cone material preference

[ddjr]

Hello. I'm wondering if cone material is the most important component in sound reproduction. I see there is carbon fiber, paper, plastic and who knows what else. In my mind it would seem paper to be the least, and carbon fiber the best as far as "good sound". I have no data to substantiate that, it just seems that way in my way of thinking. What do you audiophiles prefer? Is there an accepted "best"? Does one sound brassier, tinnier, bassier, thinner, fuller, (insert preffered adjective here) than another? I'm asking because I'm building a pair of bookshelf speakers and I want the best sound possible. I do like the klipsch speakers I have heard. They seem to be plastic cones. Anyone out there care to share their preferrences?

 

[KenM10759]

There is no one best material for speaker cones. Each type speaker does a different job, handles a different frequency range, is in a different cabinet (or none) so the variables are wide ranging.

What's good for a tweeter certainly may not work in a subwoofer. In a small two-way, the woofer-midrange needs to handle everything from the lowest to where the tweeter picks up. You'll get a hundred answers, all different. Look at what speakers you like are made from, go with that.

 

[ddjr]

Thanks Ken. The cabinets are going to be made of bubinga. A good tone wood, as far as guitar building goes. Does a cabinet benefit by being built from tonewood? Im thinking of all the mdf I've seen in cabs. I've never heard carbon fiber. I do want people's preferences, even if they're all different.id feel like I had a direction rather than listening to speakers in a best buy. We don't have any decent audio stores in my neck of the woods

 

[Steve81]

I'm wondering if cone material is the most important component in sound reproduction.

No, good engineering is the most important component in sound reproduction. It's a very simple thing to take the best drivers, the finest cabinet, and still turn out garbage. As far as cone materials go, in simple terms they all have their strengths and weaknesses. For example, a paper cone may break up earlier than a comparable metal cone, but its breakup will generally be more benign. However, assuming both drivers are of respectable quality, a good designer can make either option work quite well.

Does a cabinet benefit by being built from tonewood?

Again, no. A speaker cabinet shouldn't be adding anything to the sound.

 

[TLS Guy]

Thanks Ken. The cabinets are going to be made of bubinga. A good tone wood, as far as guitar building goes. Does a cabinet benefit by being built from tonewood? Im thinking of all the mdf I've seen in cabs. I've never heard carbon fiber. I do want people's preferences, even if they're all different.id feel like I had a direction rather than listening to speakers in a best buy. We don't have any decent audio stores in my neck of the woods

The last thing you want in a speaker is a tone wood! You want the cabinet to be as inert as possible, and ideally have no tone at all.

A speaker is a reproducer that ideally should add or subtract nothing to the original performance.

Don't focus on the cone material.

I have a suspicion you have never designed a speaker before.

In any event you decide first the parameters you want the speaker to have. Then you look for drivers than can be crossed over in a practical and realistic way. You can't pick drivers out of the air. The vast majority of combinations will be non starters.

The next step is to decide the optimal loading method for your selected woofer. Then you design and model your low frequency alignment.

The next, most crucial and difficult step is to design the crossover, which is the very heart of the speaker.

After that you are ready to design the enclosure. Once all that is done you are ready to get in the supplies and build.

I should add one step I forgot. You do need to determine the width of the speaker before you design the crossover, so you can design in the baffle step compensation.

 

[KenM10759]

If you are building a guitar, the wood and/or metal it's made of imparts it's own character to the sound, making it a unique sound. You should notice how speaker builders go to great lengths to make a totally inert cabinet, and only dress up the outside of it with a wood veneer, metal, plastic or other finish.

In a two-way, I like treated paper cones though my KEF R100 are a coated aluminum cone. Other materials are fine. It's the tweeter that may present the different materials more prominently. In general a treated silk dome is smooth, an aluminum one may be bright, a ribbon tweeter may be either. There's a lot to this and you may try a couple different tweeters (and drivers) before you settle on the sound you like best at the cost you can afford.

 

[ddjr]

Ok, CLEARLY I need much more knowledge before I jump right in... can you guys recommend any good reads on speaker-ology? Parameters, crossover points, two way/three way, baffle compensation... I had no idea. I thought to stick good speakers in a solid box was it. Oops!

 

[ddjr]

"I have a suspicion you have never designed a speaker"- you couldn't be more correct!

 

[Swerd]

I completely agree with Steve81, TLS Guy, and KenM above, about both questions, cabinet wood and speaker cone materials.

