FWIW, in passive speakers I'll tend to put an LC filter across the driver to present a short-circuit to the crossover (and driver). The result is lots of attenuation (in theory, the DCR of the inductor is the limiting factor) and lots of electrical damping for the driver.
Chris
Chris
Breakup is primarily about diaphragm resonances, so no non-linear distortion, no harmonics. You might have a non-linear compliance, motor or such, but these are not breakup related.
No idea about the harmonic type, but according to this page, there's a lot of "non-harmonic" distortion that results from chaotic motion of the broken-up cone. Not sure whether it's to be termed "linear" or "non-linear".
"When the driver cone motion becomes chaotic, sounds are still produced in the areas of the cone that are in “breakup mode.” But those sounds aren’t related to the musical signal."
Several 2-way PA systems use a 'controlled breakup' to "extend" the midrange and thereby avoid the extra costs of a separate mid-range driver and associated network components. Such mid-woofers usually use a curvilinear cone geometry. The fidelity of the resulting "extended" midrange is a subjective matter.
"When the driver cone motion becomes chaotic, sounds are still produced in the areas of the cone that are in “breakup mode.” But those sounds aren’t related to the musical signal."
Several 2-way PA systems use a 'controlled breakup' to "extend" the midrange and thereby avoid the extra costs of a separate mid-range driver and associated network components. Such mid-woofers usually use a curvilinear cone geometry. The fidelity of the resulting "extended" midrange is a subjective matter.
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I wonder if you could really call the cone movement at breakup 'chaotic'. Since Beranek we seem to agree on bell mode and concentric mode breakup (round cones and domes), but I doubt if parts of the cone move at other cycles than the voice coil does.
The net effect on acoustic output of course is another story. A cone breaking up is quite a complex radiating surface, so what to expect in place and time is hard to predict. I therefore wouldn't call this linear distortion in the classic, onedimensional meaning used in a circuit.
The net effect on acoustic output of course is another story. A cone breaking up is quite a complex radiating surface, so what to expect in place and time is hard to predict. I therefore wouldn't call this linear distortion in the classic, onedimensional meaning used in a circuit.
Breakup doesn't cause nonlinear distortion by itself but it can exagerate it. If a driver has a resonance at 3 kHz for instance then it might have a peak in h3 for a 1 kHz input signal.
Regards
Charles
One of the interesting things about hard cone breakups is the resonance peak(s) that appear in axis doesn’t necessarily appear off axis. Off axis there are other peaks and dips, at varying frequencies. Which means even you filter it out at one axis- it’s always there at other angles. (Hint: look at a normalised off axis plots)
From what I gather of the current evidence, the power response or directivity or whatever you to call it, is at least important as the on axis response.
So if we say that we want the primary resonate peaks down by 18-40dB, but off axis we can never get achieve this.
So those drivers like the Audiotechnology or Aurum Cantus AC-130F1… I’d like to see how they measure out to 90 degrees. Maybe that’s why they are favoured by some…
From what I gather of the current evidence, the power response or directivity or whatever you to call it, is at least important as the on axis response.
So if we say that we want the primary resonate peaks down by 18-40dB, but off axis we can never get achieve this.
So those drivers like the Audiotechnology or Aurum Cantus AC-130F1… I’d like to see how they measure out to 90 degrees. Maybe that’s why they are favoured by some…
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The stuff they used to sell us is pure crap ... you can have the full meal at once , flat Z , flat FR , very low disto and no ringing :
Paper woofers by Rival Acoustics – Rhythm Audio Design
No need to purify anything and hype it for tons of money!
Just good old plain engineering with care for details ...
So why are these drivers no longer in production?
Audio Mafia conspiracy?
Paper woofers by Rival Acoustics – Rhythm Audio Design
No need to purify anything and hype it for tons of money!
Just good old plain engineering with care for details ...
So why are these drivers no longer in production?
Audio Mafia conspiracy?
Who’s “they?”
The Rival’s cone/surround resonance around 800-1.2Khz, and breakup- they are all there.
You just need the right instrument/measurement resolution (20Hz) to measure/see it.
Of course you can’t see it on a 120dB scale, or 120ohm scale.
Can you hear it or does it matter and to what extent is another thing.
If you ask RAD, what what I gather Rival they lost two of their OEMs during the pandemic.
Hopefully will find a distributor like Madisound or Parts Express or Solen to pick them up.
The Rival’s cone/surround resonance around 800-1.2Khz, and breakup- they are all there.
You just need the right instrument/measurement resolution (20Hz) to measure/see it.
Of course you can’t see it on a 120dB scale, or 120ohm scale.
Can you hear it or does it matter and to what extent is another thing.
If you ask RAD, what what I gather Rival they lost two of their OEMs during the pandemic.
Hopefully will find a distributor like Madisound or Parts Express or Solen to pick them up.
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If you can read the graph there is only a mild smooth plusminus 2dB deviation which is easily compensated or leave it as it is to give the speaker some flavour ...
Most hefty priced drivers offer no breakup control at all ... seems they are coming from the late 80ties designed by some flat earth rocket engineers!
Disgusting stuff like this one what a waste of money : WAVECOR WF182BD12 (Mid-woofer 7", 8 Ohm, 160 Wmax)
lemme kill ya with this dirty cool fella :
Vifa NE149W-04 | HiFiCompass
not longer in production soon!
WHY?
too good for us?
food for thought!
Most hefty priced drivers offer no breakup control at all ... seems they are coming from the late 80ties designed by some flat earth rocket engineers!
