Looking for input: Best material for mid range cone


I had a surprise last night when I switched speakers in my system.  I've got a few pairs, but had been listening mainly to some Ascend Sierra 1, which have a polypropylene cone with a soft dome tweeter in a bookshelf design.  Anyway, I've got a pair of Tannoy Precision 6.1's, and swapped them in.  

The sound was noticeably different.  Piano sounded better, vocals had a finer quality as well, and the whole sound seemed a little more lively.  Now the Tannoys have silver interior wiring, a titanium tweeter in a coax design and are only rated for 75 watts. The cone material is some kind of pressed paper fibre.  And they are voiced to somewhat push the midrange.  But the sound was compelling.

I'm just wondering about cone material because some old Paradigms with Polypropylene were really not up to snuff, but they were quite old.  Any thoughts?
213runnin
To a lot of folk, nothing beats paper (except scissors). There is, however, no one type that will suit all. It's all in the implementation. Take Vivid, for example: all aluminum drivers made in-house with carbon fibre surrounds and it's some of the finest I've heard. 

But keeping things in a financial perspective, you can't go wrong with paper or cellulose fibre cones. They have wonderful tone that smacks of an easy naturalness which accounts for that great midrange you mentioned. 

All the best,
Nonoise
It's all very subjective. Different strokes for different folks. Cone size plays a large role as well, as does the crossover implementation.

I find that paper and plastic cones typically produce the tonal qualities that I prefer, though I've heard some metal composite cones that sound close. 

One thing I noticed is that the BBC inspired brands (all commonly regarded as having excellent midrange quality) use either some form of plastic or paper composite for their midrange drivers.
As others have noted, you will find reference level speakers with drivers made from metal, ceramic composites, kevlar, hemp and what not.  It's all good!  You will have to step up from the entry level stuff to enjoy the better driver designs out there.  
Polypropylene has always been a miserable material for cones. If you go back and read the reviews of speakers that employed that stuff back at it's peak, nobody had glowing things to say about it's sound. It has excellent damping, but it's got a horrible Young's modulus and mass. Somebody is making polypropylene cones doped with clay and minerals, but I can't remember who. 
Personally, I think the material is as important as implementation. Wilson is embracing paper after years of Focal W cone drivers. Magico likes their special recipe of carbon kink. B&W maintains their obsession with coursely woven plastic fibers. I think very highly of Focal's Flax Cone. Some materials just suck though, and polypropylene is definitely one of them. It is to midrange and woofer drivers what paper is to tweeters. 
Agreed. The material used in a driver is only one of many factors that come into play.

I've heard very good and very bad Be tweeters for instance. Fun to bs about though.

Best,

E
Thanks for the comments, my own experience is somewhat limited.  Paper does seem to be quite nice when done right.
Speed and lightness.
Best for upper bass to upper mids is ESL's.
Best for upper mids and beyond is a Plasma Tweeter.

Cheers George
@kosst_amojan,

If plastic is a miserable material for cones, why do British monitors such as Harbeth Spendor and Epos produce such an elegant midrange? Have you compared such speakers to Focal's Flax cones?  
I love KEVLAR. It gives BEST and most realistic and natural midrange
The harder materials tend to measure better but paper is very musical. 
All cones suck. Planars are the only way to go ;-).
I agree with bdp24, planars are the only way to go.
@helomech,

No, like I said in another post, I didn't waste my time listening to every single $4000 speaker produced by every manufacturer on the planet. Harbeth, to the best of my understanding, basically produces highly refined BBC monitor type speakers. I'm not at all surprised Harbeth chooses to use polypropylene cones because a primary characteristic of BBC monitors is the classic British dark tone. I wasn't particularly taken with B&W because those Kevlar cones tend to be darker too. From everything I've ever read about polypropylene cones, and specifically Harbeth, I didn't bother wasting my time hunting down a pair to listen to because nothing suggested to me that they'd be to my taste. I fully realize some people would sell a testicle for a nice pair, but I'm not one of them. 
Polypropylene not so good above 1Khz.

Basically most speakers have too large a mid range for the bandwidth they carry (results in beaming)

Stiffer materials can measure extremely well (detailed) and have wide bandwidth often extending higher in frequency but tend to have resonances or ringing (poor timbre hashy sound).

