It's all well and good using sine waves to measure a driver's frequency response but music isn't sine waves. Every fundamental note contains a plethora of overtones requiring a driver to respond to multiple frequencies at the same time.
I note that people model and post full spectrum graphs of a project's frequency response but isn't 95% of the data irrelevant? I've read posts where users are trying to flatten a hump between say 45 and 55Hz but in reality that hump does not exist. If my system is typical, the sub only reacts to signals between 35 and 50Hz so in practical terms the hump does not exist. Ironically, in a subwoofer the hump is the ultimate goal, increased SPL within the target frequency range.
Thing 1: If a driver has zero input outside the desired range is the performance affected?
Thing 2: What, in its design, governs a driver's frequency response? I am in the privileged of position of having a wealth of drivers to test. Long story short: Line up 7, 6.5" woofers. Offer all the drivers a 25Hz signal, at one end of the spectrum: the driver hits Xmax and flaps like a dying Swan, at the other, the driver ignores the signal. If the driver will not respond to a signal there's no amount of port tuning or hi-pass filters that will affect output.
I note that people model and post full spectrum graphs of a project's frequency response but isn't 95% of the data irrelevant? I've read posts where users are trying to flatten a hump between say 45 and 55Hz but in reality that hump does not exist. If my system is typical, the sub only reacts to signals between 35 and 50Hz so in practical terms the hump does not exist. Ironically, in a subwoofer the hump is the ultimate goal, increased SPL within the target frequency range.
Thing 1: If a driver has zero input outside the desired range is the performance affected?
Thing 2: What, in its design, governs a driver's frequency response? I am in the privileged of position of having a wealth of drivers to test. Long story short: Line up 7, 6.5" woofers. Offer all the drivers a 25Hz signal, at one end of the spectrum: the driver hits Xmax and flaps like a dying Swan, at the other, the driver ignores the signal. If the driver will not respond to a signal there's no amount of port tuning or hi-pass filters that will affect output.
Sorry, but it is. Read up on Fourier and superposition. This is a common misunderstanding.
Sometimes, but that depends on the user's understanding and design and the tools they may have.
Not sure what you mean here.
Motor, suspension (incl enclosure volume and shape), cone or dome shape, driven mass, port tuning etc. You've asked a large question and I don't have time to write thousands of words to answer it.
Sat on a bench bare, in free air, any driver will do this with a low freq.
The pressure wave just pushes round the edge of the cone to the rear of the cone , the path of least resistance.
Put the driver on an (infinite) baffle and retest
That doesn't happen, a drivers response drops off at a slope at either end of it's response so there is always interaction between drivers in a multi driver system.
Everything, the magnet strength and gap height, the voice coil wire size, it's electrical properties and coil length, the cone size weight and rigidity, the suspension compliance.
A driver that ignores a signal is broken.
Phase and sinewave in animation
Fourier Transform, Fourier Series, and frequency spectrum - YouTube
Fourier Transform, Fourier Series, and frequency spectrum - YouTube
Consider your comments in the face of facts. (1) In free air one driver will hit Xmax in response to frequency below its stated range where another will barely move. (2) Your comments referring to multi-driver systems are largely irrelevant in a SUBWOOFER forum. (3) "A driver that ignores a signal is broken." - this is the definition of 'frequency response'.
1)If a driver barely moves when voltage appropriate to it's power rating is applied under free air conditions, either it has very little Xmax or the suspension is very stiff, or a combination of both, unless it is broken, like a voice coil pinched in a magnetic gap, either from magnet/pole piece shift or particles in the gap.
Drivers incapable of excursion without excessive signal voltage applied are not good candidates for subwoofer use, or to quote your OP: "If the driver will not respond to a signal there's no amount of port tuning or hi-pass filters that will affect output."
Bareley moves is not the same as doesn't respond.. which is what you stated before. As with anything technical.. precise details matter.
The output of a subwoofer overlaps with the next driver up in the sound system, so no it's not irrelevant.
A subwoofer will "ignore" a 10khz signal, it doesn't really but the inductance of the voice coil is so high at that frequency that no power is dissipated in the driver. That large voice coil acts as a natural low pass filter. If a sub appears to mostly ignore a low frequency signal it could be that it has a very high power handling capacity but since we're talking about 6.5" drivers it's more likely it is so inefficient it's not worth considering.
ANY sound is a combination of sinewaves, including the trivial case: a pure tone.
Yes, so?
Showing a full Audio range graph will show how will speaker respond to any and all of them.
