Neumann KH150

[kimmosto]

You are asking as a speaker designer. This is the wrong perspective (not inherently wrong, wrong for the question I asked you). The correct perspective is that of assessment, when the design decisions have already been made and you are looking at a complete product, like the KH150. So how should we assess waveguides? By using what data?

No. That was consumer's/your perspective. Designer, manufacture or audio salesman don't select speakers for you, build listening room acoustics, locate speakers and listening point and listen there so consumer/you should be able to study differences and optimize combination of speaker, listening setup and environment. Part of that is to understand or study empirically how different concepts/constructions interact with environment and how different spectrums such as acoustic resolution and soundstage depth can be controlled and balanced.

• Doesn't matter.

This may apply your small room, but generally EDT is one the most important parameter especially if preference is high acoustical resolution / low noise due to flutter echo.

• STI is an irrelevant metric in small rooms. This is used in large buildings, classrooms, lecture halls.

Very small rooms such as <15m^2 are special cases though octave transmission index is able to indicate acoustic noise and resolution also there. I've tested that analysis from tiny 6m^2 rooms to few hundreds of m^2, more than 50 speaker+room combinations within ca. two decades. It's not perfect and all inclusive for sure because it cannot "hear" for example effect of envelopment and 3D dimensions of sound stage, but it's easy and visual for revealing differences in acoustic resolution; level and especially balance. Note that I'm not talking about weighted total STI.

• DI is meaningless on its own since its based on aggregated data. You need access groups of curves to understand speakers.

That looks intentional misunderstanding. Please interpret so that individual responses and response groups such as on-axis, LW, ER, PIR, SP are kinda "ideal" i.e. linear, and tilt of those responses/groups variates so that we have few significantly different DI tilts to compare.

All I'm really asking for is some data or evidence which—separate from speaker directivity in general—shows that waveguides produce unnatural, not open, etc., sound. If all you are really talking about is directivity, then fine, all's clear and the conversation is over. But if you are saying that waveguides have some kind intrinsic weaknesses that produce a characteristic sound, then I want to know what that means.

Of course directivity variations such as too steep tilt down or clear step in power (and PIR and DI) are the most common errors I don't love. Many commercial applications have a bit too large and deep horn/wave guide for tweeter alone. That causes some power step and power dip at crossover range with phase-matched XO. Interaction with room splits into two different frequency bands. LF...MF has low acoustic resolution without very effective acoustic treatment, and tweeter range is very dry - mostly direct sound without natural sound distribution via room. Sound does not breathe in balanced way such as with natural instruments - especially to off-axis, and listener is kinda forced to hear details at HF. Perspective to music is narrowed because focus is at HF details.
Another common problem is unbalanced compression spectrum which turns sound bright and harsh when LF radiator heats up while HF compression driver with horn maintains pressure. So LF radiator and it's power amp should be quite much over-dimensioned to maintain balance. For example 10" woofer + 1" Ti driver in a horn could be a problem.
Horns can produce also higher IMD than separate direct radiators. This can be tested with (tractrix) horn with coaxial compression driver. Lower tone to mid and higher tone to tweeter range. IMD is not necessarily very bad, but it is there. I have few old measurements in archive, but usually I don't save this kind of data. Nothing you can do it so better to listen and try to forget.
Also NBD (near band deviation, familiar with preference rating) could be two...three times higher than with conventional hifi drivers. Some coloration may remain no matter how many PEQ bands we set to DSP to make ON and LW as flat as possible. Also this is highly case-dependent because there are better and worse equipment...
The last funny feature is quite emphasized/shooting sound of some transients and percussion. I've never tried to investigate actual reason, but it might be related to "unnatural" wavefront or/and flare. I don't have horns anymore at home so please don't continue to ask data.

 

[Grotti]

No. That was consumer's/your perspective. Designer, manufacture or audio salesman don't select speakers for you, build listening room acoustics, locate speakers and listening point and listen there so consumer/you should be able to study differences and optimize combination of speaker, listening setup and environment. Part of that is to understand or study empirically how different concepts/constructions interact with environment and how different spectrums such as acoustic resolution and soundstage depth can be controlled and balanced.

This may apply your small room, but generally EDT is one the most important parameter especially if preference is high acoustical resolution / low noise due to flutter echo.

Very small rooms such as <15m^2 are special cases though octave transmission index is able to indicate acoustic noise and resolution also there. I've tested that analysis from tiny 6m^2 rooms to few hundreds of m^2, more than 50 speaker+room combinations within ca. two decades. It's not perfect and all inclusive for sure because it cannot "hear" for example effect of envelopment and 3D dimensions of sound stage, but it's easy and visual for revealing differences in acoustic resolution; level and especially balance. Note that I'm not talking about weighted total STI.

