Test Bench: The Purifi Audio PTT8.0X04-NAB-02 8” Aluminum Cone Woofer

The PTT8.0X04-NAB-02 is the fifth Purifi woofer to be examined in Test Bench. The new 8" aluminum cone woofer includes the same constant Sd surround, cone edge stiffening ring, and low magnetic hysteresis motor design as previous models. The addition of the unique Purifi NBR surround, make the PTT8.0X04 like no other in the history of woofer development. The PTT8.0X04e is rated for 350W IEC268 long-term power handling, and a 9.3mm Xmax.

The Purifi Audio PTT6.5X04-NFA-01 midbass transducer is an over-achiever, and to help understand why, Dickason talks with Lars Risbo about the research and thought process that lead to many of the features found in this woofer. Including the unique cone assembly that consists of a mildly curvilinear paper cone made with a proprietary fiber mix, a 3.13” concave dust cap, and a V-shaped edge reinforcing ring, the NBR surround, and what Dickason calls "probably the most unique surround in the history of Voice Coil’s Test Bench. This article was published in Voice Coil July 2021.

In this article, Vance Dickason characterizes the Bold North Audio BWX-6502 Midbass, which comes from a series of exciting new drivers designed and manufactured in the US by MISCO (Minneapolis Speaker Company). The BWX-6502 is built on the same platform with a similar XBL2 "dual-gap" motor design structure to the BWX-6501 model but with a cone assembly consisting of an Abaca fiber (paper) cone and a 60mm (2.4") diameter Abaca fiber dust cap, with compliance provided by a wide high excursion NBR surround, and a 3.5" diameter flat cotton spider (damper). This article was originally published in Voice Coil, January 2021.

This Test Bench characterizes the very recent BWX-6501 Midbass driver from MISCO’s Bold North Audio Line. MISCO (Minneapolis Speaker Co.) is the oldest OEM driver manufacturer in the US, founded in 1949, and Bold North Audio is its new brand, launched in 2019. The Bold North lineup was recently expanded to include two new 6.5” XBL2 motor woofers. These new models, all designed and manufactured in MISCO’s own facility in St. Paul, Minnesota, feature dual inside-outside copper shorting rings in the motor to greatly reduce distortion. This article was originally published in Voice Coil, December 2020.

In this Test Bench I characterized the 12BG76-8, a high power handling 12” NBR pro sound woofer from B&C Speakers. This month’s sample submission is in the upper range of power handling in this extensive group with a continuous power handling rating of 1000 W (500 W nominal). Applications range from two and three-way PA speakers and compact two-way designs for high SPL in limited spaces. Features for the 12BG76-8 are similar to most high-performance pro sound drivers, fairly substantial. This article was originally published in Voice Coil, October 2018.

This month, I characterized the SW275BD01, a 10.75" high-end home audio subwoofer from OEM manufacturer Wavecor. This driver has a well-appointed feature set that includes a proprietary cast eight-spoke (four twin spokes) cast aluminum frame, a very stiff black mica/paper composite cone, further stiffened by a 4" convex black hard paper dust cap. Suspension is provided by a FEA optimized low-loss (high Qm) NBR surround plus dual 6” diameter black flat conex spiders (dampers). This article was originally published in Voice Coil, October 2018.