I have been experimenting with these new LGK drivers. I have four of them in a series/parallel configuration on an open baffle with a Neo 3 pdr.
Making all of this work is very tricky. The Neo 3 becomes a completely different tweeter in an open baffle. It is one of the most transparent, and highly detailed, yet one of the most relaxed tweeters I have ever heard. However, making it work in an open baffle is very tricky. It really has to have a 3/4" deep wave guide. Side panels and any effect to the back wave also effects the front sides output. Several tests involving different types of wave guides and mounting were disastrous. But as tested right now this design gives the tweeter a beautiful response and lifts the lower range enough to hit a 97db average.
Another cool thing about the 3/4" thick wave guide is that it is cut right into the baffle that the LGK's are mounted in. This time aligns it to the voice coils of the LGK's. This is very important for open baffle designs as they stay aligned in both directions (front to back).
Running the LGK's in an open baffle is pretty tricky too. A wide baffle is the enemy. It causes a lot of surface reflections that really hurts the imaging. However the woofers need a wide baffle to separate the front and back waves and allow them to play down lower. The trick is to run a wing down one side that is pretty deep and a very short one on the other side. And the very short one (1.25" deep) is critical to the response. But the tweeter hated the short wing. With the short wing in place there is a cavity resonance at 3kHz that causes a 3db dip. So the short wing is split to not enclose the tweeter. The split short wing worked great.
Check out the pics of this test mule.
Thank you Jon Parkhurst for the test baffle.
And check out this response curve that these things make. This is a measured response of the tweeter and the LGK's individually with no crossover on them.
As a side note take a look at the response of the LGK (full range) drivers. These play to above 20kHz by themselves, but check out the comb filtering effects of playing them all together. They take a nose dive above 4kHz. I know lots of guys think they can run a line of full range drivers full range like that, and then they wonder why they have no highs. They cancel each other out in the upper ranges.
I designed a network for them that was very simplistic. I got a really smooth response. I then played them with a trio of our 12" servo subs in an open baffle. I just happen to have some of those hanging around.
The sound quality from this little combo is one of the best sounding speakers I have ever tested. Mid-range is incredible. And from 200Hz and up just crazy good across the board. I think the only speakers I'd put ahead of it would be the Super-7's from Serenity Acoustics and the LSX open baffle line sources that I designed for Mockingbird Audio. These things are that good. And a little over 95db sensitivity.
Now here is where I am looking for a little feedback... What to do from 200Hz and down?
I could series/parallel 16 of the LGK's into an array and let them really handle from about 200 or 250Hz down to 100Hz or so. This would make a very thin (4.5" wide at the front) tower with 8 above and 8 below the MMTMM, and all in an open baffle. That will make the lower ranges super tight and fast, and play down low enough to reach open baffle subs in separate towers.
The kit cost would really start getting up there, but what an incredible set of speakers....
I thought about just using our 8" servo subs under them, but I am having a tough time figuring out how to incorporate them. At a 200Hz crossover point they would have to be kept very close to the upper MMTMM. But the baffle size and shape of the MMTMM can't change. It has to be the shape that it is right now. So it is not easy to incorporate it to a wide stack of 8" woofers....
I also thought about just using 9 of the LGK's below the MMTMM, but I am not sure I can get that sensitivity up to the 95db range in those lower regions.