That looks intentional misunderstanding. Please interpret so that individual responses and response groups such as on-axis, LW, ER, PIR, SP are kinda "ideal" i.e. linear, and tilt of those responses/groups variates so that we have few significantly different DI tilts to compare.

Of course directivity variations such as too steep tilt down or clear step in power (and PIR and DI) are the most common errors I don't love. Many commercial applications have a bit too large and deep horn/wave guide for tweeter alone. That causes some power step and power dip at crossover range with phase-matched XO. Interaction with room splits into two different frequency bands. LF...MF has low acoustic resolution without very effective acoustic treatment, and tweeter range is very dry - mostly direct sound without natural sound distribution via room. Sound does not breathe in balanced way such as with natural instruments - especially to off-axis, and listener is kinda forced to hear details at HF. Perspective to music is narrowed because focus is at HF details.
Another common problem is unbalanced compression spectrum which turns sound bright and harsh when LF radiator heats up while HF compression driver with horn maintains pressure. So LF radiator and it's power amp should be quite much over-dimensioned to maintain balance. For example 10" woofer + 1" Ti driver in a horn could be a problem.
Horns can produce also higher IMD than separate direct radiators. This can be tested with (tractrix) horn with coaxial compression driver. Lower tone to mid and higher tone to tweeter range. IMD is not necessarily very bad, but it is there. I have few old measurements in archive, but usually I don't save this kind of data. Nothing you can do it so better to listen and try to forget.
Also NBD (near band deviation, familiar with preference rating) could be two...three times higher than with conventional hifi drivers. Some coloration may remain no matter how many PEQ bands we set to DSP to make ON and LW as flat as possible. Also this is highly case-dependent because there are better and worse equipment...
The last funny feature is quite emphasized/shooting sound of some transients and percussion. I've never tried to investigate actual reason, but it might be related to "unnatural" wavefront or/and flare. I don't have horns anymore at home so please don't continue to ask data.

Sorry for being OT but may I ask, what speakers you have chosen for your home or office?

 

[kimmosto]

Sorry for being OT but may I ask, what speakers you have chosen for your home or office?

This must sound really weird, but I haven't had speakers for music in years at home or office. Just small JBL and Kef for TVs and tiny Scan-Speak FRs for kitchen radio. My wife can listen seasonal music with these KH150 while baking gingerbread cookies for Christmas Nothing (including almost all own commercial designs) has been good enough for me. Advantage of silence is that ears start in virgin mode without stress and biases for every speaker design project.

 

[Curvature]

No. That was consumer's/your perspective. Designer, manufacture or audio salesman don't select speakers for you, build listening room acoustics, locate speakers and listening point and listen there so consumer/you should be able to study differences and optimize combination of speaker, listening setup and environment. Part of that is to understand or study empirically how different concepts/constructions interact with environment and how different spectrums such as acoustic resolution and soundstage depth can be controlled and balanced.

I had a long discussion in another thread where I claimed that "optimization" is a very weak goal with loose tolerances when it comes to setting up speakers. https://www.audiosciencereview.com/...h420-review-studio-monitor.33529/post-1295237

I do not believe it is possible to effectively optimize speakers at the moment using traditional acoustic metrics, beyond ensuring, primarily, a good choice of speaker, sub integration and room EQ. Optimization in the mathematical sense, where you are aiming to satisfy particular criteria is possible, hence good waveguides and, in acoustical architecture, good modelling that predicts clarity, etc., for new buildings. I think for the most part, "optimization" in the nonrigorous sense of setting up speakers at home has such a wide range of satisfactory solutions that messing around and finally calling some arrangement good is, well, says more about the person doing it than anything else.

it's easy and visual for revealing differences in acoustic resolution; level and especially balance

Level I understand as SPL. By balance you mean frequency response? Or balance in the sense of frequency response differences between different channels?

high acoustical resolution / low noise due to flutter echo.

