Driver movement

[BrokenEnglishGuy]

I have a question about the '' speed '' of a driver.
In theory a driver who can do 50 - 400hz mean the driver is not slowly enough to create these frequency.
But what about the time that the driver take to complete stop and then create the new wavelenght?
For example if the driver needs to create a 40hz and then a 33hz frequency, how we can measure the transition error between 33hz to 40hz?


It's really important that thing?, maybe the things works differently, if the driver needs to change it's motion, the time that take the driver to fully stop is not important because the next wavelenght gonna change the move of the driver? how it works?

Im guessing this is not that important, even headphones with poorly smaller drivers can create music pproperly

Also i guess, if the driver is doing a swap 20hz->500hz for example, when the driver start at 20hz and then create the next frequency: 21hz, if the driver doesn't stop properly the 21hz frequency should represent itself as a 21hz but with lots of distortion?

If the driver can swap 20hz-500hz cleanly, that mean every transition between 20hz-500hz is done properly and the speed of the driver is suficient enough to do not have an impact in music?

 

[dasdoing]

not slow enough is not a thing. every driver can produce 30Hz or even 3Hz. the question is if it is audible. you can create a 5Hz pressure wave with a folding fan in your hand, but you will never hear it because you are not displacing enough air

 

[Vini darko]

I think kipple sells a lazer measurment system for that. Its also possible using an accelerometer. Diy is doable but fairly advanced.

 

[BrokenEnglishGuy]

not slow enough is not a thing. every driver can produce 30Hz or even 3Hz. the question is if it is audible. you can create a 5Hz pressure wave with a folding fan in your hand, but you will never hear it because you are not displacing enough air

Let's keep the things simple.
imagine all of these things I talked is from a speaker -+1dB 20hz-50khz.
Im not talking about dBs, im talking about speed and time.

 

[pjug]

Also i guess, if the driver is doing a swap 20hz->500hz for example, when the driver start at 20hz and then create the next frequency: 21hz, if the driver doesn't stop properly the 21hz frequency should represent itself as a 21hz but with lots of distortion?

I would think a sweep with REW or similar would be a good approximation of a glide sweep, not stepped.

Let`s clear up some things about Sweeps

 

[BrokenEnglishGuy]

Nice.



But this is really important?, i'm guessing mostly people confuise '' the speed '' of the driver with others things like resonances or a simply roll off in the sub bass, human have a lot of problems in detecting things in a small fraction of seconds


For example, a simple '' reaction time '', mostly people got 200ms of reaction time, so there is a lot of '' lag '' in humans lol. https://humanbenchmark.com/tests/reactiontime/

 

[sarumbear]

I have a question about the '' speed '' of a driver.
In theory a driver who can do 50 - 400hz mean the driver is not slowly enough to create these frequency.
But what about the time that the driver take to complete stop and then create the new wavelenght?
For example if the driver needs to create a 40hz and then a 33hz frequency, how we can measure the transition error between 33hz to 40hz?


It's really important that thing?, maybe the things works differently, if the driver needs to change it's motion, the time that take the driver to fully stop is not important because the next wavelenght gonna change the move of the driver? how it works?

Im guessing this is not that important, even headphones with poorly smaller drivers can create music pproperly

Also i guess, if the driver is doing a swap 20hz->500hz for example, when the driver start at 20hz and then create the next frequency: 21hz, if the driver doesn't stop properly the 21hz frequency should represent itself as a 21hz but with lots of distortion?

If the driver can swap 20hz-500hz cleanly, that mean every transition between 20hz-500hz is done properly and the speed of the driver is suficient enough to do not have an impact in music?

You are confused on wave theory. There is no speed of a transducer other than the highest frequency it can generate. Frequency and wavelength are firmly linked (to the speed of sound).

 

[BrokenEnglishGuy]

You are confused on wave theory. There is no speed of a transducer other than the highest frequency it can generate. Frequency and wavelength are firmly linked (to the speed of sound).

Yes im a bit confused about the term '' speed '' some audiophiles always talk about things like his speaker is very musical because it's '' fast '' good musical timming and bla bla, but what about the time that the driver takes to stop? That thing is also linked to the frequency/wavelength?
For example, if the driver needs to play a simple slow percusion, when the driver needs to play a simple beat, every time the beat decay if the driver take too long to stop it gonna represent as distortion? because the driver cannot do the wavelength properly so that translate into distortion?

 

[mhardy6647]

The question is asking about the "speed" (velocity) of what?
Perhaps the acceleration of the cone?
The "speed" (velocity) of the sound being produced, of course, is independent of frequency.

