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Step Response: Does It Really Matter?

j_j

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yes i have listen. i want wait what others hear. others do not report what they hear. now i write. I hear in the AM tone huge wobbling(i think it wobbles around 5 hz, but i am not sure. can also be 10 hz) with headphone and my jbl same strong. the fm.wav is more clean but it wobbles too clear noticable. maybe you reduce the phase shifts to much lower. in last post i want say. when this happen with stereo signals the diffrences are much much more hear because the wobble of left and right speaker independent give the room feeling of a big reflective room


In loudspeakers, nobody (much) is debating the issue of 10 microsecond ITD limits.

That's not in doubt. But remember, if both speakers are the same, that does not affect ITD's in a given frequency at all.
 

bennybbbx

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In loudspeakers, nobody (much) is debating the issue of 10 microsecond ITD limits.

That's not in doubt. But remember, if both speakers are the same, that does not affect ITD's in a given frequency at all.

What have you do exactly with the am.wav and fm.wav example ?

it does not help on stereo music when both speakers are the same and they are slow in mid. because left and right speaker need always do diffrent movements for stereo signals.
. a slow speaker is able to play at -3 db frequency upto 5 khz. thats a period time of 200 microseconds. so how can a speaker that is only fast enough to play down to 200 microseconde the phase for correct peaks of the wave exact for ITD ?. I think thats not possible. have you look at the electrci hydraulic pdf ? . there stand text https://www.sunhydraulics.com/sites...ech_resources/rel-Prop_terms-definitionsN.pdf page 9
With low frequency, input command and output pressure remain in phase. Output pressure rises fully. With high frequency, output pressure lags input command. Output pressure does not rise fully
you can see the hydraulic can work upto 10 hz. but you can also see that the peeks are delay much(more than 70 degree).
and because of the diffrent signals the left and right speaker need play, the phase shift between left and right channel is much diffrent. because can happen that for example in the hydraulic system the next peek happen at freq 1 hz on left channel and 3 hz on right channel

when this input delay(10 hz in hydraulic) happen on a slow woofer at 6 khz, should be clear, this is not able to play ITD correct even if this woofer need only play 1.5 khz

this is the reason that need a mid speaker that is faster. best is a mid/woofer that can reach 15 khz i think. The jbl 104 BT is the best i hear so far .it sound amazing in stereo. maybe it is because the woofer is because it is coaxial(have a hole) not so heavy as have 4.5 inch membrane and it use crossover of only 1.7 khz. the mtm have 3.5 inch but crossover of 3.3 khz.

edit: also look at the distortion phase change of the LP6 depend on level. see in this post https://www.audiosciencereview.com/...oes-it-really-matter.1999/page-20#post-871821 or in this post last 2 pictures https://www.audiosciencereview.com/...oes-it-really-matter.1999/page-19#post-858839
 
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j_j

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What have you do exactly with the am.wav and fm.wav example ?

One is AM and one is narrowband FM. Absolutely identical power spectra.

it does not help on stereo music when both speakers are the same and they are slow in mid. because left and right speaker need always do diffrent movements for stereo signals.

YOU STILL DO NOT UNDERSTAND LINEAR SUPERPOSITION.
 

bennybbbx

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One is AM and one is narrowband FM. Absolutely identical power spectra.



YOU STILL DO NOT UNDERSTAND LINEAR SUPERPOSITION.

here is screenshot of your waves. seem you have measure power spectrum over longer time. in the wave can see that AM have much louder peaks and more silent valleys. in the Fm the level changes are not so much and so it sound not so loud but more constant.
am fm 2.jpg

I understand Linear superposition but it have nothing to do that a slow speaker that can produce only 5 khz(200 microsecond period time) have (depend on frequency and movement of left or right channel need play) too on frequency at only 1 khz more delay as 30 microseconds(this accuracy is need for ITD). and because the delay of slow speaker change much between left and right side depend on movement, it bring no good ITD which ican hear as reduced stereo width
 

DonH56

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Continuing to conflate ITD with bandwidth, group delay, etc. etc. etc. Maybe it's the language barrier, but it seems pretty clear the poster has made his own conclusion, and is unable or has no interest in understanding all the counter arguments no matter how well presented and backed by references and prior research. When someone believes his own conclusions to the exclusion of all contrary evidence perhaps it is time to just let it go...

We've had stereo what, almost 100 years now, and even without understanding the science there are all those folk with stereo systems who have heard stable images despite their "slow" speaker drivers to counter the proposed ITD argument.
 

bennybbbx

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Continuing to conflate ITD with bandwidth, group delay, etc. etc. etc. Maybe it's the language barrier, but it seems pretty clear the poster has made his own conclusion, and is unable or has no interest in understanding all the counter arguments no matter how well presented and backed by references and prior research. When someone believes his own conclusions to the exclusion of all contrary evidence perhaps it is time to just let it go...

