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Neumann KH80 DSP Monitor Measurements #3

Matias

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Actually @thewas opened my eyes to how well suited and effective MMM is for EQ corrections Before that I was always struggling with single and averaged multi-point sweep measurements and often got less-than-satisfying results after EQ (and consumed much more time doing so)!
Yes, just saw Charles from Kali demonstrating the method here. Will try it too later and compare.
 

dominikz

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Yes, just saw Charles from Kali demonstrating the method here. Will try it too later and compare.
FYI, these are the RTA setting I use with MMM: https://www.audiosciencereview.com/...ing-microphone-method-help.12641/#post-374973

On another note - I see you said you borrowed the speakers from a friend - did you make sure that internal DSP PEQ is reset to flat? If they were configured for some corrections in another room it could cause issues in your - and you would end-up be double-EQing them to fix it. Not sure if you can check/reset it without and iPad, though. Anyway, just a thought!
 

Matias

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On another note - I see you said you borrowed the speakers from a friend - did you make sure that internal DSP PEQ is reset to flat? If they were configured for some corrections in another room it could cause issues in your - and you would end-up be double-EQing them to fix it. Not sure if you can check/reset it without and iPad, though. Anyway, just a thought!
I asked my friend. Other than the Small Desk switch on the back of both speakers, all else is stock, that is, flat.
 

Matias

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Orderd mine. :)

Does anyone know if they are time coherent, that is, in a step response both the tweeter and woofer responses arrive at the same time? Should be as they use digital crossovers. I have my REW measurement but I don't where to see this. Or actually, I see the filtered IR but cannot be sure if they are together or not.
 

BYRTT

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Orderd mine. :)

Does anyone know if they are time coherent, that is, in a step response both the tweeter and woofer responses arrive at the same time? Should be as they use digital crossovers. I have my REW measurement but I don't where to see this. Or actually, I see the filtered IR but cannot be sure if they are together or not.

Think try a REW nearfield sweep whitin 0,5-1,0 meter right on design axis, about design axis IIRC it is 52mm below the center of tweeter, then use below calculated reference based Amir's on axis response curve to guide if crossover is of minimum phase or linear phase, if phase / impulse response / step response looks like the left side column then they use minimum phase filter 8th order @1800Hz and if phase / impulse response / step response looks like right side column filter is of linear phase, have fun and let us know here what result is : )

Mathias_XO.png
 
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Matias

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Think try a REW nearfield sweep whitin 0,5-1,0 meter right on design axis, about design axis IIRC it is 52mm below the center of tweeter, then use below calculated reference based Amir's on axis response curve to guide if crossover is of minimum phase or linear phase, if phase / impulse response / step response looks like the left side column then they use minimum phase filter 8th order @1800Hz and if phase / impulse response / step response looks like right side column filter is of linear phase, have fun and let us know here what result is : )

View attachment 119354
I lent my UMIK-1 and cannot measure right now. But I did my infamous 1 position measurement about 1.0m from each speaker pointed to the middle between them. Can someone check from the REW file below if this is time aligned or not?
https://drive.google.com/file/d/13K2yPjbXFA7vZb7qaVrGi_rA0C2CL9LN/view?usp=sharing
 
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DJBonoBobo

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Can someone check from the REW file below if this is time aligned or not?

I don´t understand your question and can not answer it. But a few things i suggest from seeing the mdat-file:
- Try not using psychoacoustic but var smoothing
- Try only EQing the two peaks at 138 and 183 Hz (same for both channels)
- Try higher stands on desk instead of tilting up
- You seem to have a big dip around 70 Hz (matching the peak at 138, i guess) because of room modes, hence the loss of bass. Try a different listening position.
- If you don´t have a measurement mic yet, consider the Neumann MA 1, although you would need an additional interface and cables.

Edit: This is you measurement in a different view (R + L average) - you can try other targets, of course:
kh80.png


Addition:
-Try not using the "small desk" switch if you use EQ anyway.
-Try putting them even closer to the wall.
 
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Matias

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@DjBonoBobo Thanks for the inputs.
- I use Psy as I understand it represents better what we actually hear psycoacoustically. Even though REW Help says "Variable smoothing is recommended for responses that are to be equalised". Interesting.
- I will fine tune the EQing later when my friend returns my UMIK-1 (no need for me to buy the Neumann MA 1), but I prefer EQing the whole range, I just won't take this measurement very seriously because it was not made with the MMM. Will post later when I get my UMIK-1 back and do the MMM.
- Higher stands were an option but I rejected because I fear they become very unstable, and I prefere the minimalism of small stands. Lounging back in my office chair my ears are exactly aligned. :)
- I prefer to adjust each speaker individually as we can see they have quite different responses between them, exciting the room differently.
- I regret not turning off the "small desk" switch before measuring. Too late now. Will do so next time.
- Putting them closer to the wall would also put them behind the monitor plane. I probably would get some bass to the expanse of imaging.
 
