A smooth FR can still have long decay in it.... The FR is relatively smooth in the area with ringing trouble. Then again I don't know if this has been smoothed.
It has been smoothed at (AFAIK) 24/octave, which still displays all major peaks and dips. Even at 1/8 oct it would show a clear dependency of CSD to FR (or vice versa).
@camplo In that first example, it looks to be a Be dome tweeter based on the breakup frequency. In some cases you can linearize this and it will be neutralized to the point it won't ring (in linear time domain), but when the driver plays this frequency after the EQ notch is applied, there still can be an extended decay time not proportional to the other frequencies. In this situation, it takes longer for the diaphragm to settle down compared to the pistonic diaphragm movement.
In the case of this driver, when playing the specific breakup frequency after EQ has been applied, the diaphragm will now have even FR, but the diaphragm motion will be non uniform, still breaking up and moving around in an out of sync way, just as before EQ was applied. The EQ doesn't fix the diaphragms physical behavior. It just flattens out the level at breakup.
So now, being the diaphragm movement is still out of sync, with breakup taking place, it will measure at a different level off axis, which shows why its important to also check FR off axis. If the response curve has the same shape off axis but at a collectively lower amplitude, that means the cone movement is completely uniform from a pistonic POV and the driver will exhibit the identical FR balance at any listening angle, just at a lower SPL.
It reality, it doesn't however happen this way, as the cone will radiate from a lower percentage of its surface area as the frequency increases. If the cone's internal dampening behavior were progressively linear in rate (ideally lossy), moving from the VC attaching point to the surround termination, the rolloff will increase at a linear, proportional rate as the frequency goes up. Driver output will then decline at a similar dB/oct rate without any breakup resonances taking place. Anytime there is a different shaped, non proportional FR curve on and off axis, there will be cone breakup present as various areas of the cone will move in different phase relationships to each other.
In the case of dome drivers, all this takes place in the opposite direction, from the VC perimeter to the center of the dome. The surround is just directly coupled to the VC and the center of the dome is subject to breakup, out of phase with the VC.
There is also the issue of the speed of sound in the diaphragm allowing the VC driven motion to propagate through the diaphragm material at very high frequencies, causing sharp peaks and dips on and off axis. In this case, there is little you can do to linearize the driver because the breakup isn't stationary in amplitude or frequency to the listening axes (plural of axis). Sometimes using a phase shield (covering specific diaphragm areas, typically the tip of the dome) can minimize the problem. In the case of a higher loss dome material, the problem diminishes, but so does the HF linearity. Drivers with deep cones have this type of issue as well and should therefor be avoided as wide banded sources. Large surrounds can also cause problems related to breakup, specifically low loss types and wider, high compliance surrounds.
All of this is why cone and dome drivers with centralized VCs will always have some amount of breakup. The best way to deal with this is staying out of the breakup area with the drivers dedicated bandwidth. Only much more shallow and gradual breakup modes can be tamed to the point they don't pose an audible degradation of the sound speaker's sound ie. no harsh resonances or peaks.
In the case of this driver, when playing the specific breakup frequency after EQ has been applied, the diaphragm will now have even FR, but the diaphragm motion will be non uniform, still breaking up and moving around in an out of sync way, just as before EQ was applied. The EQ doesn't fix the diaphragms physical behavior. It just flattens out the level at breakup.
So now, being the diaphragm movement is still out of sync, with breakup taking place, it will measure at a different level off axis, which shows why its important to also check FR off axis. If the response curve has the same shape off axis but at a collectively lower amplitude, that means the cone movement is completely uniform from a pistonic POV and the driver will exhibit the identical FR balance at any listening angle, just at a lower SPL.
It reality, it doesn't however happen this way, as the cone will radiate from a lower percentage of its surface area as the frequency increases. If the cone's internal dampening behavior were progressively linear in rate (ideally lossy), moving from the VC attaching point to the surround termination, the rolloff will increase at a linear, proportional rate as the frequency goes up. Driver output will then decline at a similar dB/oct rate without any breakup resonances taking place. Anytime there is a different shaped, non proportional FR curve on and off axis, there will be cone breakup present as various areas of the cone will move in different phase relationships to each other.
