I posted a month or so ago about building a sub, and thanks to people on the forum I was saved from making a half ass sub and wasting $. I have been reading more and more, and have decided I am going to build a dual 18 inch sub cab (49 inches wide, 23 inches tall, and 26 inches deep) 14.5 cubic feet. I am unsure on weather I should port or not. I will make up my mind when I select the driver I need. I am not loaded with cash, but want to build something decent for my band. The most demanding thing we have is bass drops ( usually 60-20 hz range). I want them to be very full, and felt in venues with up to 300 people or so. If one dual 18" sub doesn't do the trick, I will build more over time anyway I'm sure as the more I read the more of a hobby it seems I would like to pursue. I am currently stuck between two drivers and would like some help.
The first driver is Eminence Sigma Pro-18A-2 18" Cast Frame Driver
The Eminence is louder which is good in a live application, but when I look at the frequency chart (results from a box ported at 38hz) it drops off qucikly. I would like it to reach at least 30 hz with good volume and air being pushed. The Dayton goes deeper and appears more even in its response, but is not as loud. Do any of you have any suggestions.
P.S. When I build the box i would port it around 25 hz range. would this help the eminence driver hit the frequencies i need better or no.
A pair of those in your box tuned to 30hz should work pretty well. I would use three 6" x 14" ports to tune the box to 30hz. Not sure what you're using for power, but a 1000 watts takes the pair to xmax, 2000 watts is only 4 mm over xmax which is nothing for a pro woofer.
Nice I did look at those subs. You think they will hit 30hz and below with strong presence
If you're tuning to 30hz then you cant really expect anything below that point. That is effectively the cutoff for your system, and pushing a ton of power into content below the tuning point is a recipe to destroy any driver. This sub will be very strong, especially compared to most pro audio subs, but if you want the absolute maximum in the lowest registers you will need a much larger cabinet.
i was going to suggest the low rider as well for your application. an enclosure tuning of ~28hz or so is about what you are probably looking for. just be sure to run a high pass filter of some sort just below your tuning frequency if you plan on hitting them with massive amounts of power. no need to learn how "replacement baskets" work. :-)