Lowther Voigt Pipes are up and running


First, the Lowther people sent me a pair of EX3's instead of DX3's. The mistake turned out to be a great match for my Voigt Pipes! For some reason, I did not have any severe comb-filtering problems with this cabinet. But, I did have Baffle Step drop-off that was weakening the bass response and lower midrange. The 12" baffle was losing wave reinforcement at about 360Hz. So I experimented with adding some 12" styrofoam "boards" on both sides of the Pipes. Huge difference! Once I verified the baffle reinforcement that I had calculated, I then bought 12" wide oak panels the full 6' height of the speakers and added them to both sides of the pipes with piano hinges, so I could tune the "wings" by moving them back on various angles to keep the bass, and get them out of the diffraction plane as much as possible. It works great! It turns out that a few degrees backward angle on each "wing" does exactly what I wanted. The imaging stays tight and the bass is really powerful. Baffle step is compensated down to about 125Hz and the port picks up well from there down. the "wings" also provide a 3db boost of the port output so I think I am getting below 40Hz. I've heard people say these Lowther Voigt Pipes don't have much bass. With these baffle "wings" they have killer bass that is tight and deep and powerful. No noticeable holes or dips even when listening to "walking bass". I am extremely happy with the results of this project. I think that this is the key to the Voigt Pipe dilemma. I also added the parallel non-inductive resistors of 24 ohms across the terminals to reduce the impedance spike at the resonant frequency. This lowers the effective bottom end, and I think it helped to wipe out the comb-filter effects too. Comb filtering is the result of impedance/phase changes in the drivers and the pipes at odd-order harmonic points in the bass/midbass. They combine at these points to create nulls or dips at these freq's. I think that the parallel resistors reduced these impedance dips in the drivers, and hence the pipes. A smoothing effect. Seems to work, anyway. Of course, the Lowther drivers are super, super great sounding. You just can't believe how much I am shaking this 24 foot room with one watt out of my MicroZotl! I think overall, I increased the in-cabinet efficiency of the system by 3db with this "wing" mod. That would put this system at 103db with one watt input. It seems to be quite flat in response curve by listening, with some expected room modes reinforcing the bass a little bit. No noticeable "shelving" of certain freq. ranges. Great high end extension, extremely natural tone quality, dynamics to die for, and detail very much like e-stats. Solid images and good, deep, wide soundstage. I am grinning from ear to ear! I've been playing records 11 hours today. This is absolutely too much fun! I can finally get full orchestra sound without the compression that I had on my fostex system. Wait until these Lowthers get broken-in! They are already fantastic! The new Lowther mods definitely work to remove the "shout" that the older models had. No irritating "shout" in the midrange at all. I highly recommend this project to anyone. This is one killer speaker set-up! Questions or comments?
twl
Albert, believe it or not, I thought about renting a van and driving down to your place to see how you like these. I know they would sound terrific on your system. But, you would have to only just barely crack open the volume control on your system to get these babies singing. I can't really bring them down there, but I'd love to. I'm sure we'd have a fun time. BTW, these speakers are BIG. With the wings out, they stand 6 feet tall and 3 feet wide. They're solid 3/4" oak. But, with the wings on the piano hinges, they can fold back against the center section when not playing, so they can be just over a foot wide when folded. Then they just look like 6' towers. Pretty cool. Baffle compensation can be adjusted to needs of the room, if someone has a peaky room. Just by different angles of the wings. If you decide to ever try the low-power/high efficiency game, I'll work with you on some designs, if you'd like. Who knows? Maybe next year, I'll come up with some ideas to improve back-horns and have to build a pair of them.
Where did you get the wing idea Twl? Love to see a picture. Are the p/resisters recommended with the driver/enclosure literature or did you come up with it?

You probably talked about this but did you modify the Club of Norway design in any way? What was material.

If you already typed this all out just point out the thread.

I was looking at doing a Fostex/Voight design but now I think I might do a monkey see monkey do on yours. You're an inspiration!

We might want to go e-mail on some of this if you don't mind.

Thanks
I remain,