In the case of dome drivers, all this takes place in the opposite direction, from the VC perimeter to the center of the dome. The surround is just directly coupled to the VC and the center of the dome is subject to breakup, out of phase with the VC.
There is also the issue of the speed of sound in the diaphragm allowing the VC driven motion to propagate through the diaphragm material at very high frequencies, causing sharp peaks and dips on and off axis. In this case, there is little you can do to linearize the driver because the breakup isn't stationary in amplitude or frequency to the listening axes (plural of axis). Sometimes using a phase shield (covering specific diaphragm areas, typically the tip of the dome) can minimize the problem. In the case of a higher loss dome material, the problem diminishes, but so does the HF linearity. Drivers with deep cones have this type of issue as well and should therefor be avoided as wide banded sources. Large surrounds can also cause problems related to breakup, specifically low loss types and wider, high compliance surrounds.
All of this is why cone and dome drivers with centralized VCs will always have some amount of breakup. The best way to deal with this is staying out of the breakup area with the drivers dedicated bandwidth. Only much more shallow and gradual breakup modes can be tamed to the point they don't pose an audible degradation of the sound speaker's sound ie. no harsh resonances or peaks.
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Uhm, no. The diaphragm will only motion non uniform if the resonance will be excited. With normal music material (LP/record, CD, tape etc) that will not ever happen. If you don't understand that, you don't understand speakers. At all.
The off-axis FR is very important, even more important than the on-axis since it determines the sound energy in the room. However, it does not matter that much if the off-axis is dispersion constant since the reflections in the room also accumulate to the tone balance. It starts to matter when the room energy starts to differ from the direct radiated sound. That means, a speaker which disperses the sound very broadly in the mid but got a narrow dispersion in the upper mids to highs will never sound 'right' but sound too bright on-axis and too dull off-axis. That also means, a full-pistonic POV does not provide any advantage unless it also provides at the same time an equal dispersion (hint: it doesn't, that's physics). That's why many FR drivers sound a lot better than their frequency response suggests because their energy bilance in the room is better than many multi-way speakers and their impulse response is often vastly superior. I'm not sure if @planet10 can explain it exactly but he posted numerous experiences on FR speakers which confirm that. If you've followed his or mine posts, you know I'm definitely not a yes-man towards him and I've got a lot of cricics but regarding that, you know his listening experiences are true.
Well, yes. But we are talking here about midrange drivers, which means the cone issues mostly don't apply to mid dome drivers. It seems you are losing the focus of the thread and just try to reel in other drivers properties just to make an argument.
Well, dome tweeters don't have a cone breakup. You cannot apply foreign drivers properties to dome mids. Dome mids ofc have upper FR limits but it's not a real issue since modern tweeters have a very wide range of xo points and big mid domes can easily accomodate to that. That reduces the problem to just where in the frequency range the tweeter or the mid got a low enough distortion. Once you've realized that, you also learn that there isn't any problem to use the high and mid drivers just within their optimal range. The limitations 30 or 40 years ago do not apply anymore unless you ignore the measurements possible today.
Sure, that happens. But since we are now able to measure when that happens and how the drivers react, we are able to pair it with tweeters and woofers that can fit thier limits.
Oh, that. See, that's why we invented speaker crossovers. And tweeters. There are tweeters that can take up on that task. I know that's new to you but I can assure you, nobody is forcing you to use any driver above its capabilities.
Why is it that certain people feel the need to argue EVERYTHING to death?
I'm not going to respond, because it just turns into a pi$$ing contest. The only critical thing I will put my foot down on is the fact resonances are NON LINEAR in their amplitude and who cares what it takes to excite them. That just reinforces the point I'm making,.which is to STAY AWAY from any frequencies prone to excitation designing your speaker, otherwise you risk crossing the threshold, where things start ringing and there goes your dynamic range.
Please read the thread more carefully because I explain the differentiation between cone and dome drivers behaviors when they suffer from diaphragm or cone or dome or any other emissive surface break up. Yes, that VHF resonance in the example is out of hearing range, but it can still be excited mechanically or by out of band distortion components. Likewise the breakup can down modulate into the audible band causing increased IMD.
