After much thought, I have decided to design and build a lightweight bass cab using composite construction. The plan is to build a ported 2x10" with tweeter that is significantly lighter than anything available and strong enough to stand up to light gigging and rehearsals. Here are some of the ideas that motivated me to investigate the feasibility of such a project:
Is it feasible? I don't see why not. People have been building high performance airplanes, boats, surfboards, race cars, etc with composite construction for years (since early 1970's). Will it be cost effective and easy to build? Given the cost of some high end cabs out there it might be cost effective, but it will take a lot more time and effort than building with traditional methods.
I focused on a construction method known to homebuilt airplane builders as Rutan [Invalid or Expired Link Removed]. This is the method used to build Rutan(Burt) Aircrafts, and is detailed in a nice little book of the same title. I found a copy [Invalid or Expired Link Removed]for about $20 . The method is pretty simple in concept. You create a sandwich of fiberglass/epoxy, foam, fiberglass/epoxy. This gives you a sandwich panel with two stiff and strong skins on the outside that are separated by a lightweight core. This arrangement takes advantage of the fact that when you apply a load to something like an airplane wing or in this case a panel on a bass cab, the majority of the stress occurs at the outer surfaces.
Any weight savings realized with composite construction will only effect a portion of the cabs overall weight. The best I could figure, for a typical Neo 210 the weight from plywood is about 60% of the total weight of the cab, the driver weight is about 20% of the total, and the other 20% or so is from the hardware,tweeter,ports,carpet,x-over, etc. These numbers came from a spreadsheet model that I came up with. They are estimates and averages and very from cab to cab. Let's say for the sake of argument that the average Neo 210 is 44lbs. That means that the drivers weigh about 9lbs, the plywood weighs about 26lbs, and everything else adds up to about 9lbs. By my calculations, I should be able to reduce that 26lbs of plywood to 8lbs of fiberglass/epoxy and foam. I can also reduce the weight of hardware, crossover to something like 5lbs. This beings me to a 22lb cab. That's half the weight of the 44lb average. I've done some experimenting and figure that I'll be 10% higher, so I've set my design goal to 25lbs.
Here's some background info on some of the neo 210's out there compared to my design.
More to come in just a bit.
- With all these new 500W+ bass amps under 4lbs that can fit into your gig bag pocket why not build a super lightweight cab to go with it?
- My cabs are much more durable than I need them to be. Can I trade some of that durability for weight savings?
- New light weight neo drivers, same old heavy plywood construction.
- I'm an engineering dork at heart, and while exotic construction might not be necessary, I find it pretty cool.
- I enjoy building stuff, and don't see the point in building something similar to what is already out there.
Is it feasible? I don't see why not. People have been building high performance airplanes, boats, surfboards, race cars, etc with composite construction for years (since early 1970's). Will it be cost effective and easy to build? Given the cost of some high end cabs out there it might be cost effective, but it will take a lot more time and effort than building with traditional methods.
I focused on a construction method known to homebuilt airplane builders as Rutan [Invalid or Expired Link Removed]. This is the method used to build Rutan(Burt) Aircrafts, and is detailed in a nice little book of the same title. I found a copy [Invalid or Expired Link Removed]for about $20 . The method is pretty simple in concept. You create a sandwich of fiberglass/epoxy, foam, fiberglass/epoxy. This gives you a sandwich panel with two stiff and strong skins on the outside that are separated by a lightweight core. This arrangement takes advantage of the fact that when you apply a load to something like an airplane wing or in this case a panel on a bass cab, the majority of the stress occurs at the outer surfaces.
Any weight savings realized with composite construction will only effect a portion of the cabs overall weight. The best I could figure, for a typical Neo 210 the weight from plywood is about 60% of the total weight of the cab, the driver weight is about 20% of the total, and the other 20% or so is from the hardware,tweeter,ports,carpet,x-over, etc. These numbers came from a spreadsheet model that I came up with. They are estimates and averages and very from cab to cab. Let's say for the sake of argument that the average Neo 210 is 44lbs. That means that the drivers weigh about 9lbs, the plywood weighs about 26lbs, and everything else adds up to about 9lbs. By my calculations, I should be able to reduce that 26lbs of plywood to 8lbs of fiberglass/epoxy and foam. I can also reduce the weight of hardware, crossover to something like 5lbs. This beings me to a 22lb cab. That's half the weight of the 44lb average. I've done some experimenting and figure that I'll be 10% higher, so I've set my design goal to 25lbs.
Here's some background info on some of the neo 210's out there compared to my design.
More to come in just a bit.
