To illustrate the "sensitivity" of using impulse responses to evaluate the bandwidth of a system, here are some of animated plots. Impulse responses are very revealing for high frequency limitations but not for low frequency.
OK. I bite. For numerical computation reasons, frequency scaled by 1000, i.e. 0.02 -> 20 Hz and 20 -> 20 kHz. Time scale is in milliseconds.
System: 2nd order HP, Q = 0.7, at 20 Hz and 2nd order LP, Q = 0.7, at 20 kHz.
View attachment 245429
Impulse responses are very revealing for high frequency limitations but not for low frequency.
Whoa, thanks @NTK!OK. I bite. For numerical computation reasons, frequency scaled by 1000, i.e. 0.02 -> 20 Hz and 20 -> 20 kHz. Time scale is in milliseconds.
System: 2nd order HP, Q = 0.7, at 20 Hz and 2nd order LP, Q = 0.7, at 20 kHz.
View attachment 245429
There you have it, folks. The perfect audible band IR has a rise time of about 0.06ish ms and returns to zero by about 0.4ms.
Hmm, I bet that amp sounds pretty slow, time to upgrade.Hmm...
Ok, for grins:
Black - "perfect" impulse from above
Red - electrical measurement here, preamp out, one channel
Blue - speaker pair output
Green - speaker pair output with DRC
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Of course (also) in stereo. Mono can reveal something, but stereo can reveal something else. Or may I say, stereo can reveal everything relevant for stereo listening (with two ears) which is normal usage for stereo system with two loudspeakers. This is too obvious to be totally ignored.Since you mention “sound stage”… does this mean you listen in stereo as well to evaluate speaker performance? I ask because there are those who only do mono listening test evaluations for a variety of reasons.
Raw impulse responses are dominated by high frequencies and as such are not very helpful at understanding the timing behaviour of speakers by themselves. A filtered IR, Step response or ETC is much more useful.There you have it, folks. The perfect audible band IR has a rise time of about 0.06ish ms and returns to zero by about 0.4ms. At least according to me eyeballing this mockup. To be fair I think the LP filter is a little low / slow (could set it to a steeper filter at 22khz maybe) but y'all get the idea.
From now on you can call all speakers with a longer IR than 0.5ms "slow", you're welcome.
Oh, that is nice.To illustrate the "sensitivity" of using impulse responses to evaluate the bandwidth of a system, here are some of animated plots. Impulse responses are very revealing for high frequency limitations but not for low frequency.
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Raw impulse ...
Guys, you know what You are doing with the powerful tools the contemporary computer technology gives to you? I personally, with all due respect doubt that, to a degree of being close to be positively sure.Okay, so we kind of ...
I wonder what this says about reading impulse response graphs?
Guys, you know what You are doing with the powerful tools the contemporary computer technology gives to you? I personally, with all due respect doubt that, to a degree of being close to be positively sure.
I'm 100% certain that if you have a point to make it would be more useful than making snide remarks.Guys, you know what You are doing with the powerful tools the contemporary computer technology gives to you? I personally, with all due respect doubt that, to a degree of being close to be positively sure.
Nice term, the 'long-winded'. To correct for 20ms of a group delay @120Hz or so is clearly feasible, no doubt about it! But where did it come from to begin with? What is 'min phase'? What does the DSP do? In short, what can be learned from it?I haven't really learned anything interesting from any of your long-winded warnings.
As with the 'scientific papers' you introduce once in a while: no explanation, no specific reference. What does it mean: '125Hz 1/1'? Is it the filtered branch alone, or the sum after re-combination with the low-pass branch? In either case, how does it relate to what?I'm 100% certain that if you have a point to make it would be more useful than making snide remarks.
where did it come from to begin with? What is 'min phase'? What does the DSP do? In short, what can be learned from it?
The papers I linked to earlier were to provide background that touched on the audibility of group delay. They did not need an explanation or a reference they were meant to be read and demonstrate that not everyone has come to the conclusion that phase doesn't matter. The research is far from conclusive so it is really up to the individual to read and weight it. I did in fact pull an image and provide a small synopsis of one that I thought had a generally useful recommendation of keeping the group delay under 1ms to at least 300Hz.As with the 'scientific papers' you introduce once in a while: no explanation, no specific reference. What does it mean: '125Hz 1/1'? Is it the filtered branch alone, or the sum after re-combination with the low-pass branch? In either case, how does it relate to what?
There's nothing bad with fumbling around, for sure. But publishing some kind of 'result' always needs some foundations to be explained clearly. As to connect it to common knowledge. It sounds trivial, but from my practical experience doing 'science' I know that it may become the tricky part in the process. Do take the 'short-winded' detour, no good.
Some of this I expect the reader ...
You do your thing.The papers I linked ...
I don't understand why mixed flat FR and impulse respond.
But some ASR will scream at you can't hear 40kHz. However, people don't scream at ribbon tweeter that can hit 40kHz too.
Finally, you have super tweeter at 100kHz, which don't make sense if you do not know how to use it.
They are different depending what you look for. Fast rise and fall only can be seen on impulse respond. Mostly importantly, how much time for the transient to silent fast. Of course, the data is not enough only limited on single impulse graph from reviewer. There is frequency respond, however just a single number, 19kHz, 24kHz, 40kHz doesn't tell you the range of a tweeter. Phase is important in crossover point and time alignment. Of course all are correlated in loudspeaker design. That is the designer job.They are two different graphical representation of the same data (when you add phase). One can be derived from the other using math.
The spectral decay is much more useful to visualise that than the impulse response, here for example of a well controlled loudspeakerMostly importantly, how much time for the transient to silent fast.