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Neumann KH 80 DSP Monitor Review

Krunok

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The reason the reference axis was in contention with the Neumann was that it is very explicitly specified in the manufacturer instructions, and it is not at all an unusual location =]

General procedure is to measure at the tweeter axis unless otherwise specified.
Aren't those 2 statements in cotradiction? ;)

Where things have sometimes gotten complicated for me is when the tweeter is placed asymmetrically on the baffle.
And what about 3-way? Also at tweeter axis or between tweeter or mid driver?
 

Krunok

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But I have to admit, if the measured sample of the KH 80 is really, really bad, Amir's measurements would fit in the manufactures tolerance boundaries, if "strong" frequency smoothing is used.
/QUOTE]

IIRC Neumann is claiming to perform QC measurement on every speaker leaving production line so one wouldn't expect a "really, really bad" speaker to leave factory. :)
 

napilopez

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For some (clearly not all) audio engineers it is important. They use studio monitors as a tool and want best precision (and linearity) in direct and diffuse sound field. For them +-0.5dB makes a difference.

But I have to admit, if the measured sample of the KH 80 is really, really bad, Amir's measurements would fit in the manufactures tolerance boundaries, if "strong" frequency smoothing is used.

Frequency response linearity is given as +/-0.7dB from 100 to 10KHz (by Neumann). The NFS has +-0.1dB tolerance (direction of of max SPL).

Again measurements by Amir (ver -10deg, to fit manufacturer recommendation), Sound&Recording and Neumann (most inaccurate curve from their website).

First measurements without further smoothing:
View attachment 47365
Now with additional 1/3oct. smoothing:
View attachment 47366
Good point about the smoothing, but the given tolerances are 100 percent of speakers at ±0.26 dB. ±0.7dB is the deviation given for their on-axis graph, basically just showing off how flat it is. So presumably, what they're saying is 100 percent of produced speakers can match their "gold standard" ±0.7dB speakers within 0.26dB.

Aren't those 2 statements in cotradiction? ;)
Not at all:). "General" procedure is what to do if the manufacturer doesn't provide a reference. However, I've seen many speakers say between mids and tweeter. Probably about a third of them, if I had to guess. I suspect more speakers with the acoustical axis between the tweeter and woofer specify the location because it's a bit less intuitive.

And what about 3-way? Also at tweeter axis or between tweeter or mid driver?
The tweeter, but I'll let you in on a secret: I measure both. =] So far the tweeter has generally been the best measuring position. But then, I don't measure towers, so I don't know how it'd be for them, especially the taller ones.
 
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Krunok

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Not at all:). "General" procedure is what to do if the manufacturer doesn't provide a reference. However, I've seen many speakers say between mids and tweeter. Probably about a third of them. I suspect more speakers with the acoustical axis between the tweeter and woofer specify the location because it's a bit less intuitive.



The tweeter, but I'll let you in on a secret: I measure both. =] So far the tweeter has generally been the best measuring position. But then, I don't measure towers, so I don't know how it'd be for them, especially the taller ones.
My post was about speakers for which there is no manufacturer's spec.
Is there any AES scientific research that supports your theory that centre of the tweeter should be used with all types of speakers?

Personally, I would expect the optimum point to be somewhere between tweeter and mid, except for small 2-way speakers which have no mid so centre of the tweeter is a logical choice.
 

napilopez

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My post was about speakers for which there is no manufacturer's spec.
Is there any AES scientific research that supports your theory that centre of the tweeter should be used with all types of speakers?

Personally, I would expect the optimum point to be somewhere between tweeter and mid, except for small 2-way speakers which have no mid so centre of the tweeter is a logical choice.
Well, then we agree. I am mostly talking about 2-way speakers since that is the most common type of speaker and the ones we've mostly been talking about until now :).

For three ways, I definitely agree that it's either tweeter or midway between tweeter and mids, but I'd probably personally gravitate towards the tweeter(though again, I would measure both). It partly depends on the speaker height. Most 3 ways are towers, so I'd think I'd go with whatever was most likely to be at ear height - say if it's a particularly tall or short tower. CTA-2034-A has this to say:

The reference axis should be specified by the manufacturer. It approximates the direct-sound listening axis for a seated listener in the prime listening location, at a normal listening distance.

Defining the reference axis requires that assumptions be made, and perhaps for this reason manufacturers rarely specify it. Because the reference axis is needed to perform the tests described in this standard the following method shall be used to define it whenever the manufacturer has not specified it.

The starting point of the reference axis shall be either the center of the high-frequency driver (normally a tweeter) or a point midway between the high-frequency and midrange drivers. The specific point that is used shall be specified in the final report. The orientation of the reference axis depends on the design of the loudspeaker. For most conventional loudspeakers with a front baffle, the reference axis shall be perpendicular to the front baffle. If the loudspeaker design is such that there is not a conventional front baffle, the reference axis shall be in the direction of the intended forward radiation of sound from the loudspeaker.
 

