Neumann KH120 II Monitor Review

[audafreak]

Some additions:
- I know of 2 people who reported this for the KH750 (not more), and zero in context of KH150 or KH120II.
- Found the link to the discussion about this topic: https://www.audiosciencereview.com/...-monitor-alignment.17902/page-35#post-1426050 (Posts 684 to 688, @audafreak)
- I personally use a digital connection from my RME UCX II to my 2 KH750s, but, for the peace of mind only, i configured Roon to resample everything to 48khz to take the Neumann resampler out of the equation. But like i said, i don´t really hear a difference. It is hard/impossible to make a valid test, though.

Thank you. I am also picking up RME UCX II. Don't need so many I/O's really, but I want access to TotalMix and want something better than Babyface. As for the connection to monitors, considering how trustworthy Neumann is, I think it's safe to just follow their recommendation and go with SPDIF coax.

Currently I use UCX2 via digital to Neumann. Before I used different HW ADI2 DAC FS via analog to Neuman. They are both connected currently but 99% use digi UCX2 with ARC USB.
Before I resampled everything in JRiver to 48kHz like DJBonoBobo but tried to resample only below 44 and above 192 and it seems trebles are more pronounced. So this is setup I use currently :
partial resampling
UCX2
- front KH750+2xKH80 spdif out
- surround 2xKH80 analog out

7.1 input from Jriver downmixed manually in Totalmix to 4.0, of course Lfe to FL/FR, BL/BR with some crosstalk to SL/SR.

ADI2 DAC is better dac then UCX2 so I would also recommend digital way from UCX2. Or connect both and you will see/hear. But if you want to use analog, disconnect SPDIF because this input has priority.

 

[hip_adductor]

ADI2 DAC is better dac then UCX2 so I would also recommend digital way from UCX2. Or connect both and you will see/hear

So you felt that digital sounded better via UCX2 compared to analoge with ADI-2?

 

[audafreak]

So you felt that digital sounded better via UCX2 compared to analoge with ADI-2?

Yes, after some time I felt on some record it is better but was not sure. So I decided not to compare anymore and go digital. Now I am thinking about replacing front KH80 with KH120II which have also digi input.

 

[vssyla]

Is anyone messing around with the eq controls on the back of the monitors? got my pair a week or so ago, and was instantly euphoric with the sound. Read the manual and now im getting around to messing with the built in eq controls. My room isnt treated very well (working on it lol), and per the manual i calibrated -2db Low/mid, -1db high, -2db bass. Opens up the sound a lot, but the low/mid are too subdued. losing detail/perception there. I feel like a 0.5db adjustment on the low/mid there would have it perfect. Thinking about opening equalizer APO again to do this, but the only issue is i cant find any frequency specs on the speaker eq controls (i.e, what frequencies/range are targeted in the low/mid eq). also not sure what the q-factor or shelf would be on the low/mid adjustment, or what the standard is anyhow. My last monitors didnt have low/mid adjustment options, so im new to it.

May end up getting a calibration mic and using REW to get unbiased sound.

In short I feel like the eq on the back of the monitors is very powerful/noticeable, even at the smallest adjustments. I could only get as far as in between an ideal sound with it on the low/mid. I might stray away from touching it until I get more info on what exact frequency ranges are being effected so i can fine tune in equalizer APO.

 

[DJBonoBobo]

Is anyone messing around with the eq controls on the back of the monitors? got my pair a week or so ago, and was instantly euphoric with the sound. Read the manual and now im getting around to messing with the built in eq controls. My room isnt treated very well (working on it lol), and per the manual i calibrated -2db Low/mid, -1db high, -2db bass. Opens up the sound a lot, but the low/mid are too subdued. losing detail/perception there. I feel like a 0.5db adjustment on the low/mid there would have it perfect. Thinking about opening equalizer APO again to do this, but the only issue is i cant find any frequency specs on the speaker eq controls (i.e, what frequencies/range are targeted in the low/mid eq). also not sure what the q-factor or shelf would be on the low/mid adjustment, or what the standard is anyhow. My last monitors didnt have low/mid adjustment options, so im new to it.

