Okay, guys, I'll answer each question one-by-one, in order of posting.
First, Clueless, the wing idea was kind of an adaptation of a dipole radiator design I saw years ago, except I didn't have to block the front wave from the rear. I simply used the 1/8 wavelenth Baffle Step calculation to arrive at 3'(125Hz). Going wider would not have gained me anything, since the vertical baffle was 6'(3'up and 3'down from center), and the 1/8 wave rule acts upon the shortest distance. The piano hinge to adjust them was also in that dipole design I saw.
The parallel non-inductive resistor idea is not mine either, but I used it on my Fostex single driver system to great effect, so I tried it with the Lowthers too. I turns out the the Lowthers have an even higher impedance peak (50 ohms)at the resonant freq than the Fostex. It is sort of like a Zobel without the cap. Without the cap, it acts on all spikes and dips in the entire range. Making the amp having an easier load and smoothing the response. I think this helped with the comb-filtering as well as the bottom end. The trick is to pick a value that will reduce the spike as much as possible, without dropping the nominal impedance more than you have to. I wound up using 24 ohms to give me a 6 ohm nominal.
I used the exact Lowther Club of Norway plan and added the wings later. If you want to duplicate these, email me.
Patrick, I am working on getting some digital pix. They look cool.
Sean, the wings at this time are just friction held by the hinges. I will try to add a bracket and see if that improves things or not. The wings are 6 ft x 1 ft of solid oak, so they are pretty heavy. I'll check it out.
I did all the mods you suggest on my fostex system, but not on the Lowther. The baskets are cast and damped already. The new whizzer cone does away with the "shout" already too. Lowther uses a proprietary cone treatment and advises against doping. Thanks much for your interest. Good luck on your future projects too.
Clueless, yes the EX3 is a more advanced unit. I think the "can" on the back really helped keep the mids out of the port. Also eliminated the chances of "smear" from reflections into the rear of the cone.
I'm so glad that you guys are so interested in my project. It really makes me feel good to share this with people who care about this sort of thing.
One more thing, these speakers look really good. The entire front, including wings, is made from solid red oak which I carefully sanded, stained, sealed, and lacquered in natural color. No tints or colored stains, just natural grain highlights. With the wings spread, they look sort of like wooden SoundLabs, since the wings angled slightly back give them a curved kind of appearance. Large, imposing, low WAF, and very upscale looking. Definitely the coolest system I've ever made, by far. The back parts are MDF, screwed and glued, and sprayed with automotive rubberized undercoating to damp the MDF resonances. It gives a nice textured look which is also functional. Drivers are wired with 26ga single conductor magnet wire. They look fairly professional for a non-cabinetmaker. Total cost was about $1300 for everything. Sound is more like $10000. I'm going back to play more records now. Thanks, guys.
First, Clueless, the wing idea was kind of an adaptation of a dipole radiator design I saw years ago, except I didn't have to block the front wave from the rear. I simply used the 1/8 wavelenth Baffle Step calculation to arrive at 3'(125Hz). Going wider would not have gained me anything, since the vertical baffle was 6'(3'up and 3'down from center), and the 1/8 wave rule acts upon the shortest distance. The piano hinge to adjust them was also in that dipole design I saw.
The parallel non-inductive resistor idea is not mine either, but I used it on my Fostex single driver system to great effect, so I tried it with the Lowthers too. I turns out the the Lowthers have an even higher impedance peak (50 ohms)at the resonant freq than the Fostex. It is sort of like a Zobel without the cap. Without the cap, it acts on all spikes and dips in the entire range. Making the amp having an easier load and smoothing the response. I think this helped with the comb-filtering as well as the bottom end. The trick is to pick a value that will reduce the spike as much as possible, without dropping the nominal impedance more than you have to. I wound up using 24 ohms to give me a 6 ohm nominal.
I used the exact Lowther Club of Norway plan and added the wings later. If you want to duplicate these, email me.
Patrick, I am working on getting some digital pix. They look cool.
Sean, the wings at this time are just friction held by the hinges. I will try to add a bracket and see if that improves things or not. The wings are 6 ft x 1 ft of solid oak, so they are pretty heavy. I'll check it out.
I did all the mods you suggest on my fostex system, but not on the Lowther. The baskets are cast and damped already. The new whizzer cone does away with the "shout" already too. Lowther uses a proprietary cone treatment and advises against doping. Thanks much for your interest. Good luck on your future projects too.
Clueless, yes the EX3 is a more advanced unit. I think the "can" on the back really helped keep the mids out of the port. Also eliminated the chances of "smear" from reflections into the rear of the cone.
I'm so glad that you guys are so interested in my project. It really makes me feel good to share this with people who care about this sort of thing.
One more thing, these speakers look really good. The entire front, including wings, is made from solid red oak which I carefully sanded, stained, sealed, and lacquered in natural color. No tints or colored stains, just natural grain highlights. With the wings spread, they look sort of like wooden SoundLabs, since the wings angled slightly back give them a curved kind of appearance. Large, imposing, low WAF, and very upscale looking. Definitely the coolest system I've ever made, by far. The back parts are MDF, screwed and glued, and sprayed with automotive rubberized undercoating to damp the MDF resonances. It gives a nice textured look which is also functional. Drivers are wired with 26ga single conductor magnet wire. They look fairly professional for a non-cabinetmaker. Total cost was about $1300 for everything. Sound is more like $10000. I'm going back to play more records now. Thanks, guys.