ShakeIt: haptics in SimHub

Bass Shakers or Motors — which one you want

SimHub's left menu lists ShakeIt Wind, ShakeIt Bass Shakers and ShakeIt Motors as three separate entries. The first thing to get right is which of the last two your hardware belongs to, because the configuration is not interchangeable.

If your hardware plugs into an amplifier, it is a bass shaker. If it plugs into an Arduino, a USB port or is a Gametrix, ForceFeel or Next Level Racing HF8 pad, it is Motors. Some rigs run both, which is fine — they are independent.

How gain works, in plain English

This is the part that makes ShakeIt confusing until it suddenly does not. There is no single volume control — there are four, and they multiply. The official formula, verbatim:

Effect gain at one output = effect gain × effect per channel gain × channel gain × general gain

General gain

The master. Everything passes through it. Turn this down when the whole rig is too loud.

Effect gain

How strong one effect is, everywhere it is sent.

Channel gain

How strong one physical output is, for everything sent to it. Turn this down when one shaker is drowning the others.

Effect per channel gain

How strong one specific effect is on one specific output. This is the fine adjustment — the same effect can be strong under the pedals and subtle in the seat.

Because these multiply rather than add, four settings at 50% do not give you half — they give you about 6%. That is the single most common reason a setup that looks configured produces almost nothing. When something is inaudible, check every one of the four levels before you assume the hardware is at fault.

The response filters

Beyond gain, each effect has shaping controls that decide how the raw telemetry number becomes a force:

Gamma factor

Bends the response curve. Below 1 emphasises small inputs, above 1 emphasises large ones. This is how you make light kerbs noticeable without making heavy ones overwhelming.

Threshold

Ignores everything below a level. Use it to stop an effect chattering constantly at low intensity.

Minimum force

The opposite — it lifts weak signals to a level the hardware can actually reproduce. Essential for devices with a voltage floor that simply do nothing below a certain drive.

Input gain

Scales the incoming telemetry before any of the above.

Threshold and minimum force are often confused. Threshold removes the bottom of the range; minimum force raises it. On a shaker that does nothing until it is driven reasonably hard, you want minimum force, not more gain.

Why fewer effects is better

The official guidance is unusually direct about this, and it is the advice most new setups ignore:

From the official configuration guide: "Always remember that less is more… avoid fitting more than 3 effects on a single shaker/motor (not counting gear change effect being punctual)."

The physics is straightforward. One transducer can only be in one position at a time. Send it six continuous effects and they sum into a single average vibration that carries no information — you feel that something is happening, but not what. Send it three and each remains distinguishable.

Note the parenthesis: a gear-change effect is punctual — a short pulse rather than a continuous signal — so it does not compete for the same bandwidth and is excluded from the count. The same logic applies to any brief transient effect.

The practical convention the community has settled on is to split by body location rather than piling everything into one place: braking and front-wheel cues to the pedal tray, where your feet are already sensing what the front axle is doing; gear shifts, rear grip and light road texture through the seat.

Does the licence matter for haptics?

ShakeIt works completely on the free version. What the licence changes is the update rate for connected hardware — 10 times a second free, up to 60 with a licence.

For haptics this is one of the clearer cases for buying. Effects that represent something sharp — a kerb strike, an impact, a gear change — are transients, and a transient sampled ten times a second arrives blunted. Continuous effects like engine vibration or road texture are much less affected. Full detail on the licence page.

Everything in this section

• The effects, and the catalogue that does not exist What each effect represents, which telemetry drives it — and an honest account of why no complete list has ever been published.
• Setting up bass shakers Audio interface requirements, the Windows settings that silence them, channel maps and a tuning method.
• ShakeIt Motors Arduino outputs, Gametrix and ForceFeel pads, Fanatec pedal motors, threshold and minimum force.
• Wind simulator Fans on an Arduino: parts, cost, the twelve channels, and the wiring warning worth reading first.
• When shakers go silent Exclusive mode, Voicemeeter, sample rates and the known intermittent-output issue.

Common questions

Sources

• SimHub wiki — ShakeIt V3 effects configuration
• SimHub wiki