May end up getting a calibration mic and using REW to get unbiased sound.

In short I feel like the eq on the back of the monitors is very powerful/noticeable, even at the smallest adjustments. I could only get as far as in between an ideal sound with it on the low/mid. I might stray away from touching it until I get more info on what exact frequency ranges are being effected so i can fine tune in equalizer APO.

You can find this on the Neumann download page for the KH 120 II:

Source: https://www.neumann.com/downloadcenter/download?assetId=39032

The switches are always a compromise. A customized EQ filter is always better.

Edit: It looks like this is actually the KH150. I can´t find the diagram for the 120 II on the Neumann page, labels seem wrong. Anyway, they are very close - filters in the 150 are "shifted" a bit to the lower end.
Left 150, right 120II - by Sound & Recording

 

[IamJF]

Is anyone messing around with the eq controls on the back of the monitors? got my pair a week or so ago, and was instantly euphoric with the sound. Read the manual and now im getting around to messing with the built in eq controls. My room isnt treated very well (working on it lol), and per the manual i calibrated -2db Low/mid, -1db high, -2db bass. Opens up the sound a lot, but the low/mid are too subdued. losing detail/perception there. I feel like a 0.5db adjustment on the low/mid there would have it perfect. Thinking about opening equalizer APO again to do this, but the only issue is i cant find any frequency specs on the speaker eq controls (i.e, what frequencies/range are targeted in the low/mid eq). also not sure what the q-factor or shelf would be on the low/mid adjustment, or what the standard is anyhow. My last monitors didnt have low/mid adjustment options, so im new to it.

May end up getting a calibration mic and using REW to get unbiased sound.

In short I feel like the eq on the back of the monitors is very powerful/noticeable, even at the smallest adjustments. I could only get as far as in between an ideal sound with it on the low/mid. I might stray away from touching it until I get more info on what exact frequency ranges are being effected so i can fine tune in equalizer APO.

If you really want it precise ... get an MA-1 and do the calibration. Or borrow one if you are not sure.

 

[vssyla]

You can find this on the Neumann download page for the KH 120 II:
View attachment 314372
Source: https://www.neumann.com/downloadcenter/download?assetId=39032

The switches are always a compromise. A customized EQ filter is always better.

Edit: It looks like this is actually the KH150. I can´t find the diagram for the 120 II on the Neumann page, labels seem wrong. Anyway, they are very close - filters in the 150 are "shifted" a bit to the lower end.
Left 150, right 120II - by Sound & Recording
View attachment 314373View attachment 314374

ahh, didnt see these before. thank you!

 

[BubbleBuddy]

Hello everyone.

First time poster and newbie to the monitor world. I'm very tempted to upgrade to KH 120-IIs from my JBL 305p MkIIs and would love some experienced guidance.

My use case is mostly recreational listening with occasional monitoring when I practice and record guitars. My JBL speakers feel lackluster in bass performance and don't seem to capture the thump or shake of low notes. I'm seeking an endgame upgrade in the $3k AUD price range that offers better clarity across the board and especially better low-end extension and presence.

My room is 2.9m (9.5') deep and 2.7m (8.9') wide with the speakers sitting on my desk 30cm (12") from the back wall. I have done rudimentary sound treatment and hope the MA-1 adjustment could further compensate for the shortcomings. I'm in an apartment so it does not seem reasonable to add a subwoofer to my setup.

Would the KH 120-IIs be a significant upgrade to the 305p MkIIs in my use case? Should I consider other options for my goal of better bass response and fullrange clarity in a desktop 2-speaker setup? On paper these two models have similar frequency responses (44Hz-21kHz Neumann vs 49Hz-20kHz JBL) and similar driver sizes. Is there reason to think the KH 120-IIs would perform much better?

 

[DJBonoBobo]

Hello everyone.

