The IB4 Bass Reflex Alignment

Before computers were broadly available for loudspeaker bass reflex box simulations, engineers relied on "Alignments" for their designs. Such box alignments are typically named after equivalent filter functions that the high-pass response of the box was aligned after — for example, Butterworth (B4) and Bessel (BL4) — to name a few. This article, the third in this series, explores the rarely talked about Inter-Order Butterworth (IB4) alignment, mentioned originally by Richard Small and Neville Thiele.

In this July 2024 issue of Voice Coil, Vance Dickason introduces a new article series about Outboard DSP, Mike Klasco explores Diamond Coatings for Speakers, there is an updated directory of Adhesives, Coatings, Sealants, High-Tech Thin Films, Converters, and Dispensing Equipment vendors, and Claus Futtrup writes about the IB4 Bass Reflex Alignment. Vance Dickason’s Test Bench characterizes the new Scan-Speak 15W/8534T00 5.5” woofer, and D3404/606200 Metamodal TPCD tweeter.