I'm inclined to argue that cone breakup is linear. However given the directivity variations as well as the general narrowing in the region I'm also inclined to say don't use this region unless you are running full-range. I've found it possible to work with simple (low order) breakup modes.
based on what? surely you've some form reasoning or evidence to back up that assertion.
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Hand up here. One of the things i do is try to work these out, and have been at least somewhat successful.
This example is relevant to the conversation:
You can see that the FE127 that i modified has dramatically reduced the peaks at the top, but those peaks are still lingering in what you hear (Fostex FE127e, NLA a decade ago). Do note that the measurements are complied across a number of people’s measures so the conditions ar enot all the same. Mark measured mine an an anechoic chamber with a serious measure mic. Fostex publishes very smoothed curves andmackenzies measures show the low resolution at lower frequencies you expect with a gated FFT.
An example of fixing the FR but not (completely) fixing the issue. It is ALOT better than stock thou.
dave
True. Often too much thou (ie Viston B200 which is alos fixable)
In the case of this driver the peakiness is not a rising response, it is a resonance, and annoyin g(at least to many) and the EnABL certainly seems to enhance the off-axis. Th etreated drive rstill has a rising response but the peaky bits are suppressed.
dave
In the case of this driver the peakiness is not a rising response, it is a resonance, and annoyin g(at least to many) and the EnABL certainly seems to enhance the off-axis. Th etreated drive rstill has a rising response but the peaky bits are suppressed.
dave
I'd like to make sure we're on the same page. Referring to something as a linear effect does not make a judgement one way or the other about the presence or absence of non-linear effects, circumstantial or otherwise, nor does it suggest something is in a straight line.
Resonance itself is fundamentally a linear effect, as is the varying directivity found around breakup.
As I see it, the question here is whether those are the only significant effects?
I wouldn't want to comment without seeing some polars. The original does show things going on in the top half of the spectrum.
Nice drivers, good to listen to. I've coated the cones, in stages and in different ways. I may not have your experience with that but I could never get past breakup being obvious in the upper spectrum.
Even when equalised.
This is true, but probably better to say controlled chaos, a DML entire bandwidth is this chaos. No FR has yet acheived the holy grail of flat chaotic HF performance. But we keep getting closer.
The ideal nature of the resonance/chaotic structure is that more & more of the outside of the cone quits radiating and the effective cone size drops. How well this is done can be seen in any reduction of the higher frequency resonances. If we ever get to that, the FR will be quite flat.
dave
Probably to smart for that.
dave
Politics -- "Pol" Latin for "many, "tics" as in "bloodsucking creatures"
Seriously?! Thought I posted this ages ago; anytime there's an impedance mismatch there's a response change. Once the driver's pistonic limit is reached [VC dia.] its TL modes BW that travels in/on the diaphragm is damped/defracted a tiny amount at every little spec of paint [or broadband if doping]. Ditto with dust cap, whizzer bell modes. Breakup modes are just plain damped depending on added mass, number of individual patterns to diffuse them in these areas.
As for pattern design, I imagine high speed, high res photos showing the diaphragm's various major, minor, minute distortions, traveling wave patterns would help tremendously to the point where they could be reduced to relatively easy patterns to lay over/stick on to airbrush or touch up gun for large drivers, though doubt these would be nearly as attractive.
Way back when strobe lights started becoming popular, I watched an ancient RCA 'wide range' 12" working from ~40-12.5 kHz at fairly high power and couldn't believe how 'alive' it was. Kind of grossed me out actually, so can only imagine what some of today's super wide BW 'tissue' paper drivers must look like.
GM