Oh.. I am totally new to this. What program should i use to calculate a box for the Dayton UM18-22?
and do you have some tips for me? Thanks for answering
Speaker design is a little more complex than I think you have considered.
As I suspected the driver you have selected is only suitable for a sealed alignment. A vented box would be over 14 cu.ft! It would also not sound good.
This driver is intended for sealed alignment.
I have enclosed a pdf of an optimal design.
Now as is typical for sealed sub, it starts to roll off at 60 Hz and is 3db down at 32 Hz. So without equalization the performance will not be floor shaking.
Also note that cone movement rapidly increases below 60 Hz. This is because unlike a port, a speaker cones couples poorly to the room.
So to make a decent sub from this driver you need a box with heavy fill of Polyfill and a volume of 3.7 cu.ft internal volume, sealed
Now you will need a lot of power, as that increased cone excursion implies inefficiency. So the design does show room for added Eq without running the driver out of cone excursion.
You will need a powerful amp in the 600 to 1000 watt range. You will need to add a bass boost of 12 db per octave stating at 40 Hz. In order not to damage the driver you will need a high pass filter add 20 Hz of at least 12 db per octave.
Now for other reading this post, the Qtc of the design is just over 0.7. The total Qts of the driver is 0.53.
Now the design can not be lower than the Qts of the driver. For really nice tight bass you need a total Q of the system around 0.5. At 0.7 the bass starts to get a little warm, but acceptable to most. Much higher than this the bass becomes rapidly boomy.
I stress this, as there is a frequently proferred opinion on these forums that a sealed sub is inherently more musical than a sealed one. This is nonsense.
On an bass extension/spl/bass quality dollar for dollar spent the ported design will beet the sealed every time. The caveat is that both must be competently and optimally designed.
So why is this driver the way it is. A sealed design allows for a smaller compact sub.
Next question why is the Qtc of the driver were it is, on the high side? The answer is price. If the Q of the driver were higher, then the bass roll off would be higher. The Eq would have to start higher, the driver would have to handle much more power and a much more powerful amplifier would be required. So the cost and complexity would be increased enormously.
So now you see why I selected the driver I did for Ares Project. He was the one looking for a cost effective slam dunk first build. That was why I designed it the way I did.
