Simple and easy radial speaker with only one driver

[Squeak]

Ok, I'm contemplating doing a radial design with only one fullrange (commercially available) driver (currently FE126 as I want to floor-load it).

So, the first problem seems to be how to do the reflector. Where to get it or alternatively how to DIY easily?
- A simple cone seems not to be the preferred shape, but could it work? And how steep can/must it be?

- A ball would reflect most of the highest frequencies right back at the driver, so even though some use it, it seems too much of a compromise, especially when talking fullrange one driver.

- An exponential spike (mount Fuji shape) like the Duevels seems ideal, but very hard to DIY or find as a part.

- A horizontally curved panel like the Paragons (http://www.audioheritage.org/html/people/wolf/paragon.htm) seems to be the easiest way to go, but how long does it have to be to be effective? And also, it needs to be mounted horizontally so that means a wide speaker, something I would like to avoid as it limits the placing options.

- One alternative I've been thinking about is bending an oval (to compensate for anisotropy) piece of plexiglass lengwise in an obtuse angle.
Then put it at a 45 degree angle above an upwards firing driver to get a good 180 spread, instead of the 360 spread, where much of the sound goes to waist in curtains, walls and furniture.

Anyone tried something like this, or have any interesting links to simple DIY radial speaker projects?

 

[doorman]

What's your design goal?
Don

 

[Squeak]

What's your design goal?
Don

Well, I know I'm not going to get quite the bass of my current BIB, solely because of the length of the line necessitated by the driver hight (1 - 1.5 metres).
But other than that, I hope to get a good to great fullrange speaker where I and the people I love can have an "optimal" listening position anywhere in the room.

 

[Tom V]

Reflector

How about this?

Dayton H08RW 8" Round Waveguide 1" Threaded | Parts-Express.com

And if you decided you needed a tweet later for air, you know where to put it.

I am digging the concept. I am listening right now to a pair of speakers that have a down firing port onto a flat open surface, and they sound real good and image like a son of a gun. I am assuming an omnidirectional speaker wouldn't need baffle step compensation?

-Tom-

 

[Squeak]

How does the back of those look? You'd need to put a cone over that hole at the mouth. And still, I'm unsure about how the high frequencies are going to behave. Wouldn't a 180 degree reflector be overall better in this kind of setup?

 

[el`Ol]

Here is a diffusor cone for 130 mm drivers.
www.h-audio.de Elektroakustik, Lautsprechershop, Grammophonfabrik Hannover, Pa Lautsprecher, Frequenzweichenenbauteile, Lautsprecherentwicklung, PAF212, RCF Kits, DIY Lautsprecherbausatz, Studiomonitor, Fullrange Driver, www.lautsprechershop.net, Lau
Personally I prefer fullrangers with strong treble rise and no diffusor (this is my experience with 8"ers), just the ceiling reflections. I will have a pair of TLs with the Ciare HX135 ready in two weeks or so, will post my impressions here, if you don't see it as threadjacking.

 

[Squeak]

No by all means do. That is exactly the kind of input and inspiration I'm looking for.
It seems radial speakers are treated kind of like a dirty word. Every thread I've seen on the subject dies out quickly and most of them only cover the same old ground.
Here's for instance a quite good little page that shows developments in the 30's to 60's along a completely different evolutionary path, until every speaker designer suddenly started imitating bookshelf speakers. Ie. square closed boxes with all the drivers facing forwards.
Citation X and Eico HFS-2 Speaker Systems

 

[el`Ol]

It's possible that the PU diffusor cone eats treble and the metal one is more expensive.
IT IT Lautsprecher - Produktkatalog & Shop - Shop - Shop - 1384801 | 70227_J2 DIFFUSORKEGEL

 

[el`Ol]

The speakers are finished. Slim speakers, 1m high (driver on ear level facing 90° upwards, no diffusor). Rockwool stuffing 40cm on the bottom.
Listening impression:
Tops should be tilted to have the drivers 60° off axis, 90° is a bit much. When distance to the wall is not too high (about 50 cm) bass is sufficient. The FE126E in a BR runs out of the magnetic gap what causes linearity problems (I haven't listened to it in a pure horn construction, probably this would be better). I did't notice such linearity problems with the HX135. Transparency is also much better than of any other paper cone I know. Quite an expensive driver for its size but worth the money if a true point source is the goal.

