Playing with Cosmos’ new horns – WOW

[djnagle]

Dan designed and built a pair of 249hz Tractrix horns for his JBL 2445 compression drivers with TrueXtent Be diaphragms. We listen to them at his house last Saturday and we were blown away. Mind you, this was just pure listening: no measurements yet. I thing we had some fairly good and experienced ears in the room and the consensus was that they kicked serious butt. OK, so much for the emotions.

To my ear (and others can chime in) they have the biggest sound stage if ever heard. I’ve heard big sound stages before but at a certain point, the imaging falls apart. There is a lack of coherence. Not in this case. This was an experiment......that worked!!!
With the TrueXtent there is no need for a tweeter. Dan was running them on a pair of JBL XX woofer cabs with the E145 and top to bottom, the sound was clear, detailed, uniform, and dynamic. It was truly one of the best systems I’ve ever heard. I was shaking my head the whole way home.

In attendance was me, Dan, Brad, Rick, and George. And we all were amazed at how good they sounded. Going in to this project (I didn’t do anything except throw my constant support Dan’s way) I thought we would be messing with the throat for days on end, but the first rattle out of the box was damn near dead on.

So, Dan then brought the horns to my house because someone on the LHF has Dan’s diaphragms for testing. I have the JBL 2441s with Radian dias, JBL 2430 scoops with 2225 woofs, and the Big A$$ Heil on top. I did not expect the Radian to sound nearly as good as the TrueXtent but damn! With the Heil, they sound great. You can see by the pics that the horns are way up above my listening position. Didn’t matter. In the bigger room, the dynamics and soundstage only increased. It is like being at a live concert but better. The imaging is fantastic as well.

I thought, the horns at Dan’s house sounded good, but think now that in my house, they sound better than anything I’ve ever heard......that is saying a lot for me...I am picky.

Anyway, here are some pix of the monsters. Anyone in my area is more than welcome to come listen. I can garunty that you will walk away impressed. Now to build my own pair.

P.S., the top of the Heil is 72” off the floor.

[Earl K]

Very Cool Dennis !

So with those 2 different flare types, that horn would be a Tractrix / Radial , yes ?

( Johnny / yggdrasil made one of these a while back / though it had a different aspect ratio )

<> cheers

ps ; what's up ( literally ) with those pillows ?

[cosmos]

Wow, really nice compliments Dennis. Thank you!

I have to say I do think they sound great and I am happy with them.. but, it's subjective.

The pillows are in there because Dennis has been working his system pretty hard and his bass scoops are tired. They needed a nap...

[djnagle]

Well close, but no cigar. The interaction between the front wave and back wave of the scoops causes some strange peaks and vallies which I didn't like. I have very good subs that I cross at 60hz and don't need the low end re-enforcement of the back horn.....so I stuffed them. Not the best thing to do but the smoothing effect sure showed up on the plot.

[Progneta]

Beautiful setup there! That's something I would enjoy listening to! I have always seemed to appreciate the "light" top end that EMT's can add

Again, stellar setup!

-G

[djnagle]

Beautiful setup there! That's something I would enjoy listening to! I have always seemed to appreciate the "light" top end that EMT's can add

Again, stellar setup!

-G

Thanks G. With the hard wall behind the speakers and the di-pole Heils, it has a very lively sound. I think I need to build shorter boxes to get the horns down a bit, but then I listen to it, and I don't want to mess with the hugeness of the soundstage. It is giant and still retains the imaging and detail.

[djnagle]

p.s., Earl, the one scoop actually spit out that pillow while listening to it

That happens once a week or so. The inside walls where the cushions are is very rough and grabs the cushions really well. But at some volume...Doink Doink...the cushions are spit out.

[Progneta]

OOO tricky situation I once had a little project similar to yours and I shrunk things down a bit so the horns were at ear level. And another time, I just angled the horns down, so then I got that huge sound stage, but was beaming horns into my ears. I liked that

What are you crossing everything over at?

