Neumann KH 80 DSP Monitor Review

[edechamps]

I'm guessing you don't plan on remeasuring the speaker @amirm as you have many more to get through

I think it would be preferable to investigate potential issues with the measurements before moving on to other speakers. Otherwise people will keep doubting the results, and rightly so. Better to err on the safe side than potentially corrupt more reviews. If mistakes were made (such as running the speaker into bass compression or using the wrong acoustical axis, as some people in this thread suspect), then it would be nice to know so that they won't happen again on upcoming reviews.

@amirm: if you still have the speaker, would you consider doing another run at a lower output level (to rule out compression) and with the correct acoustical axis, and see if you get a response that looks more similar to other published measurements of this speaker? This would certainly produce useful insights regarding test methodology for future reviews.

 

[Thomas_A]

I think it would be preferable to investigate potential issues with the measurements before moving on to other speakers. Otherwise people will keep doubting the results, and rightly so. Better to err on the safe side than potentially corrupt more reviews. If mistakes were made (such as running the speaker into bass compression or using the wrong acoustical axis, as some people in this thread suspect), then it would be nice to know so that they won't happen again on upcoming reviews.

@amirm: if you still have the speaker, would you consider doing another run at a lower output level (to rule out compression) and with the correct acoustical axis, and see if you get a response that looks more similar to other published measurements of this speaker? This would certainly produce useful insights regarding test methodology for future reviews.

It could be a good idea to test since it is clear that several measurements on Soundstage on smaller speaker show deviations from linearity in the low bass when comparing 90 dB vs 70 dB measurements.

 

[rodtor]

I think it would be preferable to investigate potential issues with the measurements before moving on to other speakers. Otherwise people will keep doubting the results, and rightly so. Better to err on the safe side than potentially corrupt more reviews. If mistakes were made (such as running the speaker into bass compression or using the wrong acoustical axis, as some people in this thread suspect), then it would be nice to know so that they won't happen again on upcoming reviews.

@amirm: if you still have the speaker, would you consider doing another run at a lower output level (to rule out compression) and with the correct acoustical axis, and see if you get a response that looks more similar to other published measurements of this speaker? This would certainly produce useful insights regarding test methodology for future reviews.

I am in no position to contribute to this discussion on a technical level. But to the extent that this thread appears to have seen reasoned disagreement about the best test methodology, I agree that refining methodology, or at least further reflecting and deliberating about it, might be the highest priority at the moment.

 

[Thomas_A]

But compression is a physical parameter related to high SPL. If true, the test procedure just shows that, nothing else. The test equipment is accurate not matter what.

 

[BYRTT]

At approx 95 dB @ 1 meter (which was the actual SPL?) this could perhaps stress the small woofer. Compression?

Now i don't say it is so but lets say in their eagerness to stretch that small diameter mid woofer as low a reach as possible in port tuning and their measurement method whatever it is fail a bit in resolution down there compared to NFS .

 

[LTig]

I think it would be preferable to investigate potential issues with the measurements before moving on to other speakers. Otherwise people will keep doubting the results, and rightly so. Better to err on the safe side than potentially corrupt more reviews. If mistakes were made (such as running the speaker into bass compression or using the wrong acoustical axis, as some people in this thread suspect), then it would be nice to know so that they won't happen again on upcoming reviews.

@amirm: if you still have the speaker, would you consider doing another run at a lower output level (to rule out compression) and with the correct acoustical axis, and see if you get a response that looks more similar to other published measurements of this speaker? This would certainly produce useful insights regarding test methodology for future reviews.

+10

 

[napilopez]

if im reading it right, its the widest horizontal angle (left + right) where the frequency response is within -6db of the on axis frequency response. so the LSR305/305P has significantly wider dispersion

edit: actually i believe the opening angle is measured at 1khz to 10khz, not the entire range

That's interesting because the DI curves suggest the 305P has narrower directivity than the KH80 in the early reflections spectrum. But for sound power the 305P has wider DI. (In Purple and green is the KH80).