First time poster and newbie to the monitor world. I'm very tempted to upgrade to KH 120-IIs from my JBL 305p MkIIs and would love some experienced guidance.

My use case is mostly recreational listening with occasional monitoring when I practice and record guitars. My JBL speakers feel lackluster in bass performance and don't seem to capture the thump or shake of low notes. I'm seeking an endgame upgrade in the $3k AUD price range that offers better clarity across the board and especially better low-end extension and presence.

My room is 2.9m (9.5') deep and 2.7m (8.9') wide with the speakers sitting on my desk 30cm (12") from the back wall. I have done rudimentary sound treatment and hope the MA-1 adjustment could further compensate for the shortcomings. I'm in an apartment so it does not seem reasonable to add a subwoofer to my setup.

Would the KH 120-IIs be a significant upgrade to the 305p MkIIs in my use case? Should I consider other options for my goal of better bass response and fullrange clarity in a desktop 2-speaker setup? On paper these two models have similar frequency responses (44Hz-21kHz Neumann vs 49Hz-20kHz JBL) and similar driver sizes. Is there reason to think the KH 120-IIs would perform much better?

First you need a measurement at your listening position to see what your problem in bass is. It is very likely you have severe dips in your room that are not the fault of the speaker. Typical is a severe dip between 70 and 100 Hz. A different speaker probably won't help with that. Good bass in a small, almost square room is hard to achieve. Multisub, maybe.

 

[dominikz]

Hello everyone.

First time poster and newbie to the monitor world. I'm very tempted to upgrade to KH 120-IIs from my JBL 305p MkIIs and would love some experienced guidance.

My use case is mostly recreational listening with occasional monitoring when I practice and record guitars. My JBL speakers feel lackluster in bass performance and don't seem to capture the thump or shake of low notes. I'm seeking an endgame upgrade in the $3k AUD price range that offers better clarity across the board and especially better low-end extension and presence.

My room is 2.9m (9.5') deep and 2.7m (8.9') wide with the speakers sitting on my desk 30cm (12") from the back wall. I have done rudimentary sound treatment and hope the MA-1 adjustment could further compensate for the shortcomings. I'm in an apartment so it does not seem reasonable to add a subwoofer to my setup.

Would the KH 120-IIs be a significant upgrade to the 305p MkIIs in my use case? Should I consider other options for my goal of better bass response and fullrange clarity in a desktop 2-speaker setup? On paper these two models have similar frequency responses (44Hz-21kHz Neumann vs 49Hz-20kHz JBL) and similar driver sizes. Is there reason to think the KH 120-IIs would perform much better?

Welcome!
Before changing the speakers I'd suggest to invest in a measurement mic and see what kind of in-room response you're getting from your current pair. Perhaps there's some chance to optimize with placement and room EQ.
Also, I'd use higher stands for the speakers so that the tweeter is at ear height (and further from the desk surface).
Lastly, a small sub can help a lot with room effects (especially SBIR) without adding too much low frequency extension. I use an Adam Sub7 for my apartment desktop system (link).

EDIT: By the way, I upgraded from JBL LSR305 (1st gen) to Neumann KH 120A for my desktop system a while ago. While I thought the upgrade was worthwhile, I wouldn't say it was a huge improvement in sound quality. Naturally I had very similar bass issues with either loudspeaker pair since I used both at the same location. Bass issues were largely resolved by parametric EQ (to cut audible bass resonances) and by adding a sub to combat the large SBIR suckout - this would work with either pair of loudspeakers.

 

[IamJF]

KH120ii + MA1 should be a noticeable upgrade - but when playing instruments live over monitors you need a lot more SPL as with normal listening. For guitar it should be fine, lound bass guitar would need bigger speakers.
Would a combination of KH750 + KH80 + MA1 fit in your budget? My bass player has these and is very happy.

The rest - what the others say. Speakerposition! Do some tests in your room, do measurements, try stuff like putting them on the floor or in the corner and listen to the bass.
And your room could need a lot more absorption! Especially in a small room it's important to get some control in these higher modal frequencies. Naked corners in a music room ... such an opportunity ...