Making a general statement that I don't know anything about speakers because I don't agree whether resonances behave in a linear, predictable way, thats ignorant in itself.
This is a thread about dome midranges and associated information. Don't ruin it for the rest of us if you need to argue about specific theories and geeking out on science which requires a bit more in depth knowledge than generalized, absolute statements.
I'm not going to respond, because it just turns into a pi$$ing contest. The only critical thing I will put my foot down on is the fact resonances are NON LINEAR in their amplitude and who cares what it takes to excite them. That just reinforces the point I'm making,.which is to STAY AWAY from any frequencies prone to excitation designing your speaker, otherwise you risk crossing the threshold, where things start ringing and there goes your dynamic range.
Please read the thread more carefully because I explain the differentiation between cone and dome drivers behaviors when they suffer from diaphragm or cone or dome or any other emissive surface break up. Yes, that VHF resonance in the example is out of hearing range, but it can still be excited mechanically or by out of band distortion components. Likewise the breakup can down modulate into the audible band causing increased IMD.
Making a general statement that I don't know anything about speakers because I don't agree whether resonances behave in a linear, predictable way, thats ignorant in itself.
This is a thread about dome midranges and associated information. Don't ruin it for the rest of us if you need to argue about specific theories and geeking out on science which requires a bit more in depth knowledge than generalized, absolute statements.
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Oh and I probably made some spelling mistakes, but I'm sure they don't hinder the understanding of my post. Even us dumb folk over here can make mistakes... Keiner hier ist perfekt und ohne Mangel.
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Because some guy keep claiming so much wrong thing?
I'm not replying to that because there's so much more wrong what you're claiming than what's actually right. I mean, the physics of what you are talking about are so wrong, it's way beyond translating errors or even decimal points, that's magnitudes off!
@ICG For starters you could be a little more respectful and not badmouth my input as a general whole, stating there is more wrong with it than right.
Maybe take a look at who started this thread and maybe get off your high horse and try to be a little more contributing in a positive manner than putting people down if you feel they're wrong.
Maybe take a look at who started this thread and maybe get off your high horse and try to be a little more contributing in a positive manner than putting people down if you feel they're wrong.
Okay, to be constructive (okay, and opinionated), and to re-start the spirit of the thread, I'll just state my (personal) point of view.
The need for mid domes has diminished because so many mid bass drivers reproduce the mid range fairly well. The problem is, the midrange isn't just frequency response, a mid dome is just a lot more responsive and 'cleaner' than the 'typical' 17cm mid-bass. The main problem IMHO is, most ppl think a midrange driver is obsolete. Clearly, if you compare a 25mm/17cm 2-way it often lacks of resolution and sound stage - which both are not easy to quantify in measurements. For me, personally, a mid dome represents the refinement of the important voice range, stage location and 'easyness' in reproduction of the sound, unbothered by the bass, which 'simple' 2-way speakers cannot provide, no matter how well they are made. I don't think that fighting about technical details of mid domes will lead to any conclusion if it's not viewed in the context of the speaker itself.
It's a fact a dome mid will provide a better resolution than a mid-bass. If that results in a better speaker depends on how well the XO is made. In the end, the XO changes more of the sound than the drivers itself, so even 'worse' drivers can result in a better speaker if used right.
The need for mid domes has diminished because so many mid bass drivers reproduce the mid range fairly well. The problem is, the midrange isn't just frequency response, a mid dome is just a lot more responsive and 'cleaner' than the 'typical' 17cm mid-bass. The main problem IMHO is, most ppl think a midrange driver is obsolete. Clearly, if you compare a 25mm/17cm 2-way it often lacks of resolution and sound stage - which both are not easy to quantify in measurements. For me, personally, a mid dome represents the refinement of the important voice range, stage location and 'easyness' in reproduction of the sound, unbothered by the bass, which 'simple' 2-way speakers cannot provide, no matter how well they are made. I don't think that fighting about technical details of mid domes will lead to any conclusion if it's not viewed in the context of the speaker itself.
It's a fact a dome mid will provide a better resolution than a mid-bass. If that results in a better speaker depends on how well the XO is made. In the end, the XO changes more of the sound than the drivers itself, so even 'worse' drivers can result in a better speaker if used right.
