Oris Reference bass-horn (BD-Design)
by madprofessor 
, 27777 Ganderkesee, Germany, Friday, August 24, 2007, 12:17 (6087 days ago)
Hallo Bert!
I intend to buy the BD-15 woofers and the horns for them from You within the next two month.
The high-frequency cut of, of the bass-system will perfectly match my midrange-horns.
Now I got a question about the cabinet and the placement of the port.
Due to my construction, I can not use the Reference-Ulta cabinet.
What I plan to build is a longer but slimmer cabinet: The frontplate can have maximum dimensions of 440 mm wide and 740 mm hight. The length is no problem.
Basically I want to build a shape a bit similar to the Lumen White Speakers - curved sidewalls, Inside diameter getting smaller to the rear of the cabinet.
As I understand it, the frequency-response of the bass-horn is like down to about 150 Hz, which means, the rest hast to be done by the port.
One way is to place it in the front, but than its firing directly at the bass-horn. Another way would be to place it on the rear and cause the speakers have to be tilted in a bit, to use the corner-effect for the bass.
A subwoofer below 40 Hz is already existing.
So I basically need a bass-system from 400 Hz ( -3dB point) down to about 40 Hz.
And I want a sperical horn, to match the dynamic respone of midrange and tweeter.
I´m glad about any suggestions, cause I haven´t started yet the woodworks.
Best regards
Stephan
Oris Reference bass-horn
by Bert 
, Friday, August 24, 2007, 13:10 (6087 days ago) @ madprofessor
Hi Stephan,
I do not "get" what your plans are...back firing horn? With the Oris 150 pointing into a corner?
Bert
--
BD-Design - Only the Best!
Oris Reference bass-horn
by madprofessor , 27777 Ganderkesee, Germany, Friday, August 24, 2007, 16:43 (6087 days ago) @ Bert
Hallo Bert!
My plans are, to use the Oris Reference bass as intended, firing to the front.
I also want to use the same cabinet-size, but different shape.
My question was, where to place the port.
Simply think of Your Reference-System, but instead with two spherical horns for tweeter and midrange.
I include a photo of the current rig.
The starting point was, that I heard a combination of the biggest Wavac SET amp and Kharma speakers. I liked everything very much, but missed some dynamics. So the idea came up, to use the same ceramic Thiel-drivers, but to put horns in front of them. Now the midrange/tweeter-sections are as planned, but the bass used is just a compromise (was a Focal Triga System tweaked a bit formerly).
In the middle You can see a 845-SET amp for testing and driving the horns. The black Stasis amp is justfor home-cinema driving the center. The big silver amp is a DIY-Class A amp, driving the bass.
Best regards
Stephan
![[image]](images/uploaded/image325.jpg)
Oris Reference bass-horn
by Bert , Friday, August 24, 2007, 16:48 (6087 days ago) @ madprofessor
Now I remember and the question is clear.
Question about the midrange horn: why 400Hz? Can't it play lower to say 300Hz?
Best is to have the reflex port to the front which will then trigger less room modes. A small reflex system might have some advantage having the port at the back but with the Reference that is not needed.
Also, if you only need 40Hz then it would be best to make the internal volume smaller (120 liter) but then you'll have to tune the port higher...
Bert
--
BD-Design - Only the Best!
Oris Reference bass-horn
by madprofessor , 27777 Ganderkesee, Germany, Friday, August 24, 2007, 17:52 (6087 days ago) @ Bert
Hallo Bert!
Unfourtunately, the midrange-horns stop at about 330 Hz performing properly.
By adding more capacity to the x-over I can force them to play lower ( the value of x-over capacitor still smaller, than the midrange mounted in a case without horn!) I loose audible performance in the lower midrange especially with voices.
All units are measured properly ( I got all the measurement equipment needed, see : www.gecom-technologies.com )and also tuned for optimum pulse-response.
What was also very interesting: first I used much smaller horns for the tweeters, but I was not satisfied with the uniformity of sound dissipation. Now I took bigger horns, just to have near equal length like the midrange-horns - verv big improvement! The tweeter-horns also could work down to 400 Hz, but the x-over point is 3,6 kHz!.
Of course I can set the port for the Reference-bas - system also to the front, but I was wondering about interference with the backside of the bass-horn?
Best regards
Stephan
P.S. I´m located near Bremen, so I´d like very much to pick up the BD-15´s and horns at Your place, cause I´m very intersted to listen to Your new System!
Oris Reference bass-horn
by Bert , Friday, August 24, 2007, 17:59 (6087 days ago) @ madprofessor
Stephan,
Unfourtunately, the midrange-horns stop at about 330 Hz performing properly.
Ah, okay...
Of course I can set the port for the Reference-bas - system also to the
front, but I was wondering about interference with the backside of the
bass-horn?
No problem whatsoever. The air speed isn't thát high... :wink:
P.S. I´m located near Bremen, so I´d like very much to pick up the BD-15´s
and horns at Your place, cause I´m very intersted to listen to Your new
System!
No problem with that but it could trigger new idea's... 
--
BD-Design - Only the Best!
Oris Reference bass-horn
by madprofessor , 27777 Ganderkesee, Germany, Friday, August 24, 2007, 18:39 (6087 days ago) @ Bert
Hallo Bert!
Of course it could trigger new ideas - to them I´m very open!
That was one of the main reasons to ask for a visit!
Best regards
Stephan