We've had stereo what, almost 100 years now, and even without understanding the science there are all those folk with stereo systems who have heard stable images despite their "slow" speaker drivers to counter the proposed ITD argument.

dont forget in speaker tests testers say this speaker have large stereo width or large depth of field and other speakers they report fewer or bad stereo. .so if this is not because of unprecise mid woofers whats the reason for this diffrence ?. wy there are 3 way speakers with smaller and faster mid woofers, when a large woofer can also precise create mids for ITD ?. many think bigger stereo wide happen because of wider directivity of speakers. this theorie forget that the stereo width of a sound depend much on the frequency below 1.5 khz. so the directivity of a tweeter can nothing help. here is a test video. you can hear that when i do frequency below 460 hz make mono(with stereo multispreader) the room size get much smaller. or do you hear no diffrence ?.

maybe the experts here answer this questions.

which counter arguments do you mean ?. nobody can show that the LP 6 have in the frequency range upto 1.5 khz less phase time erros as 30 microseconds. I can only show alot measure screenshots that the phase delay change much depend on level it must play and it is more as 30 microseconds.

you need also notice many people that like music hear very loud which is not good for ears. when hear loud the level diffrence that reach left and right ear is also more diffrent as on low volume. So maybe need no ITD because brain can better detect diffrence

how much people can hear ITD is not clear. can you hear the direction from which side the sound come in this video ? https://www.audiosciencereview.com/...oes-it-really-matter.1999/page-16#post-843549
 

OK1

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I agree about measurements, but I don't think it is that complicated. I think that the designers of a certain German DSP-based speaker (that some people are sick of hearing about!) have approached the problem in full knowledge of what they were doing, and their relatively simple design just works. It wasn't put together by trial and error, and lots of listening, or even lots of measurements. It was, instead, based on predictions of the simple physics of driver dimensions, baffle sizes, and the role of DSP as 'glue'. I rather expect that their first prototype sounded better than 95% of all other 'high end' speakers within a day of them first trying it out.
Which German DSP based speaker would this be?
 

ernestcarl

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That was 2017 so he probably meant Hedd: https://www.hedd.audio/pages/lineariser

IMO, while linearizing phase and flattening GD can indeed measurably increase clarity (you can most definitely see this in C50 ratio, for example) the effect must be assessed in a room where the acoustics have been sufficiently dealt or treated with beforehand. Much of the “benefit” is just going to be lost if reflection-decay remains largely uncontrolled. There was a video released by Acoustics Insider in collaboration with Hedd to demonstrate their lineariser switch disabled vs active via Smaart… but that was rather underwhelming (only looking at the phase graph and nothing else) as the room was pretty bad anyway. Found the video:
 
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j_j

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That was 2017 so he probably meant Hedd: https://www.hedd.audio/pages/lineariser

IMO, while linearizing phase and flattening GD can indeed measurably increase clarity (you can most definitely see this in C50 ratio, for example) the effect must be assessed in a room where the acoustics have been sufficiently dealt or treated with beforehand. Much of the “benefit” is just going to be lost if reflection-decay remains largely uncontrolled. There was a video released by Acoustics Insider in collaboration with Hedd to demonstrate their lineariser switch disabled vs active via Smaart… but that was rather underwhelming (only looking at the phase graph and nothing else) as the room was pretty bad anyway. Found the video:
You have to remember that trailing sounds are substantially masked, so some of the acoustics (but far from all) gets quite reduced in terms of listening.
 

OK1

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That was 2017 so he probably meant Hedd: https://www.hedd.audio/pages/lineariser

IMO, while linearizing phase and flattening GD can indeed measurably increase clarity (you can most definitely see this in C50 ratio, for example) the effect must be assessed in a room where the acoustics have been sufficiently dealt or treated with beforehand. Much of the “benefit” is just going to be lost if reflection-decay remains largely uncontrolled. There was a video released by Acoustics Insider in collaboration with Hedd to demonstrate their lineariser switch disabled vs active via Smaart… but that was rather underwhelming (only looking at the phase graph and nothing else) as the room was pretty bad anyway. Found the video:
Aha interesting. I am somewhat familiar with the evolution of the HEDD speakers, who have since gone on to, in more recent times, incorporate the linearizer DSP, in firmware, in the version 2 of their studio monitors (aka Mk 2). Sent them an information request to find out if this could be turned off in firmware, as I would prefer to use the software plugin, to avoid the A to D and D to A (more of a purist mindset - theoretically doing all to keep signal quality losses, to the minimum, as these conversions would be inherent in any speaker which utilises DSP.

Still waiting for a response from HEDD, but this is the weekend(Sunday), so hopefully should get a response when the working week starts,
 

ernestcarl

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Aha interesting. I am somewhat familiar with the evolution of the HEDD speakers, who have since gone on to, in more recent times, incorporate the linearizer DSP, in firmware, in the version 2 of their studio monitors (aka Mk 2). Sent them an information request to find out if this could be turned off in firmware, as I would prefer to use the software plugin, to avoid the A to D and D to A (more of a purist mindset - theoretically doing all to keep signal quality losses, to the minimum, as these conversions would be inherent in any speaker which utilises DSP.