Fair enough. This is the kind of input I'm looking for which can expand this thread in a direction which will serve the purpose of it.
I agree, dedicated midrange drivers as such can greatly improve a speaker's resolution, soundstage and overall believable deliverance of music in a way most 2 way speakers can't accomplish. To be fair, there are many excellent cone midrange drivers out there which come extremely close to the agility and depth in resolution of a decent quality mid dome, but the main area where a cone driver often lacks is off axis linearity and bandwidth into the upper mids, which will avoid a crossover point in the more critical meat of the midrange where most of the vocal sits. I’ve heard a 3 way system where the midrange spanning from 500hz - 4k is being covered by a single 3" dome. This speaker sounded like a larger single FR point source driver and had the matching soundstage on top of it. Thats a span of 3 octaves covered by a single driver, which isnt that easy to do for just one driver. Having most of the vocal frequencies covered by one driver also helps linearize the relative phase. Even outside of the 500hz - 4k range, there's enough smooth response left to overlap into the next drivers area for seamless transition, which allows the whole speaker to sound cohesive enough to disappear into the room. Thats not so easy to accomplish with a larger speaker. The midrange used in the speaker I described was a custom designed 3" dome unit made by LPG with an alu/mg dome embossed with a pattern of rings and radial lines embossed and the dome coated with a nitride layer. The only domes I've heard which come close to this performance is the Bliesma M74A and M74B, with the Yamaha Be dome used in the NS1000 speaker being close in performance. The current range of available soft dome mids doesn't quite reach the performance level of metal dome mids, which are stiffer than all the other drivers. The soft dome mids are however much easier to work with due to the lack of upper frequency dome breakup, specifically. The SS D7608 is the most inexpensive soft dome ever made which comes close to the better mid domes. Its only significant lacking is excursion capability, which is shorter than most mid domes have.
I agree, dedicated midrange drivers as such can greatly improve a speaker's resolution, soundstage and overall believable deliverance of music in a way most 2 way speakers can't accomplish. To be fair, there are many excellent cone midrange drivers out there which come extremely close to the agility and depth in resolution of a decent quality mid dome, but the main area where a cone driver often lacks is off axis linearity and bandwidth into the upper mids, which will avoid a crossover point in the more critical meat of the midrange where most of the vocal sits. I’ve heard a 3 way system where the midrange spanning from 500hz - 4k is being covered by a single 3" dome. This speaker sounded like a larger single FR point source driver and had the matching soundstage on top of it. Thats a span of 3 octaves covered by a single driver, which isnt that easy to do for just one driver. Having most of the vocal frequencies covered by one driver also helps linearize the relative phase. Even outside of the 500hz - 4k range, there's enough smooth response left to overlap into the next drivers area for seamless transition, which allows the whole speaker to sound cohesive enough to disappear into the room. Thats not so easy to accomplish with a larger speaker. The midrange used in the speaker I described was a custom designed 3" dome unit made by LPG with an alu/mg dome embossed with a pattern of rings and radial lines embossed and the dome coated with a nitride layer. The only domes I've heard which come close to this performance is the Bliesma M74A and M74B, with the Yamaha Be dome used in the NS1000 speaker being close in performance. The current range of available soft dome mids doesn't quite reach the performance level of metal dome mids, which are stiffer than all the other drivers. The soft dome mids are however much easier to work with due to the lack of upper frequency dome breakup, specifically. The SS D7608 is the most inexpensive soft dome ever made which comes close to the better mid domes. Its only significant lacking is excursion capability, which is shorter than most mid domes have.
I've never heard of such a thing > how strange & interesting.
PS.
I never found PVA to be a 'musical' cone treatment 🙂
This is all obviously due to the fact that FR and decay times are two completely different things.
( although they do interact )
I found that out the hard way 35 yrs ago... lol
The woofers were made by Cabasse for Vieta - model number L120
Attachments
There are thousands (likely more) recipes for paper. It can be made of many different things.
I have never heard a cone — properly treated — that did not benefit from puzzlekoat/modpodge. 100s 0f them (if not more)
dave