Great post @phillb!
The significance of your point about Clayton using drivers designed and built specifically for OB use cannot be overstated. All professional loudspeaker designers/builders know the importance of that, and proceed accordingly. I’m sure there are some DIYers who have used inappropriate drivers (those designed for use in enclosures), but we’re not taking about them.
Danny Richie of course also uses drivers made to his specs, drivers made with electrical and acoustic properties tailored specifically for OB use. These include his woofers, tweeters, and NEO3 magnetic-planar tweeter. One difference between the designs of Danny and Clayton is Danny’s use of a minimum-width front baffle, partnered with the use of side "wings" to increase the front-to-back driver separation the large baffles used by Clayton inherently provide. In spite of their different approaches, Clayton’s design talent and resulting OB loudspeakers have received high praise from Danny.
Also good is your mention of subs not blending well with OB’s. Planar loudspeaker lovers have for decades dealt with that reality. No matter how good the box sub was, it sounded "separate" from the planar loudspeaker. In the 1960’s the 24" Hartley was used by many QUAD ESL users, Mark Levinson using it in his HQD (Hartley sub, double QUAD ESL’s, Decca Ribbon Tweeter) loudspeaker. Infinity used servo-feedback sealed-enclosure subs with their IRS and RS-1b speakers, and many other attempts could be cited.
There are numerous reasons for the difficulty of achieving the desired blending---which I won’t go into here, except in one regard:
In the 1980’s, Finnish company Gradient introduced an OB/dipole sub designed and built specifically for the QUAD 63. They followed it up with an OB/dipole for the ESL (aka 57). Though compromised by sub-par design, build, and maximum SPL, it showed the way. OB sub design flourished amongst DIY loudspeaker designers/builders, including a very young Danny Richie.
Meanwhile, Harry Pearson at TAS had come up with the idea of replacing the sub towers of the Infinity IRS with the bass panels of the Magneplanar Tympani loudspeakers, two 16" X 72" panels per side. Mated with the m/t panels of the IRS (which housed line-source arrays of EMIM and EMIT planar drivers), the sound produced was the finest many people have ever heard---to this day. Finally: full-range (except for the bottom half-octave: below 30Hz) reproduction, completely planar. Unfortunately, the resulting combo required a LOT of floor space, so was impractical for most.
Along comes Danny Richie. His GR Research company was started to sell loudspeaker kits to the DIY community, with an emphasis on OB design. GR Research was offering a number of OB loudspeaker kits, along with a sealed sub. Though very much liking OB bass, he resigned himself to the fact that it’s limitations presented a challenge he was unable to resolve to his satisfaction.
But then Danny heard about a company introducing a new (patented) servo-feedback woofer (Rythmik), which just happened to also be in the State of Texas (in Austin). Danny proposed to Rythmik designer/owner Brian Ding his idea of mating Brian’s servo-feedback woofer/amplifier with a woofer designed by Danny for OB use, a pair of the servo-feedback woofers installed in an OB/dipole frame.
As I’m sure you know (or have guessed), the product came to market. If you have heard the bass produced by the Magneplanar Tympani loudspeaker, you already know what to expect from the GR Research OB/Dipole Sub, but without the latter’s missing bottom half-octave (and massive power amp requirements!). For any OB or planar loudspeaker owner who wants not just more bass, but bass that sounds like it’s being produced by their loudspeaker, it is now available.
The significance of your point about Clayton using drivers designed and built specifically for OB use cannot be overstated. All professional loudspeaker designers/builders know the importance of that, and proceed accordingly. I’m sure there are some DIYers who have used inappropriate drivers (those designed for use in enclosures), but we’re not taking about them.
Danny Richie of course also uses drivers made to his specs, drivers made with electrical and acoustic properties tailored specifically for OB use. These include his woofers, tweeters, and NEO3 magnetic-planar tweeter. One difference between the designs of Danny and Clayton is Danny’s use of a minimum-width front baffle, partnered with the use of side "wings" to increase the front-to-back driver separation the large baffles used by Clayton inherently provide. In spite of their different approaches, Clayton’s design talent and resulting OB loudspeakers have received high praise from Danny.
Also good is your mention of subs not blending well with OB’s. Planar loudspeaker lovers have for decades dealt with that reality. No matter how good the box sub was, it sounded "separate" from the planar loudspeaker. In the 1960’s the 24" Hartley was used by many QUAD ESL users, Mark Levinson using it in his HQD (Hartley sub, double QUAD ESL’s, Decca Ribbon Tweeter) loudspeaker. Infinity used servo-feedback sealed-enclosure subs with their IRS and RS-1b speakers, and many other attempts could be cited.
There are numerous reasons for the difficulty of achieving the desired blending---which I won’t go into here, except in one regard:
In the 1980’s, Finnish company Gradient introduced an OB/dipole sub designed and built specifically for the QUAD 63. They followed it up with an OB/dipole for the ESL (aka 57). Though compromised by sub-par design, build, and maximum SPL, it showed the way. OB sub design flourished amongst DIY loudspeaker designers/builders, including a very young Danny Richie.
Meanwhile, Harry Pearson at TAS had come up with the idea of replacing the sub towers of the Infinity IRS with the bass panels of the Magneplanar Tympani loudspeakers, two 16" X 72" panels per side. Mated with the m/t panels of the IRS (which housed line-source arrays of EMIM and EMIT planar drivers), the sound produced was the finest many people have ever heard---to this day. Finally: full-range (except for the bottom half-octave: below 30Hz) reproduction, completely planar. Unfortunately, the resulting combo required a LOT of floor space, so was impractical for most.
Along comes Danny Richie. His GR Research company was started to sell loudspeaker kits to the DIY community, with an emphasis on OB design. GR Research was offering a number of OB loudspeaker kits, along with a sealed sub. Though very much liking OB bass, he resigned himself to the fact that it’s limitations presented a challenge he was unable to resolve to his satisfaction.
But then Danny heard about a company introducing a new (patented) servo-feedback woofer (Rythmik), which just happened to also be in the State of Texas (in Austin). Danny proposed to Rythmik designer/owner Brian Ding his idea of mating Brian’s servo-feedback woofer/amplifier with a woofer designed by Danny for OB use, a pair of the servo-feedback woofers installed in an OB/dipole frame.
As I’m sure you know (or have guessed), the product came to market. If you have heard the bass produced by the Magneplanar Tympani loudspeaker, you already know what to expect from the GR Research OB/Dipole Sub, but without the latter’s missing bottom half-octave (and massive power amp requirements!). For any OB or planar loudspeaker owner who wants not just more bass, but bass that sounds like it’s being produced by their loudspeaker, it is now available.