Perhaps by resolution you mean dampened reflections vs. direct sound? I wrote my views on that recently: https://www.audiosciencereview.com/...speakers-monitors.17448/page-116#post-1364306

Many commercial applications have a bit too large and deep horn/wave guide for tweeter alone. That causes some power step and power dip at crossover range with phase-matched XO. Interaction with room splits into two different frequency bands. LF...MF has low acoustic resolution without very effective acoustic treatment, and tweeter range is very dry - mostly direct sound without natural sound distribution via room. Sound does not breathe in balanced way such as with natural instruments - especially to off-axis, and listener is kinda forced to hear details at HF. Perspective to music is narrowed because focus is at HF details.
Another common problem is unbalanced compression spectrum which turns sound bright and harsh when LF radiator heats up while HF compression driver with horn maintains pressure. So LF radiator and it's power amp should be quite much over-dimensioned to maintain balance. For example 10" woofer + 1" Ti driver in a horn could be a problem.
Horns can produce also higher IMD than separate direct radiators. This can be tested with (tractrix) horn with coaxial compression driver. Lower tone to mid and higher tone to tweeter range. IMD is not necessarily very bad, but it is there. I have few old measurements in archive, but usually I don't save this kind of data. Nothing you can do it so better to listen and try to forget.
Also NBD (near band deviation, familiar with preference rating) could be two...three times higher than with conventional hifi drivers. Some coloration may remain no matter how many PEQ bands we set to DSP to make ON and LW as flat as possible. Also this is highly case-dependent because there are better and worse equipment...
The last funny feature is quite emphasized/shooting sound of some transients and percussion. I've never tried to investigate actual reason, but it might be related to "unnatural" wavefront or/and flare. I don't have horns anymore at home so please don't continue to ask data.

That's clear and fair, and thank you. I would consider all of this a discussion of frequency response in its 3D aspect, i.e., directivity. I seriously doubt the audibility of other areas. Take wavefronts, for example: it is impossible to have conventional speakers reproduce correct wavefronts. Physical reproduction wavefronts of would require spatial sampling on the recording side and complex arrays on the playback side. Psychoacoustically however I'm sure physical reproduction isn't necessary, since our ability to localize sound is loose, and doesn't map onto physical source locations. With conventional stereo (or unconventional, like UHJ), we are simply limited with regard to what we can expect our soundsystems to do. Maybe at some point better perceptual criteria will be defined that will simplify the problem and making speaker building simpler, for stereo or other playback concepts.

You asked what I prefer before: I'd say speakers are an incredible amount better than 20 years ago. But I'd prefer not to listen to speakers and instead be totally immersed in an audio scene indistinguishable from normal scenes. Whenever we hit that point speaker technology will have reached some apex where everything done until now will be considered archaic. That hasn't happened and isn't possible currently, so what I'm left with is a number of competing, contradictory approaches, none of which are perceptually accurate. So it becomes easier to listen to flaws. The only reason I would rank good waveguided speakers above, say, open baffle, is that I have not encountered examples with directivity that's as finely controlled as in the Neumann models.

Back to the KH 150. A lot of what you mention is in fundamentals of design and can be seen in the choices the Neumann engineers made. For example I think the notable change in slope for DI and ERDI just under 2kHz is audible, as are the low Q resonances off axis around 3kHz and 8.5kHz. This is definitely related to the waveguide, but I do not think alternative tweeter mountings are adequate or represent significant benefits. I'm confident that waveguide refinements in speaker design are as fundamental as modelling bass loading. Even a flat baffle is a waveguide: a flat one.

 

[kimmosto]

Level I understand as SPL. By balance you mean frequency response? Or balance in the sense of frequency response differences between different channels?

Already mentioned few times: level and balance of acoustic resolution (/clarity) as a function of frequency. Result is produced by combination of speaker, room acoustics and locations. Most powerful method to increase and equalize balance of clarity is room acoustics. Horn for tweeter alone is weak method though it is cheap to build and easy to sell because increases resolution where hearing is the most sensitive for details.
Anyway, I'm done with repeating and reading beliefs and long and complex theorizations.

 

[tktran303]

Anyway, I'm done with repeating and reading beliefs and long and complex theorizations.

From my POV if one is not active in R&D of loudspeaker design, nor is a transducer designer, one doesn't have the lucky fortune of having deeper understanding of the difficulties and challenges and thus potential solutions and their pros and cons. This is clearly elucidated when our friend thought we were calling out the waveguide decision as a flaw- it is not. A waveguide has many pros. And really only a few cons with need further elucidation.

For the sake of our other readers following along, may I take the liberty of answering your question Kimmo;

1) What are main targets for horns / wave guides?
2) Is there alternative solution(s) for horn / wave guide to achieve majority of main targets, and what they are?

