Final questions before I build... (1 Viewer)

[BryanDO]

Hey guys, I'm designing a new box for my Shiva. It'll be ported with a 4" flared port and a 250 watt amp. Theres a boost of 4db at 25hz on my amp that I think is giving me problems. The sub right now is in a 3 cu ft enclosure tuned to 22hz. The sub bottoms out at frequencies around 30-40. Can someone help me with a solution to get rid of that bottoming out and still have the output? I was thinking a smaller box, different tuning? Getting another amp isnt an option, I'm stuck with this one due to money. I'd appreciate any input, thanks.

Also, how do I calculate the length of a port thats flared? I know how to do it with regular ports but not flared, how long the the center peice be kinda thing, do I add, subtract anything?? ... thanks.

 

[Mattak]

What are the specs of your current setup (internal dimensions, port dimensions, etc)?

 

[Rob Formica]

With a 4db boost at 25Hz... have you considered a sealed enclosure? It would provide you with a flatter response... and reduce your problem with bottoming. It will actually put the boost to good use...

The shiva is excursion limited in most vented enclosures... which will only be worsened by the bass boost.
Rob

 

[BryanDO]

Mattak, the dimensions are 25x22x16 externally using 3/4" MDF. So 23.5x20.5x14.5. This equates to 4.05 cu ft internal less the driver, amp, bracing, port. The box is actually closer to 3.3 cu ft internally. The port is 4" flared using the whole 12" center peice. The box isnt well braced and there no fill.

I had a sealed enclosure before, 3cu ft in a large room and the bass repsonse wasn't that great. I may try a smaller sealed box.