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Step Response: Does It Really Matter?

Cosmik

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I have less time and patience for tinkering, I want fewer boxes, fewer speakers, fewer cables, fewer magic gizmos, etc. ...
...which is why my new system is being built around ...a turntable...

Does not compute. (literally!)
 
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DonH56

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Don't get me wrong, I enjoyed my decade of electrostatic listening. I could even argue that owning panel speakers at some point is a necessary right of passage for a serious audio enthusiast.

But after futzing with them and placement and EQ and subs for years, I think I have a handle on their strengths and weaknesses, I'm ready to move in another direction -- which, will of course, expose me to a different set of strength and weaknesses and I'll bemoan that X speaker doesn't do Y as well as electrostats.

Ultimately, though, I'm becoming less of an audiophile. I have less time and patience for tinkering, I want fewer boxes, fewer speakers, fewer cables, fewer magic gizmos, etc. I just want to come home from work, decompress, and, for an hour or two, listen to some good music on a good system while avoiding audiophile nervosa.

Luckily, the bar for 'good system' (enjoyable, without horrible defect, although not state of the art) has come way, way down in cost and complexity from what it was decades ago. I'm ready to embrace that and simplify, which is why my new system is being built around an all-in-one electronics box, a turntable, and 2 speakers. Everything else is in software.


Been there, done that, for decades, and recently switched to conventional speakers just "because". That said my Maggies were pretty dialed in, but at nearly 30 years old figured they were going to die one of these days and wanted to change while I was still working and a few years from retirement. OK, more than a few, but while I could still hear and afford something nice.

Zero desire to pull out my old TT, however. I got rid of the majority of my LP collection long ago, and have not felt the urge to futz with a TT again. Don't even have a good place for it in my current media room. Ripped all my CDs to a NAS and using a SONOS:Connect; planning to switch to a local server of some sort because the network is not always reliable in the basement (across the house and two stories below the router). Messing with the speaker setup and EQ is usually a one-shot affair, albeit generally drawn out over several weeks/months. Messing with the TT and LPs is at every play, plus semi-constant maintenance.

Probably just me...
 

Fitzcaraldo215

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But there's the rub...if I need more dynamic drivers to make the electrostatic sound right, what's the point of having the electrostatic?
Many, many systems benefit considerably from subwoofers and room EQ, even many big mother, all dynamic speakers, and not just electrostats.

Why use an electrostat? Why use a multi-way dynamic speaker with cone woofers and separate cone/dome/horn, etc. mid- and dome/horn, etc. tweeters? The answer, of course, is physics, materials, etc. along with careful engineering trade-offs. Every driver and driver type has its limits, but also special strengths within those limits.

So, MLs emphasis from the original Monolith on has been on electrostat hybrids with cone woofers, since bass reproduction has very specialized characteristics in any system. Cone bass drivers are used almost universally in engineering speakers for the special problems of bass reproduction. But, I once owed the ML CLS, allegedly full range. It was a fraud, even using subwoofers. They were just too thin in the mid/upper bass, above where the subwoofers could fill in. ML had not solved the dipole cancellation problem with that approach, and continued mainly with the hybrids with better success.

However, nothing does a better job of reproducing the deep bass than a subwoofer, engineered specifically for that purpose, and it is typically powered separately and offloads deep bass duties from the main speakers. Plus, it can be placed in the room for best response independently of the main speakers, even in multiples to better spread good deep bass around the room.

BTW, a strength of the electrostat, even in a hybrid system, is that they can operate full range above the xover to the woofer. So, there is no passive xover in the critical 2-3k Hz range, where the ear is most sensitive, as is all too typical of so many 2/3 way dynamic systems.
 

RayDunzl

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watchnerd

watchnerd

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BTW, a strength of the electrostat, even in a hybrid system, is that they can operate full range above the xover to the woofer. So, there is no passive xover in the critical 2-3k Hz range, where the ear is most sensitive, as is all too typical of so many 2/3 way dynamic systems.

Before the advent of modern DSP crossovers, I would have said the 'no crossover in the listening range' was one of the killer attributes of electrostats.

