Test Bench: Stereo Integrity’s TM65 mkIV High-Performance 6.5” Woofer

This Test Bench addresses the Stereo Integrity TM65 mkIV High-Performance 6.5” woofer. Stereo Integrity is an interesting new company that is aiming at both home audio and automotive/mobility applications. Features for the unique TM65 mkIV include a black anodized aluminum cone and black anodized dust cap. Suspension is provided by a tall NBR surround plus a flat 105mm diameter Nomex spider with a linear roll configuration. Total depth of this driver with its proprietary frame and motor structure is a mere 58mm (2.28”).

Dayton Audio’s SIG180-4 is part of a woofer series with five cost-effective, high-performance models, ranging from 4” to 10”. All drivers include single-piece concave aluminum cones, polyimide vented voice coil formers, open cast-aluminum frames, plus indexed shallow transition NBR surrounds. Rated for 80W RMS power handling capacity, the SIG180-4 woofer features a FEA-optimized ferrite motor design and a 1.25” voice coil wound with round copper wire.

This article compares motion feedback technologies applied to speakers. A recognized expert in this field, Reinhold Lutz explores how to achieve a nearly perfect electro-acoustic transfer function, including a detailed control strategy of different types of sensors. A great exploration of how a closed-loop feedback system is able to improve loudspeaker linearity.

This article revisits 20 years of Room EQ Wizard (REW), one of the mainstays in the audio measurement tool landscape with a strong user base. What started out as a side project for John Mulcahy, the creator and only developer, evolved to become a very complete and useful suite for both enthusiasts and professionals - a comprehensive set of measurement software tools bundled in a free package. This entertaining history of REW is also a fit way to commemorate the software's 20th anniversary.

The latest version of Listen's flagship audio test software, SoundCheck 21, allowed audioXpress to review also the latest Listen AmpConnect 621 USB-controlled multichannel audio test interface. The innovative algorithms and increased measurement capabilities of this powerful and flexible software, together with the AmpConnect 621 analyzer, combines all the functionality required for audio testing in the lab bench or in the production line. This article was originally published in audioXpress, March 2024.

Voice Coil March 2024 focuses on speaker enclosures with a unique directory of innovative material ideas, followed by an always insightful patent review, where James Croft revisits the pivotal Dinaburg invention. For Test Bench, this month Vance Dickason characterizes the SIG180-4 6.5” woofer from Dayton Audio’s Signature Series, and a midbass shallow-profile 6.5” driver, the Stereo Integrity TM65 mkIV.

The March 2024 issue of audioXpress includes an overview of the latest Audio Test and Measurement solutions, a review of the Listen SoundCheck 21 and AmpConnect 621 test suite, and a tribute to 20 years of Room EQ Wizard (REW). Learn how to build a True-RMS Voltmeter and what's behind the myth of Second Harmonic Distortion. Learn how motion feedback technologies can be applied to speakers, and how our hearing process affects our audio listening experiences, and much more. Dive in now!