Can anyone comment on what cone material is likely to be at the forefront of full-range design? There seems to be some distinct camps including paper types and metal types - and no doubt several other evolving materials.
Is the advance of full-range speaker technology favouring one direction for cone material, or is there a wide distribution?
andy
Is the advance of full-range speaker technology favouring one direction for cone material, or is there a wide distribution?
andy
Well, you're dead wrong, so there!
Actually, I've got better things to do, like studying the Russo-Japanese Battle of Tsushima. I believe nearly everyone reached the same conclusion on the outcome of that little disagreement.
Best Regards,
Terry
it's probably much easier to be this gracious in victory, but still a reminder of chivalry that's not so common today - hiding behind the anonymity of a keyboard and armed with selective memory and revisionism.
what was Rozhestvensky's response to this rather touching personal comment?
But it is not very easy to make an objetive assessment of subjective notions such as clarity, kind of life, directness, vividness, and even ...timbre.
Neither is it clear whether all these qualities are supposed to be present in the recordings or allowed to be added to it by the system, owing to positive euphonics effects for enhanced sense of clarity, sense of life, sense of..., sense of... etc...
My own (positive anyway) experience with DHT tells me that though your signal part is very short, there are very strong (sonically) ingredients in it, and i agree that a single resistor can audibly change the whole sonic signature of an amp...
But i am afraid that this has little to do with the question of whether FRs are TECHNICALLY good enough vs a 2 way design...
Hello GDO - I enjoy your posts, and these are all very good points. And as you say, these questions of amplification are not the main issue here - I'm here to learn and find out about what might be in the next 5 years of full-range speaker unit design.
What do you think yourself?
Andy
Well, you're dead wrong, so there!
Actually, I've got better things to do, like studying the Russo-Japanese Battle of Tsushima. I believe nearly everyone reached the same conclusion on the outcome of that little disagreement.
Oh yes. Just ask Alfred Mahan & Jack Fisher. Total consensus on that one.
Given that Tsushima was the most decisive fleet action of the mechanised age, it's still mired in controvesy. FWIW, my personal take is that a lot of this has been caused by people considering it through post-Fisher lenses & forgetting the realities of the late-Victorian era.
Not true, it has to have a foundation of bacon, and be drenched in maple syrup!!Canadians will eat anything
don
I think it does depend somewhat on the nature and cause of the deviations in response as to whether they lend themselves to being corrected by EQ, or whether its even appropriate to try - and you can't always tell just by looking at a line on a frequency response graph, as it doesn't tell the whole story.
If we're talking about fairly broad band non-resonant phenomena like baffle step, or just a general upwards trend in response, or things of that nature then I believe that EQ is an appropriate course of action with no real down side.
If the source of the response anomaly is a mechanical resonance, you get into a lot more murky water, especially with large full range drivers which are extremely complex in their behavior at high frequencies (doubly so for dual cone drivers) compared to more conventional bandwidth limited drivers that you aren't using much past their piston range.
If the resonance is low Q (lets guess and say below about 2) and stable (doesn't shift with temp/humidity etc) and is not highly directionally sensitive (doesn't just manifest in certain on or off axis directions etc) then I think it can be compensated for with EQ, provided that it's done very accurately.
In theory if the resonance is minimum phase then if you get the centre frequency/depth/Q of your notch all correct you'll improve not only the amplitude response but also the transient response and decay response.
On the other hand in my experience high Q resonances typical of uncontrolled cone breakup are too narrow and unstable to be notched out precisely even with a digital EQ.
Sure, if it's a big peak you can pull the peak down in amplitude to get an overall flatter response which will make it sound more balanced and less objectionable, but the unmistakable tell-tale signature of a high Q resonance (caused by the long decay time seen on a cumulative spectral decay plot, like the one I posted of the FE207E) which tends to sound like harshness or edgyness still remains.
For these type of cone resonances I've found damping modifications are the best and probably only solution. If you can damp most of the troublesome cone resonances you can eliminate most of the ringing from the decay response, which generally flattens the frequency response as well, whereas attempting to flatten the frequency response with EQ alone when high Q resonances are present does little to improve the decay response, and sometimes makes it worse.
On my Coral's I've made damping modifications to the main large cone which consist of 12 small adhesive foam blocks stuck to the rear of the cone in the outer 20mm around the perimeter in a particular staggered pattern, and the improvement in the already reasonably good CSD is quite dramatic. More importantly they sound better too.
A cumulative spectral decay plot is really helpful here because although resonances generally cause peaks and dips in a frequency response graph, not all peaks and dips in the response are due to resonances, so the CSD really helps to sort between the two.
(If you look at the CSD of the Fostex and Coral, both are relatively non-flat by +/- several dB over the 2-10Khz range, but one has a very poor decay response and the other is excellent, something you can't tell from looking at the frequency response alone)
I've found a good correlation between perceived quality and a good CSD response. A driver with a relatively lumpy FR response can still sound very good if the CSD is fairly clean and free of obvious resonances IMHO, and this applies especially to full range drivers which just about all have lumpy responses.
To me, a good CSD is a sign of a good quality "clean" sounding driver, whilst a flat frequency response makes for an accurate sounding speaker. (Good tonal balance) The two are intertwined but are not one and the same.
It's possible to have a response that's not very flat but doesn't have any serious resonances, (will "sound good but measure bad", if FR is your only measurement) or conversely have a response that looks flatter but has "buried" resonances in it. (Which will measure well on a FR graph but sound bad)
Directivity control does matter, but I don't think the conventional wisdom of "the wider the dispersion at high frequencies the better" that a lot of multi-way designers follow is the correct approach.
