For this purpose, small signal simple bending of the cone at higher frequencies.
I know, we had exactly this conversation in another topic not that long ago...because they amplify sound mechanically, amplify distortion products generated in the driver motor and thus appear as peak in distortion plotYou can see distortion peak disappear if you put passive notch filter in series with the driver, but it stays if you put notch filter in parallel with the driver.
Both filters would reduce current from (voltage) amplifier through voice coil at breakup frequency leveling acoustic frequency response of the system, but only the increased series impedance reduces current from driver motor distortion mechanisms. If the distortion was from the breakup itself, it would disappear in acoustic measurements with both filters.
The breakup amplifies (or attenuates, depending on angle you observe at) any current through voice coil in acoustic domain, I imagine the beakup as mechanical amplifier.
But @AllenB said again that there is no harmonic distortion around cone breakups.
And again, you only have to see hundreds of distortion plots just to see that is not true.
So I don't even understand why you would say that?
Earlier when I said..
Say that the response increases at breakup, but only on-axis and only at the frequency of the harmonic of distortion at a lower frequency. There you could seem to measure more distortion.
He chose different wording
I don't know if its true, I'm not professional enough to know if breakup can cause harmonic distortion, perhaps it does. It certainly amplifies distortion from the electric domain which appears as if the breakup made the distortion but comparing results with series or parallel notch shows the distortion came from electrical domain.
You could measure distortion off-axis, if there is distortion caused by the breakup it should still show up even though frequency response at breakup frequency had a dip, because it is a relative measure, right? if the distortion was already in the system and amplified by the breakup, or attenuated instead as we chose such off-axis angle, that should show as reduction in distortion instead of spike, right?
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My apologies, maybe I misread, but I still don't understand the comment?
If we don't talk about the lower harmonics that can be measured and seen in the distortion plots, why would you be interested if a harsh breakup mode on itself would distort?
You don't want to me near that breakup mode to begin with?
In fact, because it reflects back with lower harmonics in distortion, usually you like to be roughly an octave away (lower) anyway.
Therefor the question itself becomes kinda irrelevant?
If we don't talk about the lower harmonics that can be measured and seen in the distortion plots, why would you be interested if a harsh breakup mode on itself would distort?
You don't want to me near that breakup mode to begin with?
In fact, because it reflects back with lower harmonics in distortion, usually you like to be roughly an octave away (lower) anyway.
Therefor the question itself becomes kinda irrelevant?
Perhaps there is misunderstanding
Lets take a driver which shows 10db peak on acoustic freuqency response measurement, 10db cone breakup peak on-axis at 3kHz.
Now acoustically measured 3rd harmonic distortion plot shows peak at 1kHz and it means that 3rd harmonic of 1kHz got amplified by the breakup because it lands right on it at 3kHz. The breakup does not cause lower harmonics or anything like that, it's just how the distortion is plotted, harmonics of (some) lower frequencies land on the breakup and get amplified by the breakup and the peak on graph is plotted on the "root frequency".
Frequency response plots are made with constant voltage sweep with very low output impedance amplifier. Any peak in the frequency response plot at these high frequencies must happen in mechanical/acoustic domain, otherwise it would show up as low impedance in impedance plot because it is current what makes force to the cone and turns into SPL, at peak there should be higher current, but at constant voltage and relatively constant impedance the current must be same but still there is peak in frequency response. There must be mechanical amplifier, the breakup, and it happens regardless of current in the circuit. Any current gets extra boost in acoustic domain by the breakup, just like on the frequency response measurement rig.
So, the breakup always happens unless you change the driver or modify the driver mechanically. Any current in voice coil at 3kHz will get additional 10db on-axis boost from the breakup including any harmonics of lower frequencies. Say you have low-pass filter at 1.5kHz, the breakup still happens and boosts 3rd harmonic distortion of the 1kHz 10db! The crossover is in electrical domain and does not change distortion mechanisms on the driver, nor mechanical properties of the breakup.
