The simple answer is yes, there are many reasons to not use this in a ported enclosure. To give you a good, general (and overly simplified) understanding of woofer construction and where each works best, think of it a bit like a range. Most woofers fall in the middle of this range and are a good compromise for either a sealed or ported configuration. But, some are a bit more specialized and have certain design characteristics that really lend them more towards one end of the scale or the other. As you move from the middle in one direction, you come to drivers that absolutely work better in a ported box. If you kept going in that direction, you'd get to woofers at one extreme of the scale, that absolutely need a horn-loaded application. Going back to the middle again, and continuing, you get to woofers that absolutely need a sealed box to work correctly. If you kept going in that direction, you'd eventually get to the opposite extreme on this scale and that's woofers that need an open baffle! An "infinite baffle" is a highly specialized type of open baffle woofer, with specific attributes that make it work it's best in this type arrangement. In short, you're talking about using a woofer with the exact opposite design features of a woofer designed for a ported box. You couldn't hardly get any further from what you want in a woofer for a ported box! There are many very simple "modelling" programs out there that will fool you into thinking that the wrong kind of woofer might work in the wrong kind of situation. This is because they are programed as a guide to give you a starting point for your enclosure, based on the assumption that you have started in the right ballpark. IF you start with something that is all wrong, then you will get goofy predictions because these simplistic programs leave out tons of factors that would reveal why an IB woofer won't do well in a ported box and a horn needs a certain type of driver and the compromises involved in the drivers that are somewhere in the "happy middle." Do some reading sometime on driver theory and construction. Don't be surprised if your head starts hurting really fast! haha! If you want to make your life easier, though, just go with the established guidelines and you'll be a lot closer. For a ported alignment, look for a woofer with a Qts of around .3, a Fs fairly close to where you want your F3 to be and an EBP right around 100. EBP is what you get if you divide your Fs by your Qes. If you are in love with this driver--and what's not to love, right?--then try building a "sealed aperiodic" box for it. I've descibed such a thing in an answer below. A purely aperiodic alignment is designed to "leak" in a controlled fashion and, as such, give a woofer designed for a sealed box what it wants (in a way), at the expense of the deepest bass. BUT WAIT!!! If the way it "leaks" is controlled even further, such that it has somewhere to go OTHER than outside the box (aka, into another box), then the deep notes are preserved! Even better, you need to keep in mind that bass does not function like mids and treble. From about 200 Hz up, speakers play INTO a room. From there down, the room is functionally PART of the speaker and so the speaker plays as a PART OF the room; they are inseparable! What does this mean? I'm glad you asked! It means that if you design a subwoofer to have a flat response in a theoretically anechoic environment (which is nothing like where you live), in an actual room it will boom and be exaggerated at certain frequencies. BUT, if you design a sub for the room it is to play in, then you can take advantage of things like room gain and you'll understand how to get your 15 Hz subsonics, without using things like ports; which are tricky business and seldom work the way you thought they would! A sealed aperiodic design is far more predicable and smoother. NOT TO MENTION, it lets you play with this woofer, which you seem to be fond of. I understand. It's a great one! The design I describe below is 332 liters. If you really want a bigger box--for whatever reason--then use two IB's in an opposed alignment, utilizing a double-sized sealed aperiodic. Beyond giving you more output, it will GREATLY increase the cleanliness of the bass and vastly reduce the vibration of the system. By the way, you will probably never see a correctly designed ported system that realistically goes down to 15 Hz at any good volume, that would be practical to play inside your home. This is because such a port would need to be about 14 to 18" internally and at least 56" long. Anytime you model a speaker and the numbers indicate that the port will be less than three times the diameter, then you know something is wrong and it's not going to work out. This woofer models to the extreme of this and wants a port that is @150 times too short! This is because it needs such a large box, that the port length shrinks to something ridiculous like 1/3", while being 16" wide! It may work out on paper, but that's only because of over simplified models that use just ratios and formulas to determine dimensions, not true models. A true model would show you in an instant that the required port would have currents that collapse upon themselves and never establish the required resonance! It gets far too complicated to try to explain here. Anyway... I gave you a place to start. Let me know how it goes!
Date published: 2014-10-10