[Danny Richie]

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.

Anyway...

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. 

Interest?

[Tyson]

What about just making the woofers side firing?  Mount them in the long wing.

[Folsom]

Yes.

Make the subwoofers fire out (left and right), and titled up. Best sound? Well I always prefer them aiming out. Aiming up a little seems to work really well and stop the bass from annoying the ever-loving-hell out of everything/everyone else nearby. For size you could mount drones on the opposite side of them, if they're in a box. That or aim the port the same as the sub. Whether or not you get issues that bass traps can be used for, etc, it seemed to pale to the good imaging and room cohesion of resonance that I would get with subs firing that direction. I didn't seem to lose any frequencies like with forward firing. Back firing was awful.

That's my inclination, but you're way more educated than I on this...

It'd be nice to get the LGK's down to 150hz.... I've found that works pretty good for crossover point, so long as it's stereo subwoofers. The imaging of that range seemed to remain intact. I dunno about 200hz, you tell me 

[Tyson]

I think the only problem with mounting the subs OB is that they cancel out going forward.  Maybe mounting below the other drivers, facing forward, but oriented side by side instead of on top of each other.  This would give you a wider base and make the speaker heavier toward the bottom, which is probably a good thing in an OB with lopsided rear wings.  3 of the 8" OB woofers firing forward, and acting as a base for the speaker would look pretty cool too, IMO - like a giant, upside down T.

[Danny Richie]

What about just making the woofers side firing?  Mount them in the long wing.

Only if they're sealed.

[Danny Richie]

It'd be nice to get the LGK's down to 150hz.... I've found that works pretty good for crossover point, so long as it's stereo subwoofers. The imaging of that range seemed to remain intact. I dunno about 200hz, you tell me 

With a line of them in an open baffle I should be able to get them down to the 100Hz range. The short wing might have to get deeper towards the ends though. So a deeper wing on the top and bottom, only 1.25" deep around the mids and not there for the tweeter.

I'd brace it well from side to side and it would be a thin little wedge.

A line of them in an array would be the ultimate. I just wonder if it would get too expensive for most to even consider.

[nickd]

Danny, can you give us a rough number on the "Line" kit cost? That sounds like it may be the ticket.

Ebag and I have been chatting about similar build using Neo 10's and a Neo 3 in open baffle. The wing and 200-300 hz bass crossover and complicated baffle shape do pose some new "opportunities". Is it possible to use a quad of M165NQ woofers to give it some bass?

[Danny Richie]

Danny, can you give us a rough number on the "Line" kit cost? That sounds like it may be the ticket.

Ebag and I have been chatting about similar build using Neo 10's and a Neo 3 in open baffle. The wing and 200-300 hz bass crossover and complicated baffle shape do pose some new "opportunities". Is it possible to use a quad of M165NQ woofers to give it some bass?

The only way for the Neo 10's and Neo 3 to work is to do what I did for the Super-7. The baffle design is critical to those drivers working.

The M165NQ drivers are awesome, but 4 of the 8 ohm version in a series/parallel will only reach 91db.

Cost breakdown of the arrays I proposed:

2) Neo 3 pdr's $174
40) LGK's $1,360
Crossover parts, wire, etc, estimated $300

Options for the lower end....

4) SW-12-16FR woofers (2 per side) $716
6) SW-12-16FR woofers (3 per side) $1,074
2) A370PEQ servo amps $758

[jparkhur]

Also, when looking at cost, there is no huge box to build. One sheet of Mdf or good maple ply something and you have the enclosure.  If you diy, it's time consuming, and if you shop it around you will add to your total.  For as little as 2k you could have something more valued at 7 k or 8 k. There are those if us who can build it and those who have it built. To each his own, but look at what you get in value and more importantly performance.  Wow the curve is flat like my belly used to be!  ( Baltic only comes in 5 foot sheets )

P

[Tyson]

Any reason not to do 2 or 3 of the 8 inch OB servo woofers oriented horizontally instead of vertically? 

Or, maybe have an 8 inch above and below the current setup and make make it a WMMTMMW setup?  I don't really see a way to add the below 200hz bass without making the speaker larger.

[jparkhur]

Baffle size has to stay the same.  Maybe make a stand slash box for it to sit on or just put it on a super v bottom.  ?????? 

[Jonathon Janusz]

I know from previous discussions that using the 12's this way would have some issues with resonances from the side panel size, but how about using a stack of the 8's angled like the woofers in the V2?  Shorter side panels shouldn't have the same resonance problems as with the larger drivers and mounting them at an angle to the front should narrow the overall front baffle width?

[jparkhur]

8 s at a 45 would be interesting

[Tyson]

Yeah, just do an H-frame, but orient it horizontally instead of vertically.  Use it as a stand.  Or integrate it into the speaker.  It might look odd, but then it's already an odd looking speaker.

[Tyson]

When you say baffle size has to stay the same, does that mean baffle width?  Or does that mean baffle height too?

[jparkhur]

The h frame could actually be vertical since the width is less than 8 inches. That would get the tweeter up close to ear level.  It is odd looking but.....

[jparkhur]

Width, height can change if we put in 20 of them.   Danny wanted them close together. I made ones that were further apart, not so good.

[pslate]

Super cool 

Hey what's that bad about sealed servo subs? I say the sealed side firing 8" servos make a lot of sense. What do you think Danny? Would that kill the magic? It could be nice way to lower the price.

[mlundy57]

What about two designs, one the $3,300 21 driver towers with separate OB subwoofers like Danny mentioned and a second model that would consist of the 5 driver OB sections pictured sitting above an enclosure with two 8" servo subs. You could use a stand of some type to decouple the upper section from the lower one, similar to the Linkwitz LX521. Based on the above costs I would expect this smaller version to come in around $1,800. Here are a couple of pics of the LX521 showing how the OB top end is separated from the OB bottom end.





Mike

[ebag4]

My vote is a pair of 12" servos per side, of course I already have the servos so I am a little biased.  My other thought is that we could run three eights under them in something resembling one of my previous builds:




Instead of the 15" we could use 3 servos.

I noticed when Jon was using the 8's with the full range drivers he did not use an H frame.

Danny, how would these compare with the coax of the V1?  Would the music still have the same weight from 200Hz and up?