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Understanding How the Klippel NFS Works

carewser

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Yeah -20db is crazy, it's almost like a sonic vacuum
 

amirm

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today i search for yamaha HS step response to see if there can find some for yamaha HS. here is a step response from this site.seem Amir have the module only resolution is not so good. i think the important stuff is only in first 10 ms see. so a resolution 1 line 1 ms is good. question is wy newer tests have no step response. maybe @amirm can tell something to this. in this test can find step response https://www.audiosciencereview.com/forum/index.php?threads/yamaha-hs5-powered-monitor-review.10967/
Step functions don't provide much useful information so I don't post them anymore. For the Yamaha, let me see what I can find.
 

pozz

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Yeah -20db is crazy, it's almost like a sonic vacuum
That's not quite the right way to think about it.

dB SPL is relative to atmospheric pressure, and is also a logarithmic quantity. "Sound" is a local variation superimposed onto that baseline pressure. Works the same way as addition of sinewaves.

Looking at some numbers: 1 atmosphere is 101,325 Pascals, or 194dB SPL. We live in that more or less constant pressure field. A -20dB SPL pressure variation is equivalent to 0.000002 (2×10⁻⁶) Pascals. Combining them nets you 101,235.000002 Pa. So it's not the absence of sound, but rather a very, very small example of it that is barely detectable against the background.
 

bennybbbx

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Step functions don't provide much useful information so I don't post them anymore. For the Yamaha, let me see what I can find.

The yamaha have step response.
I think slower step response often bigger bass/mid have give less stereo width. maybe you can do the test with headphones. part 5 part 6 and part 7. the last upload compare speakers with much diffrent impulse responses. The speaker below 1 ms to reach 0 are much better in stereo width and room feeling at least for me.

did you hear diffrence ?.

the speaker with slow step response sound dull and muddy in compare even if correct with roomeq in the distortion example. i have boost high additional with EQ so that lp6 sound more simular in compare to MTM. maybe i should not boost the speaker with slow step responses with additional EQ and so slow transients additional to hear better ?. distortion guitars have lots change in amplitude so is a hard test and slow step response speakers smooth the edge of the distortion more, so they sound dull and muddy. when i think more the EQ boost that LP6 sound simular to other is not correct, because for non distortet songs it sound too bright.

so if other not hear that stereo width is smaller on slow step response speaker, they hear that transient rich sounds sound muddy and dull. https://easyupload.io/m/ghiaf1

https://www.audiosciencereview.com/...of-the-synth-sound-in-the-attached-mp3.18401/

Happy new year to all
 
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ctrl

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[off-topic] Step response

I think slower step response often bigger bass/mid have give less stereo width.
The speaker below 1 ms to reach 0 are much better in stereo width and room feeling at least for me.

No loudspeaker that also emits low tones has a step response that reaches zero after 1ms.

If a loudspeaker reproduces a 20Hz signal, one oscillation period alone requires 50ms.

The complete step response of an ideal loudspeaker (2-Way, LR4@1kHz) with an f3 of 30Hz looks like this:
1609521878560.png

The zero value is only reached after >40ms.

For comparison, here is a totally crappy (ideal) loudspeaker (2-Way, LR4@1kHz), which already drops out at 100 Hz in the low frequency range:
1609522081388.png


A step response that is as "short" as possible is not a measure for "much better in stereo width and room feeling". Your observations are more likely to be coincidental.
 

bennybbbx

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[off-topic] Step response



No loudspeaker that also emits low tones has a step response that reaches zero after 1ms.

If a loudspeaker reproduces a 20Hz signal, one oscillation period alone requires 50ms.

The complete step response of an ideal loudspeaker (2-Way, LR4@1kHz) with an f3 of 30Hz looks like this:
View attachment 102864
The zero value is only reached after >40ms.

For comparison, here is a totally crappy (ideal) loudspeaker (2-Way, LR4@1kHz), which already drops out at 100 Hz in the low frequency range:
View attachment 102865

A step response that is as "short" as possible is not a measure for "much better in stereo width and room feeling". Your observations are more likely to be coincidental.

see in this thread. i have post step response from 300-3000 hz. the LP6 is very slow too. https://www.audiosciencereview.com/...lar-speaker-dynamics.7742/page-17#post-621814 because it is offtopic now for Klippel thread maybe you write in the linked thread about step response. before i join there was more written about step response, so i write too about it
 

Few

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And I happen to be viewing it right now, as I'm finding the email alert that you posted! Thanks very much for doing that interview and sharing it.
Few
 

MZKM

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But I've never seen any test report that includes these remaining parts of the CTA-2034-A — neither in reviews nor from manufacturers. So much for a supposedly industry standard that no one seems to observe :(

Too bad neither Amir nor Erin measure the Max SPL of the speaker (I think it’s an additional costly add-on). It’s done similar to the CEA-2010 standard, just that the distortion thresholds are tighter.

What I dislike about the standard is that it’s missing speaker sensitivity. For Max SPL they state to use 100Hz-5kHz. For getting the level of active speakers calibrated they say to use 500Hz-2kHz. For the upper -3dB range they say to use 100Hz-1kHz.

I can generate the recommended subwoofer crossover levels from the standard though. You simply use the 100Hz-1kHz average SPL and calculate the lower -3dB, then out of 80/100/120/150 Hz you choose whatever is higher than this -3dB lower point.
 

hardisj

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Too bad neither Amir nor Erin measure the Max SPL of the speaker (I think it’s an additional costly add-on).

