This means my samples had to be ABABABAB and couldn’t be scrambled in to something like ABBABAAB. I verified which speakers that A and B represented after I listened to a group of samples. I know this was imperfect.
I used only classical solo piano pieces as my test tracks for two reasons. A) When playing solo piano music, KH120 often sounded a little shrill, and I couldn’t fix that no matter how I change the placement or use Dirac to add a steep high-frequency tile. B) I needed the music to be as simple as possible. Having multiple instruments in a piece means more spatial information. The more complex the music was, the easier I could identify the speakers by their placements. I did not try to identify which speakers were playing from samples A and B. Rather, I simply put a check next to the samples that I found more pleasing.
The Measurements
@amirm has measured the KH310 a few weeks ago. Guy Layfield from Neumann has posted KH120’s measurements done at Kippel in Germany. Neumann’s website also provides detailed official measurements.
The responses below are my in-room measurements. Both were using Dirac full-range correction. These were taken when the KH120s and KH310s were placed individually before and after the test, not when they placed next to each other, and not when the responses I listened in my blind test.
Can you guess which pair of responses is the KH310+sub, and which pair is the KH120+subs?
The Result
I call a single A or B a sample, a pair of A B a trial, and 8 samples or 4 trials a set.
Set One: Nocturne Op. 9/1
B A B A B A B A
X√ X√ X√ √X
A is better on 3 trials, B is better on 1 trial.
A=KH120
B=KH310
Set Two: Prelude Op. 28/1
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Set Three: Prelude Op. 8/24
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Set Four: Etude Op. 10/1, Etude S. 144/3
A B A B A B A B
√X √X √X √X
A is better.
A=KH310
B=KH120
Set Five: Ballade Op. 2, Kavierstucke Op. 76/1, Glasswork, Etude No. 9
B A B A B A B A
X√ X√ X√ X√
A is better.
A=KH310
B=KH120
Set Six: Jeux d'eau, M. 30, Nocturne Op. 9/1, Ballade No. 1, Prelude Op. 28/1
B A B A B A B A
√X √X √X √X
B is better.
A=KH120
B=KH310
Total Preference of the KH310:
42/48 samples
21/24 trials
5.25/6 sets
Basically, except for the first 3 trials, I always preferred the sound of the KH310+sub over the KH120+sub in the following 21 trials.
Keep in mind that I couldn’t randomize the samples, I could only randomize the first 2 samples of each set. I think 5/6 is the best number to describe my sccuss rate, i.e., I preferred the KH310 five times out of the six first trials after the two remotes were scrambled.
The Impression
Blind Testing: As I mentioned before, KH120 often had a tiny bit of shrillness when playing classical solo piano pieces. The shrillness of KH120 was inaudible to me when playing symphonies, concertos, black metal, or pop songs, but it irritated me in a very subtle way when playing simple piano notes. KH310 simply does not sound shrill, and that was the main reason I prefer the KH310 in my test.
Sighted Listening: When listening to other genres of music, the gap between these speakers was painfully obvious. Even when the shrillness of the KH120 is not presented, the KH310 had more depth, clarity, authority, smoothness… you name it. Any subjective rhetoric that you are familiar with when switching to a bigger speaker can be used to describe what I heard.
I am not sure what causes the shrillness of the KH120. According to my measurements at my normal listening volume, Both the KH310 and the KH120 produced distortion below the noise floor of my room, so it probably wasn’t due to the distortion. Their frequency responses and directivity are similar, the smaller KH120 might even be better, so it probably wasn’t that either.
The shrillness is probably not caused by the tweeter but the woofer. I found one particularly shrill piano note from the sheet music of a piano piece. The fundamental of that note is at only 349Hz, meaning this note does not activate the tweeter until its sixth harmonic. My theory is that, when holding the tweeter and sub constant, the combination of a dome and a big woofer is better than a small woofer. Quite an obvious explanation, isn’t it? But it isn’t so obvious in the CEA2034 data.
The Afterthought
Neumann studio monitors are known for their near-flat on-axis frequency responses and well-controlled directivity behaviors. According to Harman’s research, these two merits, along with the bass extension, are the dominating factors for predicting the preference ratings of the listeners. The KH310 scored 6.2 standalone and 7.6 with sub. We don’t have the data to calculate a score for the KH120, but given its similarity to other Neumann and even Genelec speakers tested by the NFS, I assume the KH120 would score at least 6 standalone and 8 with sub. That should mean the KH120 is as good as the KH310, and the KH120+sub is as good as the KH310+sub, right?
Well, not from my experience.
If I remember correctly, @MZKM posted that the preference rating formula starts to underpredict the actual preference when the rating goes above 6. I believe this is the case here. From what I heard, If the KH120 was rated 6 standalone and 8 with sub, then the KH310 would be 10+. I have yet to find any piece of music that sounds better on the KH120+sub than on the KH310+sub. Even when the shrillness of the KH120 is not present, the KH310 still sounded much fuller and heavier, like if the sound was solid. The KH310 makes the KH120 sound like gas.
I am not throwing shade on Harman’s research. I chose these Neumann studio monitors mainly because their CEA2034 data and presumed preference ratings are quite good. The CEA2034 data available on ASR and other sites have helped me avoid many unworthy options. These measurements allowed me to purchase the KH120 and KH310 without audition and have no regrets. Nonetheless, they have limitations, and it is beyond my understanding of acoustics and speaker design to identify what these limitations are.
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