I think it would be preferable to investigate potential issues with the measurements before moving on to other speakers. Otherwise people will keep doubting the results, and rightly so. Better to err on the safe side than potentially corrupt more reviews. If mistakes were made (such as running the speaker into bass compression or using the wrong acoustical axis, as some people in this thread suspect), then it would be nice to know so that they won't happen again on upcoming reviews.

@amirm: if you still have the speaker, would you consider doing another run at a lower output level (to rule out compression) and with the correct acoustical axis, and see if you get a response that looks more similar to other published measurements of this speaker? This would certainly produce useful insights regarding test methodology for future reviews.

This is ultimately how I feel as well and why I've been so picky up to now. Just trying to be considerate about balancing Amir's effort and the usefulness of the data. I'd be fine with the results in the review if the correct SPL level and compression were noted, as well as the incorrect reference angle. But certainly, I'd prefer a retest if possible =]

 

[edechamps]

But compression is a physical parameter related to high SPL. If true, the test procedure just shows that, nothing else. The test equipment is accurate not matter what.

Absolutely. What I'm trying to say is, when one sees a frequency response measurement, especially something like a spinorama, one would naturally assume by default that it was made with the DUT operating in its linear regime. If it wasn't, then one could argue the data is misleading. Of course I don't mean to say that compression and other kinds of non-linear distortion are irrelevant, but they should be presented separately - not intermingled with the baseline frequency response results.

 

[napilopez]

Absolutely. What I'm trying to say is, when one sees a frequency response measurement, especially something like a spinorama, one would naturally assume by default that it was made with the DUT operating in its linear regime. If it wasn't, then one could argue the data is misleading. I don't mean to say that compression and other kinds of non-linear distortion are irrelevant of course, but they should be presented separately - not intermingled with the baseline frequency response results.

Truth, very well put.

 

[Thomas_A]

Now i don't say it is so but lets say in their eagerness to stretch that small diameter mid woofer as low a reach as possible in port tuning and their measurement method whatever it is fail a bit in resolution down there compared to NFS .

View attachment 47114

I have no idea about the linear x-max of that 4 inch woofer so it could be other reasons as you say. Here is e.g. the PSB mini speaker with a 4 inch driver (diff linearity 90 vs 70 dB):

 

[oivavoi]

That's interesting because the DI curves suggest the 305P has narrower directivity than the KH80 in the early reflections spectrum. But for sound power the 305P has wider DI. (In Purple and green is the KH80).

View attachment 47115

I'm struggling to understand what this means, tbh...

 

[napilopez]

I'm struggling to understand what this means, tbh...

The Directivity Index and Early Reflections Directivity Index curves are the difference between the Sound power curve/Early Reflections Curve and the Listening Window (sometimes the on-axis, but usually the listening window). The higher the DI curve, the greater the difference between the off axis data and the on axis data, meaning the speaker is more directional at that frequency.

In other words, a perfect omnidirectional speaker would have a perfectly flat DI curve with 0dB difference throughout the frequency range - super wide directivity. A speaker with very narrow directivity in the highs would have a very steep slope.

In the above graph, the Neumann has slightly wider directivity in the early reflections domain, which you can see because the green curve is below the Blue curve behind it. But the newman has but slightly narrower directivity in the 360/spherical sound power domain, which you can see because the purple curve is higher than the red curve behind it, at least from about 2k to 18K.

 

[oivavoi]

The Directivity Index and Early Reflections Directivity Index curves are the difference between the Sound power curve/Early Reflections Curve and the Listening Window (sometimes the on-axis, but usually the listening window). The higher the DI curve, the greater the difference between the off axis data and the on axis data, meaning the speaker is more directional at that frequency.

In other words, a perfect omnidirectional speaker would have a perfectly flat DI curve with 0dB difference throughout the frequency range - super wide directivity. A speaker with very narrow directivity in the highs would have a very steep slope.

In the above graph, the Neumann has slightly wider directivity in the early reflections domain, which you can see because the green curve is below the Blue curve behind it. But the newman has but slightly narrower directivity in the 360/spherical sound power domain, which you can see because the purple curve is higher than the red curve behind it, at least from about 2k to 18K.

