[StephaninMelb]

I've been thinking that a light-weight enclosure can be developed that can hold a Fender Blackface or Silverface Twin Reverb Chassis. For an open-back combo I don't believe that it is technically necessary to have a large heavy wood (or plywood or MDF or particleboard) cabinet to contain the speakers. These materials just add unnecessary weight and do little acoustically in an open-back configuration.

One design I have envisioned replaces the entire cabinet with a hollow rectangular frame made out of polished aluminum tubes. The technology uses the same alloy tube materials used to build light-weight bicycle frames and the same construction methodology.

With this design the whole speaker cabinet structure disappears. The chassis is housed in a piggy-back enclosure mounted on top of the frame. The frame would be designed to quickly snap apart into sections for portability and the head would lift off.

The speakers would work well mounted on the front of a fibreglass or aluminum nacelle (tube) shaped structure. Just envision a shape similar to a nacelle holding a jet engine underneath a wing. These speaker nacelles would snap mount onto the aluminum tube frame. Wiring would be contained inside the tubes. All electrical connections to the speakers would be an automatic click fit.

The rear of the speaker nacelles would have a fibreglass sealed reflector and the sound would be bounced forward through two tubes running parallel to the nacelle housing. The exit ports would be angled 10-15 degrees off centre to increase dispersion.

Two of these speaker units could be suspended between tubular frame uprights. With Neo speakers and a light-weight frame it should be possible to get a Twin Reverb weight down to around 40-50 lbs.

Tolex covers with snaps (like covers used on boat cockpits and pick-up truck beds) could be used to cover the frame sides if someone wants a "closed" cabinet look.

An alternative to the speaker nacelle folded horn approach would be to use a more traditional compact 212 speaker cab mounted in a vertical configuration inside the aluminum combo frame. This would actually have superior sonic dispersion compared to standard combo side-to-side speaker arrangement inside a combo cabinet. Speakers in a vertical configuration have more ideal dispersion than in a horizontal configuration (which is why PA columns are often setup this way).

An example that illustrates how a compact speaker container can work is that companies such as TC Electronic build a 2 x 12 speaker cab in a very compact shape (e.g. RS212 Bass cab), much smaller and lighter than the typical combo box enclosure. Essentially in an open-back design you can get rid of most of the box and associated weight. I think it is possible to go further and build a folded compact semi-closed speaker system.

To complete the light-weight Twin, a reverb tank would be mounted on two aluminum tubes that running horizontally between the upright frame tube supports. The reverb lead wiring would be routed inside the aluminum tubes.

Do you think there is a market for light-weight Twin amps, Twin clones or light-weight combos? If yes what technical features would you like to see?