The breakup is there even if you have a crossover at any frequency, or EQ dip it. Filters only precondition the electric signal. Your EQ just dips input signal by 10db and the breakup boosts it back by 10db and you would measure flat response (on-axis) acoustically, nice. Meanwhile the breakup boosts everything, also harmonics of lower frequencies or power amplifier noise if it is active system and so on. On active system your amplifier could make 7th order distortion product to ~428Hz sound which would get boosted by the beakup 10db even though you had low pass filter at 500Hz in DSP.
One must use passive parallel notch in series with the driver to reduce all current through voice coil at 3kHz, which would precondition all noise and harmonics as well, including those from amplifier or driver motor backEMF.
If this was exactly what you ment then the misunderstanding is on my side.
It reflects back to lower frequency only in the graphs!
Lets take a driver which shows 10db peak on acoustic freuqency response measurement, 10db cone breakup peak on-axis at 3kHz.
Now acoustically measured 3rd harmonic distortion plot shows peak at 1kHz and it means that 3rd harmonic of 1kHz got amplified by the breakup because it lands right on it at 3kHz. The breakup does not cause lower harmonics or anything like that, it's just how the distortion is plotted, harmonics of (some) lower frequencies land on the breakup and get amplified by the breakup and the peak on graph is plotted on the "root frequency".
Frequency response plots are made with constant voltage sweep with very low output impedance amplifier. Any peak in the frequency response plot at these high frequencies must happen in mechanical/acoustic domain, otherwise it would show up as low impedance in impedance plot because it is current what makes force to the cone and turns into SPL, at peak there should be higher current, but at constant voltage and relatively constant impedance the current must be same but still there is peak in frequency response. There must be mechanical amplifier, the breakup, and it happens regardless of current in the circuit. Any current gets extra boost in acoustic domain by the breakup, just like on the frequency response measurement rig.
So, the breakup always happens unless you change the driver or modify the driver mechanically. Any current in voice coil at 3kHz will get additional 10db on-axis boost from the breakup including any harmonics of lower frequencies. Say you have low-pass filter at 1.5kHz, the breakup still happens and boosts 3rd harmonic distortion of the 1kHz 10db!
The crossover is in electrical domain and does not change distortion mechanisms on the driver, nor mechanical properties of the breakup.The breakup is there even if you have a crossover at any frequency, or EQ dip it. Filters only precondition the electric signal. Your EQ just dips input signal by 10db and the breakup boosts it back by 10db and you would measure flat response (on-axis) acoustically, nice. Meanwhile the breakup boosts everything, also harmonics of lower frequencies or power amplifier noise if it is active system and so on. On active system your amplifier could make 7th order distortion product to ~428Hz sound which would get boosted by the beakup 10db even though you had low pass filter at 500Hz in DSP.
One must use passive parallel notch in series with the driver to reduce all current through voice coil at 3kHz, which would precondition all noise and harmonics as well, including those from amplifier or driver motor backEMF.
If this was exactly what you ment then the misunderstanding is on my side.
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edit time over: And as you say any harmonics caused by the breakup itself would show up above the breakup frequency, multiples of 3kHz, not very interesting or important as long as the 3kHz 10db amplified highly directional mixed bag noise sticks out.
What I mean is harmonic distortion caused by cone breakup feels irrelevant, but any other distortion that got amplified by the breakup would be relevant. I think this is what AllenB also wrote and got questioned
Perhaps its just how we imagine / picture the stuff in our heads. For metal cone you don't hear the sound itself at break up frequency but all the distortion products from lower frequencies that are amplified by the breakup at the breakup frequency, so the nasty sound you perceive could be though as of being a cause from the breakup. The perception is caused by the breakup, even though the distortion comes from somewhere else. Hopefully misunderstandings got solved
What I mean is harmonic distortion caused by cone breakup feels irrelevant, but any other distortion that got amplified by the breakup would be relevant. I think this is what AllenB also wrote and got questioned
Perhaps its just how we imagine / picture the stuff in our heads. For metal cone you don't hear the sound itself at break up frequency but all the distortion products from lower frequencies that are amplified by the breakup at the breakup frequency, so the nasty sound you perceive could be though as of being a cause from the breakup. The perception is caused by the breakup, even though the distortion comes from somewhere else. Hopefully misunderstandings got solved
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Yeah we had this conversation before, first wanna see some measurements and proof of this though
Unfortunately I don't have any woofers atm that have such a distinct breakup peak.
