Contemplating what it would take to have an omni speaker like our Radials, but be open baffle and single driver and no crossover.  Not too much to ask.  I’ve been pondering it for awhile now.

It can't be omni unless the wavefront is somewhat close to horizontal as opposed to pointing at your face.  That creates an interesting problem with what to do with the back wave among other things.

I would have had a proof of concept of this idea a lot sooner but as usual I tried to overcomplicate it.  You can’t maintain a title of zen master very long if things get simplified by becoming overly complex.  Today I let the Audio Gods trick me into a solution on all four counts.

Problems to overcome are:

1) How to couple the open baffle to at least one boundary (floor) so it will have bass without a woofer.

2) How to keep from hearing the back wave at the same time as the front wave as will be the case when an open baffle is horizontal above the floor.

3) How to maintain focus with being reliant on the distance from the front wall behind the speakers.  Normal open baffles must be to the inch a specific distance from the front wall for perfect focus.  Omni speakers like the Radials will maintain focus and a good image regardless of this distance.

4) Do it with a single driver per side and no crossover.


Because after all, the only thing that can really be better than an open baffle is an omnidirectional open baffle that somehow has bass and good focus.

I'll let you ponder it for awhile before I reveal how it is done with proof on concept photos and possibly a video demo as well.

Steve

... OMG it is so good!!!   The imaging and stage are just DEEP.  However, don't get too excited.  My agreement with the Audio Gods is that it's only about the sound, never looks or marketing.  And not entirely surprising the answer to my question was not what one would expect and will be seen by many as unsightly and ridiculous.

Ask me if I care. You won't be hurting my feelings but probably won't score any points with the Audio Gods either.  ; )

Kamran I'm just going to apologize to you ahead of time for the rabbit hole this is going to shove you (and others) down.

This sounds fascinating!

Brian

I’m guessing that there are other Decware followers/forum members who, like me, are much more interested in the sound, and not so concerned about the looks. (Although I will admit that some of the systems showcased here, like Charlie’s, Groovy’s, Geno’s, and others that I can’t think of at the moment, are gorgeous). So color me intrigued, as well.

Randy

Coming from someone who owns/loves the Decware radial sound….I’m intrigued to say the least!!  Looking forward to this thread.

Dom

Hey Other Lon,

I don't know how old your cat is, mine just turned 21.  When she was younger, she was constantly looking for mischief.  However, in the past year, she has mellowed out, so something for you to look forward to perhaps - in a few more years

Shaking a bunch of keys works good for me. Especially around electronics.  ;)
Tony, 21! That’s something to celebrate!

The board on the top was added for projection... something the normal open baffle has that I don't want to loose.
 

DESIGN NOTES/OBSERVATIONS


It is the shadow created by the bottom (now top) of the speaker and the thick wood blocks under it that makes everything work.  Rotating the lower wood block by 90 degrees deletes the shadow by allowing the driver to shoot sound directly on the wall behind the speaker which in turn reflects back to the listener.  I tried this and the sound was artificially large, more open sounding and defocused.



The more open sounding was created by the absence of reflection from the lower block of wood coloring the sound in the lower midrange.  This was easily fixed by leaning a piece of 2 inch foam in front of the block at an angle creating a diaphragmatic absorber. (not shown in the picture)

The box-less sound of open baffle is accomplished in this setup be keeping the rear wave energy from hitting the front wall.  The white lines are showing the shape of the rear wave on both the floor and walls.  This wavefront is largely absent of high frequency content eliminating the time smearing conflicts between the front and rear wave that would normally occur.

Initial listening tests have confirmed the imaging and soundstage are superior in this configuration to the obvious competition which is the open baffle set up the normal way.

A big advantage I hoped for with this design was to get a similar soundstage as I get from the HRv2 speakers when I am setting in a tall listening stool but when kicked back in the lower more comfy listening chair.  That is exactly what I got, which is btw a little something I have been chasing since the original HDT design in 1991.  The comb filtering effect that occurs on the floor between the speakers and listener are non-existent now.

Driver choice - knowing it probably wouldn’t be ideal I first tried the F15 driver, but I detected an urge to add a tweeter, and the bass which is so tight on that driver became over damped with such a close proximity to the floor.  If you’re going to listen to a radial driver to sound flat the driver will have to have an on axis peak in the highs so I chose the Fast-15 which has just that.  Also that driver has a softer suspension and the proximity to the floor actually tightens up the bass similar to the F15 in the ZF15L baffle.  Also it drops a bit lower which is nice.

The bass is simply killer good - over the top good I would say.  Clean, textured, open, musical, believable.

Everything is perfectly balanced so far as I can tell.  It just sounds wonderful, the way I like it.

The irony is that I didn’t like the presence peak in the Fast-15, and missed the tight bass of the F15, and now the bass is tight and the peak is gone.  No crossover, EQ, or manipulation, just this magic angle of 37.5 degrees and the distance from the cone to the floor.