 

[BrokenEnglishGuy]

The question is asking about the "speed" (velocity) of what?
Perhaps the acceleration of the cone?
The "speed" (velocity) of the sound being produced, of course, is independent of frequency.

the speed of how much takes the driver to stop itself and if it's important in the real world ( music )

 

[mhardy6647]

the speed of how much takes the driver to stop itself and if it's important in the real world ( music )

sounds like acceleration to me.
Perhaps you're interested in the property referred to as damping?

 

[BrokenEnglishGuy]

sounds like acceleration to me.
Perhaps you're interested in the property referred to as damping?

I guess it's kind of a damping of the driver what i talk but im not sure
Mostly people when talk about the speed hear when the drivers sounds'' quicker'' or each hits sound less softer, but in my experiences things like that are the resonances from the bass in the room or things like that, or just the bass doesn't get right in the room, for example this guy listened to 2 speakers, but the kef bass are hardly to get right since it's a rear port with low tunning, the canton in the other hand has front port with higher tunning, more room friendly.
Both without any treatment or in room EQ.

It's not about that, it felt like it's slow to come back to rest. Think it Has nothing to do with the port as port manages the extension or boom but I heard no boom on the r11, instead it sounded like it was more slow. Something like drivers go to front and they comes to stop in a relaxed way making bass soft in general. That's a non issue for me, as I want to listen to a softer sound for relaxing. The canton on the other hand was like high tension spring. It was more noticeable in songs like stimela by Hugh masekala, the drum rolls are fast, canton presented them very agile with starts and stops in between each hit on the kef, it was softer, but much faster than most cheaper speakers I heard. The ports on the kefs were closed with some foam so may be open them would have improved it.

Anyway for me, the kef was 3600 and even its something that won't work for me, I can resell it due to the good reviews and the fact that kefs official offers are over. Canton had a nominal discount and the price was 5k. I could buy an amp for that extra money, although I wish I could take both of them home and give them a trial.

 

[sarumbear]

Yes im a bit confused about the term '' speed '' some audiophiles always talk about things like his speaker is very musical because it's '' fast '' good musical timming and bla bla…

Most audiophiles create their own own universe with their own physics and maths. If you are interested in technology and learn how transducer work I suggest you start by taking a wave theory 101 course. It’s never too late to learn.

In summary: amplifier moves the driver cone in sync to the audio signal. Speed of that movement is its frequency. Signal starts and stops as fast as the cone can move. That is the maximum speed, hence the maximum frequency the driver can generate.

 

[DVDdoug]

The movement of a "perfect" driver will exactly-match the electrical signal (voltage).

Real world "complex" waveforms contain many simultaneous frequencies and the movement will follow the waveform. Complex wave shapes (or "sudden changes") can be synthesized from a combination of sine waves or "broken down" (analyzed) to their sine wave components.

Of course, a woofer can't respond fast enough to reproduce the high frequencies, but for example it can go from 20Hz to 40Hz fast-enough to accurately reproduce the waveform (and convert it to sound) and of course it can reproduce 20 & 40Hz at the same time. Any "faster changes" (higher frequency components) are reproduced by the midrange and/or tweeter to accurately reproduce the sound in the air.

Now... If you are "playing" a square wave through a 2-way or 3-way speaker the crossover introduces phase-shifts so you don't get an acoustic square wave. But luckily, our ears are hearing the frequency components (harmonics) and it sounds exactly like a square wave.

If you play a high frequency square wave there are components above the audio range that represent the "instant" rise & fall of the "wave". The tweeter (and possibly the electronics) filter-out those harmonics and you get something closer to a sine wave. But as long the tweeter covers your hearing range, this low-pass filtering has no effect on what you hear.

 

[TheWalkman]

I think I understand where Broken is coming from. Let me see if I can state this a bit differently.

The reproduction of a sine wave is a smooth, continuous function and it’s easy to visualize a speaker cone moving smoothly in and out to produce the given wave.

Music (and most sounds) are complex wave forms. It’s easy to picture these irregular waves on an oscilloscope. Picturing the cone movement to create complex sound is a bit of a quantum leap in abstraction (at least to me.)

Is the complex sound and the resulting cone movement essentially a Fourier addition of lots of sine waves to create the resulting sound wave?

Since we know that waves add and subtract, are there micro interactions between the different sound waves are coming off of the same speaker cone, that cancel or reinforce each other? (Or is that the normal case and our ears interpret that as the music we expected.)

To Broken’s point, is there something like a Nyquist function describing the physical attributes of a speaker and cone that defines the highest frequency a speaker can accurately reproduce. Does a speaker need to physically handle movement at some multiple above the highest frequency it can accurately reproduce? If so, what is that multiple?

(Does that make any sense?)

 

[BrokenEnglishGuy]

Thanks

Most audiophiles create their own own universe with their own physics and maths. If you are interested in technology and learn how transducer work I suggest you start by taking a wave theory 101 course. It’s never too late to learn.

