[el`Ol]

Hello all!

I startet my diy carreer with a pair of Ciare CH250 in OB. Later I discovered that the Ciare HX201 can be used 90° off axis, facing the ceiling and this gives good concert hall experience. While I never missed anything concerning imaging I find TQWT resonating tube bass is clearly a step backward compared to an OB. So after being more or less happy about my compromise for months I now decided to do the following experiment. Take open backed boxes with the Ciare on top and the Eminence Beta-15 in front. I would start with a 40x60x100cm box, the ciare close to the front and the Eminence close to the floor, but this is just "out of the belly".
Is anybody out there who can give me measures based on knowledge?


Thanks, Oliver

[scorpion]

Make some prototype, it is worth a try. I think the Eminence Beta-15 is an exellent choice. Perhaps you could make the top movable with hinges or
something so that you could try different angles. There is also a question of resonances in the open back box. 60 width and 40 depth ?

I'll see what Behringer DCX2496 can do for my Ciare CH250s.

/Erling

[el`Ol]

I built it and it works!
It has slightly less precision in imaging than the monopolar variant and adds that dipole-typical extra air. But the realism is unchanged and still far beyont front-firing concepts. And I am so glad I am back to free-breething bass, no more resonating tubes!

There is only one upgrade I have in my mind:
I ask myself whether the Kilomax 18 moves enough air to get more bass without a larger baffle. This picture lets me think...
http://img91.imageshack.us/my.php?image=schwebendereminence8vl.jpg

[Rudolf]

I built it and it works!
It has slightly less precision in imaging than the monopolar variant and adds that dipole-typical extra air. But the realism is unchanged and still far beyont front-firing concepts. And I am so glad I am back to free-breething bass, no more resonating tubes!

I still can´t imagine precisely what you built. Could you provide us with some drawing or picture of your construction? Is the Ciare closed in the back?

There is only one upgrade I have in my mind:
I ask myself whether the Kilomax 18 moves enough air to get more bass without a larger baffle. This picture lets me think...
http://img91.imageshack.us/my.php?image=schwebendereminence8vl.jpg

I once had a short discussion with Winfried Posselt, the designer of this no-baffle Kilomax. He found it producing more than sufficient sound pressure for his quite large room. I have his equalisation diagram for the Kilomax: 19 dB between 10 and 100 Hz.

[scorpion]

I still think that an angled top would be good to test. The HX201 has almost flat response 30 degrees off axis, see Hobby HiFi. 
One thing that I have planned to test some time is to arrange a reflective surface, glass perhaps, above an upward facing unit. The reflections
should be directed toward the listening area. I think this will provide sharp stereo and a wide sweet spot.

/Erling

[el`Ol]

I tried tilting in different angles with my test enclusures, also reflector cones and I liked the simple upfiring design best. Here is a link to the picture:
http://www.diyaudio.com/forums/showthread.php?s=&postid=1212588#post1212588

[scorpion]

I suppose you bi-amp, where do you cross to the Ciares ? Do you have to boost bass ?

/Erling

[el`Ol]

I have a simple passive 12dB x-over at with 10mH / 68µF. I don`t know wheter I poled the bass drivers right, I just tried and used the setting that gave more warmth in the lower midrange, so probably it`s correct. Concerning bass I now tend to building a ripole with Eminence Kilomax 18.