carbon fiber cones?

Status
Not open for further replies.
Jump to Latest
T

thoriated

Member
Joined 2003
#1
I wonder what people think of speakers with carbon fiber cones?

It occurred to me today that I could probably construct such a cone (once I make a mold to shape the carbon fabric). The biggest knock I've heard against carbon fiber cones is their break up modes, but it seems to me that I might be able to compensate for that with a resin impregnant that is regarded as having generally good damping characteristics.

The final objective would be to come up with a speaker with an extremely low moving mass while retaining high strength in the cone and high efficiency while not giving up on reasonable power handling.

Anybody have opinions on this?
 
#2
I built with Audax 100 co's. Yeah, they had a nasty breakup mode that sounded like a snake hissing. I got rid of the breakup (damped it out actually) by applying glue to the cones. But I think it made the cones too heavy.

You might have to play around with sandwiching the cone or using different amounts of resin, but if you are creative and keep trying, I am sure you can come up with a cone that is light and strong.

JJ
 
#3
The prototype cones that Dan Wiggins showed me a few years back were pretty neat, it's really too bad they never really made it into distribution. Very strong and light, Dan (a physically imposing man) demo'd them by slamming them against the edge of a countertop, without any resulting damage.

Best Regards,
TerryO
 
#4
Yes. I think it is a great material for speakers (subwoofers especially)....not to mention its good for body parts on your car. Durable, light, yet strong and good looking. But I personally think that it would be best for use in drivers 4 inches or bigger in diameter, not so much dome tweeters and anything that won't play mids and lows. But yea it's definitely possible so good luck.
 
#6
If you can find the extremely thin carbon fiber material just mentioned, I'd suggest building the drivers as two layers held together by an adhesive that damps the resonances (as suggested by JJ). That's what is done with the higher end Rockport speaker drivers and their responses look almost textbook perfect---no nasty breakup. I don't think this is going to be an easy diy project, but it would be very cool if you could make it work.

Few
 
#8
I'm not generally a bih fan of carbon fibre srivers, but...

The CSS SDX7 is constructed as an air tight later of some sort of plastic with a loose weave of carbon fibre strands. Once i have impregnated the loose strands with puzzlekoat these are very nice woofers, with no seeming breakup (response rolls off nicely at 950 Hz.

dave
 
#9
In the 'old days', it seems many 15" drivers had Mms around 40 grams or so, and some modern day guitar speakers also have exceptionally low moving masses, but of course at the cost of reduced power handling.

I'm wondering what would be possible with a carbon fiber cone with a moving mass comparable to these speakers but high enough rigidity to handle at least a hundred watts continuous. I haven't verified this, but doesn't it seem reasonable that about 3db of sensitivity might be gained by reducing the moving mass by half?

If I'm not barking up the wrong woofer, it might be possible to make a good sounding direct radiator using a carbon fiber cone with as much as 104db/w/m sensitivity below the breakup region. I'd call it a 'green' speaker🙂 it it can be made that efficient without a significant compromise in SQ.
 
#10
🙂
 

Attachments

  • billederden blå cafe 027 (wince).jpg
    billederden blå cafe 027 (wince).jpg
    16.8 KB · Views: 720
#11
Don't confuse power handling with SPL capability and mass of the cone. Thermal power handling is typically set by the coil size and other motor and venting details. This probably explains the correlation you think you're seeing between moving mass and power handling. Lighter moving mass drivers were probably designed with smaller coils so they can't handle as much power. While relationships between coil and cone mass can be important at higher frequencies, you don't have to maintain them if they don't let you meet your design goals. You could make a very light cone (as long as the material allowed you to) with a very large coil that would handle a large amount of power.
 
#12
Hi -


The radiating surface constitutes the majority of the moving mass in most direct radiator bass drivers, and, over the last several decades, to handle higher power in the mass market without the risk of buckling or excessive breakup, has tended to be made heavier (thicker) when presented with higher power requirements.

A JBL E130 has only 60 grams moving mass, with reasonably high power handling, but I am hoping to get both somewhat lower moving mass and somewhat better SQ overall if I can resolve the damping issue, by looking into carbon fiber cone construction.

Voice coil technology has certainly advanced also, but I believe even a 4" diameter short edgewound aluminum wire VC on a Nomex or Kapton former capable of handling up to 200 Wrms such as as JBL uses in some of their pro drivers doesn't weigh much more than ten grams, if that.

Btw, does anybody know who can make such a VC to spec? I suppose I could cannibalize an old JBL driver or two, but that's not as good an option.
 
#13
I must say I prefer nanoparticle carbon crystalline structure purpose made by organic microorgamisms and formed into a perfect mix of rigidity, breaking stress, tearing stress, flexibilty and weight. This ultra advanced carbon fiber structure, C6-H12-O6, has been proven the best possible cone material over and over again when used correctly.
 
#14
I read the Boominator thread. I like the solar charging capability particularly.

Actually, the carbon fiber cloth and the impregnants are readily available because they are used in lightweight modeling and such. I have a "secret recipe" of impregnants that I want to try that I think I can use to tweak the damping with the carbon fiber.
 
#16
I believe a major problem with these cones, carbon fiber, glassfiber and kevlar fiber, is actually the orientation of the fibers

Its ordinary braided industrial fiber matt
Doesnt seem to fit the shape of a speaker cone
The finer ones may be better though
I have a Focal with the finest fiber kevlar I have seen

There is a VERY thin and fine glass fiber matt, I think its called monofiber
It actually looks more like paper, with no direction of the fibers

I cant understand why this type is not used, I believe it would be much better
 
#18
454Casull said:

Paper has oriented fibers.
Click to expand...

Paper I believe is more like chaos oriented 😀

You can get that in glass fiber as well, as in the monofiber monofiber I mentioned...and in the cheapest glassfiber

More expencive carbon and kevlar will normally have all fibers oriented in the same two directions...I guess thats what braided means
Some have all fibers oriented in the very same direction, and the fibers are hold together with glue until used

ok 🙂
 
Status
Not open for further replies.
Top Bottom