The Cab 27 is a two way compact high-performance bass instrument loudspeaker that features 2 proprietary PJB 4 ohm 7-inch drivers wired in series (8 ohm total) designed to handle high power levels of bass frequencies with extremely low distortion. A proprietary 3 inch (magnetic liquid cooled voice coil) cone tweeter augments the high-frequency component giving it a fully extended range. The result is a tweeter that has great dynamic range, lower distortion and smoother frequency response.
The PJB dual vent system is designed to handle extremely high air velocities without distortion. A hyperbolic vent aperture at both ends of the elliptical tubes allows the air to flow through smoothly with less air turbulence and noise. The result is cleaner sounding deep bass. The Cab 27’s frequency response is so smooth; it can easily double as a vocal monitor or as a music playback speaker.
Cabinet construction includes panels of plywood and medium density fiberboard providing it rigidity and less vibration, while making it lightweight. Other features include heavy duty vinyl/carpet covering, “kickproof” shock mounted steel grill, heavy duty recessed handle for easy carrying and rubber feet positioned to allow the cabinet to be used vertically or horizontally.
Though small by bass amp standards it is fully capable of handing 5 string bass fundamentals down to the low B string. The cabinet is precisely tuned using multiple loudspeaker analysis programs to reduce cone movement at the lowest frequencies, and to increase low frequency output. We employ a full size anechoic chamber for acoustic measurements and a laser scanning Doppler interferometer to analyze cone movement in 3D across the whole audio spectrum. PJB has put huge emphasis on research and development which is why no other small cabinets sound like a PJB.