Meaning it contains useful information.
Audio range is 20Hz-20kHz, it´s proper and normal to show the full graph.
Maybe you are personally interested in a very narrow band, and the rest intensely annoys you, but that doesn´t turn it into a standard.
HOW do you know that?
That you don´t have a hump there doesn´t mean nobody else does.
What I suspected.
There is a wide World outside your home.
Not really, a flat response within the passband is much more accurate.
"Single note Bass" is the curse of 30´s and 40´s pentode output amps (combined with abysmal high Q weak magnet stiff speakers which led to Triode outputs and NFB which were the largest single step advance in Audio quality.
Oh, and Car "Bass" systems too , those you hear thumping (and nothing else) from 3 blocks away
You can have zero input to speaker using a manually tuned oscillator and of course not setting it outside "desired range", any musical program will contain multiple frequencies which will reach the speaker , of course more or less attenuated, depending on crossover slope.
But no practical crossover is a vertical walls "brickwall".
As mentioned above, a ton of things.
And I mean A TON
In theory "everything can be simulated", but of course then you need accurate models for everything too.
In general, only most basic ones exist (for example TS parameters) and they *assume* a lot, such as cone moving like a rigid piston, ignoring the multiple ripple waves moving center to edge and back, each "ring" section resonances, dustcap resonances, adhesives rigidity, etc.
Oh, I thought you said "a wealth".
Ok, what does "line up" mean?
All 7 in a line on a table?
No way to test subwoofers, by any means.
What does THAT mean?
You mean the Audio spectrum?
You mean the variety of speakers?
You mean the different (spectrum of) responses to exact same signal?
You mean the spectrum of levels, from zero to Max?
PLEASE rewrite in a more clear way.
Of course, medicines do not cure dead people.
Easy, one has high compliance, the other is rigid/stiff.
Subwoofers are not used *alone* but as part of .... ummmmm .... "multi driver systems".
No, that is the definition of a broken transducer, period.
By the way, you did not even mention said signal frequency, why add that after the fact?
And any working speaker will not ignore any Audio frequency,worst case it will put out something very attenuated.
Again: if you apply 25Hz to a (working) speaker, it will move, even if you have to touch cone to feel it.
I do not expect much acoustic output from small speakers, lying face upon a table, fed lowest frequencies.
But of course, Science comes to help, check how this intrepid experimenter DEMONSTRATES in no equivocal terms that his Amplifiers DO produce abbundant Bass.
In a setup exactly similar to yours, go figure:
DIY Powerful Ultra Bass Amplifier 8 Transistor D718 , No IC , Simple circuit - YouTube
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A music signal is not a sine wave or waves. For math convenience, it can be broken down into sine waves and that ensemble of waves changes instantaneously as music plays. You can see that in the gyrations of a real-time (FFA) RTA.
As far as I know, studying the capabilities of a music reproduction in term of capabilities of reproducing the band of sine waves is a trustworthy way to characterize the sound. Prolly.
B.
As far as I know, studying the capabilities of a music reproduction in term of capabilities of reproducing the band of sine waves is a trustworthy way to characterize the sound. Prolly.
B.
It's about a dying swan. Can a base driver be both audible and not and also have stillborn frequencies? The latter I know nothing about but the other can be observed by sliding this fader to the left
Online Tone Generator - generate pure tones of any frequency
There are also phenomena such as ghost resonance and and rected copper. Can affect some but difficult to lead in evidence. Some need time to play in the mechanics but at the same time it's not listed on Wikipedia. My 2 cents.
Online Tone Generator - generate pure tones of any frequency
There are also phenomena such as ghost resonance and and rected copper. Can affect some but difficult to lead in evidence. Some need time to play in the mechanics but at the same time it's not listed on Wikipedia. My 2 cents.
Yes.. but that is more about the limitations of human hearing. As frequencies drop it takes more and more amplitude to be audible, and if you get low enough sound is felt with the body more than it is heard with the ear. This is because the most sensitive range of human hearing is 500-5khz which just happens to be the meat of the human vocal range. See the Fletcher Munson curve.
Actually ALL sound is nothing more than a string of air pressure levels over time. Divide up time and plot a point there. it is nothing more complicated than that. If a speaker confuses you look at the digitization of music. it is a voltage level at a discrete moment in time. One after the other. It is only our ability to use our memory and our brains ability to string it together that makes it music. All a dac does is vary the output voltage very quickly A speaker responds to it.. The real magic happens between our ears,