Radial wave fronts - In real life there is never a sound that will hit your ear that emanates from a round cone other than a trumpet.  Everything else is basically omni, so it is somewhat futile to expect to perfectly reproduce a 3D sound field with two cones, or even flat or curved panels because they are 90 degrees to the ground and real sound does not launch from a flat or curved plane exactly 90 degrees from the ground.  Just making a case for radial speaker design.  It sounds the most natural when done right.

This was a proof of concept and my thinking was that if successful figure out a way to do it in a tower speaker more like say the ERRx or something.  Now that I know how to compute the angle it may be possible, but I can tell you now it will never sound like this.  This is big and effortless with wrap around scale that just won’t come from anything else…

Also it is so rock solid 3D from everywhere, that if all speakers could do this, it might be worth asking the Audio Gods if it is possible to adjust the aperture and focal depth of the sound stage.  The ability to soften the background and spotlight a certain depth would be control on a level no audiophile has ever experienced, myself included of course.  But the focus and density I am getting from everywhere suggests that we could probably go to that level if we knew how with a speaker like this.

Getting any open baffle placed in the right spot has always been difficult from the stand point of getting that perfectly deep focused sound stage. The speakers really had to be in the exact right spot.  Not these, these are easy.  They are going to image far better in every case and in every room when compared to the standard vertical baffles.

It will be fun to watch peoples faces who listen to this.  I've been hearing all kinds of stuff that I didn't know was there simply because the layering is so superior.

Happy listening : )

Steve

That Steve. He keeps it interesting, doesn’t he? Love it.

Randy

Steve….as soon as I saw the photos I had a huge smile on my face. This setup/design mirrors stage monitors that I used to use when I was in a band playing the guitar.  As most already know…musicians on stage need monitors to hear what they are playing in a concert setup.  

Out of curiosity….is the angle degree that you established similar to the angle that stage monitors project for musicians on stage?  

With my Err’s…I had built small platforms with a layer of rubber underneath it for them to sit on.   This was done for two purposes…one was to accommodate my listening chair, and two was to decouple my speakers from the hard wood floor.  These is my first design with cheap wood, but the second design is going to made of a nice hardwood that will have a hidden platform on the backside to accommodate a shelf that will house a removable “sled” that will allow me to mount my huge Miflex capacitors to replace the stock ones.  

Steve…can you setup a prerecorded listening demo with an A/B comparison with regular OB’s and your new design concept?  I would love to hear the difference in the bass and soundstage.

Dom

Damn, you got me thinking of making a road trip! Nice adaptation to an excellent speaker.

John

Bought a solid core door off Craigslist yesterday. 96”x34”x1.75”. $30. I’ll make the baffles from that. $15 apiece. Not the nicest looking at the moment, but a little bondo and some TLC, and they’ll be all right. I don’t really care that much about the aesthetics with this project, anyway. The only problem with the whole transaction is that the door weighs 106 lbs, according to the seller. I had to cut it in half while it was still in my truck to get it into the garage. Gotta wait for a while to order the drivers, tho. Got a little carried away with audio purchases these last few months. Need to let my credit card cool off a bit.

Randy

Step one was to make a hinged panel that opens up to the correct angle so that the speakers can be flipped.

It can be opened for when the speaker is flipped.  See, I will be demoing these speakers both ways, so it has to be super easy.

Here is actually the correct way that the panels were to be mounted.

Then the tweeters are installed.  The tweeters have their own binding posts making them an accessory that can be installed with two screws.  I set them at 5 degrees back angle, but they have a range of around 220 degrees so they can point beyond straight up or straight down or anywhere in between.

Cap is connected directly to the tweeter and the binding post.  No wire, no boards.  The other lead is 2.5 inches of silver/teflon wire between the tweeter and binding post.  That might sound insignificant, but compared to most speakers, even my house speakers, it is vastly superior.  This has only two solder nodes.  The house speakers have around twenty.



So with this setup, bi-wiring is required.  I used ZWIRE on the 15 inch driver and ZFOCUS on the tweeter.  

Absolutely fabulous!
Might you reshape the square tweeter board with curved sides to look like the melon shaped main baffle?

Brian

Wondering how room dependent this new configuration is? Will 38 degrees give the same result in every room? Maybe best to give the bottom hinge panel a variable angle setting.

In my room with the lazy boy recliner at 45 degree tilt, my head is positioned in a place that provides insane soundstage depth, width, and height.



John

The angle is easy to find because the sound stage gets better and gets worse.

I'm thinking that your "wing" thing, where the tweeter mounts, has more to do with reflected sound than anything else.  I know a lot of the Audio greats spent time and effort on reflected sound:  Altec Lansing in the 50's, Bose in the 60's/70's/80's.  I've even heard the JBL Paragon is, in part, a reflected sound design.  What would that mean?  Maybe you would want to make the wing angle adjustable?  Shape it like a parabolic disc?  Or the opposite of a parabolic disc?


Dan

Pic of the fast 8 baffles