Stacking Speakers Safely

Stacking speakers safely comes down to three things: lift heavy cabs as a team, keep each stack's centre of gravity well inside its base, and tie down anything that people, bass or wind could move. Suspending cabs overhead is a separate discipline for qualified riggers.

The loads involved

The driver alone is a serious weight: a WM1850/8 is 20 kg before it goes in a box. The plywood of a scoop or reflex cab built round it adds more, so a loaded 18" sub cab is a two-person lift at minimum. A falling stack of them can cause serious or fatal injury.

Lifting

UK manual handling law puts three duties on employers: avoid hazardous manual handling so far as reasonably practicable, assess the risk of what cannot be avoided, and reduce that risk as low as reasonably practicable. A crew of mates is not an employer, but the method is the right one.

• Avoid the lift. Castors, dollies, sack trucks and ramps first; carry only where you have to.
• Plan the route. Clear obstacles, prop doors, check steps and floor surfaces before anyone picks up.
• Enough people, one caller. One person calls the count so the load comes up together.
• Technique. Legs not back, load close to the body, no twisting under load.
• Handles. Fit proper recessed handles at the build stage, placed for the cab's balance point. See finishing speaker cabinets.
• Kit. Toe-capped boots and grip gloves.

Stack stability

A stack tips when its combined centre of gravity moves outside the footprint of the bottom cab. Height raises the centre of gravity, so the same push or lean moves it further; a narrow base gives it less room before it crosses the edge.

• Firm, level ground. Confirm the floor or stage can take the total load. Outdoors, spread it on solid boards and avoid slopes.
• Heaviest at the bottom. Subs on the floor, mids and tops above.
• Square and aligned. Each cab sits fully on the one below, edges flush. Stacking corners and runners help.
• Height. Follow the designer's or maker's guidance where it exists, and keep stacks wider than they are tall where you can.
• Castors. Lock them, or remove them, on any cab that has something stacked on top.
• Crowd separation. Barriers between the public and the stacks at public events; nobody climbs or leans on them.
• Wind. A tall stack has a large side area. Strap and anchor outdoors, and take stacks down if the weather turns.

Sustained low-frequency vibration walks cabs across hard floors. Check stacks through the night and use anti-slip matting. For layout see anatomy of a sound system; for rig size see how many subs do I need.

Ratchet straps

Straps tie a stack into one unit or anchor it to a fixed point. Check the rated capacity on the label and retire any strap that is frayed or has a damaged ratchet. Tighten to hold, not to crush corners or finish; use edge protectors over sharp edges. Never stand on a stack to fit a strap.

Loading a van

• Payload. Add up cabs, amps, cable and crew against the van's rated payload. Overloading lengthens braking, degrades handling and is an offence.
• Heavy and low. Heaviest cabs on the floor against the bulkhead, weight spread across the axles.
• Pack tight. Gaps let loads build momentum under braking. Fill them with lighter gear or padding.
• Lash everything to the van's load-lashing points with ratchet straps.
• Protect the drivers. Grilles never carry the weight of other gear.
• Unload in reverse with the same lifting discipline.

Rigging and flying

Suspending speakers is not a DIY job. In the UK it falls under the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), which cover the planning of lifting operations and the thorough examination of lifting equipment. Flown cabinets need certified hardware rated for the purpose, rigging points engineered into the box, and planning and inspection by competent people. Never fly a home-built cab or hang speakers from improvised fixings. If an event needs flown PA, hire a professional rigging team.

After the event

Strike stacks top first. Before the next job, inspect each cab for cracked corners, loose handles and damaged fixings; a cab that has taken a knock may have loosened driver bolts. See testing a new cabinet.

Sources: HSE, manual handling and LOLER guidance, checked October 2026; Wavemark WM1850/8 spec sheet. This page is general guidance, not a risk assessment.