Softer materials with weave or fabric or pulp paper mash can be great because of internal damping (get very clean background or exceedingly good timbre)however they suffer from linearity issues (limited bandwidth due to breakup)

In a three way softer materials for cones can work extremely well. In a two way stiffer material is often the best compromise to coverthe audible range in only two drivers.
planar speakers are favored by most of cats.
Where do you guys come up with these blanket claims? "Polypropylene not so good above 1Khz." Based on what? My speakers have a 7" plastic cone and play up to 3kHz with hardly a lick of distortion. They play much cleaner than numerous other speakers I've heard with exotic cones. There's good and bad examples of almost every speaker diaphragm material. I've heard aramid cones that sounded like complete garbage, and some that sound great, the same for paper, plastic, titanium, and aluminum. I've owned speakers with plastic tweeters (oh no! Over 1khz!) that blew away some well regarded silk domes.

To my next point: size matters! Any loudspeaker engineer worth his salt can tell you that a material's performance can heavily depend on the size of the diaphragm, the frequency range it's asked to cover, and the SPLs it's asked to play. It's true that large plastic cones CAN struggle with higher freqs, while paper cones exhibit their best virtues in the larger sizes. I haven't heard many good sounding paper tweeters, however, like with most materials, I'm sure there's exceptions out there.

OP, 
It really comes down to personal preference and the quality of design. Speaker sound is the most subjective aspect of a system. One person's euphoric midrange will make another's ears bleed.
I have owned rega rs5, which utilize paper cone for both midrange (5") and woofers (7").  The midrange on these speakers was outstanding - natural and transparent, it is really their big selling point.  I have never got the same with kevlar (B&Ws at twice the price, and Wharfedale at equivalent price).
The new line rx also employs doped paper cones... Haven't heard them; I am not sure how they compare to the rs.
It’s so interesting to read the varying thoughts on this topic. My issue is not the frequency range that poly can reproduce, but what it sounds like while doing so.

The Tannoy Precision bookshelfs I found so enjoyable have the tweeter crossed over at 1600 Hz, which is much lower than the Sierras. Perhaps that also has something to do with it?

I suppose there are no absolutes in speaker design, except that opinions will differ!
Poly cones can have huge variances in tonal qualities, just as other materials can.

The Poly cones of my Epos Epics sound different from those of my Spendors, which sound different from those of Harbeth. Polycarbonate has derivatives, similar to metal alloys. Then there's the effect of the basket material, the basket's frame design, the cone surround material, implementation of dust cap or phase plug, the spider, and the voicecoil design. All have an effect on the driver's sound. 

A plastic driver with bullet dust cap will have different tonal characteristics from one with a bullet phase plug. 

It's my opinion that the real test of  quality drivers (and components in general) is whether you can listen to them for long periods without fatigue, get lost in the music, and forget about the system. Often times, people automatically perceive "different" as being superior. Though, if they listen to these excitingingly different speakers for long periods, fatigue sets in, or they end up returning to their previous pair. You might find the Tannoys to be superior now, but consider how much time you've spent with them since swapping out the Sierras, and consider how you feel after a 2 hour plus listening session. You might be surprised if you swap the Sierras back in after a few weeks, then again, maybe not.

Generalizations in regard to cone material are just that: generalizations.


Wow, interesting thread with no right answers.  If you want to talk measurements, you need a driver (cone is only part of a driver and then it's the crossover and other materials that make up a great speaker.  The mids shouldn't stand out. If they do, then you lose coherency, which isn't what high end audio is about.  

A great mid driver needs to be fast.  This is the one advantage that the ribbons and planers seem to have, however to properly reproduce a square wave (a great speaker must have excellent measurements in addition to sounding great), you have to have a driver that will be as pistonic as you can get.  The cone needs to be as light weight as possible AND as strong as possible to display the speed of a ribbon or planer (or as close as a driver will come).  

Only a few materials have been mentioned in this thread.  Right now, the best (again, subjective, but being used by Vandersteen with it's balsa wood cone wrapped by a specific carbon fiber that was chosen for it's sound quality over many listening sessions) seem to be cones made of carbon fiber.  Some companies are using a carbon nano composite and they are also fast and strong, but I've yet to hear one that is piston in nature and it doesn't produce a musical tone to my ears, but others will disagree.  

