Hi,
I see that often the step response is not included in the tech specification of many common brands,while I think this parameter is impotant becouse lets us know how “fast” the tweeter is and therefore if it can accurately reproduce all the details.
I have compared these misurations:
Bliesma T34A-4
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t34a-4
SB Acoustics Satori TW29TXN-B
https://hificompass.com/en/reviews/satori-tw29txn-b
and from what I see in the step response the Satori TW29TXN-B is much more faster then Bliesma T34A-4 and frankly did not expect this as I thought the Bliesma T34A-4 was superior to the Satori in this aspect as well, but apparently I was wrong.
And so maybe I should reconsider the Satori, in my next 3 way project (Woofer: Scan Speak 26W_8534G00, Midrange: SB Acoustics Satori MW16TX-8, with crossover cut 250 Hz, 2.5 Khz )
Then there would be the preference of the “relaxed” sound to consider. In the hificompass.com review:
https://hificompass.com/en/reviews/bliesma-t34a-4-34mm-alumag-dome-tweeter
they called it relaxed perhaps precisely because of its “slowness” but this is just theory.
I like to understand better if this paramenter "Step response" is important, or is perhaps something secondary.
What do you think ?
Thank you !!
I see that often the step response is not included in the tech specification of many common brands,while I think this parameter is impotant becouse lets us know how “fast” the tweeter is and therefore if it can accurately reproduce all the details.
I have compared these misurations:
Bliesma T34A-4
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t34a-4
SB Acoustics Satori TW29TXN-B
https://hificompass.com/en/reviews/satori-tw29txn-b
and from what I see in the step response the Satori TW29TXN-B is much more faster then Bliesma T34A-4 and frankly did not expect this as I thought the Bliesma T34A-4 was superior to the Satori in this aspect as well, but apparently I was wrong.
And so maybe I should reconsider the Satori, in my next 3 way project (Woofer: Scan Speak 26W_8534G00, Midrange: SB Acoustics Satori MW16TX-8, with crossover cut 250 Hz, 2.5 Khz )
Then there would be the preference of the “relaxed” sound to consider. In the hificompass.com review:
https://hificompass.com/en/reviews/bliesma-t34a-4-34mm-alumag-dome-tweeter
they called it relaxed perhaps precisely because of its “slowness” but this is just theory.
I like to understand better if this paramenter "Step response" is important, or is perhaps something secondary.
What do you think ?
Thank you !!
It does not have the significance you assign to it. It is more an indication of the response, which of course is something you can control.
The step response appears to be faster on the Satori but I wouldn't give anything on it.
Firstly, the step response is very coarse in measurement points, in the x-axis as well as in the y-axis (The x-axis got a vastly different scale too). Same on the waterfall. The latter is still useful but I wouldn't bet my (well, non-existent) house on it. Both measurements were done differently.
Secondly, The first rise on the impulse probably happened between the time where two samples were taken, looking 'slower'. The main thing these measurements show are the high frequency resonances which have a massive impact on the decay. If you want a hard, stiff ..well, that sounds kinda bad.. dome material, you have to live with these resonances. In many cases these will not be excited as much as in the measurements, the XO plays a big role in that too. The high frequency resonance was probably parasitic, delaying the impulse answer. But that also means that the impulse answer would differ off-axis, likely be better. The resonance(s) of the Bliesma are on a lot lower frequency than the Satori.
Thirdly, a much bigger dome does naturally have a slower rise time but that also depends on the driver and a different measurement method can significantly change the graph. If you want a fast rise time, a big dome isn't the best choice for that and if that's criterium #1, then you should look at drivers with vastly better moving mass/motor ratio and higher efficiency/spl. Like big AMTs, magnetostats/leaf tweeters or real ribbons.
What would really make it interesting would be to compare the distortion but they didn't post any on the Bliesma.
Firstly, the step response is very coarse in measurement points, in the x-axis as well as in the y-axis (The x-axis got a vastly different scale too). Same on the waterfall. The latter is still useful but I wouldn't bet my (well, non-existent) house on it. Both measurements were done differently.
Secondly, The first rise on the impulse probably happened between the time where two samples were taken, looking 'slower'. The main thing these measurements show are the high frequency resonances which have a massive impact on the decay. If you want a hard, stiff ..well, that sounds kinda bad.. dome material, you have to live with these resonances. In many cases these will not be excited as much as in the measurements, the XO plays a big role in that too. The high frequency resonance was probably parasitic, delaying the impulse answer. But that also means that the impulse answer would differ off-axis, likely be better. The resonance(s) of the Bliesma are on a lot lower frequency than the Satori.
