Thiel Audio
An American high-end speaker manufacturer founded in 1976. Through founder Jim Thiel's phase-coherent design philosophy, they developed unique speakers characterized by first-order crossovers and aluminum drivers. They created masterpieces like the CS2.4 and CS3.7, but after the founder's death in 2009, they went astray and went bankrupt in 2018. They have currently stopped new production. While technically excellent with rational design philosophy, they had fatal problems with corporate continuity.
Overview
Founded in 1976 by university friends Jim Thiel, Tom Thiel, and Kathy Gornik who borrowed USD 25,000, this American high-end speaker manufacturer started in a garage in Lexington, Kentucky, and later built their own 35,000 square foot factory, exporting products to over 30 countries. Through the Coherent Source technology developed by founder Jim Thiel, they maintained a unique design philosophy that emphasized phase coherence and time coherence.
They debuted with the CS01 in 1977 and created masterpieces like the CS2.4 and CS3.7, but after Jim Thiel’s death in 2009, they were sold to investor David Griffin in 2012 and moved to Nashville. Five CEOs changed hands in five years, continuing to drift by releasing products that abandoned Jim Thiel’s design philosophy, leading to bankruptcy and liquidation in 2018. They have currently stopped new production and no longer exist as a company.
Scientific Validity
\[\Large \text{0.7}\]Thiel’s phase-coherent design is clearly supported by measurement data. The CS2.4 achieved excellent frequency characteristics of 36Hz-25kHz ±2dB, and the CS3.7 achieved 33Hz-26kHz ±2dB. In THD measurements, the CS2.4 recorded very low distortion at 1kHz/100dB, and the CS3.7 recorded approximately 0.25% THD+N at 1kHz and 10kHz. Time-axis alignment through first-order crossovers is theoretically correct and confirmed by measurements. However, there are also practical constraints such as the resonance characteristics of aluminum drivers and the difficulty of driving due to the 4Ω design.
Technology Level
\[\Large \text{0.8}\]The technological capability of using aluminum drivers across all frequency ranges and achieving phase-coherent design through first-order crossovers was industry-leading. The CS3.7’s combination of a coaxially arranged 25mm aluminum dome tweeter, 114mm flat aluminum midrange, and 254mm flat aluminum woofer achieved acoustic characteristics close to a single point source. The bass extension through passive radiators was also cleverly designed. The low distortion characteristics particularly evident in measurement data tell the story of the design’s high level of completion. However, the basic design did not change significantly from the 1970s, and the introduction of DSP and active technologies was delayed.
Cost-Performance
\[\Large \text{0.2}\]For products with 36Hz-25kHz characteristics equivalent to the CS2.4 (used USD 2,200), the KEF Q350 (USD 600) can be cited. CP = USD 600 ÷ USD 2,200 = 0.27. For products with 33Hz-26kHz characteristics equivalent to the CS3.7 (used USD 5,500), the KEF R3 (USD 1,200) exists. CP = USD 1,200 ÷ USD 5,500 = 0.22. While phase-coherent design and aluminum driver technology are excellent, new purchases are impossible due to corporate bankruptcy, and in terms of pure measurement performance, there is approximately a 3-5 times price difference.
Reliability & Support
\[\Large \text{0.0}\]Due to bankruptcy in 2018, they no longer exist as a company, so official support has completely ended. Sales revenue became USD 154,884 in 2017 and USD 0 in 2018, and they were liquidated with assets of USD 900,000 against debts of USD 1,800,000. Currently, Coherent Source Service, operated by former employee Rob Gillum, was providing service for Jim Thiel-designed products from before 2012, but after Gillum’s retirement, it was taken over by Gary Dayton. However, this is only unofficial support, and reliability as a company has been completely lost.
Rationality of Design Philosophy
\[\Large \text{1.0}\]Jim Thiel’s theory that “phase coherence and time coherence are the most important elements in acoustic reproduction” was extremely rational from an acoustic engineering perspective. All design decisions had clear theoretical foundations: phase alignment through first-order crossovers, consistent acoustic characteristics through aluminum drivers, and achieving single point sources through coaxial arrangement. The technical approach to achieving “rich, lustrous bass” and “unified sound” was ideal from a pure acoustics standpoint. No unscientific elements were included, and the attitude of emphasizing both measurement data and listening experience can be highly evaluated.
Advice
Thiel Audio went bankrupt in 2018 and is currently not producing new products, so new purchases are impossible. They remain popular in the used market, with masterpieces like the CS2.4 and CS3.7 still trading at high prices. They are technically excellent, and the unique acoustic characteristics of phase-coherent design provide experiences that cannot be obtained elsewhere. However, since official support has ended, repairs in case of failure will depend on limited services. If you prioritize pure sound quality and are willing to accept the risks, we recommend choosing later, highly refined models like the CS2.4 or CS3.7. As a corporate lesson, this also shows an example that excellent technology alone does not guarantee business continuity.
(2025.07.05)