I have yet to hear as haunting a mid as the Vandersteen 7's and this is one reason I'm a fanboy.  Can't help it and in years to come if someone else does it better, then I'll be a fanboy of their speakers.  What so many don't realize is that a great mid bass speaker MUST have a very very fast mid.  The midrange truly is 90% of what we are hearing and the problem with so many on the market is distortion.  

I've only liked a few ribbon speakers.  I do like some planers too.  The key to any system is matching components also.  

See how there is no correct answer per say.  Maybe in the future, we will get other materials that will be made in 3D printers that will crush what's currently on the market, but for now, my money is on the Vandersteen Carbon Fiber cones for both midrange and tweeters.  JMHO
I'm not saying my speaker is better, just a different approach than most - that I am extremely happy with -  it uses a Morel 2 1/8" soft dome midrange.

http://www.theabsolutesound.com/articles/gershman-acoustics-sonogram-loudspeaker/

I've heard there are a couple of other companies out there using a 2" dome also

The Sonograms are very dynamic, detailed and smooth.

I've stopped looking for speakers since buying these

Regards - Steve


I've never heard cone speakers that could match the midrange and highs that ESL's give you!
Hifisoundguy, I have. In fact, I’ve heard significantly better in comparison in my systems.

Waste of time to debate cone material as though one is universally superior.
I'd submit that there is no "best."  A lot of it is preference and most of the rest depends on other construction, enclosure, crossover, and synergy with the rest of the system.  For awhile I thought I hated metal cones, particularly aluminum.  Bought a few that seemed striking and wonderful, at first, but then wore my ears down and down.  Once that "sound" was set, always seemed to be grating, even in some otherwise really good or fairly expensive speakers on audition.  Until I heard the aluminum coned mids in Canton's Reference line and reinforced when I heard the magnesium coned Seas W18.  To my ears, those are fantastic.

But, I really like some paper coned mids, and, most may disagree, but I liked some of the plasticky graphite whatever they were called Infinity mids from the 90s.  Many others as part of whole speaker, as well.

The cone material is just one factor in the design and finished product and sound, ime.

Planars/ESLs, of course, can sound great, too.  Whatever floats one's boat the highest.
I'll put my strong support behind big planars and electrostats. More sensitive to position than an arthritic porn star though. If I had a more ideal room I may have more deeply considered a pair. My ancient AMT1's are real happy campers in my spare bedroom, much more so than my listening room, just because of the simple shape. 
Whatever floats your boat is the right answer.  I do however like the Youtube video that Vandersteen puts out showing the pistonic nature of their Carbon Fiber cones/drivers they hand build in Cali.  The planers and ribbons can not recreate that and neither can the paper cones in the video (They are from a very expensive, high end brand speaker). 

To me, accuracy is so important as are measurements when they design these speakers.  a great designer can and often will design a speaker on measurements and know what it will sound like.  Then they will listen and tweek accordingly.  They will listen to various materials and some take the cheap route and tweek an off the shelve driver or use an exotic material for sound, but much of the time for marketing.  I didn't listen to Vandersteen's until they started to use carbon fiber technology and to my ear it's made the most significant difference in speaker sound when utilized correctly, than an material I've heard in over 30 years or so.

For those who haven't heard the model 7's or 5's you really should take your favorite recordings and go listen.  I did and ended up switching speakers a few years ago.  There are still many speakers out there that I like, but none that I love like the Vandersteen's.  Getting value at the higher end is rare and I do appreciate that also, but it's still all about the sound.