Krunok

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Most 3 ways are towers, so I'd think I'd go with whatever was most likely to be at ear height - say if it's a particularly tall or short tower.
LOL
Who's ear, yours or mine? I'm 187cm, you may be taller or shorter. And then there is the sofa height.. I don't think term "ear height" has any practical meaning when it comes to floorstanders. :)
 

napilopez

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LOL
Who's ear, yours or mine? I'm 187cm, you may be taller or shorter. And then there is the sofa height.. I don't think term "ear height" has any practical meaning when it comes to floorstanders. :)
Again, "say if it's a particularly tall or short tower =]'' I also don't think there's much meaning for an average height tower. Just pick whichever axis you prefer if not specified, or better yet, measure both. But if you've got a giant tower... might be better to measure from a lower position. And vice versa.

That said, John Atkinson found the average listener ear height to be 36 inches =] Having trouble locating the source though.
 
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Juhazi

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Reference axis is often said in the user manual of speakers, but not always even for hifi. Still, it is not at all easy to get the smoothest response at that axis! With modern waveguide tweeters, 5-10deg off-axis is often the best! Vertically delay/phase matching doesn't always happen at ref axis either. Most active speakers don't use dsp for xo (eg. JBL LSR series, most Genelecs), but analog xo circuits without tuned delays.

Tall speakers often have the tweeter on top, above listener's ear level. This may help to get best phase match at listening spot height! A tilted or stepped baffle is used to set back the tweeter which helps delay matching.

Normal domestic hifi listening happens in farfield (1-4 meters), and then direct on-axis response loses it's importance to "Early Reflections" and "Sound Power" averaged responses. Even for nearfield monitoring on-axis response is perceived as dominant only above 1-2kHz.

Designers with modern methods must define optimal design axis, but there is no fixed location for that. Common practise is to set it at midline between tweeter and mid for 3-ways. Some 2-ways have it on tweeter axis, others at midpoint between woofer and tweeter like KH80. Reference design distance should be told too!

https://www.audioholics.com/loudspeaker-design/understanding-loudspeaker-measurements
http://www.tolvan.com/index.php?page=/xdir/xdir.php
http://www.acousticfrontiers.com/speaker-off-axis-understanding-the-effect-of-speaker-toe-in/
https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_help_20.pdf
https://nsmt-loudspeakers.com/Mastering-Series-white-paper
 
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amirm

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Thread Starter #470
Amir seems to think that when he has the best measurement system, we must stop complaining. Sad.
That's nonsense. I am trying to get you guys to stop obsessing over small differences in frequency response. I have not even bother to put in the calibration for my microphone in there because 1 dB here and there is not material. You are missing the forest from the trees here. Speaker has flat response on axis. That is what they advertise, and that is what I found.

I am determined to not lead you guys down a path that is totally inappropriate with respect to speaker measurements. How is this going to work? On every measurement you are going to hound me to test and re-test every theory until you are satisfied that my measurements match someone else's with unknown test conditions are identical? That would be sad. And it is sad now that I can't get this simple message across with respect to speaker testing.

What do you think your ears are? That they care about these tiny differences when assessing two different speakers?
 
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amirm

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Thread Starter #471
CTA-2034-A has this to say:

The reference axis should be specified by the manufacturer. It approximates the direct-sound listening axis for a seated listener in the prime listening location, at a normal listening distance.

Defining the reference axis requires that assumptions be made, and perhaps for this reason manufacturers rarely specify it. Because the reference axis is needed to perform the tests described in this standard the following method shall be used to define it whenever the manufacturer has not specified it.

The starting point of the reference axis shall be either the center of the high-frequency driver (normally a tweeter) or a point midway between the high-frequency and midrange drivers.
Translating, you best get used to reference point being different between spinormas of different speakers. The standard puts no value on 100% accuracy of this point. And neither do I. I don't sit and listen with my head in a vice. Near-field monitoring is even worse since movement relative to speakers is much more than far-field.
 

Krunok

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Speaker has flat response on axis. That is what they advertise, and that is what I found.

Not true. Although you were using the most sophisticated mesurement device that exists your measurements put your KH80 outside of Neumann specs, as shown by @ctrl. And although Neumann claims they measure every specimen they produce as part of their quality control you keep repeating that everything is ok. But it isn't: either Neumann spec is too optimistic or your measurements were not precise enough. If latter is the case, it certainly isn't Klippel's false because they specified 0.1dB of precision, so the only thing that can be false is measurement procedure.

So everything is not ok, either Neumann spec or your measurement procedure. We need to remember herre that KH80 is not JBL One Series 104, it costs $500 and not $50 and main reason for that is extremely linear frequency response, which your measurement didn't confirm. And that is the problem.
 