I actually do provide a Max SPL. But per an IEC standard. The parameters of which are always referenced in my results. After testing the CTA-2034 method, I made the choice not to use the CTA-2034 Max SPL spec.

One thing with the CTA-2034 Max SPL is that it takes FOREVER. I actually do have the module. So, I am speaking from experience. It took >5 hours once on a bookshelf speaker. And, frankly, I find it less useful/insightful than the IEC method. In fact, I prefer the IEC method because it allows me to take in to account "long term" (60 seconds) compression and distortion with multitone signal (which represents music signal). And the Klippel module shows this data (which is what I present to you guys). The IEC test uses multitone stimulus that covers 20-20k (or whatever I tell it to). The CTA-2034, on the other hand, is just a series of tone bursts. Much like the CEA-2010 method. I don't find this useful at all and, thus, I purposely choose to use the IEC method for my max SPL testing.

TL;DR: CTA-2034 sucks for max SPL, imho. I'll stick with what I'm already doing which is using multitone stimulus per the IEC method.
 

hardisj

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Did you do it for the D&D?

Did you ever compare the max SPL between methods?

Nope. That was the only one I haven't tested for max SPL. Weather.


Didn't compare. Two totally different tests; I didn't expect them to yield the same number. I care more about the effects of compression over a long term than I do about 6ms instantaneous burst compression. ;)
 

MZKM

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Nope. That was the only one I haven't tested for max SPL. Weather.


Didn't compare. Two totally different tests; I didn't expect them to yield the same number. I care more about the effects of compression over a long term than I do about 6ms instantaneous burst compression. ;)
Gotcha, was just wondering if close enough to where the 2034’s classifications could be applied.
 

hardisj

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Gotcha, was just wondering if close enough to where the 2034’s classifications could be applied.

TBH, I've considered dropping the max SPL testing. It seems hardly anyone mentions it. And TBH I can't recall the last time I actually referenced it for anything. And it takes a long time to run... on top of needing things to be quiet and I still am at odds with the outdoors for some speakers (weather, external noise). It's stressful. As silly as it sounds, it's a mental stressor because you have to have good conditions and as soon as someone comes down the road with a loud car, there goes the test. Out the window. It's frustrating as hell.

I do have the max SPL for the Kef R3. I am running it for the JBL HDI-3800 right now (literally, as I type this). But the wind here is causing me issues with >10kHz.

I'm about to try the CTA-2034 max spl test again now that I have the means to provide a room correction filter. Will see how that goes. Not holding my breath, though.
 

MZKM

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TBH, I've considered dropping the max SPL testing. It seems hardly anyone mentions it. And TBH I can't recall the last time I actually referenced it for anything. And it takes a long time to run... on top of needing things to be quiet and I still am at odds with the outdoors for some speakers (weather, external noise). It's stressful. As silly as it sounds, it's a mental stressor because you have to have good conditions and as soon as someone comes down the road with a loud car, there goes the test. Out the window. It's frustrating as hell.

I do have the max SPL for the Kef R3. I am running it for the JBL HDI-3800 right now (literally, as I type this). But the wind here is causing me issues with >10kHz.

I'm about to try the CTA-2034 max spl test again now that I have the means to provide a room correction filter. Will see how that goes. Not holding my breath, though.
Too bad only some manufacturer‘s list the actual “power handling” (however they find that). Most just do “recommended wattage” or ”minimum wattage“ and use it as a marketing spec (somehow the bookshelf is 25W-100W and the higher sensitivity tower is 100W-250W, or some 5-digit speaker is 500W-1000W).

Have you ever compared your Max SPL in reference to the spec’d wattage?
 

hardisj

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Here is what I mean about this stuff taking a long time and it being damn near impossible to do these lengthy tests without some risk of an external noise source coming in and corrupting the results (neighborhood kids, my family, cars, etc). With the CEA-2010 tests there are only about 8 tones or so and it doesn't take long to hit the max SPL. And if something gets messed up, I just repeat that one test. But with the CTA-2034 max SPL test it can take hours. And it cycles through 25 frequencies tested. From low voltage to high (or until the DUT hits max SPL). Imagine having a regular house with regular neighbors and regular noise and expecting it to be quiet for that long.

As you can see in the image below, I am running the CTA-2034 max SPL test. Look at the bottom left. "Estimated Time 174 minutes".

This kind of testing is best served to a remote location with zero external noise. Not because you can't work around it. You can. But you wind up devoting an entire day or more just to making sure you are testing at opportune times and you have to be present during the test. Want to go somewhere? Better think again. You're babysitting data today! It's nice outside and you want to go hit some golf balls?! HA! Fat chance! Otherwise you might have a bad data point because some random loud noise or wind gust came up and you were inside, unaware of it.

This is the stuff I wish people knew. All the nitty gritty details of what goes in to completing tests like this. It is a royal PITA and a huge, huge time sink. And on top of that, this isn't even my job. So when people say to Amir, myself or others, "why don't you do yyy test" instead of just saying "thanks" for what is provided ... well, hell, sack up and do it your damn selves. :p :D (not targeted at you @MZKM , just in general)

1615584119728.png
 

hardisj

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ha! Well, 32Hz and 40Hz needed a LOT more voltage than 30v to hit their max SPL. So, I had to go back and change the max allowable voltage permitted by the script.

Now the estimated time to completion is 206 minutes. :eek:

If I even wind up posting this data, this is probably gonna be a "when I have the time and feel like it" sort of test.

1615585802704.png
 
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