Also, if what you're saying is true, you're basically saying that it's a measurement artifact?
Or in other words, what's the actual result?
What's also interesting, is that I have seen very little (none) about this in proper literature.
That's not how it reads lol
Doesn't matter, but it sounded a bit like break-up peak isn't important for distortion.
Which is just a bit to simplified as an answer for the reasons you mentioned above.
Yep Well just applying logic to put together current drive stuff and purifi papers and passive xo's in general, so that it makes sense to me. Damping factor and stuff. In short it is only about the circuit impedance transducers are part of, and how it affects things, where the impedance is from and how it all interacts and eventually shows up in acoustic domain, current making force and what happens past that. I think it's all been there for long time but perhaps in hard to understand format, at least this is how I got it all together
edit. jeah sorry had to do multiple edits on all the posts.
Well just applying logic to put together current drive stuff and purifi papers and passive xo's in general, so that it makes sense to me. Damping factor and stuff. In short it is only about the circuit impedance transducers are part of, and how it affects things, where the impedance is from and how it all interacts and eventually shows up in acoustic domain, current making force and what happens past that. I think it's all been there for long time but perhaps in hard to understand format, at least this is how I got it all together edit. jeah sorry had to do multiple edits on all the posts.
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Don't read too much into it. I'm talking about what is primarily a simple resonance of the diaphragm.. and resonance itself is a linear phenomenon.
Well I guess, I just never seen it in the literature is what I was trying to say.
(and I read an awful lot!)
Anyway, who stands up as a volunteer to just do some simple tests? lol
Because apparently we are all to "lazy" to do it ourselves
The test is pretty simple, find a driver with a distinct break-up peak.
Measure its distortion, do the same test with a passive notch as well as an active notch.
Yes, although how the resonance acts on itself (vs amplitude for example), isn't always linear.
Since it's dependent on the behavior of the materials (in this example).
Another example, a port/pipe resonance is also not linear because of compression effects (boundary layer) and non-linear behavior of the air (mass).
So it's very easy to misread that as well
I am talking about literature, books, papers or articles, not just discussions.
Yet, still, having a theory is fine, but practical experiments and proof is mandatory to show that those are actually true.
Something that the guys from Purifi seem to ignore for certain ideas.
Which is fine, but at that point it's nothing more than just a theory.
Nothing more than a hypothesis.
Yet, still, having a theory is fine, but practical experiments and proof is mandatory to show that those are actually true.
Something that the guys from Purifi seem to ignore for certain ideas.
Which is fine, but at that point it's nothing more than just a theory.
Nothing more than a hypothesis.
It is true, because there is no such thing as "the transfer function of perception." Contrary to what your AI question claimed, there is no correlation between IMD and THD to perception,. hence there is no "threshold of perception."
That is unlikely to impossible as they are basically the same thing.
No, "breakup" is linear, although it can, as mentioned above, add gain or loss to the harmonics created by a nonlinearity.
They can be seen in the distortion plots, sure, but the breakup does not cause any harmonics to be created.
So you're saying as well, that this is just a measuring artifact basically?
our blog post had measurement data validating the theory. It has also been independently verified by Rasmus in the FB DIY loudspeaker project PAD group. Not sure what you miss?
exactlyYep
edit. jeah sorry had to do multiple edits on all the posts.