[djnagle]

It is tricky. I am thinking about laying the scoops down on their sides and putting the horns right above the woofs, just to see what it sounds like before I build new cabs. It won't be idea bass wise, but I will be able to get an idea of how the mids and tweets will sound at that height.

I am crossing the woof/mid at 500hz and letting the mid run out all the way, then crossing the Heil in at 8K and of course letting that run out all the way.

I am letting the woofs run down all the way and crossing my subs in at 60hz or so. With the cushions in the scoops, the bass is much tighter then with them out but it is still a little loose for my taste. I think the proper sized vented cab would be best.

Hopefully I will be able to do some room measurements this weekend. Cheers.

[Progneta]

Sounds pretty darn good! Regarding the loose bass, I always felt that scoops could get loooow bass, but always just a smigg sloppy. A nice bass reflex seems to work good and let a subwoofer handle the rest. I havent heard your scoops, but I can tell you they sure are pretty!

[Mr. Widget]

I think the proper sized vented cab would be best.

I think so too.

I agree that you should mess around a bit with physical placement. You could try the boxes sideways but perched on bricks or a temporary wooden structure. Keep in mind that having a baffle that extends to the floor vs. a stand mounted speaker will affect the sound. (unlike dented tweeter domes) To deal with this a friend who manufactures commercially successful "audiophile" mini monitors designed stands that effectively extend the baffles to the floor. On the other end of the spectrum, my ADS L910s sound better on their stands with an air gap below... they designed them that way for a reason.

I would guess your current configuration is more or less like a stand mounted woofer cabinet. Of course having a "variovent" (pillow) and the structure of the back of the horn will all have their effects as well.


Widget

[djnagle]

Agreed Widget and Progneta. I have Martin Logan 12" sub drivers that ML uses in their $140,000.00 TOTL system. They are in the corner cabs and are driven by BASH 300 plate amps.

I am thinking of a tall cab made of 1.5" MDF that is divided internallly: the top half for the woofs (tuned proper) and the bottom half for the subs firing downward. I play at a machine shop on Tuesday nights and I can make 5" spikes out of 4" aluminum round stock for feet.

I will be giving up the ability to move the subs, so as a test I will pull the subs out of the corners and set them up next to the scoops facing down off the floor 5". If it sounds good, then maybe that would be the way to go. If not, I will build normal height woof cabs.

Any thoughts on this idea???

[djnagle]

Sounds pretty darn good! Regarding the loose bass, I always felt that scoops could get loooow bass, but always just a smigg sloppy. A nice bass reflex seems to work good and let a subwoofer handle the rest. I havent heard your scoops, but I can tell you they sure are pretty!

Thanks Progneta, the guy who built them is a professional cabinet maker and he built them for himself. They are absolutly to spec.....I don't thing JBL could have built them tighter to spec. I hate to sell the cabs but if I can get tighter bass with proper vented or sealed cabs, I will. Cheers.

[Progneta]

Thanks Progneta, the guy who built them is a professional cabinet maker and he built them for himself. They are absolutly to spec.....I don't thing JBL could have built them tighter to spec. I hate to sell the cabs but if I can get tighter bass with proper vented or sealed cabs, I will. Cheers.

Regarding putting woofers in the same cabinets, usually when I have "subwoofers" I like to keep them separate so I can place them in different areas of the room. As you know, some spots sound better than others. I am not as familiar as many genius audio guru's on this site, but I am always amazed that small changes to cabinets and moving them around has a great influence in sound. I once helped a friend who was lacking bass in his theatre room. It was on the second floor and his bass was being lost to the floor, so we the put the subwoofer on spikes and presto! fixed

[Mr. Widget]

Regarding putting woofers in the same cabinets, usually when I have "subwoofers" I like to keep them separate so I can place them in different areas of the room. As you know, some spots sound better than others.

One of the benefits of separate subs is just that flexibility... I would keep them separate.


$140K my ass... you obviously need some proper JBL subs.


Widget