The cabinets are going to be made of bubinga. A good tone wood, as far as guitar building goes. Does a cabinet benefit by being built from tonewood?

A speaker cabinet should be made as inert and resonance free as possible. That's why MDF is used so often. It is much more resonance free than any hard wood. Good quality, void-free plywood can also be used.

In addition to the inherent resonance of any hard wood, as well as the expense of exotic woods like bubinga, there is also the problem of dimensional stability. Solid wood expands and shrinks as the humidity changes through the seasons. This will happen even if it is kiln dried and elaborately sealed on all sides. A six-sided box, a speaker cabinet, made from solid wood will become so stressed by these dimension changes, that the wood can split. It may take 2 years to happen, but it will happen. MDF doesn't expand and shrink as the weather changes. It's surface remains flat allowing for easier finishing. There are stunning looking bubinga veneers I've seen. I don't know their cost, but if you were considering solid bubinga, you probably weren't worried about that.

Hello. I'm wondering if cone material is the most important component in sound reproduction. I see there is carbon fiber, paper, plastic and who knows what else. In my mind it would seem paper to be the least, and carbon fiber the best as far as "good sound". I have no data to substantiate that, it just seems that way in my way of thinking. What do you audiophiles prefer? Is there an accepted "best"? Does one sound brassier, tinnier, bassier, thinner, fuller, (insert preffered adjective here) than another? I'm asking because I'm building a pair of bookshelf speakers and I want the best sound possible. I do like the klipsch speakers I have heard. They seem to be plastic cones. Anyone out there care to share their preferrences?

Now to your question about cone materials. Much is said about the sound qualities of different cone materials, especially woofers or mid wooofers. Some people swear that the sound from one type or another is the best. Others say a properly designed crossover can make any driver sound good without revealing the material of the cone. The reason is in the higher frequency behavior and misbehavior of the woofer, and how that varies with the cone material. Here is some reading on the subject:

First read Crossovers 101, http://www.salksound.com/wp/?p=135. It's short and informative. It walks you through a simplified version of designing a crossover for a 2-way speaker. You should read the whole article, but I'll focus only on what its says about woofer cones at high frequencies. It shows the raw frequency response curve of a 6½" metal coned woofer, that could be aluminum or magnesium alloy.

The writer, Dennis Murphy, says, "As for the mess from about 4,000 -8,000 Hz–a lot of that is due to natural resonances at higher frequencies that are inherent in the cone material and the whole mechanical system formed by the cone, surround, and suspension. That’s the dirty little secret of most woofers, and, as we will see, a large reason why good crossover design is so important."

Similar misbehavior (sometimes called "break-up") happens at higher frequencies for any woofer regardless of it's material. It varies with the size of the driver and the material of the cone. Larger drivers misbehave at lower frequencies than smaller drivers. Also softer more flexible materials, like paper or plastic, misbehave at lower frequencies than stiffer materials, like glass or carbon fiber, Kevlar, or metals. But the stiffer materials usually behave much worse than softer materials. Murphy's major point about this problem is that the crossover must filter out those resonances so the listener doesn't hear it. Some other speaker makers choose the exact opposite. They deliberately want to show off their cone material as a marketing feature. B&W is notorious for wanting everyone to know their speakers feature highly resonant, and sometimes harsh sounding, bright yellow Kevlar cones.

Your next reading assignment is a "white paper" published by Harmon Kardon, written by Floyd E. Toole and Allan Devantier. http://support.infinitysystems.com/home/technology/whitepapers/cmmd.pdf

It discusses in more detail what happens as speaker cones go from soft flexible materials like paper or plastic, to stiffer materials. While this is a good treatment of the subject, remember that it also intends to market the ceramic metal matrix cones sold on Infinity speakers. ("Ceramic Metal Matrix Diaphragm" is HK's marketing term for a type of aluminum oxide commonly known as alumina.) It's major point agrees with Dennis Murphy, in that a good sounding woofer or mid woofer should be filtered by the crossover to suppress the misbehavior noise in the upper frequencies. Their point about their own CMMD product is that, compared to bare aluminum cones, their aluminum oxide coating raises the frequency at which the misbehavior noise begins. It makes the job easier for the crossover designer. Similar results are found in magnesium oxide cones in the Seas Excel drivers, and a hard brittle white ceramic material in Accuton woofers. Both of these makers produce expensive but very good sounding drivers.