 

[BubbleBuddy]

First you need a measurement at your listening position to see what your problem in bass is. It is very likely you have severe dips in your room that are not the fault of the speaker. Typical is a severe dip between 70 and 100 Hz. A different speaker probably won't help with that. Good bass in a small, almost square room is hard to achieve. Multisub, maybe.

KH120ii + MA1 should be a noticeable upgrade - but when playing instruments live over monitors you need a lot more SPL as with normal listening. For guitar it should be fine, lound bass guitar would need bigger speakers.
Would a combination of KH750 + KH80 + MA1 fit in your budget? My bass player has these and is very happy.

The rest - what the others say. Speakerposition! Do some tests in your room, do measurements, try stuff like putting them on the floor or in the corner and listen to the bass.
And your room could need a lot more absorption! Especially in a small room it's important to get some control in these higher modal frequencies. Naked corners in a music room ... such an opportunity ...

KH120ii + MA1 should be a noticeable upgrade - but when playing instruments live over monitors you need a lot more SPL as with normal listening. For guitar it should be fine, lound bass guitar would need bigger speakers.
Would a combination of KH750 + KH80 + MA1 fit in your budget? My bass player has these and is very happy.

The rest - what the others say. Speakerposition! Do some tests in your room, do measurements, try stuff like putting them on the floor or in the corner and listen to the bass.
And your room could need a lot more absorption! Especially in a small room it's important to get some control in these higher modal frequencies. Naked corners in a music room ... such an opportunity ...

Thanks for your responses! I honestly hoped to hear that the KH120ii's would be a major drop-in upgrade without having to rethink my setup. My speaker position is pretty restricted, but I've thought about adding bass traps to the rear corners of my room if that would be worthwhile (further research TBD). Should I not expect the KH120ii's to give much better bass performance than my 305p's even in the same environment?

I went to a showroom yesterday and directly compared the last-gen KH120 against the Genelec 8030C, Yamaha HS5, ADAM T5V, and KRK ROKIT 5. In the same room, the KH120 and 8030C seemed to produce drastically deeper and fuller bass than any of the lower-end models. Unfortunately they didn't have the JBL 305p to do an A/B comparison, but I assume it would have been similar to the HS5 and others. Does this not seem right? I'll have to check again and make sure the high-end samples didn't sneakily include a subwoofer that I didn't notice...

EDIT: I would also love to try some room measurements but only have my phone and a basic USB desk mic to record with. I'll do some research and see if I can figure out how you guys produce those SPL/frequency response charts!

 

[mmi]

In the same room, the KH120 and 8030C seemed to produce drastically deeper and fuller bass than any of the lower-end models.

If you want bass I wouldn’t shy away from trying some other speakers. I recently AB’d KH120s and 8030s against Dynaudio BM5mk3s and, given the use case I was imagining (living room) preferred the Dynaudio’s simply because they sounded 90% as clear but dug a lot deeper.

 

[dominikz]

Thanks for your responses! I honestly hoped to hear that the KH120ii's would be a major drop-in upgrade without having to rethink my setup. My speaker position is pretty restricted, but I've thought about adding bass traps to the rear corners of my room if that would be worthwhile (further research TBD). Should I not expect the KH120ii's to give much better bass performance than my 305p's even in the same environment?

I went to a showroom yesterday and directly compared the last-gen KH120 against the Genelec 8030C, Yamaha HS5, ADAM T5V, and KRK ROKIT 5. In the same room, the KH120 and 8030C seemed to produce drastically deeper and fuller bass than any of the lower-end models. Unfortunately they didn't have the JBL 305p to do an A/B comparison, but I assume it would have been similar to the HS5 and others. Does this not seem right? I'll have to check again and make sure the high-end samples didn't sneakily include a subwoofer that I didn't notice...

EDIT: I would also love to try some room measurements but only have my phone and a basic USB desk mic to record with. I'll do some research and see if I can figure out how you guys produce those SPL/frequency response charts!

