This forum is as a good a place as any for thinking out loud about the successor to the Ariel and ME2's. Since my fall in the terrible Colorado snowstorms of January, I've been recovering, and probably won't be doing any serious audio design until the summertime.
But I can still think and write, and have been making occasional posts in John Atwood's Clarisonus blog. One perennial question I always get is how to build an Ariel with XYZ drivers (and of course a different crossover and cabinet). As mentioned in my Web page, it take me about six months to design a speaker, and isn't something I do on a whim, or something to "use up" some drivers that are lying around.
The Ariel is now about 12 years old, and my tastes have changed a bit in the meantime. No, I'm still not a fan of horns, even though the horns I've heard here in Colorado are some of the best I've ever heard anywhere. Fabulous micro and macro dynamics, but I still have reservations about tonality with classical music, especially the big-scale choral music I enjoy so much.
The speakers design I'm exploring these days are large-diaphragm dipoles - hearing both the Linkwitz Beethovens and the Bastani Apollo was a revelation about the dipole/open baffle sound. Interestingly, both the Linkwitz and Bastani designs get to similar place via completely different methods: Linkwitz with extensive equalization and multi-amping with high-power transistor amps, and the Bastani with extensively modified 12" near-full-range drivers, and a subwoofer and supertweeter to fill out the range.
Both the Linkwitz and Bastani have stunning dynamics - almost in horn territory without the colorations - and the spaciousness and 3-dimensionality of electrostatics. I can see why many Europeans are turning to open-baffle designs: they do things that never happen in conventional speaker boxes.
Of course, there's never a free lunch: dipole speakers have unique design challenges all their own. The most obvious is the tilted frequency response that starts a half-wavelength below baffle width. Linkwitz attacks this with multiple crossovers, multiple drivers, and complex low-level equalization, which straightens everything out again. Bastanis, by contrast, stretches a single 12" driver to its limits, and helps it out below 220 Hz and above 8 kHz with a subwoofer and tweeter.
What I'm contemplating is a bit of both and a little different: a prosound 12 or 15" coaxial driver, with efficiency of about 97 to 99 dB/metre, and a supplemental 12 or 15" driver that comes in below 160 to 250 Hz (switch-selectable to match room characteristics). The upper driver runs full-range, and is acceptable with any Qts. The lower driver has a Qts from a 0.6 to 0.8, and carries the bass in the region where the dipole 1/f effect starts to be significant. Below 80 Hz, bass is carried by stereo subwoofers in close proximity to the dipole array, and the subwoofers are independently powered by their own amplifiers.
The dipole array as I'm imagining it has either 2 or 3 drivers: one full-ranger, of very high quality, and one or two bass-fill drivers, with tapped air-core inductors adjusting the overlap region. Dipoles in particular need to compensated for room-response, due to their unusual radiation pattern, and the inability of the user to optimize imaging and distance from the wall/corner at the same time. By adjusting bass-fill driver overlap and subwoofer levels, the response in the 20 to 500 Hz region can be optimized for the room, without compromising image quality (which is controlled by the mid and HF response of the driver).
Yes, this is very different speaker than the Ariel, although I hope to retain the midrange spaciousness and natural voice quality in the new design, along with a 15 to 20 dB increase in dynamic range.
75For the current state of this project (known as the LTO) see here:
https://production.diyaudio.com/community/index.php?posts/3189501/
And here:
https://production.diyaudio.com/community/index.php?posts/3190604/
75
But I can still think and write, and have been making occasional posts in John Atwood's Clarisonus blog. One perennial question I always get is how to build an Ariel with XYZ drivers (and of course a different crossover and cabinet). As mentioned in my Web page, it take me about six months to design a speaker, and isn't something I do on a whim, or something to "use up" some drivers that are lying around.
The Ariel is now about 12 years old, and my tastes have changed a bit in the meantime. No, I'm still not a fan of horns, even though the horns I've heard here in Colorado are some of the best I've ever heard anywhere. Fabulous micro and macro dynamics, but I still have reservations about tonality with classical music, especially the big-scale choral music I enjoy so much.
The speakers design I'm exploring these days are large-diaphragm dipoles - hearing both the Linkwitz Beethovens and the Bastani Apollo was a revelation about the dipole/open baffle sound. Interestingly, both the Linkwitz and Bastani designs get to similar place via completely different methods: Linkwitz with extensive equalization and multi-amping with high-power transistor amps, and the Bastani with extensively modified 12" near-full-range drivers, and a subwoofer and supertweeter to fill out the range.
Both the Linkwitz and Bastani have stunning dynamics - almost in horn territory without the colorations - and the spaciousness and 3-dimensionality of electrostatics. I can see why many Europeans are turning to open-baffle designs: they do things that never happen in conventional speaker boxes.
Of course, there's never a free lunch: dipole speakers have unique design challenges all their own. The most obvious is the tilted frequency response that starts a half-wavelength below baffle width. Linkwitz attacks this with multiple crossovers, multiple drivers, and complex low-level equalization, which straightens everything out again. Bastanis, by contrast, stretches a single 12" driver to its limits, and helps it out below 220 Hz and above 8 kHz with a subwoofer and tweeter.
What I'm contemplating is a bit of both and a little different: a prosound 12 or 15" coaxial driver, with efficiency of about 97 to 99 dB/metre, and a supplemental 12 or 15" driver that comes in below 160 to 250 Hz (switch-selectable to match room characteristics). The upper driver runs full-range, and is acceptable with any Qts. The lower driver has a Qts from a 0.6 to 0.8, and carries the bass in the region where the dipole 1/f effect starts to be significant. Below 80 Hz, bass is carried by stereo subwoofers in close proximity to the dipole array, and the subwoofers are independently powered by their own amplifiers.
The dipole array as I'm imagining it has either 2 or 3 drivers: one full-ranger, of very high quality, and one or two bass-fill drivers, with tapped air-core inductors adjusting the overlap region. Dipoles in particular need to compensated for room-response, due to their unusual radiation pattern, and the inability of the user to optimize imaging and distance from the wall/corner at the same time. By adjusting bass-fill driver overlap and subwoofer levels, the response in the 20 to 500 Hz region can be optimized for the room, without compromising image quality (which is controlled by the mid and HF response of the driver).
Yes, this is very different speaker than the Ariel, although I hope to retain the midrange spaciousness and natural voice quality in the new design, along with a 15 to 20 dB increase in dynamic range.
75For the current state of this project (known as the LTO) see here:
https://production.diyaudio.com/community/index.php?posts/3189501/
And here:
https://production.diyaudio.com/community/index.php?posts/3190604/
75