The Idea

Implementing the Plan

The Case Cart

Details

Sometimes the process of discovery is a learning experience. I have a small fortune invested in a graveyard of espresso machines. It would have been cheaper if I had plunged ahead and purchased the Pavoni, a frightfully expensive piece of chrome and brass, in the first place. But then, I would have missed some interesting times.

The process of refining and rebuilding my sound cart has been a similar learning experience. The present configuration is a joy; it is maneuverable, passes over cables and curbs easily, provides good protection for the equipment, organizes the peripherals, and requires minimal set-up and strike. But I spent the down payment on a Bimmer getting here.

My very first sound cart was the folding, vertical aluminum cart manufactured by Audio Services (from, I am told, a Skyline Sound design) and presently made by PSC. Since then I have been through a variety of configurations including a Magliner cart and a cart made of interlocking shipping cases. I've now returned to the old Audio Services cart but with extensive modifications.

Being basically lazy, I wanted a cart which would permit me to keep the equipment built so it wouldn't be necessary to assemble and connect all the components in the morning and then pack it all up at the end of the day. I wanted to be able to roll the cart, with the equipment fully assembled, into the truck at the end of the day and back onto the set the next morning without worrying about what might transpire overnight. I also wanted a minimal footprint so I could fit into tight quarters and the ability to cope easily with stairs, curbs and other obstacles. And I wanted to be able to load the whole business into my Volvo wagon so I could easily do one-day assignments without buying a truck.

Implementing the Plan

The arrangement which works best is actually two carts. The PSC cart is fitted with shock-absorbing platforms which secure and protect the major components. Ancillary equipment is organized in a couple of drawer cases which "coffin-latch" together and attach to a rolling platform. The cases incorporate working surfaces in their design so there is a place to set up the laptop, solder a bad connection, etc. Ideally they are set up close to the vertical cart, like a secretary's return, but they can be left close behind. If circumstances require working on the second floor, the case cart can stay at the foot of the stairs. That way gear is conveniently close by but without the necessity of humping all the heavy gear over obstacles.

I've had two collaborators in this endeavor: Patrick O'Reilly at A&S Case has handled all of the custom case fabrication and Chinhda has machined the cart sub-assemblies and worked out design specifics to implement my broad objectives. A&S is in the custom case business but this project required more than just making cases to a particular set of dimensions. Patrick and I conferred about special materials and construction techniques to keep weight under control without sacrificing utility. Chinhda's work should already be familiar to most of you; he manufactures the aluminum and steel cable hooks sold at Coffey Sound and LSC.

The cart conversions consist of three sub-assemblies:

1. A shock absorbing platform for the recorder

2. A shock-absorbing drawer for the mixer

3. A wheel conversion

Working with a camp chair of normal height, it is no longer necessary or desirable to have the gear high on the cart. The mixer drawer pulls out from below the top shelf of the cart but above the arms of the chair so I sit in a normal position with the mixer on my lap. This also gives room for my knees. The recorder platform is on the regular top shelf so the meter is right in front of me as I work. An inverted "U" of aluminum fits onto the recorder platform to protect it from falling C-stands, dust, etc. This can be left in place while working or it can be removed and fitted to the "handle" shelf of the cart to make an additional shelf. At the end of the day it is returned to the recorder platform and clamped down for secure protection. Both the mixer and recorder platforms are machined from aluminum and suspended using the rubber mounts designed to transport live shells in tanks. A positive lock holds the mixer drawer in fully open, fully closed, and several interim positions. Mounting hardware secures the recorder and mixing panel; they remain in place even if the cart is completely inverted. At the end of the day (or whenever the cart is moved) the mixer slides back into the cart where it is protected by its shock mounts and by being within the frame of the cart.

PSC has provided the cart with 16" bicycle wheels and 3" castors. We decided to substitute 20" wheels to make it easier to pull the cart over curbs and up stairs and to roll over cables. Regular 20" bike wheels are used but the axles are punched out and the wheels fitted with different bearings to permit a different kind of axle. The bicycle axles require support on both sides but a heavier duty axle can be attached to the cart directly without any need for a flying buttress type support on the outside. This also makes possible a conversion to a dually wheel configuration. With dually wheels, the cart can negotiate soft, muddy ground without sinking in. By taping the wheels together we think the cart can also handle beach sand but that is, as yet, untested. Single wheels are the normal configuration to easily pass through doors. Change over requires propping the cart on a half-apple and using a wrench but can be accomplished in just a few minutes whenever necessary. We also changed the mounting location from the outside of the frame to the inside to improve balance and to minimize the increase in exterior dimensions caused by the larger wheels. Even with the 20" wheels, the cart rolls right into my Volvo. Since the equipment is secured, the cart can ride lying down without risk to any of the gear. We're considering further modifications which would place the axle mounts on slides and use mountain bike shock absorbers to further buffer the equipment.