1. The horn or waveguide simultaneously lifts the low end of the tweeter allowing a lower Fc on the high pass filter AND reduces the dispersion pattern on the top end. Third, it moves the acoustic centre backwards along the z-axis, which may facilitate easier/less parts for passive crossovers for phase alignment at the crossover frequency with the midwoofer. By lowering the crossover point one can cross over to a larger woofer than if using a raw tweeter alone. By using a larger woofer, that allows for higher displacement-limited SPL and lower non-linear distortion AND. By lowering the Fc of the tweeter, a more affordable tweeter can be used, compared to one that is more robust or has other design features that allows it to play lower. The marginal cost of the plastic waveguide/horn low, so once the initial tooling is done it's very affordable. So these are all wins for wave-guided dome tweeters. For high SPL the use of compression drivers with waveguides or horns allow for dispersion control, which is helpful in attenuating sound where it's not desired. Horns can be designed for all kinds of dispersion patterns. eg. 90x60, 80x50, 60x30 degrees, 110x20 degrees to direct the sound where it’s needed and away from where it’s not eg. Audience or performer.

Now in entirety, the KH150 measures very well. Perhaps a 6.5" 2-way I would buy, rather than waste time designing my own.

But could something perform equally well, or perhaps even better without a waveguide? Particularly when using small eg. 6.5” or smaller midwoofer? My answer is a resounding yes!

The alternative is to use a more robust tweeter that can crossover lower matched to a mid-woofer that has better dispersion. The downside it generally the more robust tweeter has features that may drive up the cost. However; another solution is to put smaller driver to help match the dispersion of the upper end of the woofer and the lower end of the tweeter. then a woofer is also needed. This add to the cost for an extra mid sized driver and band pass filter. All which adds to cost in a passive speaker. In an active speaker another amplifier is needed.

It's no wonder horns and waveguides have been picked up in the pro-audio and performance audio world; highly competitive/price sensitive and SPL output (throw distance) is of utmost importance. Many high value designs are 2 ways with waveguides but as one moves up the price ladder, it's not unusual that the top model is a 3 way with dedicated midrange.

 

[dickiefunk]

Wonder when Neumann are going to announce the KH120mk2's? Really curious to see if there are any significant changes other than adding DSP.

 

[FutureFrenzy]

Wonder when Neumann are going to announce the KH120mk2's? Really curious to see if there are any significant changes other than adding DSP.

I wonder if there is a dsp version planned for KH 310

 

[dickiefunk]

I wonder if there is a dsp version planned for KH 310

I seem to recall Neumann posting something stating that they are adding dsp to their entire range. Can’t remember where I read it though

 

[thewas]

I strongly doubt though it will be on the current KH310 but on its successor.

 

[Pearljam5000]

It's been available for a while and still no review anywhere

 

[thewas]

It's been available for a while and still no review anywhere

Sound & Recording has measured and reviewed it since some weeks https://www.soundandrecording.de/equipment/neumann-kh-150-2-wege-nearfield-monitor-im-test/

 

[Pearljam5000]

Sound & Recording has measured and reviewed it since some weeks https://www.soundandrecording.de/equipment/neumann-kh-150-2-wege-nearfield-monitor-im-test/

Thanks
But it's still weird there isn't more feedback and buzz around them

 

[hege]

Thanks
But it's still weird there isn't more feedback and buzz around them

To be fair, it's still just a basic 6.5" 2-way studio monitor. While very good, not very cheap. It's nice that it has DSP. I don't personally see what is so exciting or groundbreaking about it. Again, it's probably great for it's purposes.

 

[sibi1865]

I seem to recall Neumann posting something stating that they are adding dsp to their entire range. Can’t remember where I read it though

If so, it would be nice if that included retrofits.

 

[badboygolf16v]

If so, it would be nice if that included retrofits.

That ain't going to happen, and it's catered for by buying a KH 750 anyway.

 

[LTig]

But it's still weird there isn't more feedback and buzz around them

Your's is enough for me.

 

[DJBonoBobo]

I seem to recall Neumann posting something stating that they are adding dsp to their entire range. Can’t remember where I read it though

January 10th 2017: "We will add more solutions, products and a new DSP functionality to our entire range of Neumann studio monitor systems in the near future. The next new Neumann studio monitor will be the KH 80, which we will be showing this at the NAMM Show in Anaheim this month."

Source: https://www.mixonline.com/recording...ctor-audio-recording-at-sennheiser-electronic

Mr. Fraissinet left Neumann 2019 though.

 

[dickiefunk]

January 10th 2017: "We will add more solutions, products and a new DSP functionality to our entire range of Neumann studio monitor systems in the near future. The next new Neumann studio monitor will be the KH 80, which we will be showing this at the NAMM Show in Anaheim this month."

Source: https://www.mixonline.com/recording...ctor-audio-recording-at-sennheiser-electronic

Mr. Fraissinet left Neumann 2019 though.

Yep that’s the one

 

[DJBonoBobo]

The KH750 came later and added DSP functionality to the whole range - maybe he was referring to that.