Still waiting for a response from HEDD, but this is the weekend(Sunday), so hopefully should get a response when the working week starts,

Not sure why you think those conversions even matter here… but ok.

The hardware switches are nice for those who do not want to set things up on a desktop computer GUI, however, A/B comparisons are going to be very slow and clunky — you’d have to go to the back of the speakers and subwoofer and turn the knobs each time! It would be easier to do listening comparisons in real-time were full control of the monitors’ internal DSP “lineariser” also fully switchable at the click of a mouse button on the desktop as well.
 

bennybbbx

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I have not post before in this thread. Here is the step response of a 2. order allpass 1.5 khz (which do 360 degree phase shift and the FR is exact linear). in stepresponse Allpass have slower rise time (around 500 microseconds to reach 100%) .The 1.5 khz 2 order 12 db Lowpass(around 400 microseconds to reach 100%). Step response is able to show the time align of tweeter and woofer and it show if phase is good as additional delay in rise time. If can see a phase diagram of the mid range driver is of course better. to get more precise results you can subtract the rise time of a ideal LP filter from the speaker. I create the filters insde REW , do export Filter response as wav and load that in.
step response allpass,  1.5 khz LP.jpg


allpass phase.jpg
 

songOVERsound

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I understand what “step response” is, but I don’t understand what “group delay” is or “impulse response”

How similar are all of these units of measurement? Can a “step response” be a looked at as a “group delay” or an “impulse response”?
 

j_j

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I understand what “step response” is, but I don’t understand what “group delay” is or “impulse response”

How similar are all of these units of measurement? Can a “step response” be a looked at as a “group delay” or an “impulse response”?
A step input is nothing but the integral of an impulse (delta function). Therefore you can learn from the step response everything you learn from the delta function.

The group delay (a function of frequency) can be calculated directly from the impulse response.

Hence they are all related. If you want to learn about all of this, you've got some math ahead of you.
 

songOVERsound

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A step input is nothing but the integral of an impulse (delta function). Therefore you can learn from the step response everything you learn from the delta function.

The group delay (a function of frequency) can be calculated directly from the impulse response.

Hence they are all related. If you want to learn about all of this, you've got some math ahead of you.
Ahhh. Thanks! Knowing that they are all based off of impulse response puts my mind at ease for the time being.

I’m looking at Geithain speakers measurements and the step response isn’t perfect. I’ll be getting the Trinnov Nova which can manipulate the impulse response, and was wondering if it would improve the step response in the picture included
 

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Holmz

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Ahhh. Thanks! Knowing that they are all based off of impulse response puts my mind at ease for the time being.

I’m looking at Geithain speakers measurements and the step response isn’t perfect. I’ll be getting the Trinnov Nova which can manipulate the impulse response, and was wondering if it would improve the step response in the picture included
To a point it can, but if every other driver is inverted, then in the XO band it gets difficult.
And I am not sure that the phase can be rotated 180 degrees… probably it can, with a FIR filter.
 

bennybbbx

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I understand what “step response” is, but I don’t understand what “group delay” is or “impulse response”

How similar are all of these units of measurement? Can a “step response” be a looked at as a “group delay” or an “impulse response”?

the best information for timeprecision is the group delay. step response is a better than nothing solution about timing because there is no speaker tester that show group delay or phase. but luckily some speaker testers show step response. With the step response you can see at least diffrences from optimal stepresponse. that can see in step response time errors you can verify by look at the step response of allpass. a allpass is 100% linear in frequency it have only phase shifts https://www.audiosciencereview.com/...es-it-really-matter.1999/page-21#post-1267723 the group delay of an allpass look as this and you can see best the timing on which frequency how much is wrong. in µsec
group delay allpass 1.5 khz.jpg
 

songOVERsound

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To a point it can, but if every other driver is inverted, then in the XO band it gets difficult.
And I am not sure that the phase can be rotated 180 degrees… probably it can, with a FIR filter.
I believe Trinnov uses FIR filters and I know that Trinnov corrects phase. So it probably can do what you’re saying?
 

dougi

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I believe Trinnov uses FIR filters and I know that Trinnov corrects phase. So it probably can do what you’re saying?
I would think so. DIRAC can, so surely Trinnov could? See my post here where I compare Room Perfect to DIRAC on my Lintons. For some reason, DIRAC (full range) with my NADC3050LE rather than MiniDSP flex does not correct the step/impulse as much. I have no idea why!
 

j_j

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I would think so. DIRAC can, so surely Trinnov could? See my post here where I compare Room Perfect to DIRAC on my Lintons. For some reason, DIRAC (full range) with my NADC3050LE rather than MiniDSP flex does not correct the step/impulse as much. I have no idea why!

This is kind of in a place I can't discuss presently, but with an FIR filter you can do many things you can not do with an IIR filter.
 
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