Test Bench: Purifi Audio’s PTT4.0X04-NFA-01 Home Audio 4" Midbass.

This Test Bench addresses Purifi Audio’s PTT4.0X04-NFA-01 4” midbass, which is very similar to the PTT6.5X reviewed in Voice Coil July 2021, and includes the same constant Sd surround and low magnetic hysteresis motor design. The distinct cone assembly for this driver consists of a flat profile paper cone made with a proprietary fiber mix, a concave dust cap that covers about 90% of the cone surface, plus the addition of a V-shaped edge reinforcing ring glued around the outside rim of the back side of the cone. Compliance is provided by a unique NBR surround, which as in the PTT6.5X surround, deserves to be explored, motivating Vance to discuss it with Purifi’s co-founder Lars Risbo.

A new Danish audio company, founded by Bruno Putzeys, Lars Risbo, and Peter Lyngdorf was recently announced. The name is Purifi Audio, and as you can guess from the founders involved, the venture promises Class D amplifiers with record-breaking performance "unmatched by amplifiers of any operating class." But the new company will be doing more than amplifiers, since it also revealed a new 6.5" woofer with "magnitudes lower intermodulation distortion across frequency and SPL."