In summary: amplifier moves the driver cone in sync to the audio signal. Speed of that movement is its frequency. Signal starts and stops as fast as the cone can move. That is the maximum speed, hence the maximum frequency the driver can generate.

Ty, since everyone are saying claims the hobby is very confused, seems to be if you got a speaker you instantly became an engineering loudspeaker , that's a book?

The movement of a "perfect" driver will exactly-match the electrical signal (voltage).

Real world "complex" waveforms contain many simultaneous frequencies and the movement will follow the waveform. Complex wave shapes (or "sudden changes") can be synthesized from a combination of sine waves or "broken down" (analyzed) to their sine wave components.

Of course, a woofer can't respond fast enough to reproduce the high frequencies, but for example it can go from 20Hz to 40Hz fast-enough to accurately reproduce the waveform (and convert it to sound) and of course it can reproduce 20 & 40Hz at the same time. Any "faster changes" (higher frequency components) are reproduced by the midrange and/or tweeter to accurately reproduce the sound in the air.

Now... If you are "playing" a square wave through a 2-way or 3-way speaker the crossover introduces phase-shifts so you don't get an acoustic square wave. But luckily, our ears are hearing the frequency components (harmonics) and it sounds exactly like a square wave.

If you play a high frequency square wave there are components above the audio range that represent the "instant" rise & fall of the "wave". The tweeter (and possibly the electronics) filter-out those harmonics and you get something closer to a sine wave. But as long the tweeter covers your hearing range, this low-pass filtering has no effect on what you hear.

And what happen with the time that takes the driver to change from 20hz to 40hz? it's kind of a instant thing?
Or even worse, if the cone it's doing 30hz waves which are very slow and the cone needs to move a lot, and he next wavelenght it's 350hz, the driver needs to stop itself very quickly for create the new wavelght, which is 350hz, very different and faster, how much time it takes?
Is instantly and there is no problem?, if the driver cannot do it sufficiently great, the driver gonna show that thing as distortion?

 

[Crosstalk]

Most audiophiles create their own own universe with their own physics and maths. If you are interested in technology and learn how transducer work I suggest you start by taking a wave theory 101 course. It’s never too late to learn.

In summary: amplifier moves the driver cone in sync to the audio signal. Speed of that movement is its frequency. Signal starts and stops as fast as the cone can move. That is the maximum speed, hence the maximum frequency the driver can generate.

So there is no overhang possibility?

Consider two transducers with same cone one with a very elastic suspension and the with very tight suspension.

If we send a single 40hz peak it should go forth and back 40 times and stop immediately. But is there a possibility at even if the intensity isn't same as the main signal the speaker continues to vibrate for more time slowly decaying the signal until it comes to rest? The one with the tighter suspension may stop faster and the one slower might resonate more? Having a very tight suspension may also have other problems not associated with speed. Or this isn't even a consideration in transducer design?

 

[sarumbear]

Thanks

Ty, since everyone are saying claims the hobby is very confused, seems to be if you got a speaker you instantly became an engineering loudspeaker , that's a book?

101 is the suffix that denotes a starter course.

 

[sarumbear]

So there is no overhang possibility?

Consider two transducers with same cone one with a very elastic suspension and the with very tight suspension.

If we send a single 40hz peak it should go forth and back 40 times and stop immediately. But is there a possibility at even if the intensity isn't same as the main signal the speaker continues to vibrate for more time slowly decaying the signal until it comes to rest? The one with the tighter suspension may stop faster and the one slower might resonate more? Having a very tight suspension may also have other problems not associated with speed. Or this isn't even a consideration in transducer design?

How a transducer is behaving can be understood by analysing it’s frequency response. Including everything you and others are asking and/or concerned.

 

[BrokenEnglishGuy]

Anyway if for example, the driver doesn't have enough self damping, the driver should stop slowly and keep '' ringing '', but if the driver need to do a faster wavelenght while it's ringing, there will be a raise of distortion in the next wavelenght?


I mean, in the first escenario is a driver playing 40hz wave and then 350hz wavelenght, the second one was play while the driver keep ringing in their first miliseconds
The second scenario is the same driver but only playing the 350hz wavelenght, in this scenario the driver gonna produce the 350hz wavelenght better?


Te second scenario is closer to the reality, but a frequency swap plays the entire 20hz->400hz so.. i don't know, but is not like that test set a permanent wavelenght of 40hz and then start to play randomly upper frequency above 40hz like
40hz -> 300hz
40hz -> 350hz
40hz -> 333hz
And so on, you cannot measure how these transitions are done? or it lacks of an objective purpose? and the swap 20 hz -> 400 hz is enough?