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LTig

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I don´t understand your question and can not answer it. But a few things i suggest from seeing the mdat-file:
- Try not using psychoacoustic but var smoothing
- Try only EQing the two peaks at 138 and 183 Hz (same for both channels)
- Try higher stands on desk instead of tilting up
I haven't followed the thread for a long while but I second this. It made a big improvement in SQ with my Genelec 8020a. In fact so big that I don't need to activate any of the dip switch controlled EQs (at least not with the activated the 80 Hz low cut required for use with a sub).
 

ernestcarl

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- Try higher stands on desk instead of tilting up

I also suspect the irregularity in the HF is related to the fact that the monitors are too close to the desk, and the acoustic axis not being in the ideal flat horizontal plane. Those isoacoustics stands look too short even with the upward angling.


Using Neumann's own desk stands would be perfect in this situation -- but... I'm sure there are also cheaper alternatives out there.
 

hyperplanar

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Orderd mine. :)

Does anyone know if they are time coherent, that is, in a step response both the tweeter and woofer responses arrive at the same time? Should be as they use digital crossovers. I have my REW measurement but I don't where to see this. Or actually, I see the filtered IR but cannot be sure if they are together or not.
Neumann’s website has this graph, which indicates the crossover is linear phase and the woofer/tweeter are time coherent.
1616330578949.jpeg
 

Matias

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To the left my friend's IsoAcoustics ISO-L8R130 that I am returning, and under his speaker (mine will take some time to arrive, they are backordered) my unit, the new version ISO-130.

isoacoustics.jpg


Both have the option of using 4 long tubes to increase the height, but I fear for the stability, since I have children. Plus it looks nicer closer to the desk, and it is at my ear level.

ISO-130-clean.jpg
 
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Joaquinín

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Could you check the if your kh80 preserve correct phase? I have mine connected to Gustard X-16 dac through XLR (Phase Inversion Disabled at the dac menu), and Dirac Live measurements tell me the phase output of both speakers is inverted. Dirac can solve that, but I would like to know who is inverting polarity (X-16 or Kh80).
 

DJBonoBobo

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Both have the option of using 4 long tubes to increase the height, but I fear for the stability, since I have children. Plus it looks nicer closer to the desk, and it is at my ear level.

Your ETC shows a reflection very close to the source. This could be the desk (but also display or chair). You could measure without the chair again and see if it disappears. Also you could try the longer tubes and see what happens to this. If the higher/longer tubes are better, you could consider securing the monitors to the wall with an M6 screw and a little chain or cord to prevent them from falling.

Ear height is a good argument against this, of course. An alternative would be placing absorbers on the desk... Only showing things to you you could try, your choice in the end.

Screenshot 2021-03-21 142847.png
 

Joaquinín

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I also suspect the irregularity in the HF is related to the fact that the monitors are too close to the desk, and the acoustic axis not being in the ideal flat horizontal plane. Those isoacoustics stands look too short even with the upward angling.


Using Neumann's own desk stands would be perfect in this situation -- but... I'm sure there are also cheaper alternatives out there.
I bought the K&M desk stands. Build quality is impressive, but I have serious doubts about the design. Its"C" shape means the top stand-speaker flexes vertically very noticeably if you apply the smallest force. The Neumann desk stands design (or those designs with a central pillar) seem to avoid that. In my case, desktop positioning means 1) I can't increase the distance to my ears more than 90 cm (which I am not sure is ideal, 120-140 cm would be less fatiguing and enlarge the size of the sonic picture), 2) even if my desk is very solid and heavy, made of metal, I don't like to feel It vibrate under my arms. I think I may eventually buy separate stands. I'm going to wait and see if I can get used to this close distance.
 

Matias

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Interesting how Neumann applied a metal sticker under the grill in front of the tweeter, probably to reduce the on axis response, all calculated and measured, of course.

Webp.net-resizeimage.jpg
 
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thewas

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Interesting how Neumann applied a metal sticker under the grill in front of the tweeter, probably to reduce the on axis response, all calculated and measured, of course.
This is a very old trick to control dispersion on the last octave, I know quite many 1980s loudspeakers (and even own few of them) who have it.
 

ctrl

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This is a very old trick to control dispersion on the last octave, I know quite many 1980s loudspeakers (and even own few of them) who have it.
I would even go so far as to say that most metal and ceramic tweeters that do not show significant resonance above 20kHz use a phase plug (exceptions would be some Bliesma tweeters(?), for example).

Still regularly used today by Seas, ScanSpeak, SBAcoustics...
 
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