Any loudspeaker's bass performance will be largely affected by the room it is in, and by where you put it (and yourself) in the room. Simply put - at low frequencies the room will overlay it's own response over any loudspeaker you put in the same spot. Unfortunately that means that any drop-in upgrade may not provide the desired step-up in sound quality.
BTW, the difference in anechoic low-frequency extension between the JBL 305P MKII and Neumann KH 120 II is around 6Hz - that is approximately two semitones (E1 vs F#1), looking at the fundamental frequency.

This is why it really pays off to learn to measure and tune the in-room response. If you're after great bass quality really there's no better place to start than to do in-room measurements (I advocate the moving microphone method - MMM).
Regarding measurements and speaker setup, I've collected short instructions with some references recently for a different member, perhaps you will find it useful: link.

If you only have a desk mic for now, I'd still suggest to try and do some REW measurements with it - while the results will not be absolutely accurate (since you don't have the mic calibration curve), they may provide qualitative guidance on issues you might be seeing - e.g. you might detect bass suckout is happening at certain frequencies and you could then play with loudspeaker placement and see how the response changes.
If your microphone is omnidirectional and flat at low frequencies you might even get results comparable to a calibrated measurement mic at low frequencies - see this comparison I did between Rode NT2A in omni mode vs a 3rd party calibrated Dayton EMM-6.
Still, I'd suggest to get a calibrated measurement microphone so you have a known point of reference going forward.

Hope this is helpful!

 

[IamJF]

Thanks for your responses! I honestly hoped to hear that the KH120ii's would be a major drop-in upgrade without having to rethink my setup. My speaker position is pretty restricted, but I've thought about adding bass traps to the rear corners of my room if that would be worthwhile (further research TBD). Should I not expect the KH120ii's to give much better bass performance than my 305p's even in the same environment?

When your problem is with the ROOM and positioning no speaker will solve that.
KH120ii will give a better bass performance but when you are sitting at an chancellation point you will not hear it.
So you can just buy them and give it a try or do some measurements and look what's the problem and then be sure new speakers wil help.

I went to a showroom yesterday and directly compared the last-gen KH120 against the Genelec 8030C, Yamaha HS5, ADAM T5V, and KRK ROKIT 5. In the same room, the KH120 and 8030C seemed to produce drastically deeper and fuller bass than any of the lower-end models. Unfortunately they didn't have the JBL 305p to do an A/B comparison, but I assume it would have been similar to the HS5 and others. Does this not seem right? I'll have to check again and make sure the high-end samples didn't sneakily include a subwoofer that I didn't notice...

KH120ii bass performance is really good for the size.
But when you are mainly into getting way more bass - check a subwoofer and learn how to measure to do a proper setup. Or buy KH750 + MA-1 and let them do the setup ;-) (and later upgrade to KH80 or KH120ii)

EDIT: I would also love to try some room measurements but only have my phone and a basic USB desk mic to record with. I'll do some research and see if I can figure out how you guys produce those SPL/frequency response charts!

Don't do measurements with a cardiod mic - when you can't rely on them they are worthless and lead to false conclusions.

Corner bass traps are always good to have! But they are (by far) not enough to fight standing waves. My first advice when doing acoustics in small rooms - think in surfaces, not panels. You need a lot to bring control in such a room. But it's the best investment you can do.

 

[dominikz]

Corner bass traps are always good to have! But they are (by far) not enough to fight standing waves.

Agreed. Also, corner bass traps usually won't help at all with SBIR-induced peaks and nulls which can cause severe bass suck-out and/or resonances.

Corner bass traps are always good to have! But they are (by far) not enough to fight standing waves. My first advice when doing acoustics in small rooms - think in surfaces, not panels. You need a lot to bring control in such a room. But it's the best investment you can do.

