Step Response: Does It Really Matter?

[neRok]

I still haven't wrapped my head around all the implications of the fact that "REW's SPL plot is an accurate view of the magnitude response of the system's transfer function", and how that relates to the "volume" of dynamic signals like music. I've seen in REW that if I take my room measurement and also make a "min phase copy", then they have the same SPL. But if I then look at the filtered impulse, things look very different, because the min phase version has a lot more SPL packed into the earliest waves possible. So those impulses have the same magnitude, but do they still sound the same?

So when I compare the 2 speakers above, I wonder the same thing = if the magnitude is the same, does the ratio of early:late energy vs the peak energy moment matter? I had an idea to compare the 2 speakers SPL response with frequency dependant windows. I realised if they weren't weren't time aligned that the results were not comparable (because FDW is pegged to different t=0?), so I edited one response so that the delay was baked in. I chose 148Hz, which was an area where the SPL was the same.


And then I compared the FDW at different cycle lengths, and I again see that the HS5 seems to deliver its energy quicker;


There is a difference here, and the difference is not "SPL". What is this apparent difference?

Edit: As the freq moves away from the aligned point (148Hz), GD differences presumably creep in to the FDW results. But that can't be responsible for the 1dB difference at 148hz.

Or maybe a better a question to ask is, if there is a difference in speed/accuracy beyond group delay caused by the box/filters, where in REW can this be seen?

 

[Deleted member 48726]

I think it would be good to see too. If 2 speakers have comparable FR, max SPL, features, cost, etc - then GD would be a good differentiator because it reflects driver quality, cabinet design (ported vs sealed, volume vs tuning freq), and filter affects. I think GD would be better to see than Step/ETC because it specifically shows 1 thing, whereas Step/ETC can look 1 way but actually be 2 different things.


Maybe? I don't know enough about that side of things. Thinking about it, say there are 2 woofers that are the same except 1 has a stronger magnet. If you were to put equal voltage to each woofer, wouldn't that mean the stronger one would be louder (because the stronger magnet would react with more force against the voltage)? So to have the same SPL, wouldn't the stronger one need less voltage? And maybe that comes with other drawbacks? Is that what QTC measures as a ratio?

Anyway, as an experiment I thought to check the "filtered impulse" to see if there was any difference between HS5 vs IN8 whilst ignoring GD, and it seems there is a slight difference.

First I compared each speaker to a dirac impulse at a frequency they both operate strongly at;
View attachment 310982 View attachment 310981

Is the dirac impulse "perfect" when looked at in this regard? Because the HS5 seems to "build up" quicker than it, and "let down" quicker too. Is that indicitive of an overly strong magnet?

Comparing the 2 speakers to each other at the same frequency;
View attachment 310980

REW aligned them so that their 100% peaks were inline. This also shows the HS5 building up quicker and letting down quicker. Maybe this is splitting hairs, but the HS5 might be better, because the HS5 only has 2 peaks over 90% (-1 and 0) whereas the IN8 has 3 (-1, 0, and +1).

Maintaing that alignement but looking at different frequencies;

• 100Hz looks similar: View attachment 310983
• 170Hz is similar, but HS5 is getting worse (nearly 3 over 90%) whilst IN8 has improved (only 2 over 90% now): View attachment 310984
  
• 200Hz shows HS5 has gotten worse with 3 peaks over 90%: View attachment 310985

The alignment was starting to get off at 200Hz, so I let REW re-align them;

• At 200Hz it now looks like IN8 builds up faster and lets down faster: View attachment 310987
  
• 135Hz looks different when viewed this way: View attachment 310986

I thought maybe that wasn't the "fairest" alignment, so I manually set this one;
View attachment 310989 View attachment 310988

So I don't know if everything I've just done is actually showing magnet differences, because they seem to swap between 2 and 3 strong peaks. If 2 strong peaks was indicitive of better, than neither is always better.

A more powerful permanent magnet (flux density) would make the "repellant thrust" of the coil, which is actually an electromagnet, (and thus the diaphragm) more powerful compared to a magnet with lesser flux density. Logically this would make the sensitivity of the driver higher. -If all other components of the driver are equal.

 

[Andysu]

do step response mic up close each speaker driver , DSP crossover ( make sure you have enough amp power first ) do each step on LF then do HF only get the response to look like the crossover curve , i think with each step , you'd all run out of PEQ power before you even start doing it , if not 20,100 PEQ filters then only going to do not even half of it , that's mt take on it , how i have looked at whole thing , simply not enough PEQ , anyway just enjoy if that is what you like ? just haft to accept it as it is presented for now , until someone like , behringer make a serious DSO multi channel 20,100 PEQ cheaply

REW
no smoothing direct freq sweep it follows that L-R -24dB spot on
use smoothing 1/48 , 1/24 1/12 1/6 1/3 1/2 1/1 it looks smooth

do the same repeated test mic close to speaker its a shambles of a mess , each bass driver have to have same in the room , its hard work but not impossible . impossible to PEQ seat to seat , so only get a best possible and that is all that can be done with that

but the speakers drivers each need to be PEQ they look like rough wood or rough wall filler that needs cheap sandpaper to make it smooth , PEQ is sandpaper for speakers and its not cheap , its large and heavy in size compared to real sandpaper but the principles , are more or less the same

20,100 PEQ then i can do real EQ of the speakers up close as the stages need be done are as , what i say follows !