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napilopez

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Translating, you best get used to reference point being different between spinormas of different speakers. The standard puts no value on 100% accuracy of this point. And neither do I. I don't sit and listen with my head in a vice. Near-field monitoring is even worse since movement relative to speakers is much more than far-field.
I was trying to avoid tagging you =P

Well, this is of course true, and I have no trouble using different reference points, and do so myself.

But I find it just supports my view. Your listening window will vary depending on what your center point is. Otherwise no need to ever angle speakers or aim them. Sometime it doesn't make a big difference, others it does. And it makes a particularly big difference in the nearfield because small motions will cause relatively big changes in angle, as you implied above. It also matters more with narrow directivity designs (part of the reason I gravitate towards wide directivity designs in the first place).

So ill aim my speaker wherever it sounds the best, so I have more slack for moving around. Usually that's where the manufacturer recommends. And as the document says, whatever axis is used should be specified. Not a huge deal when you have 360-degree data, but not everyone will go out and look for the best curve.
 

MZKM

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Not true. Although you were using the most sophisticated mesurement device that exists your measurements put your KH80 outside of Neumann specs, as shown by @ctrl. And although Neumann claims they measure every specimen they produce as part of their quality control you keep repeating that everything is ok. But it isn't: either Neumann spec is too optimistic or your measurements were not precise enough. If latter is the case, it certainly isn't Klippel's false because they specified 0.1dB of precision, so the only thing that can be false is measurement procedure.

So everything is not ok: either Neumann spec or your measurement procedure.
Neumann also states:

Reproduction accuracy between 100 Hz and 10 kHz:
100% of loudspeakers produced: ±0.26 dB
80% of loudspeakers produced: ±0.23 dB
50% of loudspeakers produced: ±0.17 dB

±0.7 target with 80% tolerance being ±0.23dB gives us ±0.93dB, aka a 1.86dB window.
That post you referenced shows ±1.3 dB, aka a 2.6dB window, so we are less than 3/4 of a dB off (even less of using 100% tolerance). Not to mention they used the -10° V axis, which I stated in another post that it was not the most smooth axis.

EDIT: Subtracting in the ±0.1 dB of the NFS brings us to a 2.4dB window, meaning just 0.54dB (±0.27dB) off.
 
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amirm

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Thread Starter #475
But it isn't: either Neumann spec is too optimistic or your measurements were not precise enough.
Precise enough? An electroacoustic measurement? The heck you are going to do with that precision? Using to set your watch?

And what is your theory anyway? That the amp in there limited at the playback level without lighting up its LED? So? Which is more real-life usage? What I did or whatever they did to supposedly avoid it?
 

Krunok

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Neumann also states:

Reproduction accuracy between 100 Hz and 10 kHz:
100% of loudspeakers produced: ±0.26 dB
80% of loudspeakers produced: ±0.23 dB
50% of loudspeakers produced: ±0.17 dB

±0.7 target with 80% tolerance being ±0.23dB gives us ±0.93dB, aka a 1.86dB window.
That post you referenced shows ±1.3 dB, aka a 2.6dB window, so we are less than 3/4 of a dB off. Not to mention they used the -10° V axis, which I stated in another post that it was not the most smooth axis.
Let me remind you that 3/4 or 0.75dB off is not a small thing when you need to confirm that 100% of loudspeakers produced are within ±0.26 dB.
0.75dB is more than 3 times larger than 0.26dB.
 
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Krunok

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Precise enough? An electroacoustic measurement? The heck you are going to do with that precision? Using to set your watch?

And what is your theory anyway? That the amp in there limited at the playback level without lighting up its LED? So? Which is more real-life usage? What I did or whatever they did to supposedly avoid it?
I don't have a theory. Proposal was that you repeat the measurement with recommended level and reference axis. If you get a result within Neumann spec all is good. If you don't, then either Neuman spec is off or your Klippel doesn't measure with sufficient precision to measure speakers as KH80.
 
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amirm

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But… that's neither here nor there. The reference axis, according to CTA-2034-A, is, by definition, where the manufacturer says it is. There's no need to "find" it or to "verify" it.
Of course there is if you are going to argue that the manufacturer used it in their measurements and I didn't. You have a picture of their setup on how they created their graphs?
 
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amirm

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Thread Starter #479
I don't have a theory. Proposal was that you repeat the measurement with recommended level and reference axis. If you get a result within Neumann spec all is good. If you don't, then either Neuman spec is off or your Klippel doesn't measure with sufficient precision to measure speakers as KH80.
Not going to do. I am not going to reward bad intent. The future of what we are doing is what is at stake. I can just see the same losing the high level picture and insisting in minutia in every review.
 

Krunok

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Not going to do. I am not going to reward bad intent. The future of what we are doing is what is at stake. I can just see the same losing the high level picture and insisting in minutia in every review.
If I were you I would like to know if the device I paid so much is performing according to Klippel's spec. On the other hand, independent measuring of any device has always been about confirming or denying manufacturer's specs, so outcome should be clear if KH80 deliverd or not.

So how did we come to bad intent? To me it seems it is about vanity..
 
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