Implementation, as I said before is KEY....hard to argue that.  
Post removed 
That's why I like my Focal. It's very hard to end up with a lousy speaker if it's designed to exhibit good measurements all around. The buying public seems to de-emphasize measurements far more than designers and professional reviewers. I've grown to highly appreciate the measurements Stereophile does because they're very predictive of what a speaker will sound like. 
Stiff and light with breakup significantly out of the crossover frequency 

simple really

till you try try and build it.

look at energy storage and pistonic motion IF you are not a science denier...
I became a planar guy after I purchased the Martin-Logan Aeon 12 years ago.  Since then, I have owned Magnepan 1.7 and Quad ESLs (I think the model was 2805) .  I still have the Maggies, but I am not using them.  A few months back I purchased a pair of Kipod 2 speakers used at a very nice price.  The Kipod speakers use aluminum speakers machined from blllets of solid aluminum for the midrange and woofer.  While they are very expensive if purchased new, you can expect to pay 25% of the  new cost for a good used pair.  These speakers are incredible in the midrange and the soundstage, tone, etc. are spectacular.  I prefer the sound of the Kipods over any speaker I have ever heard.  Save your pennies and look for a good pair of used Kipods or other YG speakers with aluminum drivers. 
@russ751,

How can the Kipods be any good when made of such an antiquated material? Don't you know that good speaker drivers require super exotic composite materials, the more exotic the better......😂
Actually that's not at all what it being said. What's being said is that many companies are using better quality materials and implementing them properly.  To take a good thread and make a post that sarcastically puts down good companies is silly isn't it?  

Just look at the measurements of these drivers that utilize new materials and driver concepts.  Hard to argue with great measurement AND great sound.  Have you heard the Vandersteen 7 mk2's set up properly?  What about the other speakers that are using up to date technology?  Maybe you have, but to make a blanket statement like that says otherwise.  

Not one person has said anything negative about the other posters love of his speakers, so not sure why you would have a sarcastic comeback.  Interesting...
I am repeating a bit. The textbook ideal material avoids resonance leading to phase distortion.  Another issue is avoiding frequency dependent vibration transmission radially through the cone, a property of solid materials but not air. (ESL is a clever answer as they do not require rigidity to avoid phase/distortion issues). Then the quality of material can depend on the manner in which it fails to handle those objectives, e.g. damping. These failings lead to a multitude of designs to approximate the ideal. A tip-off to complexity is the plethora of blended materials in cones. A lot of other factors come in to play that have been mentioned, and another is cost. I think it is hard to say what is best without more qualification. 

I have a pair of old, $2K speakers with Vifa PP midrange drivers. The midrange is certainly not THE best, but it is great compared to competition at that price including Paradigm.
It is hard for me to accept that aluminum is an "antiquated" material, especially when it is CNC machined to very close tolerances.  The process of making these speakers is very expensive, which is reflected in their price.  The sound is exceptionally distortion free, detailed, and tonally accurate.  The most beautiful speakers I have ever owned.  Think again helomech!! 
Any material used in diaphragm will have properties that require attention to gain optimal operation. Beryllium as an example has very high self damping (stiffness of cone) but doesn't exhibit much internal damping (ability to dissipate excess energy within the material). While the operating range of one will be greater, care to ensure you stay within its operating range for its given size and construction.

I would like to address carbon fiber, since its brought a number of times but aspects of it should be known. There are so many grades of carbon fiber and the epoxies used, construction method employed, and design parameters in that you can come to some very wildly different results with the very same material. You could spend an considerable amount of time in FEA design between differing grades, weaves, shapes, etc. The modulus alone could vary by a factor of five just by simply changing from a low modulus to high modulus fiber. The expense of high modulus fiber is notably more and typically forgoes some tensile strength when modulus increases. But in this application, tensile strength matters little with it being well beyond what is required in nearly all grades. The latest development in this area has been the infusion of graphene in the epoxy, which aids in producing a more uniform carbon fiber sheet. This will further extend how light a driver cone could be made without any loss of stiffness. This still doesn't account for the mass of the voice coil, former, surround, etc. 

So when your looking for the best material, it must include a completed design. Only with this, combined with the desired operating range and crossover implementation could one select the best material within a given cost. I do mention cost since its very easy to gain a marginal improvement for an extreme cost, one which is better spent in other areas of the system.
In terms of completed design, I'm a big fan of composite construction. This includes the Focal W sandwiches, rohacell, carbon fiber laminates, and the cut paper designs used by ScanSpeak (my personal faves).

There's also some newer designs I'm curious about such as the Satori  papyrus / Focal materials using unusually long plant fibers, and Eton also has some interesting ideas about marrying magnesium to resin.
mmeysarosh51 posts07-04-2017 10:24pmAny material used in diaphragm will have properties that require attention to gain optimal operation. Beryllium as an example has very high self damping (stiffness of cone) but doesn’t exhibit much internal damping (ability to dissipate excess energy within the material). While the operating range of one will be greater, care to ensure you stay within its operating range for its given size and construction.

