Poll for carbon fiber cabs owners

[gtirard]

Carbon fiber is often used as a replacement for steel, as it can (in many places) save weight.

Replacing wood is different. Carbon fiber composite is 3x the density of maple - it’s far more dense than any wood. So, if you want to make a light weight cabinet from carbon fiber, you need to use thin cross sections. That brings with it vibration, damping, and strength (impact) issues that need to be managed

It’s a good material for some applications. I’m not sure this is the best application for it

From what I understand, GR Bass has developed a special panel, made of layers of CF + damping material/foam + CF.
It has the same accoustic properties as wood, and the foam compensates for the high density of CF.
The panels are thinner and lighter than tradditional plywood, but it's more difficult to hold everything together and avoid vibrations.

 

[agedhorse]

Even @agedhorse asked about this CF structural integrity (I vaguely remember ). In fact I was surprised because he works in the PA world also and designs cabinets and expected him to know. But it looks like it is not used widely as you would expect. I might be wrong in what I remembered and my search did not point to his post about it - apologies in advance. I'd be interested in what he says about CF use for cabs.

I have asked about it several times, all the research and experience I have seen have showed that it is a much more difficult material to work with than it appears.

I also worked for the company that owned Ovation Guitar, the engineers behind that technology were some of the best in the world… they developed the first successful composite helicopter rotors and the manufacturing technology supporting it.

 

[micguy]

From what I understand, GR Bass has developed a special panel, made of layers of CF + damping material/foam + CF.
It has the same accoustic properties as wood, and the foam compensates for the high density of CF.
The panels are thinner and lighter than tradditional plywood, but it's more difficult to hold everything together and avoid vibrations.

Making a panel with the same acoustics properties as wood... there are a lot of things going on in wood and in composite panels - they are never going to have all the same properties. GR may have come up with something with similar damping, or similar density, or similar stiffness, but making all those things "the same" at once isn't going to happen. It may be a great panel, but that claim is not realistic.

 

[Zooberwerx]

The composite looks good to me...it's the substrate which concerns me given this particular application. Using foam as a foundation is nothing new but this stuff reminds me of the foam-core board Susan uses in her art studio.

Riis

 

[tubedude]

Maybe a hybrid approach using layers of CF bonded to an internal layer of styrene foam.

 

[Zooberwerx]

Maybe a hybrid approach using layers of CF bonded to an internal layer of styrene foam.

I thought that's what it was but using interwoven layers (one per side) sandwiching a foam substrate.

Riis

 

[JazznFunk]

The problem, as was discussed at length in a prior thread about carbon fiber cabs, is that bonding/securing the individual panels together isn't as easy as it would seem, and there have been problems with corners/seams coming apart, as well as trim.

The only way you're really going to get a carbon fiber cab to be as structurally reliable as people want it to be is to construct and fire in the autoclave, a seamless box where 5 sides are bonded as one unit, then the front side where the speakers and wiring goes in is inserted and secured separately. But that would result in a MUCH more expensive per-unit price versus assembling separate panels together and hoping for the best.

 

[logdrum]

The Acoustic Image Doubleshot and upshot cabinets are made with some sort of carboard reinforced possibly with epoxy or something similar, In the US, those paper cylindrical tubes are used as concrete forms usually as foundations for post, I have used it as the form for my back porch and it's going 26 years now, outside, Okay we are not exactly a wet state but where I am in wetter than the rest of the state. They are still there - my point is that they are tough and also light and probably the same properties as MDF. They are also light - 15 lbs for the doubleshot with 2 10 inch drivers mounted in opposing fashion like the Barefoot Studio monitors. You can mount any of their light amps and the heaviest will be 20 lbs. for the 2 channel Clarus. Yep the drivers are inefficient but good enough to use for horn driven big band, RIP Dr. Jones If he was still around, it will be interesting to hear what he has to say about CF.

 

[mikecd1]

Is the baffle also made of the CF as well on the GR cabs? I know on the new Markbass MB58 cabs that the baffle is made of wood and the cab panels are their new material. I'm sure the baffle material has some effect on the sound.

 

[JimChjones]

Maybe a hybrid approach using layers of CF bonded to an internal layer of styrene foam.

Definitely not.

A carbon skin each side of a lighter weight core is utterly conventional, but styrene foam makes for a piss poor core. There are all sorts of materials used, from end grain balsa through foams of various densities, often polyurethane, to honeycomb structures. All these have pros and cons. There is nothing very difficult about building a carbon bass cab per se. The challenges come in building one that is cheap enough and road worthy enough, but still light enough to justify the extra cost.