Unfortunately room acoustics improvement is not a simple matter, and there are even conflicting views on what the goal should be in 'small' rooms.
E.g. while most conventional studio control rooms are heavily treated, dr. Floyd Toole argues (in "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms", which I highly recommend reading for anyone interested in HiFi) that heavy treatment is not necessary in normally furnished rooms if well-designed loudspeakers are used, properly positioned, properly integrated with subwoofer(s) and if room EQ is applied to the low frequencies. This view is often contested, but I haven't really seen any compelling hard evidence to the contrary.

So personally I'd always recommend to first try to optimize what one already has (e.g. by playing with positioning and EQ), and then to see if any additional investment is needed.

 

[IamJF]

I did a lot of work in and with small rooms and a part of my bussines is room acoustics.
Toole has the view of doing acoustics for CONSUMERS. There is a lot of content how side reflections are beneficial etc.
That's not what I am searching in a professional critical listening environment! There are different ways to do that but MY way for my situation was to implement a non environment room - so very little room influence. And this worked out very well, never had mixes translate so good. Cause you simply hear what's on your source and mixing decisions are clear and easier.
For causual listening - this room is not enjoyable for many. I love the precision but people miss the "surrounding, integration" of the sound and the room. And that's fine - having a glass of wine and relax you probably don't want to hear that the mic was on the edge of distortion during recording or that the compressor from the bass is pumping a little to much. You want a surrounding experience, to be with the musicians.

So my advice for CRITICAL listening - get some basic absorption first (which is already a lot) and then do some measurements to finetune. Don't hang a few pannels - wasted money, it's not enough. And when you want to build a dedicated room and take it serious - choose an acoustic concept and go for it: https://www.soundonsound.com/techniques/sos-guide-control-room-design
My room only startet to work really good after doing a proper on/in wall speaker installation - which is part of the design. But now it's a joy to work with.

(You need to get controll in the 80-250Hz area in small rooms - this is where the "boxy" sound comes from (these resonances are higher as in big, open rooms). And get multi sub/double bass array/at least good positioning + EQ or other geometrical approaches for the frequency response lower than that. There are great absorbers to save space like BCA. Do A LOT at the ceiling. And you can gete a room you can professionally work with)

 

[dominikz]

I did a lot of work in and with small rooms and a part of my bussines is room acoustics.
Toole has the view of doing acoustics for CONSUMERS. There is a lot of content how side reflections are beneficial etc.
That's not what I am searching in a professional critical listening environment! There are different ways to do that but MY way for my situation was to implement a non environment room - so very little room influence. And this worked out very well, never had mixes translate so good. Cause you simply hear what's on your source and mixing decisions are clear and easier.
For causual listening - this room is not enjoyable for many. I love the precision but people miss the "surrounding, integration" of the sound and the room. And that's fine - having a glass of wine and relax you probably don't want to hear that the mic was on the edge of distortion during recording or that the compressor from the bass is pumping a little to much. You want a surrounding experience, to be with the musicians.

So my advice for CRITICAL listening - get some basic absorption first (which is already a lot) and then do some measurements to finetune. Don't hang a few pannels - wasted money, it's not enough. And when you want to build a dedicated room and take it serious - choose an acoustic concept and go for it: https://www.soundonsound.com/techniques/sos-guide-control-room-design
My room only startet to work really good after doing a proper on/in wall speaker installation - which is part of the design. But now it's a joy to work with.

(You need to get controll in the 80-250Hz area in small rooms - this is where the "boxy" sound comes from (these resonances are higher as in big, open rooms). And get multi sub/double bass array/at least good positioning + EQ or other geometrical approaches for the frequency response lower than that. There are great absorbers to save space like BCA. Do A LOT at the ceiling. And you can gete a room you can professionally work with)

Sorry if my previous post came out as overly critical or argumentative - it was not my intention. I of course agree that some people may prefer the specific sound presentation that various kinds of room treatment may bring, and I see nothing wrong with that.

