PMC Twenty5 23i

ATL Technology

DEEPER, CLEARER, CLEANER BASS & MORE

• Greater detail & more natural
• A full, rich sound at any volume level
• Deeper bass from a smaller cabinet

The source of PMC’s legendary natural, realistic sound is the Advanced Transmission Line (ATL) bass-loading technology, professionally proven all around the world.

ATL uses energy generated by the bass unit in a much more intelligent, efficient way than speaker designs based on ported or sealed boxes.

Deeper bass from a smaller cabinet

Across the frequencies where the transmission line is active, the air inside the line actually stiffens and couples to the back of the drive unit cone (this is how the cone motion is controlled by the transmission line). When this happens, the apparent moving mass of the cone is significantly increased, thereby lowering the effective resonant frequency of the drive unit. The effect of this is that the speaker can now produce significantly deeper bass, with greater headroom and less distortion than would be possible from that same drive unit in a sealed or ported cabinet.

Because the transmission line is so well damped with acoustic foam in order to absorb the unwanted mid and high frequencies radiated into the cabinet, the quality of the bass produced by a transmission line speaker is also incredibly accurate and well damped, with greatly improved time-domain characteristics than is seen in most simple ported speakers.

Same frequency response at all volume levels

Unlike the Helmholtz resonance that ported speakers use to increase their bass response, a transmission line does not change its efficiency with signal level. A ported speaker will lose bass output at low signal levels, as its port will not become efficient and active until a significant amount of energy is being input into the system. This is why many ported speakers wont ‘come alive’ until they are turned up fairly loud. Conversely, a transmission line speaker will retain its full, extended frequency response at all playback levels, meaning that it can be trusted to give completely accurate sound from intimate, low level monitoring sessions to full reference level playback.

PMC’s Laminair™ aerodynamic vent takes audio performance to the next level, by applying ATL aerodynamic principles from high-performance engineering used from F1 to Le Mans and creating an even smoother, laminar air flow at the exit from the transmission line.

ATL designs involve air moving at high speeds and under pressure.Reducing turbulence and drag at the ATL vent reduces resistance, increases efficiency, eliminates air noise and provides bass with supreme timing and the widest possible dynamic range.The combination of ATL and Laminair takes audio quality to unparalleled new heights:

• Faster, cleaner bass and higher definition sound throughout
• Turbulence is eliminated, increasing the efficiency of the ATL
• Removes air noise — only the music remains
• Higher maximum output and bass with supreme timing and dynamics

Aerodynamically honed duct for effecient airflow