Hi Grant, Chris & others,
One of the things I have tried to with my projects was to find solutions that are not generally provided by manufactures – The PM90 was designed to provide maximum SPL and quality on a pole mount speaker above 100Hz, The double 15” + Horn drum fill was to provide a double 15 that did not suffer from the typical comb filtering found with this combination, and the
Double 10 was designed to be small, light and extremely powerful without compromise. I think RCF has now addressed this design with their new TT4.
The idea of this design is to do something different again, a box with two different angels – 25 degrees and 15 degrees. I don’t think any one has an angle as tight as 25 degrees … (?)
The reason to have two different angles is to get enough volume for the LF drivers. If you have two steep angles of 25 degrees or more there will not be enough volume for the LF drivers.
The other issue is if you try to make the angle too steep the sides will hit the compression driver. In this case the 25 degree side will requires part of the side to be a cut out to accommodate the DCX464 compression driver. It will be about 3mm from the outer edge of the box at one point.
With 25 degrees you can array two boxes to giving a total coverage angle of 110 degrees. At the same time the all LF drivers will be in close proximity to minimize phase cancellation etc.
In addition you will be able to arrange the boxes with tight-pack angles of 30, 40 & 50 degrees by using 15+ 15 degrees, 15 + 25, or 25 + 25 degrees boxes. While the reduced angles will have will comb filtering problems, it may be useful under some conditions … I need to do some testing first see how well it will work … but international deliveries are slow at the moment..
If and it’s a big IF you can array the boxes at these angle and get acceptable results you can then do different DSP settings for the various combinations and box numbers.
The other thing that will be different is the reflex port will be on the back of the box. This will cost a dB in LF efficiency but there will be improved phase response and less LF behind the box over the intended operating range … a little bit of passive directional control.