But, these days, with active DSP speakers being as good as they are, I just don't see that as such a big advantage anymore. Tying this all back to the thread, below is the step response for the Dynaudio Focus XD 200, with its DSP crossover / EQ:

916DF200fig5.jpg


Those results are simply superb. If step response matters, that result is superior to any measured hybrid electrostat I've seen.

The spectral decay is equally great. These are not vibratory monkey coffins of yore:

916DF200fig6.jpg


(All graphs courtesy of Stereophile)

Unless I subjectively prefer the radiation pattern of panel speakers, I don't see any objective reason these days to prefer them to digitally EQed multi-way dynamic speakers. Some of the biggest advantages of panels (lack of crossover, good impulse response) can now be addressed digitally in dynamic speakers.
 

Fitzcaraldo215

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Was that a measurable problem?
Reliable audio measurement tools were not available in the Paleolithic era. And, I was purely an unsophisticated "ears" guy back then, with much less live concert experience. But, increasingly over time and with my development of better listening standards, there was not any doubt about the existence of this issue. I just have no details about what the frequency response curve looked like. I do think it was pure dipole cancellation
 

Fitzcaraldo215

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Before the advent of modern DSP crossovers, I would have said the 'no crossover in the listening range' was one of the killer attributes of electrostats.

But, these days, with active DSP speakers being as good as they are, I just don't see that as such a big advantage anymore. Tying this all back to the thread, below is the step response for the Dynaudio Focus XD 200, with its DSP crossover / EQ:

916DF200fig5.jpg


Those results are simply superb. If step response matters, that result is superior to any measured hybrid electrostat I've seen.

The spectral decay is equally great. These are not vibratory monkey coffins of yore:

916DF200fig6.jpg


(All graphs courtesy of Stereophile)

Unless I subjectively prefer the radiation pattern of panel speakers, I don't see any objective reason these days to prefer them to digitally EQed multi-way dynamic speakers. Some of the biggest advantages of panels (lack of crossover, good impulse response) can now be addressed digitally in dynamic speakers.
I am not disagreeing. Actives with DSP are new paradigm with excellent prospects. If buying new today, who knows, I might go in that direction. But, I am not also not believing that these few measurements tell the whole story, which is complicated.
 

Cosmik

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I am not also not believing that these few measurements tell the whole story, which is complicated.
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.
 

oivavoi

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I think this is the moment to come clean: I have never really understood this "step response" thing. I've tried to read about it, but it's still fuzzy to me. It's still unclear after this thread.

Could someone please have patience with me and make a "step response for dummies" explanation, using layman terms? :)
 

j_j

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Relatively, yes. But I should think FIR can slide things earlier or later however the filter is designed.

If an FIR is symmetric, it has constant time delay. Yes, it is possible to design an FIR that is not constant delay, but it's rather uncommon.
 
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watchnerd

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I think this is the moment to come clean: I have never really understood this "step response" thing. I've tried to read about it, but it's still fuzzy to me. It's still unclear after this thread.

Could someone please have patience with me and make a "step response for dummies" explanation, using layman terms? :)

This is as good an explanation as I've read anywhere, a digest version of JA's AES papers on the topic:

https://www.stereophile.com/features/100/index.html
 

j_j

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I may be sleep-deprived myself, and may be answering the wrong question, but if we are talking 6 inches then around .5 milliseconds (500 micro) seems more appropriate.

ITD, depending on head, maxes out at about .9 milliseconds for very, very close sources, but that varies by hat size a lot. For more distant sources, .5, .6 milliseconds thereabouts.

And yes, the ITD DL is more like 5 MICROseconds. zzzz
 

RayDunzl

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Could someone please have patience with me and make a "step response for dummies" explanation, using layman terms?

Impulse Response - that's looking at the waveform in the air, which (digitally) could be produced by a single full-scale byte of data. A "tick".

Step Response - that's looking at the waveform in the air, which (digitally) could be produced by a transition, from say "0" to "full scale" and the signal remaining high.

