Danny Richie of GR Research describes and explains how he designs loudspeakers.

Agreed @grannyring. That's Danny's greatest field of expertise, and the most overlooked and undervalued in loudspeaker design (Richard Vandersteen and Siegfried Linkwitz being notable exceptions).

For those not wanting to watch the entire video, at least skip ahead to the end, where Danny will give you a free education in basic crossover design.

Thx for sharing !
i am in process of designing a tapered vented box and low pass for a TAD TL-1603 driver… always good to hear others perspectives / process and importantly priorities 

And yes, there is a LOT more to filter design than catalog shopping for boutique caps, etc…

@tomic601: The following may be of interest to you Jim, as it came from Roger Modjeski. I gave him a call, knowing that he used subs with his QUAD ESLs.

Danny Richie always talks about designing crossovers for specific drivers, using the x/o to mitigate the performance limitations of the drivers. In my conversation with Roger, he stated the QUAD panels have a resonant frequency in the upper end of double digit frequencies. He therefore used a crossover frequency of 100Hz, 4th-order (24dB/octave), for both high and low pass.

The Rythmik plate amp includes a 24dB/octave x/o slope, from 25Hz up to 120Hz. And with the plate amps supplied with the OB/Dipole woofer kit, the sub may be used up to an incredible 300Hz, so can be used in place of the stock woofer in the Eminent Technology LFT-8b (which crosses from it’s magnetic-planar driver to a sealed-enclosure 8" woofer at 180Hz), a killer combo. The OB/Dipole Sub is also perfect for use with any and all Maggies, and dipole-planars in general.

For years I used a KEF B139 woofer in a transmissionline loaded enclosure with my QUADS, but the Rythmik/GR Research OB/Dipole Woofer is a whole ’nother ballgame. Like Eminent Technology, Modjeski employed a sealed 8" woofer with his QUADS. Me, I want that bottom octave.