To my mind roadworthy is the big challenge. I've raced carbon race boats, and they are treated with great care, because a lightweight race boat (and a boat 12 feet by 6 feet by about 18inches deep may come out under 80lbs) will dent like buggery if you're not careful with it. By contrast we want to be able to sling our cabs in the van at the end of the evening, and they can't have any more protection than maybe a cloth cover, because it would defeat the object to stuff the thing in a flight case!
Cost of manufacture is also an issue, because ideally one would want to lay up the back, sides top and bottom as a single unit, but that precludes using prefabricated carbon panels. Also customers are going to demand a mirror finish clearcoat, with all the fibre nicely oriented and neat, which adds more difficulty. This is all very soluble with good tooling and adequate investment, but everything is tending to force both cost and weight up.

I'm comfortable enough with carbon/foam construction, and I've done a reasonable amount of it on race boats, but I don't make my home built cabs that way. Partly because by using sophisticated wood construction I can get lighter than most commercial cabs anyway, and partly because I find building with wood fun, and building with carbon/foam a pain in the neck.

 

[Jeff Scott]

Huh, I guess there is such a thing as too light.

Yes. In the mid '80s I bought a Contax T with its screw-on flash unit. Great camera, fantastic image quality......if you could hold that super light and tiny camera steady. I returned the Contax after a week or so and never bothered with those types of cameras (the various Minox cameras were similar).

 

[darev]

never bothered with those types of cameras (the various Minox cameras were similar).

Only once did I have to smuggle out surreptitious pictures of diplomatic documents using a Minox C camera. I liked the form factor and it never got in my way or bound up during all of the explosions, fights, gunshots, and the big boss. Once I made it back to HQ though, they never could read what was on the pictures from all the motion blur. I didn't get the girl, either.

Minox B/C cameras review: look cool, take terrible pix. You also won't get the girl.

Edit: typo

 

[Gervais Cote]

Definitely not.

A carbon skin each side of a lighter weight core is utterly conventional, but styrene foam makes for a piss poor core. There are all sorts of materials used, from end grain balsa through foams of various densities, often polyurethane, to honeycomb structures. All these have pros and cons. There is nothing very difficult about building a carbon bass cab per se. The challenges come in building one that is cheap enough and road worthy enough, but still light enough to justify the extra cost.

To my mind roadworthy is the big challenge. I've raced carbon race boats, and they are treated with great care, because a lightweight race boat (and a boat 12 feet by 6 feet by about 18inches deep may come out under 80lbs) will dent like buggery if you're not careful with it. By contrast we want to be able to sling our cabs in the van at the end of the evening, and they can't have any more protection than maybe a cloth cover, because it would defeat the object to stuff the thing in a flight case!
Cost of manufacture is also an issue, because ideally one would want to lay up the back, sides top and bottom as a single unit, but that precludes using prefabricated carbon panels. Also customers are going to demand a mirror finish clearcoat, with all the fibre nicely oriented and neat, which adds more difficulty. This is all very soluble with good tooling and adequate investment, but everything is tending to force both cost and weight up.

I'm comfortable enough with carbon/foam construction, and I've done a reasonable amount of it on race boats, but I don't make my home built cabs that way. Partly because by using sophisticated wood construction I can get lighter than most commercial cabs anyway, and partly because I find building with wood fun, and building with carbon/foam a pain in the neck.

I know that in the aerospace industry, they use some honeycomb structures filled with a hard foam named rohacell and then apply their carbon fiber/resin on it with great success. Extremely lightweight and almost indestructible.

 

[ThinCrappyTone2]

a bassist came by to jam one night with a carbon fiber 2x12 cab. Ridiculously light, sounded good, but it was coming apart already, so my first impression was “flimsy”.

 

[Zooberwerx]

a bassist came by to jam one night with a carbon fiber 2x12 cab. Ridiculously light, sounded good, but it was coming apart already, so my first impression was “flimsy”.

How so? Not picking, just curious as to whether the failure smacks of a previously cited issue.

Riis

 

[7bridges]

Magico, a Bay Area High-End speaker company uses CF in all of its M-series loudspeakers. They aren't light weight and they definitely aren't cheap! I would expect these to hold together pretty well over time.
Magico Loudspeakers — Music. Revealed.

 

[ThinCrappyTone2]

How so? Not picking, just curious as to whether the failure smacks of a previously cited issue.

Riis

One of the corner seams was separating

 

[mntngrown]

Only 1 post about Markbass composite cabs so far. I recently got the MB58R 104 pure but have only used it at several rehearsals. It sure is an easy one hand load upstairs to the studio. I think I read a post where a member claimed the composite got soft in a hot car. It was not cheap, but I have not been back to the chiro!

 

[Gervais Cote]

a bassist came by to jam one night with a carbon fiber 2x12 cab. Ridiculously light, sounded good, but it was coming apart already, so my first impression was “flimsy”.

Ouch !

 

[blastoff]

im pleased that "cans of carrot fiber" is currently leading the polls.