The Physics of Open-Air Projection: DVC Drivers and Neodymium Flux

Designing audio systems for motorcycles presents a hostile acoustic challenge: the signal-to-noise ratio is constantly under attack. Unlike a car cabin, which traps bass and blocks wind noise, a motorcycle exposes the speakers to an open field moving at 70 mph. The “room” is effectively infinite, meaning there is no boundary reinforcement for low frequencies. To overcome the roar of the engine and the white noise of the wind, the system requires brute force controlled by precision mechanics. The Kuryakyn 2719 MTX Road Thunder addresses this through the use of Dual Voice Coil (DVC) drivers and high-grade magnetic flux.

The Mechanic of Power: Dual Voice Coil (DVC)

A standard speaker has one coil of wire wrapped around a former, sitting in a magnetic gap. A DVC driver has two independent coils.
1. Power Handling: By splitting the electrical load across two distinct coils, the driver can accept more total current without overheating. Heat is the enemy of speakers; it increases impedance (power compression) and can melt the coil glue. The DVC design doubles the thermal surface area, allowing the Kuryakyn unit to sustain its 300-watt peak output without thermal failure during long rides.
2. Force Factor (BL): The interaction between the current in the coil and the magnetic field creates the force ($F = B \times L \times I$) that moves the cone. With two coils, engineers can maximize the length of wire ($L$) in the gap, generating more motive force. This extra “shove” is critical for forcing the stiff cone to move enough air to produce audible mid-bass against the wind pressure.

N42 Neodymium: The Magnetic Engine

The strength of the motor system is defined by the magnetic flux density ($B$). The Kuryakyn system utilizes N42 grade Neodymium magnets. * Flux Density: Neodymium is a rare-earth material capable of generating magnetic fields ten times stronger than traditional ferrite magnets of the same mass. The “N42” designation indicates a Maximum Energy Product of 42 MGOe (Mega Gauss Oersteds). * Control: A strong magnetic field acts like a stiff suspension for the voice coil. It grips the coil tightly, starting and stopping the cone movement instantly. This high “damping factor” prevents the speaker from flapping loosely (distortion) at high volumes. It ensures that the snare drum crack at 65 mph is sharp and defined, rather than a muddy thud.

Silk Dome Tweeters and Directivity

High frequencies (treble) are directional—they beam like a flashlight. Low frequencies are omnidirectional—they spread like a lightbulb. On a bike, if the treble isn’t pointed at your ears, it’s gone.
The Kuryakyn 2719 employs 1-inch silk dome tweeters. * Material Science: Silk is naturally damped. Unlike metal domes, which can ring or sound harsh at high volumes (listener fatigue), silk retains a smooth response even when driven hard. * Dispersion: The dome shape creates a wider dispersion pattern than a flat cone. This ensures that even as the rider moves their head or leans into a turn, the high-frequency content—where the clarity of vocals and guitars lives—remains consistent.

Future Outlook: Active Noise Cancellation?

While current tech relies on passive power, future motorcycle audio may integrate Active Noise Cancellation (ANC). By placing microphones in the helmet or on the fairing, the system could generate an inverted phase of the wind noise, electronically “deleting” the background roar before it even reaches the rider’s ears, allowing for lower, safer listening volumes.