Disgusting stuff like this one what a waste of money : WAVECOR WF182BD12 (Mid-woofer 7", 8 Ohm, 160 Wmax)
lemme kill ya with this dirty cool fella :
Vifa NE149W-04 | HiFiCompass
not longer in production soon!
WHY?
too good for us?
food for thought!
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It's one thing to insist that a driver be usable into this region, but lucky for us the point is moot. It also narrows in directivity and this starts in the same upper region. It was destined to be crossed. If you run a woofer up too high and then cross to a dome with wide, hard hitting lower treble you'll notice the hole below the cross and the tweeter will stand out.
I have done long listening tests while prototyping with DSP lately.
I am very sensitive to breakups ��
Severe breakup issue manifest itself on listening as severe ringing like the worst possible tinnitus.
Milder breakup issue results in glare (for lack of a better term) on low volume and distortion on higher volume.
By using vintage alnico drivers (light paper cone & fabric surround) l thought my system would have the least offensive of breakup problems.
Even so my tests were still quite surprising (tested 8" and 15" drivers):
Crossing high and with shallow filter, first impressions are always positive. However with longer and deeper listening one starts hearing the breakup. Certain songs are more revealing of course.
Then I started testing lower co points and steeper filters. As I went lower and steeper the sound got cleaner and cleaner. I do not think one can get to the bottom of things by just looking at measurements.
My final design is a three way with BG Neo8S planar top, 4x5" BMR mid and 15" cone woofer. CO points 700 and 175hz all LR48db. Once you experience this it is impossible to go back to the world of ugly breakups.
I am very sensitive to breakups ��
Severe breakup issue manifest itself on listening as severe ringing like the worst possible tinnitus.
Milder breakup issue results in glare (for lack of a better term) on low volume and distortion on higher volume.
By using vintage alnico drivers (light paper cone & fabric surround) l thought my system would have the least offensive of breakup problems.
Even so my tests were still quite surprising (tested 8" and 15" drivers):
Crossing high and with shallow filter, first impressions are always positive. However with longer and deeper listening one starts hearing the breakup. Certain songs are more revealing of course.
Then I started testing lower co points and steeper filters. As I went lower and steeper the sound got cleaner and cleaner. I do not think one can get to the bottom of things by just looking at measurements.
My final design is a three way with BG Neo8S planar top, 4x5" BMR mid and 15" cone woofer. CO points 700 and 175hz all LR48db. Once you experience this it is impossible to go back to the world of ugly breakups.
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Variations on a new OB project
Here is the thread... You may see the picture of the final prototype on page 3. I am having a marble woofer frame built. I will share the final speaker once it is finished.
Here is the thread... You may see the picture of the final prototype on page 3. I am having a marble woofer frame built. I will share the final speaker once it is finished.
Was researching answers my own question,
I think the answer is- it depends; which is not a very satisfying answer. But like life sometimes it can be complicated.
If the resonance is far away from the pass band, eg >2 octaves, and it’s down far enough it may be masked by the tweeter, in which case there’s little reason to suppress it.
Secondly some drivers show a high Q resonance that appears at the same frequency at all off axis angles-e.g. SEAS magnesium cones. Other drivers show the primary peak changes at different off axis angles. In the former a notch filter will effectively strike out the resonance; in the latter it doesn’t work as effectively for the off axis angles, in which case there’s probably grounds not to use a notch filter.
I’ve seen a low pass of the SB 15CAC with only 3 elements by someone I respect.
Measurements matter but listening matters, If it’s not audible it’s probably not worth throwing extra parts at.
I once measured a low level of harmonic distortion spread over an octave.
This Pointed to a rub/buzz type thing that was completely inaudible.
I couldn’t hear it but hunting it down anyway- it turned out that the tweeter wasn’t completely screwed right into the baffle.
I still screwed those 4 tweeter screws in tighter and remeasured- the distortion was gone.
That made me feel better. So humans are not always Rational creatures. So I get that.
I think the answer is- it depends; which is not a very satisfying answer. But like life sometimes it can be complicated.
If the resonance is far away from the pass band, eg >2 octaves, and it’s down far enough it may be masked by the tweeter, in which case there’s little reason to suppress it.
Secondly some drivers show a high Q resonance that appears at the same frequency at all off axis angles-e.g. SEAS magnesium cones. Other drivers show the primary peak changes at different off axis angles. In the former a notch filter will effectively strike out the resonance; in the latter it doesn’t work as effectively for the off axis angles, in which case there’s probably grounds not to use a notch filter.
I’ve seen a low pass of the SB 15CAC with only 3 elements by someone I respect.
Measurements matter but listening matters, If it’s not audible it’s probably not worth throwing extra parts at.
I once measured a low level of harmonic distortion spread over an octave.
This Pointed to a rub/buzz type thing that was completely inaudible.
I couldn’t hear it but hunting it down anyway- it turned out that the tweeter wasn’t completely screwed right into the baffle.
I still screwed those 4 tweeter screws in tighter and remeasured- the distortion was gone.
That made me feel better. So humans are not always Rational creatures. So I get that.
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I had no problems in a full range driver with a resonance of +6 db at 4khz to tame it with an appropriate dsp filter.
Before compensation there was a resonance at this frequency in the burst decay - after compensation the burst decay was completely clean.
So what? A resonance is not audible any more when electrically compensated. Maybe compensating a too long ringing is not good but a moderate ringing seems to me no acoustical problem.
Before compensation there was a resonance at this frequency in the burst decay - after compensation the burst decay was completely clean.
So what? A resonance is not audible any more when electrically compensated. Maybe compensating a too long ringing is not good but a moderate ringing seems to me no acoustical problem.