I would like to address carbon fiber, since its brought a number of times but aspects of it should be known. There are so many grades of carbon fiber and the epoxies used, construction method employed, and design parameters in that you can come to some very wildly different results with the very same material. You could spend an considerable amount of time in FEA design between differing grades, weaves, shapes, etc. The modulus alone could vary by a factor of five just by simply changing from a low modulus to high modulus fiber. The expense of high modulus fiber is notably more and typically forgoes some tensile strength when modulus increases. But in this application, tensile strength matters little with it being well beyond what is required in nearly all grades. The latest development in this area has been the infusion of graphene in the epoxy, which aids in producing a more uniform carbon fiber sheet. This will further extend how light a driver cone could be made without any loss of stiffness. This still doesn’t account for the mass of the voice coil, former, surround, etc.



I agree that you must take into account a complete design as I've stated before. When your looking for the best material, it must include a completed design. Only with this, combined with the desired operating range and crossover implementation could one select the best material within a given cost. I do mention cost since its very easy to gain a marginal improvement for an extreme cost, one which is better spent in other areas of the system.
Yes any driver needs to be a total design involving all of its components. You are correct in saying all materials have a distinct sound that is why the Vandersteen Model Seven drivers (tweeter, mid, mid-bass) use extreme modulus uni pre-preg with high modulus graphene loaded matrix 29% front and back with balsa as a truss form and damper between them. Balsa has 8 times the compressive strength of rohacell yet is a very effective noise damper (note used in Corvette floorboards to damp road noise). All this used in all drivers involved 100Hz and above offers less color or sonic characteristics then ever achieved.

@russ751,

You misread my post regarding aluminum drivers. It was sarcasm. I was referring to the fact that aluminum drivers are far from a new concept, yet many highly regarded manufacturers continue to use them in everything from bass woofers to tweeters.

I was making fun of some companies that use uncommom composite materials, often as a pure marketing ploy. They know the public majority has come to assume that any fiber composite material is inherently better than traditional materials, whether used for ballistic vests, car chassis’, or speakers. Consumers likes exotic materials because it leads them to believe they received a high-value product. Little do they realize that some of the best materials for speakers have existed for many decades. Some people read "hemp," "flax," "carbon fiber," "graphene," "Kevlar," and their minds instantly associate these less common materials with high performance and high cost. However, companies like YG, Revel, Spendor, Stirling Broadcast, ProAc, and others continue to prove that these materials do not necessarily perform any better as speakers than aluminum, plastic, or paper.

They don’t always understand that every composite has strengths and weaknesses and countless variations as already mentioned.
And s many of the composits do sound better than what we've had if implemented properly. 
ATC addresses off-aixs frequency response as well as dynamics with their CLD fabric cone. I was thinking about them with respect their successful low distortion, high-dynamic speakers:

"An ideal speaker system should have phase response linear with frequency, which in simple terms means that all frequencies produced by the driver reach the listener’s ear at the same time. This eliminates partial cancellation of certain frequencies due to their arrival at the listening point out of phase. Phase shift is a result of resonances in the drivers, as well as a consequence of the design of crossover network filters.

Careful driver design assures an amplitude response free from any broadband (low Q) resonance. Conventional design wisdom tells us that a stiff speaker cone is ideal for wide on-axis frequency response. However, poor off-axis frequency response and multiple resonances that color the sound make a non-flexible cone less than optimum. The conventional approach to resolving this problem is to highly damp the motion of the cone, but this dramatically reduces the efficiency of the speaker.

One of ATC’s approaches to eliminating resonant peaks in the driver is to use a heavily damped fabric cone with sufficient structural integrity to sustain high power levels. Constrained Layer Damping (CLD), an ATC innovation, uses a “sandwich” cone construction, with a damping layer molded between two lightweight fabric cones. As the cone assembly flexes, the damping material absorbs the shear energy between the two layers, offering dramatically more efficient damping than conventional methods. This design reduces harmonic distortion, minimizes resonances that affect on- and off-axis frequency response, and, since it offers less loss than standard damping techniques, dynamic headroom is improved.