The fact that a full range driver, suitably equalized can still sound very good, puts a lie to this. Too wide a dispersion at high frequencies (aka, flush mounted dome tweeter) is just as bad as too narrow, but for different reasons.
One advantage of the directivity profile of a full range driver is there is no sudden change in directivity in the upper mid/lower treble region where you would typically see a crossover to a tweeter, ("power response bloom") so although it does get very directional by the time you reach 10Khz or more it does so smoothly and progressively.
On a multi-way design I like waveguide loaded ribbon tweeters a lot, and one reason is they introduce deliberate directivity control that a flush mount dome doesn't have - the ones I have maintain a steady 90-110 degrees horizontal directivity all the way from 20Khz down to 2Khz. This helps minimize the power response bloom at the crossover frequency and sound closer to the FR driver coherence.
The downside to the FR driver is that to get an acceptable balance in a typical room you have to slope the treble response and therefore the on-axis response up - and the amount of upwards slope depends on the room and the distance to the listener.
This makes a full range driver a lot more "room sensitive" so it's difficult to design a full range speaker that will sound well balanced in different rooms without at least some adjustment of the treble, but if you're building the speakers for yourself to use in your own room and applying your own EQ it's not really a big deal.
Despite their shortcomings I think it is largely coherence that make full range drivers sound good - in a multi-way design there are a hundred different ways to mess up the crossover that will result in a loss of coherence, (with some design approaches having no chance to achieve coherence in the first place) but with a full range driver even if there are quite large (and arguably unacceptable) anomalies in the frequency response, you can always guarantee that they will, by definition, remain coherent.
(I still maintain that there is a lot to be gained by attempting to improve the overall frequency response balance as well of course
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Hi Simon,
I read your posts carefully! One question puzzles me - since you and Dave and many others do aftermarket improvements to speaker units and the consensus seems to be they sound better, why don't the manufacturers release similarly modified units? Possibly as a special order variant? Is it just because they look Heath-Robinson which might not be good for the advertising image?
andy
I read your posts carefully! One question puzzles me - since you and Dave and many others do aftermarket improvements to speaker units and the consensus seems to be they sound better, why don't the manufacturers release similarly modified units? Possibly as a special order variant? Is it just because they look Heath-Robinson which might not be good for the advertising image?
andy
Not true, it has to have a foundation of bacon, and be drenched in maple syrup!!
don
Who doesn't like bacon with a side of syrup. Try rapping it in a crepe, or skinny pancakes, as we call them. Skinny seems inapropriate. Sorry OP and others for the unimportant banter. Just sharing opinions!
Yes, and big FRs sound much better than they measure because the room actually helps to flaten that sometimes awfully rising on axis slope.
I found a few days ago this old paper from the french magazine L'Audiophile (1984 )which shows interesting measurements of Lowther PM6, like directivity factor, power response, as well as different FR measurements anechoic and in room.
Probably these things help understand why and how the famous "Lowther shout" might be a minor issue providing you do not pretend to use them as a nearfield monitor...In mono, from a corner of Sakuma restaurant, they might even sound lovely...
In french:
Le PM6 etsacourbe de rponse -1- (P.Jouenne - G.Alcuri)
Le PM6 et sa courbe de rponse -2- (P.Jouenne - G.Alcuri)
Attachments
Issues....You mean like the gigantic 2.6Khz whizzer cone resonance on the FE207E ?
I've not had a whizzer cone Fostex in my system for any serious length of time. The popularity of the big drivers is, i believe, a function of the natural male tendency to say, mine is bigger than yours.
Their best drivers have no whizzers. The sweet spot for single driver use is 4-5". If you are happy to add helper woofers the 3" are very good, particularily the "sigma in disguise" FF85K.
dave
So what are the mods that will allow me to turn this sows ear into a usable silk purse ?
Details described in many places. You can also do the optional 98 cent whizzer trick.
Still, my preferenc eis for the smaller whizzerless drivers with similar treatment levels.
dave
Yup, this is all very true. A clean CSD is another way of stating tha the response in the time domain in more important.
Again, this is consistent with my own experience.
My listening experience generally matches with the on-axis curve - the flatter the better. When I've tried to tilt it up, it generally ends up sounding too bright. May be its just my room.
And they also allow you to design crossover in more benign places of the frequency spectrum.
I have been an advocate of paper cones, but given literally millions of possible recipes for paper, there is huge room for differences in execution.
Metal is a solid engineering material with well defined properties even one when considers alloys. Metal cones have recently made a seriously big leap forward with the introduction of proven multiform cone forming from the Japanese auto industry. Better tolerances on the order of 100x, allow for much higher levels of control.
All of the parts interact with each other, the cone must work in harmony with the suspensions, the motors, the voice coil and the support infrastructure (ie basket)
In the end it comes down to execution and how all the parts come together into a whole.
dave
You got a problem with sherbert, eh?
Dave, you got any ideas when the new A7's will be headed this way?
Ground zero...............
The late Babb Lorelei IME...............
Day one of an infinite number................
Physics, it's the law, so until you can figure a way to 'cheat' Mother Nature we're never getting past square one.
That said, my memory of RCA's 15" LC-1A did big band, symphonic music surprisingly well as does the small Babb and why I believe that a blending of the two designs combined with intense development of diaphragm design could eventually yield a 'good enough' solution, but I see no way for it to ever be cheap unless built in huge quantities in a robotic factory to get the required quality control. The way the market is going though, I don't see it ever happening.
GM
I expect them to arrive at Madisound sometime around end July. They were quite surprised with how quickly the 1st batch evaporated and have duly beefed up their position. Get your orders in now.
dave
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