Diagnosing Design Issues Using the Klippel Distortion Analyzer

The founder and principal of Redrock Acoustics, renowned for offering engineering and design services, Patrick Turnmire has tested thousands of driver samples during his career, including countless for Voice Coil's Test Bench. Having recently reopened access to its Klippel testing and transducer analysis services, Turnmire shares his vast experience, advising on how to make sure the tests are robust enough to clearly see the loudspeaker performance.

In the first issue of Voice Coil for 2024, Patrick Turnmire writes about "Diagnosing Speaker Design Issues Using the Klippel Distortion Analyzer." James Croft reviews a Devialet patent. And in Test Bench, Vance Dickason characterizes the new DE350-8 Ultra-Compact 1" Compression Driver from B&C Speakers, and the new LM10n Wide Band Ribbon Transducer from Radian Audio Engineering. This issue also features an updated directory of 2024 Earphone and Headphone Manufacturers and Parts Suppliers.

Redrock Acoustics, the company founded by Patrick Turnmire, announced the launch of a new website that also signals the return of the company to offering loudspeaker testing services. Renowned for offering engineering and design services, Redrock Acoustics is again opening access to services that include Klippel testing and transducer analysis. Visitors to the new website will find information about all services, and the SpeaD transducer development software, as well as other design tools.

This Test Bench explication focuses on the Dayton Audio Epique MMAG E150HE-44 "full-range subwoofer," in itself an interesting concept. Like its larger E180HE-44 brother in the Epique line, the E150HE-44 is based on the patented Multiple Magnet Air Gap (MMAG) technology invented by Enrique Stiles. The two new Dayton Audio Epique MMAG woofers were designed with direct support by Enrique as an independent transducer engineering consultant, working in conjunction with the engineering team at Dayton Audio. This article was originally published in Voice Coil, December 2021.

This review discusses a patent that applies to speakers designed for new immersive audio formats in home applications and Dolby Atmos, in particular. Not surprisingly, the patent was awarded to Dolby Laboratories Licensing Corp. As the patent was granted, Voice Coil provided an extensive and informative review - recommended reading for anyone considering entering this important home-theater market segment. This article was originally published in Voice Coil, February 2016.

The driver for this month’s Test Bench explication comes from the UK. Volt sent the 12” RV3143 Studio Monitor woofer, which is probably the most uniquely designed woofer to come across my desk in a while — there is no frame on the back side of the driver! The Volt Radial Technology consists of a front-mounted eight-spoke proprietary cast aluminum frame that is mechanically coupled to both the back plate and to the top of the pole structure/phase plug, in contrast to a normal rear frame that is only coupled to the motor front plate. This article was originally published in Voice Coil, December 2017.

This interview was published in Voice Coil August 2013. Nearly 10 years since Patrick Turnmire, of Redrock Acoustics, had started providing Voice Coil with valuable Klippel data for Vance Dickason’s the Test Bench column. In this interview Patrick Turnmire explains his work with his company, Redrock Acoustics.

The amount of flux running through the pole in a conventional “Hamburger” motor structure is a key loudspeaker design element that is often a limiting factor in the design process. PoleSolver is a design tool from Redrock Acoustics that makes all the different calculations quick and easy. An article originally published by Voice Coil, August 2010.