I have - in another thread - demonstrated that both the log sine sweep calculated step and impulse responses are essentially identical to the waveform seen at the microphone by actual single-byte impulse and step (using a low low frequency square wave) excitations of the same speakers.

Look here: https://audiosciencereview.com/forum/index.php?threads/impulse-response.1765/
 

Cosmik

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Could someone please have patience with me and make a "step response for dummies" explanation, using layman terms? :)
This is how I would see it:
If you literally feed a step signal (it's low, then it suddenly goes high and stays there) into your system, then what do you pick up with a microphone monitoring the speaker? What you get is quite revealing of how the speaker has been put together.

Conventional wisdom says that the time domain response doesn't matter much as long as the frequency magnitude response is flat, so a genuine step is unimportant - it can be staggered or similar. Some people (like me) would say that it can't do any harm to get a real step response if it can be done e.g. with DSP. Fetishising it would be pointless, however, if it only occurred at some single point in space and fell apart completely everywhere else.

The perfect omnidirectional speaker would give you a duplicate of the input (or rather the 'AC equivalent' that decays over time) at any point in space. For obvious reasons, a speaker that is a composite of several drivers of finite size and separated by finite distances is unable to do this - but some 'geometries' are better than others. The perfect directional speaker (thus controlling the effect of room ambience) would give you the same response but it would be attenuated in level as you went off axis sufficiently.

In a real room, reflections will contaminate the measured step response if they reach the microphone within the time frame in question. It might be tempting to say, therefore, that the response is in error - but it wouldn't be. It would merely be a step response plus ambience, but you wouldn't be able to tell how close the speaker was to a step response by looking at the result. For this reason, step response is measured anechoically (or pseudo-anechoically in a large room, with the reflections sufficiently late to not contaminate the measurement).

Step response is rarely measured with a literal step input, but is usually derived mathematically from a sinusoidal frequency sweep. However, the oft-cited square wave test is effectively a direct measure of the speaker's step response if the frequency is low enough.

(Would anyone here agree with this assessment..?!)
 

Fitzcaraldo215

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Pretty darned good, Cosmik. I think it fair to say that we would prefer buying a speaker that has a better looking step response measurement. But, I don't think we really know how important/unimportant that is to preferences we might choose under double - blind listening conditions.
 
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watchnerd

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Step response is rarely measured with a literal step input, but is usually derived mathematically from a sinusoidal frequency sweep. However, the oft-cited square wave test is effectively a direct measure of the speaker's step response if the frequency is low enough.

Kind of.

This how John Atkinson describes his method:

"MLSSA feeds the loudspeaker a pseudo-random sequence of rectangular voltage pulses. By performing a cross-correlation function between the test signal and the signal picked up by a microphone, the host PC can calculate the system's impulse response. It is important to remember that this is the calculated impulse response, not the response of the speaker-under-test to an electrical impulse. As pointed out to me in 1991 in a private communication by Verity's Graham Bank, then with Celestion, the two are not the same. The loudspeaker might well behave differently when presented with the low-dynamic-range MLS pulse train than it would when driven by a high-dynamic-range single impulse. The assumption is also made that a linear system is being tested and that is not necessarily the case. The presence of nonlinear behavior in the loudspeaker being tested leads to spurious "echoes" or reflections in the calculated impulse response...

I use the MLSSA software to calculate a loudspeaker's step response from its impulse response. A plot of the step response appears to give more-or-less equal visual weighting to the outputs of all of a speaker's drive-units. You can now glean a lot more information about the lower-frequency drivers, as well as getting a good idea of how time-coherent the speaker is.
"

Read more at https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-2#BKFjxHXB0dbHpSdU.99
 
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watchnerd

watchnerd

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Pretty darned good, Cosmik. I think it fair to say that we would prefer buying a speaker that has a better looking step response measurement. But, I don't think we really know how important/unimportant that is to preferences we might choose under double - blind listening conditions.

Olive / Toole think it's not that important.

Or, to put it differently, it ranks much much lower than flat-ish amplitude and controlled directivity in their testing.
 
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