 

[Squeak]

Maybe you could try an experiment for me? Put two curved reflectors over the drivers, like two identical buckets or something, at a 45 degree angle or so, with the opening facing up towards you. And then tell me how that sounds.

I don't really get what you are saying about the Fe126e, but it's about it not being loaded enough in a back radiator, right?

 

[el`Ol]

I just hung two 7cm diameter spheres low above the cones and that was sufficient to restore the transparency. In earlier experiments with 8" drivers I found that large 90° reflectors cause a flat image and a strong ceiling reflection is desirable.
The main difference between the FE126E and the HX135 is that despite the neodymium magnet the Ciare has a very weak motor because most of the field is "wasted" in a long air gap. In the Fostex the coil covers most of the air gap, what makes the motor stronger, but using it correctly means using a design that limits excursion (like a horn). In the Fostex-recommended BR hybrid the cone movement is visible, what shouldn't be with this driver. But the Fostex colorations are not unpleasant, I wouldn't say it's an ugly-sounding driver. The weak point of the Ciare is that as an 85 dB sensitivity 5" driver it is not free enough of compression for orchestra music, so my main system will stay my 200 Hz/5000 Hz crossover 10",6.5",3/4" speakers.

 

[Squeak]

I just hung two 7cm diameter spheres low above the cones and that was sufficient to restore the transparency. In earlier experiments with 8" drivers I found that large 90° reflectors cause a flat image and a strong ceiling reflection is desirable.

And you don't find the treble lacking? I guess it has to do with how high your ceiling is and the padding of your room. I can't imagine my 2,75 m ceiling doing anything good for the sound and there is curtains right behind my speakers.
My instinct tells me sound has to come mostly from the horizontal plane, not from above and certainly not from below.

 

[el`Ol]

With the Ciare HX201 the treble was sufficient without diffusor and the measurements confirmed this. My current main system has the HX160 90° of axis, what also measures quite well. With the HX135 I didn't do measurements yet, but 60° off axis or with the little sphere I am pleased. If you are sure you are going to use a diffusor cone you could also think about a driver without treble rise like the Mark Audio Alpair 10 or the Tangband W5-1880 or maybe larger drivers. Then you would have to use a low absorption diffusor cone and the option with the little sphere is gone.

 

[el`Ol]

Further report:
Having the drivers facing each other gives the 60° but sounds somehow unnatural. Tilting the speakers eats height and depth and gives a more conventional presentation. The little sphere has some problems especially with voices. My favourite solution: Making the speakers lower. Then they are no longer slim and nice, but tonally and spacially the best solution. Maybe a pyramid-shape would be a way to let them not look crude and keep diffraction low.

 

[el`Ol]

I did the test by standing up, not by building smaller speakers. When the speakers are max. 50 cm high one probably also has sufficient floor loading and needn't get so close to the walls. The rooms in my house are just 220 to 250 cm high, but graaf has been successful with similar speakers in larger rooms also.

 

[Perplexed1ne]

It seems to me that this is a conversation that is occurring lots of places but maybe this is what you are talking about and would find helpful:

Pluto introduction

I must confess that it is all a real head scratcher for me having had no concrete listening experience to these designs nor trusting drivers that don't look me straight in the eye. For instance I was noticing people using helper super tweeters that are rear facing. Subwoofers I get, non directional, and I have heard them facing the floor, facing the side, and facing the listener. But things get directional above normal whale belching frequency. So here you and others are pointing drivers to the ceiling, with and without diffusers. I don't get it. But then it took me some time to understand designs and listen to speakers what ain't got a proper box and show their backsides. I admit I was baffled.

 

[c2cthomas]

But then it took me some time to understand designs and listen to speakers what ain't got a proper box and show their backsides. I admit I was baffled.

Hmmmmmm......... and now it appears that you are OB - Openly Baffled.

 

[Squeak]

How about a large FR firing up (like Fe126e), with or without reflector and a smaller one (like Fe83e) firing forwards, with the better HF spread of a smaller driver? You avoid the crossover for a tweeter that way and get the advantage of two FR drivers "filling in" each others holes and weaknesses. But still, the sound will have a small delay from the upfiring, but still much less than roomreflections. Anyone tried a two driver FR setup were the drivers are different?

 

[el`Ol]

Treble filling just requires a tweeter with the right sensitivity and a capacitor. I would be more afraid of the lobing problems of two fullrangers.

 

[Squeak]

But they are oriented at right angles to each other. Interference would only happen at low frequencies and not be much worse than what already happens with a port/horn.