Thirdly, a much bigger dome does naturally have a slower rise time but that also depends on the driver and a different measurement method can significantly change the graph. If you want a fast rise time, a big dome isn't the best choice for that and if that's criterium #1, then you should look at drivers with vastly better moving mass/motor ratio and higher efficiency/spl. Like big AMTs, magnetostats/leaf tweeters or real ribbons.
What would really make it interesting would be to compare the distortion but they didn't post any on the Bliesma.
The Step is derived from the Impulse. I use it to look at the time offsets and driver polarity of a speaker system. I would just look at the CSD's or the Impulse.
Rob 🙂
Rob 🙂
That’s right.
Mass is not an indicator of the ability to respond fast. Neither is a sharp looking step response, any more than it is simply another way of looking at response
Mass is not an indicator of the ability to respond fast. Neither is a sharp looking step response, any more than it is simply another way of looking at response
A low mass/motor ratio also improves the efficiency - which not only benefits the spl but also improves the slew rate. You aren't wrong, it depends a lot on the construction of the driver but that doesn't mean the mass/motor relation is wrong either. From AMTs to ribbons or magnetostats or even horns, the driver principle is ofc changes a lot but in genreal on comparable drivers (ie dome tweeters) it indeed comes down to bigger motor and less mass equals higher spl. In praxis the high spl is not needed so the drivers are optimized to achieve a lower xo frequency. While the most drivers on the market follow that principle, the pyhsics of 'low mass + strong motor equals high spl' is definitely not wrong, physics confirm that even if following that it means to sacrifyce a low XO frequency is the compromise you have to take.
Really, it's not wrong. High mass domes or CDs often excite the resonances first before the whole dome actually reacts, that's the way resonances work, easily excited and storing energy longer than the rest of the system. That's not 'clever arguing' but actual physics.
E: A lot of resonances are out of phase to the membrane, no mystery there either.
Physics eh? That's important.
Let's make this clear. If the diaphragm moved any faster you'd alter the response, and that we don't want 😉
As Dr Geddes once put it..
Also..
That's a point where Dr. Geddes was so very wrong. Among other claims. You want the diaphragm follow the signal as closely and fast as possible. If it doesn't do that, you'd alter the response. And time and frequency domain.
Just mentioning or quoting a 'renowned' name does not make it right.
I can keep this up as long as you like 😉
Since the driver has no knowledge of where to stop, what does it do? If the diaphragm moves any faster to the applied signal, the sensitivity increases.
Once the sensitivity increases, the diaphragm needs to move faster just to keep up with the greater output level.
Back to square 1.
Since the driver has no knowledge of where to stop, what does it do? If the diaphragm moves any faster to the applied signal, the sensitivity increases.
Once the sensitivity increases, the diaphragm needs to move faster just to keep up with the greater output level.
Back to square 1.
Many thanks for all, is clear that this paramenter is not so important like what I thought. That's better
Most impotant question:
Here the full measure for both drivers:
BlieSMa T34A-4
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t34a-4
SB Acoustics Satori W29TXN-B
https://hificompass.com/en/speakers/measurements/satori/satori-tw29txn-b
which one you choose in my place in combination of Woofer: Scan Speak 26W_8534G00, Midrange: SB Acoustics Satori MW16TX-8 and why ?
Have you some direct experience on both ?
Most impotant question:
Here the full measure for both drivers:
BlieSMa T34A-4
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t34a-4
SB Acoustics Satori W29TXN-B
https://hificompass.com/en/speakers/measurements/satori/satori-tw29txn-b
which one you choose in my place in combination of Woofer: Scan Speak 26W_8534G00, Midrange: SB Acoustics Satori MW16TX-8 and why ?
Have you some direct experience on both ?
Could you be a bit more specific about what exactly you mean by "much faster"? What part of the step are you referring to?
Personally I would choose the one which sounds more tolerable to me in the long term. Unfortunately this is often hard to predict from graphs.
The woofer sets the stage for overall capability, so the Satori tweeter looks ample. The Bliesma seems marketed more as a direct radiator alternative to compression drivers. But I'm looking at the "mid-woofer" as not really fitting the rest. Way too much Xmax.
It's most likely not, and the plot for the Bliesma is incorrect/unprofessional in that it misses a proper time scale and it is obvious that the scale doesn't match the Satori plot.
Further, the time resolution is not good enough anyway (sample rate way too low), the ragged responses are not real.
Totally incompetent job in my book (and only God knows if they even used a qualified mic which should have at least 50kHz bandwidth, preferably 100kHz).
The step response is just a different representation of the frequency response (magnitude + phase). They contain the same data. Depending on what you are looking for, one is more helpful than the other.
That may be so, but a limited sampling rate won't accentuate peaks if they aren't really there. It may miss peaks, but a good interpolator should fill those in. According to the Nyquist theorem you only really need just over 2 samples per cycle to reconstruct a sine wave. Nobody said that the samples themselves have to hit every peak.