The combination of mechanical damping and electrical damping from the power amplifier keeps the system tightly controlled, providing well defined bass and midrange detail."

http://www.transaudiogroup.com/wp-content/uploads/2015/06/ATC_Engineering_Goals_and_Approaches.pdf
the most transparent midrange drivers i have heard are made of aluminum.  but their properties usually need one incredible crossover to tame the break up distortion and rapidly rising response.   see the joseph audio speakers with infinite slope crossovers.  

my favorite speakers use ceramic-sandwich mid-range drivers. it’s very light and stiff, and i have found that it’s speed and transparency mates well with ribbon tweeters for a one-piece sound.....and a seamless mid-range-tweeter is super critical to my ears.

other driver materials seem to miss my preferred proper balance of ’life’, ’detail’, and ’tonal purity’. either they are too up front, too hard or too dull sounding. these are subtle things but for many years i’ve found my personal sonic viewpoint best with ceramic.

like any driver type, getting the most out of the ceramic mid range requires adapting it properly as it’s so transparent it can ring and such if not executed with great care. it’s not plug and play. but it’s ceiling seems to be higher when done right.....to my particular ears.

YMMV, my 2 cents, and all that stuff.

@helomech 

I've got speakers with those fancy Focal F cones. They sure as hell weren't the reason I bought them. They do what they do well. That's the bottom line. 

A lot of people put an obscene amount of emphasis on the tonal purity a driver or it's diaphragm material are capable of. To me that's a secondary consideration because I don't listen to much music where the recording engineer seemed obsessed with the tonal presentation. The space and ambience tends to be a higher priority. I bought the Focals because they're exceptional at recreating a space. Is that what flax does? Seems that way. Polyglass isn't exactly space age material though, being little more than a paper cone spritzed with micronized glass, and it does imaging better than plenty of aluminum drivers. 

Worth pointing out, Wilson is getting great results from well built paper, some say better than the Focal W cones they used in many of their products. The speed of sound through paper can approach speeds near what you see in steel if you make it right. W cones are limited in that. On the other hand, I've never heard of anyone complaining about the results Magico gets with their hyper-exotic construction and materials. 

Ultimately, I think too many people in this hobby develop strange obsessions with diaphragm materials when the world is full of exceptions to their opinions. Can a metal tweeter be smoother than a soft one? Yeah. Can paper outperform carbon fiber and Kevlar? Yeah. Can flax do better than paper? Sounds like it from where I'm sitting. Can paper humiliate everything I've ever heard? Good chance it can. I think it pays to be agnostic about such things as materials. 




Implantation is what it's all about. Been discussed already and it's nearly impossible to say no to, lol.  That said, I think if implemented properly, many of today's materials that weren't available years ago, can and do often sound better than the materials of yesterday. That will constantly be the situation. Even Ribbons are now using better materials to achieve better results IMHO.  I was never a ribbon guy, but I've heard some nice ones recently that don't make me want to walk out of the room after a half hour of listening.

It's all personal and as someone stated in the beginning of this thread, there is no one right answer or wrong answer.  My favorite speakers are using a carbon fiber sandwich with a balsa wood core for the stability etc... while some others like others.  Just like anything else, it's personal.  

The one material I WILL say is outdated is a pure paper cone that isn't treated.  It will sound different depending on the moisture in the room.  It really does.  
That's a loaded question as it depends on way too many factors. On a 3-way I prefer a 4-5" pulp cone for low mid as long as it is fully crossed over by 1200-1400 hz. I like the natural timber and tone of the pulp cone.  Electrostatics are nice for upper mid on up. Remember the early 70's SAE's with the electrostatic panels for mid and HF. They used a 4" between the 30 lb. Gauss woofers (Ceramic coated 12" pulp woofer cone with 17 lb magnet!) and the stats that was as thin as tissue paper with something added to the pulp that made them quite stiff. AR had a really nice  spider-less 2 1/2" paper cone in the AR12 that was strong and imo better than the dome in the ar10 and ar11. Some of the 2"-4" domes did work well. Got to love the choices.
The wood that my viola is made from, is the best material.

IT SOUNDS JUST LIKE AN ACTUAL VIOLA! ;)