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Transient response...

#21
ThisBass said:
If the tens lack some low end (versus different sized drivers) then the "assumption" is right that the drivers respond "better" to transients.
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Yeah. I'm thinking that we have two very different phenomena here.
The engineers talk about 'transient response', and AIUI poor transient response has a relationship to poor frequency response and in the end is a kind of distortion (in the technical sense, not the Boss DS-1 sense).

By contrast other folks talk about poor response to transients, and if I understand them right then the phenomenum is all about sonic events which, allthough very short in human terms, are probably at least an order of magnitude longer than the wavelength of a note.
 
#22
JimChjones said:
By contrast other folks talk about poor response to transients, and if I understand them right then the phenomenum is all about sonic events which, allthough very short in human terms, are probably at least an order of magnitude longer than the wavelength of a note.
Click to expand...

Wavelengths are physical dimensions - the wavelength of a low E is about 27 feet. Transients are events that are short in time - typically quoted in milliseconds.
 
#24
JimChjones said:
Yeah. I'm thinking that we have two very different phenomena here.
The engineers talk about 'transient response', and AIUI poor transient response has a relationship to poor frequency response and in the end is a kind of distortion (in the technical sense, not the Boss DS-1 sense).

By contrast other folks talk about poor response to transients, and if I understand them right then the phenomenum is all about sonic events which, allthough very short in human terms, are probably at least an order of magnitude longer than the wavelength of a note.
Click to expand...
Just another example what is going on under the hood with "transient response".

I short pulse 100msec generates nothing but a short noise (plop).
A short sine burst 100Hz that counts 10 cycles generates just the the same sound (a short plop) like a 100msec pulse.

Actually the frequency spectrum generated is very similar for both signals because.
Both signals are transient
the envelope shapes look very similar on both signals.

These are nothing but (very simple) considerations where we get lost of our friend Mr. Fourier
 
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#26
I guess the bigger the speaker area, the bigger chance the cone will move less uniformly as a unit thus the transients would be distorted/not produced as appropriately as they would with a smaller cone. I'm thinking out loud here but it does make sense at the moment in my mind :)
 
#29
Manipulating cone/coil weight with stiffness is one way to alter the midrange response (among other things) of a speaker.

Examples of 15" speakers with very low moving mass (light weight cone/coils) are the JBL: D-130 and to a lesser extent the 2220/2220A and MI-151, EV Force 15 and EVM-15L, and certain OEM versions of the earlier Eminence Delta 15 platform. These drivers can have extension above 5kHz (with the JBL having a better polar pattern due to the aluminum dustcap that's attached directly to the top of the bobbin and acts as a HF radiator.

Between different 15" drivers, the air mass as a variable drops out. There are examples of fairly heavy 10" driver cone/coil assemblies also.

Inductance also factors into bandwidth, and there are ways to modify effective inductance by altering the pole piece geometry and adding a demodulating ring or cap.

This is a complicated subject with no simple answer IME.
 
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#30
JimChjones said:
and if I understand them right then the phenomenum is all about sonic events which, allthough very short in human terms, are probably at least an order of magnitude longer than the wavelength of a note.
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Especially the very short events (dynamic events) generate a (noisy) spectrum which (in general) is not suitable anymore to predict sonic harmonics.
 
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#31
MYLOWFREQ said:
I guess the bigger the speaker area, the bigger chance the cone will move less uniformly as a unit thus the transients would be distorted/not produced as appropriately as they would with a smaller cone. I'm thinking out loud here but it does make sense at the moment in my mind :)
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Partial resonance at the cone surface should be considered as a design goal.
The rings in a cone you can notice wih some speakers out there are not meant for only cosmetics ....

edit, btw, the imagination of speaker movement is nothing but an emerge of reactive acoustical power.
 
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#33
I suspect that transient response is a red herring. For one thing, it's inseparable from frequency response. There's no way to test whether a transient response effect is audible in the absence of a frequency response effect except under contrived circumstances (e.g., all-pass filters) that don't correspond to real effects in speakers.

At lower frequencies where cone breakup is not occurring, the basic electromechanical model that's used in the speaker modeling software is quite accurate. And as I understand it, within that model, speakers that have the same frequency response curve also have the same transient response function. If a speaker is "faster," it's probably because it has a higher cutoff frequency. It could have a lower Q, but Q tends to be controlled for other reasons such as avoiding a response peak near cutoff.

It's interesting that we talk about transient response in speakers but not in amplifiers. The EQ circuits in preamps have their own transient response behavior. In fact, a classic high pass filter has the same transient response as a speaker -- a speaker is an electromechanical high pass filter. Yet we hear transient response in speakers because we think of big massive cones moving slowly, but we don't hear transient response in filters because there's not a simple mechanical analogue to think about.
 
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#35
Often, designers will intentionally lower the transient response of some parts of an amplifier's design to improve the playability under some conditions. Rolling off the high end, for example, does exactly this.
 
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#36
beans-on-toast said:
Perhaps partially because speakers are the weak link in the signal chain, filtering out some of the detail in the amplifier signal. The same can be said about some output transformers, perhaps the second weakest link.
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At least the output transformer is inside a feedback loop, so its effects are minimized at normal signal levels.
 
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#37
Transient defined as any sudden change.
High frequency to low frequency. Softer to louder loud to soft etc etc.

It's common argument in bass equipment, HiFi or car stereo. Same " myths" that 10" speakers are " faster" and larger ones are " slower"

Yes of course the music would change pitch if it was moving slower.

But it's just figure of speech to describe the listener hearing better or poorer transient response of certain systems

Real known issue and downfall of reflex or ported systems. Is reduced cone movement above and below Fb or the tuning frequency. Which effects transients. Especially if the port is active and another frequency comes in above or below the tuning frequency.
Likewise complicated waveforms like bass guitar or music doesn't have equal waveform half cycles. So the resonance of the port isn't picture perfect like the model predicts. And again has a " slowed" inaccurate response. With transients above and below port frequency.

It's been well noted and said even with car subwoofers. That 8" and 10" woofers are " faster" or more accurate.

Specially just like bass guitar 10" drivers are more commonly used in sealed systems. And transient response is extremely quick and accurate with sealed 8" and 10" systems.

Smaller cone at high SPL or being pushed hard is less likely to have cone rocking distortion. Or less distortion all together since a smaller cone is less likely to flex or bend around the voicecoil.

Voicecoil can move rather quickly. But the larger cone area can't always move as quickly under high force. Or fast transients from high to low.

Problem with high bandwidth full range bass drivers is your expecting maybe 50hz to 3000hz so the cone has to be thinner for high sensitivity and upper frequency response.

It's more susceptible to cone rocking or bending. You can reinforce the cone but sensitivity will drop. Likewise bandwidth.

With a sub nobody's worried about bandwidth above 80 to 150 hz so you can reinforce the krap out of the cone and surround and use a huge huge magnet for transients.

I've found the happy medium with car subs is a sealed 12" application. Transient response is incredible and fast in sealed system. And the sensitivity is higher than a 10" so it requires almost half the power to get things moving.

Most players probably don't notice the lag of ported systems. Unless your use to a very snappy and fast sealed system. Having used sealed 810s for years I notice it right away.

Ported 10" being faster....heck no. most annoying thing is high tuned systems 50hz and above and I tend to stay away from ported 10" and even annoying high tuned anything 12" etc etc. Unless it doesn't make the pretty pictures in a modeler people think that work. And tend to tune 10hz below Fs to get to a decent tune frequency for bass. Like 40hz or below
 

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