Klippel NFS vs. Real Physics: How Klippel Sound Field Separation Erases Real Enclosure Resonances show with Klippel examples

[user44455555]

Hi all and @Erin

I compared the raw Free-Field Measurement with Klippel's calculated Direct Sound Only model using the Sound Field Separation algorithm. It becomes obvious that the Room Reflection Compensation aggressively cuts the time window in the low end, completely erasing the speaker's actual cabinet and port resonance. There is also not tell which speaker it is from Klippel. Maybe Klippel owner can verify it more and compare a 2 mm meter measure with a 2 mm measure and use soundfield separation compare with a measure outdoor. You can see the Sound field separation (left part of picture) look strange at 56 ms in Level at Time Cursor Window. keep in mind klippel show times in diffrent format. left window 0.06 sec and right window 60 ms. the vertical cursor is around 60 ms so you can see the huge diffrent between the spectrogram. In the demo i can not change the ranges it show because there need click run . but when click on run license error come. So Demo Limit.

The klippel Software can legally use to show the webexamples that can download on klippel page too. here is link how can do https://www.avnirvana.com/threads/k...how-casevibration-all-vibrate-synchron.17211/

to select the database examples see in above screenshot you need choose this database from klippel page

to change the time in level at Time Cursor you need press alt+enter. go to display tab and enable show cursor. Only then come a input box für time cursor and frequency cursor. you can also click on spectrogram to change it.

also keep in mind, when you change a measure and it have not open the window, you need it open manual on left below or it show old measure.

It seem it is not possible that a software can decide which is enclosure resonance and which is room resonance in bass range.

enclosure resonances are huge in bass, can see with a 2 mm measure. seem can not trust the Klippel sound field separation. upto 300 hz no laser is need so use the Klippel at 2 mm distance and measure with disable Sound field separations give much more realistic values. On scope can see, all speakers are far away from perfekt and can enhance alot. the best i have with fewest enclosure resonances is the JBL 104. left the green is signal send to speaker. purple is output at 2 mm from speaker. this is far away from minphase. also a speaker with more bass should be get better results as the JBL 104 when it is min phase. but bigger speakers get worser results in bass, because of enclosure resonances in bass. to feel sound better at same volume, it is important that the transient of attack and release is fast as the original 96 hz fit to 48000 hz sample rate perfect, so need no filter window(rectangle is this) in the generator
.

 

[user44455555]

another screenshot that Klippel sound field Separation did not work correct at low frequency

Level at time Cursor display show that after 9.89 ms at 300 hz the level is ~-42 db. group delay show at 300 hz only diffrence of 2 ms to 500 hz upto 20 khz. the group delay of 23 ms is realy long. but when klippel show group delay of 25 ms at 300 hz, then the level at Time cursor can not suddenly at 10 ms -42 db and most of the the frequency - 60 db. and the level at frequency cursor at 104 hz stayn always the same with -60 db.

Level at time cursor Window is the same feature in the klippel that REW show in spectrogram with time slice . here can see https://www.avnirvana.com/threads/f...ectrogram-show-slice-at-time-in-ms-add.17088/

that there are many worse speakers out and closed speakers are dead is possible the reason because the speaker reviewer and testing did not show the timing. people think when the speaker sound boomy, its the room and they live with that or did not buy speaker and in

this happen also when bassport is at 45 hz much

https://rmsacoustics.nl/papers/whitepaperbassreflex.pdf

Bassreflex Systems for Very Low Frequencies
A disadvantage of using a resonator is that it collects energy which is delivered
back with some delay after the input signal is terminated, causing coloration of the
sound by a delayed resonance at the resonance frequency of the Helmholtz resonator.
The delayed resonance can be limited by damping which dissipates the vibration
energy into heat. With a standard bassreflex system damping is determined by
the loudspeaker-actuator in combination with the amplifier. A second damping
factor is the dissipated energy of the port which is difficult to tune as it is influ-
enced by the shape of the port and the amount of damping material used inside
the cabinet near the port. T

so to get better speaker quality we need correct timing measure.
Bass reflex only bring 6 db more bass but lots of problems. 6 db more can also get with double stroke speakers. the movement unlinearity of long stroke speakers can be eliminate with a DAC lookup table. Because the spinorama show only frequency at 0 ms and so it is blind for timing problems of speakers.

I gues on spinorama you can measure a Cayon with a speaker and it give good bass for this small speaker. but did not show the huge resonances a cajon have. a cajon is a musical instrument which is design to have nice sounding resonances. there is for around 64$ a mainl mini cajon with speakers. maybe this can measure with a klippel

People hear worse timing too, This can see with the infinity history. I hear long time ago a infinity RS 6001 https://de.scribd.com/doc/289482001/RS-6001-Technical-Sheet . this was the only Infinity i ever heard and it was the worsest boomy speaker i hear in my life

But it was hyped from reviewers and they tell when people tell it sound worse. Buy a very good(expensive) amp to let sound it good. now can see at scriptd the crossover circuit it have. Everybody with electronic knowledge or ask AI know the 6 mH and 45 mH in the bass driver crossover reduce the damping of the amp massive. the infinity brand soon leave the market. that reviewers hyped infinity speakers does not help. Because of missing good timing tests infinity did out of a non bass port speaker to get more bass for the reviewers a very bad crossover design to boost the bass and think people did not hear it.