Hope this answers your questions.

 

[ddjr]

Swerd, thank you. I see I have some learnin' and planning ahead of me!

 

[Swerd]

Swerd, thank you. I see I have some learnin' and planning ahead of me!

I like your enthusiasm, and I certainly don't want to discourage it. Once you learn what is involved in designing good speakers, you might decide that you'd be better off building a DIY design made by an experienced designer who owns all the needed measuring gear and knows how to use it well. There are plenty of such designs on the internet, and they have been built and tested by others. I know that works for me. I like to think of it like cooking good food. I can follow a good recipe and get good results, but I'm no chef. I can't invent a good recipe on my own.

Stay in touch as your speaker design ideas evolve.

 

[KenM10759]

One thing to be watching yourself about in building a speaker is overall cost. If I were building one, I would stop at nothing to get the "best of everything" in materials. SEAS drivers, REAL tweeter, Dennis Murphy crossover, high end binding posts and so on. Worse, I would insist upon having the best tools for each step, from power saws, shapers, joiners, clamp tables and more.

All speaker designs are always a compromise on something otherwise they'd all cost $300,000 a pair. You just have to have a little education to know what you want, what you must have and what you can sacrifice.

No matter what, don't go into it thinking you'll save a wad of cash. You don't have the economies of scale. Do it because you want complete ownership and pride.

 

[Swerd]

One thing to be watching yourself about in building a speaker is overall cost. If I were building one, I would stop at nothing to get the "best of everything" in materials. SEAS drivers, REAL tweeter, Dennis Murphy crossover, high end binding posts and so on.

I'll extend this line of thought to it's logical endpoint . Order one of Dennis's existing Philharmonic Audio designs, and ask that Jim Salk build the cabinets and veneer them with bubinga as in this example. Explore the Galleries at http://www.salksound.com/home.htm, for other veneer ideas.

 

[speakerman39]

I completely agree with Steve81, TLS Guy, and KenM above, about both questions, cabinet wood and speaker cone materials.
A speaker cabinet should be made as inert and resonance free as possible. That's why MDF is used so often. It is much more resonance free than any hard wood. Good quality, void-free plywood can also be used.

In addition to the inherent resonance of any hard wood, as well as the expense of exotic woods like bubinga, there is also the problem of dimensional stability. Solid wood expands and shrinks as the humidity changes through the seasons. This will happen even if it is kiln dried and elaborately sealed on all sides. A six-sided box, a speaker cabinet, made from solid wood will become so stressed by these dimension changes, that the wood can split. It may take 2 years to happen, but it will happen. MDF doesn't expand and shrink as the weather changes. It's surface remains flat allowing for easier finishing. There are stunning looking bubinga veneers I've seen. I don't know their cost, but if you were considering solid bubinga, you probably weren't worried about that.
Now to your question about cone materials. Much is said about the sound qualities of different cone materials, especially woofers or mid wooofers. Some people swear that the sound from one type or another is the best. Others say a properly designed crossover can make any driver sound good without revealing the material of the cone. The reason is in the higher frequency behavior and misbehavior of the woofer, and how that varies with the cone material. Here is some reading on the subject:

First read Crossovers 101, http://www.salksound.com/wp/?p=135. It's short and informative. It walks you through a simplified version of designing a crossover for a 2-way speaker. You should read the whole article, but I'll focus only on what its says about woofer cones at high frequencies. It shows the raw frequency response curve of a 6½" metal coned woofer, that could be aluminum or magnesium alloy.

The writer, Dennis Murphy, says, "As for the mess from about 4,000 -8,000 Hz–a lot of that is due to natural resonances at higher frequencies that are inherent in the cone material and the whole mechanical system formed by the cone, surround, and suspension. That’s the dirty little secret of most woofers, and, as we will see, a large reason why good crossover design is so important."

Similar misbehavior (sometimes called "break-up") happens at higher frequencies for any woofer regardless of it's material. It varies with the size of the driver and the material of the cone. Larger drivers display their misbehavior at lower frequencies than smaller drivers. Also softer more flexible materials, like paper or plastic, display that misbehavior at lower frequencies than stiffer materials, like glass or carbon fiber, Kevlar, or metals. But the stiffer materials usually behave much worse that softer materials. Murphy's major point about this problem is that the crossover must filter out those resonances so the listener doesn't hear it. Some other speaker makers choose the exact opposite. They deliberately want to show off their cone material as a marketing feature. B&W is notorious for wanting everyone to know their speakers feature highly resonant, and sometimes harsh sounding, bright yellow Kevlar cones.