Thanks! Understood it better now!

 

[q3cpma]

Sorry if this has already been asked, but does predicted room response take a distance parameter? Since the listening window's contribution could possibly be higher than 12% in a nearfield situation. Guess room size and (possibly involuntary) treatment should also matter, but that's another matter.

 

[napilopez]

Sorry if this has already been asked, but does predicted room response take a distance parameter? Since the listening window's contribution could possibly be higher than 12% in a nearfield situation. Guess room size and (possibly involuntary) treatment should also matter, but that's another matter.

It does not.

 

[jhaider]

And „Made in China“ vs „Made in Ireland“ - which is important for some people and their decision what to buy.

Some KH80s are made in the Czech Republic. I have one of each.

 

[amirm]

Seems like we have lost the plot here.

Folks, we are talking about mechanical devices here. This is not some precision measurements of electronics. Heck even there I see variations. You guys are honestly debating one or two dB here and there???

As I said before, the most likely outcome of these measurements will be the speakers to avoid. They will show large deviation from what is considered "good." We are spoiled so far measuring speakers that are designed to measure well so far so differences are small. But this is no ticket to think that we have to have ultra accuracy to know what to do with the measurements.

As I have said before, other measurements have potential errors in them as well. Anechoic measurements is the gold standard relative to in-room measurements. But they are only an approximation to true, free-field response of a speaker. Heck, we don't even know if our microphones match to the degree you all are fighting over.

I reported that based on my measurements, this speaker has very flat on-axis response. That is all we need to know. Not, "oh wait, why is there a 1 dB dip at 200 Hz relative to this other person's measurements."

The list of speakers to measure has grown to nearly 25 now. I can't keep chasing these little differences when they have no value at all in overall assessment of a speaker. Please learn to allow variances here.

 

[sweetchaos]

As I said before, the most likely outcome of these measurements will be the speakers to avoid. They will show large deviation from what is considered "good."

100% agree.

 

[Mawclaw]

Hmm. I dont have the technical backing to comment on the nitty gritty on this but I will wade in anyway lmao.

As I said before, the most likely outcome of these measurements will be the speakers to avoid. They will show large deviation from what is considered "good." We are spoiled so far measuring speakers that are designed to measure well so far so differences are small.

If the goal is to just find speakers to avoid than the current procedure is fine. It might make sense to avoid any speakers like the Neumanns that have a large amount of quality measurements available and just focus on potential "offenders" or interesting speakers without a solid suite of data. If more is going to be asked of the data set maybe more needs to be done to refine the setup.


Only things that seem glaring to a relatively uneducated audio person are below-

-It seem that the speaker was run at too high of output level based on the spec sheet.
-The manufacturers acoustical axis wasn't used.

It makes sense to at least try to follow the manufacturers recommendations. If the equipment I sell was reviewed contrary to the cut sheet I would be pretty sceptical.

 

[amirm]

-It seem that the speaker was run at too high of output level based on the spec sheet.

As I noted, I am standardizing on Soundstage loudness standard so that we can compare my results to them. They use 90 dB at 2 meters. That is 106 dB at 1/3 meter. They say that they lower the level if the speaker strains. I did not hear these strain. Higher volumes allow more exclusion of noise for even more accurate measurements.

This is the manufacturer spec:

I am assuming that is at one meter. At 1/3 of meter then, it should be able to produce 119 dB which is well in excess of the level I measured at.

-The manufacturers acoustical axis wasn't used.

That doesn't matter. The Klippel system does not care what the speaker looks like. It wants the tweeter axis because it will have an easier time computing the spherical coefficients for the field expansion. Setting it to the wrong spot simply increases the complexity of the soundfield it has to compute. It performs a post measurement analysis and reports on its difficulty to do so. There was no problem at all in this case.

I also don't know how Neumann computed the acoustic center anyway. That could just be the axis they want you to listen at, not some type of accurate measurement of soundfield that resulted in that.