1 check B-chain of system how it appears some parts will have some oddness in freq that make need simple PEQ attenuation to make each channel now appear equally the same
2 check amplifiers direct electronically see if there needs be any adjustment to make freq curves all overlap transparently
3 mic in front of each speaker and each speaker part should be in same 3d space of the room say middle of the room , each speaker ( has its own 20,100 PEQ filters for bass oo only half would be needed , half for HF when it comes to using individual independent PEQ for that HF horn ) yes hard work !

how many multi fantasy beheringer 20,100 PEQ ? i don't know how long is a cheap ball of a piece of string ? 32 channels 64 channels all XLR 19" rack mountable
i think 64 channels and can always add another 20,100 PEQ 64 channels

i have looked at my PEQ and if i see what i see then it be same as what i see on your extreme expensive system , crooked EQ , i seen romans PEQ better , lol

so next final stage
4 PEQ part of the seating area or getting most seats seating areas within a narrow dB technical tolerance and that's it , all that can be done with it , now sit down and play theatrical laserdisc cbs/fox scope Dolby Stereo of return of the jedi ,

i have missed out a lot in the above , as mind we can think , an auto-EQ is not like supercomputer hal 9000 , or should be hal 20,1000 lol
then maybe leave the auto 20,100 to do the freq sweep with , mic close to speaker driver , yes , yes , yes no not " harry does yes "

yes , i just had cheap idea , see this is why 250,000 years of free advanced human developed mind is free

i keep that , yes under my hat for now , meow

20,100 down to 0Hz to 20,000khz , no point going above 20,000khz , other than that system will only entertain , a dog cat and pet bat
we can look at the 30,000 50,000khz but we can't hear it , same deal with astronomy , we can see it but we can't land on it to touch it as we only have short , and its distance away from this solar system , and the many issues that can happen with 0 possible help , same deal , now how does it taste ?

20,100 PEQ otherwise step EQ talk is pointless its okay electronically but once it reaches that £1billion pound speaker it still looks crocked

meow

 

[ernestcarl]

impulses have the same magnitude, but do they still sound the same?

It depends. In-room, some of the time domain excess is "correctable" (so we can do AB or ABX listening tests), but much of it also is not. The directivity or off-axis responses will also heavily influence what you hear more. Recall the whole never ending debate between Genelec vs Neumann monitors of the same size...

if the magnitude is the same, does the ratio of early:late energy vs the peak energy moment matter?

Sure. Listen to your speakers outdoors vs inside a tiled bathroom or empty room -- in all scenarios even if you force-equalize the magnitude flat do you think they will sound exactly the same? The answer should be obvious.

is a difference in speed/accuracy beyond group delay caused by the box/filters, where in REW can this be seen?

The tranducers are not going to be identical in all parameters... In REW, look at some of the other plots that depict frequency-time information e.g. CSD, wavelet spectrogram. For example, HF drivers have different decay profiles and breakup characteristics depending on materials and engineering design.

 

[egellings]

Also, I have to hop on the earlier conversations about electrostatic speakers. One poster said he'd moved on from them, finding them dynamically unconvincing - not 'pressurizing the room' the way box/dynamic speakers do. I moved on from electrostatics (Quade ESL 63s) for the same reason! I was for a while seduced by that particular boxless 'transparent-sounding' aspect of the electrostatic sound. But it seemed after a while to have a sort of ghostly, removed character, as if I were listening to a performance happening through a window in a different room.
When I'd throw in my older smaller box speakers (a pair of old Thiel 02s) it's like the room came alive with the energy of musicians. Drums, bongos just seemed to "whap!" the air right there, like someone was in the room playing the instrument. It just seemed more palpable and dynamic and affecting.

I added the gradient sub to the Quads - some may remember it was a dipole sub designed specifically to match the radiation pattern of the Quads, and the Quads sat on top making for a seamless monolith. They remain to my ears the most seamless combination of dynamic sub with a panel that I've heard. Yet, I still found the 'problem' above persisted and I moved on to box speakers, never looking back.

I've heard a great many Martin Logan hybrids over the years, and my friend owns a pair of ML hybrids as well. Every time I'm struck by the same impression: wow at that cool electrostatic presentation in the mids up, but that same old weightlessness. I get why some people think that adding a dynamic driver in to the design for the lower frequencies gives back some dynamic palpability. But what I always hear is a discontinuity: instruments ranges covered by the dynamic driver have some weight and air-moving drive - e.g. bass instruments - but as the range moves to higher frequencies there is that weightless quality. My friend thinks his MLs rock just fine because once he feels those bass notes hitting from the woofer section, well....there you go! They rock! But for me, it just doesn't work as I find the rest of the spectrum dynamically bereft. Put on Rush and geddy lee's bass can be felt, but Lifeson's guitars don't seem to have the same drive - they are more like a sonic mist you could just walk through rather than the killer impact you hear from a guitar through their cabinet amplification.

So, I get both the anti-panel and pro panel opinions. I enjoy visiting panels - and in fact would own Quad ESL 57s if I had the room to store them when not listening. But it's more a nice place to visit than a place to stay for me.



A buddy of mine had a pair of 'stats and lived alone in his own house so he could do this. He put cut-outs in the wall behind the 'stats and fitted them into the openings. The openings in the wall lead to a bedroom, so there was plenty of rear space that would not restrict diaphragm motion. Bass was superb and extended in both rooms.