Your next reading assignment is a "white paper" published by Harmon Kardon, written by Floyd E. Toole and Allan Devantier. http://support.infinitysystems.com/home/technology/whitepapers/cmmd.pdf

It discusses in more detail what happens as speaker cones go from soft flexible materials like paper or plastic, to stiffer materials. While this is a good treatment of the subject, remember that it also intends to market the ceramic metal matrix cones sold on Infinity speakers. ("Ceramic Metal Matrix Diaphragm" is HK's marketing term for a type of aluminum oxide commonly known as alumina.) It's major point agrees with Dennis Murphy, in that a good sounding woofer or mid woofer should be filtered by the crossover to suppress the misbehavior noise in the upper frequencies. Their point about their own CMMD product is that, compared to bare aluminum cones, their aluminum oxide coating raises the frequency at which the misbehavior noise begins. It makes the job easier for the crossover designer. Similar results are found in magnesium oxide cones in the Seas Excel drivers, and a hard brittle white ceramic material in Accuton woofers. Both of these makers produce expensive but very good sounding drivers.

Hope this answers your questions.

Very informative Richard. BTW, is the term "ringing" the same as break-up? Have heard that term used a lot and not really sure what they are referring to. Just curious is all. Looks like you can explain it a bit better to me.

Cheers,

Phil

 

[shadyJ]

Very informative Richard. BTW, is the term "ringing" the same as break-up? Have heard that term used a lot and not really sure what they are referring to. Just curious is all. Looks like you can explain it a bit better to me.

Cheers,

Phil

Ringing is left-over energy in the cone, a decay after the signal. It's what happens when the cone isn't stopping when it is supposed to.

Break-up is when the cone ceases to move uniformly, ie the center of the cone which has the VC former behind is is moving out of sync with the edges of the cone. When the speakers break up, the frequency response goes all to hell, it can be nasty. It typically happens when a driver is tasked to play frequencies above where it is comfortable, and the center of the cone is moving faster than the edges, although there are different types of break-up modes.

 

[speakerman39]

Ringing is left-over energy in the cone, a decay after the signal. It's what happens when the cone isn't stopping when it is supposed to.

Break-up is when the cone ceases to move uniformly, ie the center of the cone which has the VC former behind is is moving out of sync with the edges of the cone. When the speakers break up, the frequency response goes all to hell, it can be nasty. It typically happens when a driver is tasked to play frequencies above where it is comfortable, and the center of the cone is moving faster than the edges, although there are different types of break-up modes.

I see. Thanks for the info. Have been reading a lot about speakers lately and the word ringing is mentioned a lot. Appreciate it.

Cheers,

Phil

 

[Swerd]

shadyj has it right, or at least the same as I understand it.

Ringing can happen at any frequency range. An example is a single bass note that rings on and on because the cabinet dimensions are wrong for the woofer.

Break-up is when a speaker cone no longer operates like piston, but instead moves back & forth in different places on the cone's surface. The picture on the left shows a Kevlar woofer breaking up at 3500 Hz, and on the right a different woofer (metal alloy?) doing alright at 3500 Hz.

 

[Swerd]

I found a few more figures showing break-up. First is a Dayton aluminum 18 cm (7") woofer. Dark blue is the raw unfiltered frequency response, and the light blue shows how a well-designed low pass filter suppresses the break-up noise.

Here are cartoons of break-up in motion

And proper pistonic motion

 

[TLS Guy]

Ringing is left-over energy in the cone, a decay after the signal. It's what happens when the cone isn't stopping when it is supposed to.

Break-up is when the cone ceases to move uniformly, ie the center of the cone which has the VC former behind is is moving out of sync with the edges of the cone. When the speakers break up, the frequency response goes all to hell, it can be nasty. It typically happens when a driver is tasked to play frequencies above where it is comfortable, and the center of the cone is moving faster than the edges, although there are different types of break-up modes.

You have to remember that break up is often associated with a resonant mode, and that means stored energy.

 

[ddjr]

I DID build a pair of tower speakers years ago that we still use. There are 2 8" woofers and 1 tweeter in each. I put a kenwood auto audio crossover in them. One woofer is bass, the other is mids. They actually sound pretty good to my untrained ears. The cabinets are solid jatoba, and like an above post said, they have cracked.