There are some other mods still in the works. Folding handles on the frame opposite the big wheels will help in negotiating stairs by providing a firm hold for a second man. We also intend clip-on handles, similar to the arrangement for a Fisher dolly, will make it possible for four people to carry the whole cart over very bad ground. With the equipment bolted in place in protected mounts, this kind of transit becomes practical for short distances.

The Case Cart

Rock & roll style shipping cases are typically made from plywood covered with a plastic laminate and fastened together by a frame of steel and aluminum. They can be filled with foam, like a still camera case, or fitted with plywood drawers, rack mounts, and other hardware. This makes for a very strong container but a very heavy case. Some of these trunks are like traveling with an armoire. That's ok for a case that will sit in the car or on the truck most of the time but not acceptible for a case that will accompany me onto the set. Patrick suggested using a new board made of plastic instead of plywood. This material looks just like a white plastic version of corrugated cardboard box material. A surface plastic material is laminated for the exterior finish and it is impossible to disinguish the plastic case from the plywood case until you pick one up. The plastic is much lighter. I implored him to go one step further and make drawers out of the corrugated plastic. This presents some design problems as the plastic cannot be fastened with staples or screws and would not easily accept regular drawer glides. After several trials A&S came up with a design which involved cutting a drawer "pattern" from a single piece of plastic, bending up the sides and riveting it all together. Instead of drawer glides, an aluminum channel affixed to each side of the drawer slides in a channel of slightly larger gauge attached to the inside walls of the case.

We were able to substantially decrease the weight of a case but these things still have considerable heft from the frame and hardware and, of course, the contents. Rather than one monster case, we elected to build two cases which would fasten together with roto-latches (aka "coffin latches"). That way each case is a manageable weight for shipping or loading into the car. Instead of castors for moving about the set I had Chinhda construct a frame with 8" pneumatic wheels. The frame incorporates roto-latches to secure the cases so everything locks together in a single unit. With 8" wheels it rolls right over cables and a single person can easily get it over curbs. The whole business is 32.5 inches tall when mounted on the wheels and the top of the top case is finished in carpet to create a useful work surface.

Details

Some of the specifics of the case layout are peculiar to my rig. I'll share a few of them in the hopes that you can reciprocate with good ideas of your own.

I like to work with an outboard limiter; I find it more transparent than the limiter in the Cooper. All the good limiters seem to require AC power so I've installed a DC-AC inverter and an isolation transformer (to clean up the power) in one of the cases. A small, removable panel gives cable access. Having these units off the main cart effectively controls inductive hum and noise. Neil Stone made a wiring harness which really simplifies the application. DC power from the battery and return AC power from the inverter are bundled together and carried in a single 5-pin cable, identical to my duplex cable. The cases with the inverter are connected or disconnected from the cart with a single 5-pin duplex.

The top case is consumed by one large drawer. I had A&S affix aluminum rails to the inside walls of the drawer and a piece of masonite slides on those rails. With the drawer open this provides a work surface in addition to the carpeted case top. The masonite is smooth on one side to make a writing surface and carpeted on the other to make a work surface. Emergency cable repairs can be made with the security that falling parts will safely land inside the drawer.

Case doors latch in the middle and are hinged at each side. They open out and form small wings on each side. I use those wings to hold a cup holder, a divider box with commonly needed tools, a video monitor, and other things I don't want to hunt for.

My script, equipment manuals, and other documents are in a Pendaflex-type file which is mounted on aluminum rails and slides at right angles into the case. Always having a script handy is useful for those occasions when production adds a scene not on the sides.

I've used this rig on one small picture and a couple of one or two day assignments and it has been a real pleasure. I'm no longer trying to dock a Magliner battleship which requires two tugboats to maneuver it into harbor. I'm no longer dismayed by a flight of stairs because the components can easily break down into lighter weight units. Also the larger wheels on the main cart provide additional leverage for stairs. Even going from deck to deck on the Queen Mary wasn't too exhausting. And the small main cart allows me to be close to the action. Of course, on some films I would welcome the excuse to be as far from the director as possible but that's another story.

There are still some details to be worked out. I am still waiting delivery of the aluminum fittings which permit making a ramp to roll the whole business into my car. I'm in the process of making additional handles to facilitate rolling the cart up a ramp with the top shelf & handle folded under. Chinhda and I are still developing the dually wheel configuration. Eventually the cable hooks will all be replaced with a folding design Chinhda is developing. But these are details. As it sits now, the cart fulfills its design objective of providing a lightweight and mobile platform which allows equipment to be safely stored and transported completely built.

Finishing Up

Ramps are now complete. We found that motorcycle ramps offered the best solution. They are made of extruded aluminum which forms a channel to hold the wheels in alignment. A pair can be had for about $100 at various motorcycle shops. Intended for use with pick-up trucks, they need to be cut down slightly to fit into a station wagon. We put the excess aluminum channel to good use by fabricating a tray to hold the battery on the backside of the cart. This makes good use of otherwise wasted space, frees up a shelf, and improves balance by placing the heavy battery on the other side of the fulcrum. It also simplifies cable paths. As with the mixer and recorder, everything is secure and can be laid on its side for transport.