But most people don't have the luxury to experience different types of treated rooms under similar conditions to test their preference. Further, I'm personally not aware of any formal research confirming that e.g. acoustic non-environment is preferable for tasks like mixing and production, which is why I'm cautious about such topics (even if treatment is widely adopted in the industry; note that this is not evidence in itself). If such research exists I'd be very interested in it!

• EDIT: One of the very few relevant studies I know of is this AES article by King et al. Apparently the conclusion was that audio professionals could quickly adapt to any of the tested environments, and that otherwise test subjects had different individual preferences regarding lateral reflections (though it seems these preferences couldn't be unambiguously linked to success in the mixing task). They did however notice that strong lateral energy impacted mixing performance initially, but subjects soon adapted and could work efficiently. The study and some of its conclusions were mentioned in this Audioholics article.
• EDIT2: I just found this AES article by Leonard et al that found the environment was a significant factor when mixing reverb - apparently more reverb was applied when mixing in the less reflective environment, but the reverb level preference distribution was narrower when mixing in the more reflective environment. Both studies are referenced in chapter 3.4 of this MSc thesis.

Investing in room treatment can be pricy, and on the other hand there is a chance people might be happy already after doing simple repositioning and EQ (which is cheap) - this is why I tend to recommend the latter as a first step.

 

[hip_adductor]

Guys, any suggestions with this latest measurement? KH120II x 2 and KH750 x 1 to the immediate left of my left monitor. Placement options limited.

 

[IamJF]

Sorry if my previous post came out as overly critical or argumentative - it was not my intention. I of course agree that some people may prefer the specific sound presentation that various kinds of room treatment may bring, and I see nothing wrong with that.

But most people don't have the luxury to experience different types of treated rooms under similar conditions to test their preference. Further, I'm personally not aware of any formal research confirming that e.g. acoustic non-environment is preferable for tasks like mixing and production, which is why I'm cautious about such topics (even if treatment is widely adopted in the industry; note that this is not evidence in itself). If such research exists I'd be very interested in it!

• EDIT: One of the very few relevant studies I know of is this AES article by King et al. Apparently the conclusion was that audio professionals could quickly adapt to any of the tested environments, and that otherwise test subjects had different individual preferences regarding lateral reflections (though it seems these preferences couldn't be unambiguously linked to success in the mixing task). They did however notice that strong lateral energy impacted mixing performance initially, but subjects soon adapted and could work efficiently. The study and some of its conclusions were mentioned in this Audioholics article.
• EDIT2: I just found this AES article by Leonard et al that found the environment was a significant factor when mixing reverb - apparently more reverb was applied when mixing in the less reflective environment, but the reverb level preference distribution was narrower when mixing in the more reflective environment. Both studies are referenced in chapter 3.4 of this MSc thesis.

Investing in room treatment can be pricy, and on the other hand there is a chance people might be happy already after doing simple repositioning and EQ (which is cheap) - this is why I tend to recommend the latter as a first step.

Non environment is just one solution for a neutral listening room! I know colleagues who would never work in such a room

The problem starts with a small room. It's very hard to get at least the first 10ms free of reflections which would be the minimum for a neutral listening setup. Diffusion only works in a pretty narrow bandwidth (not frequency neutral!) or only redirects the sound (half round "diffusors", easy to build and help against flutter but not "real" diffusion. I like them a lot ). And you need some distance to diffusors - otherwise you get combfiltering!
Many concepts with a more live acoustic simply require big and high rooms.

In former times you also needed a big room for non environment cause you needed about 1m for the absorption. A 3,2m x 5m x 2,7m room ... you have 1m width left . Which of course didn't stop me and with the help of modern developments (BCA, DBA etc) you can also realise the concept in a much smaller room.

If you ever experienced a controlled listening situation ... you are not happy with a reverberant and mushy room . But most people don't know the difference, even hobby musicians/mixers often don't know rooms with good control at low frequencies. (Foam panels don't do that ... regardless what manufacturers say. Physics and not advertisment)
Acoustic materials are not expensive and available in your hardware store! But you need to know what to do and build your room yourself, it takes time.