Whiseworks - NTM™ filter technology

What are WHISEWORKS - NTM™* filters all about?

A WHISEWORKS - NTM™* Crossover Filter is a new type of electrical/acoustical filter offering significant performance advantages over all previous crossover filter types in audio applications. The filter was developed by Neville Thiele (pronounced "Teel").

How does it work?

The WHISEWORKS - NTM™* crossover uses a unique notched response to achieve a very steep roll-off rate outside the pass-band.
The 4th order WHISEWORKS - NTM™ crossover amplitude response looks like this:

*WHISEWORKS - NTM™* and WHISEWORKS - Neville Thiele Method™ are trademarks of Precision Audio Pty.Ltd

You will see that notches in the responses speed-up the rate of roll-off. Beyond the notch, the response rises again, but remains respectably attenuated.


Like the Linkwitz-Riley crossover shape, WHISEWORKS - NTM™ crossovers maintain a flat amplitude response against frequency, and hold the drivers in-phase throughout the crossover region, preventing beam tilting. Additionally however, the 8th order WHISEWORKS - NTM™ filter gives the fastest roll-off rate of any of the common crossover shapes. The 4th order WHISEWORKS - NTM™ filter also offers the best group delay flatness of any crossover shape with a roll-off of at least 24dB/Octave, whilst offering a higher cut-off rate than any other 4th order crossover.

For many years, Linkwitz-Riley crossovers have been the 'industry standard' as they offered the best compromise for most of the important parameters.

The new WHISEWORKS - NTM™ crossover shapes now represent the optimal combination of characteristics for most applications, assuring it at least a place alongside Linkwitz Riley, if not becoming the new industry standard.

Also, take a look at the whitepaper.