DevilDriver

It is coming down to semantics, really, but in any room, the limitation in low frequency response will almost always be linear displacement.

What site is this?

I would love some here. We haven't had enough this year and it will make it hard on the crops locally. Plus, I just really love precipitation.

Also, my ~1 year journey with agnosticism is over. I have officially lost all patience for religion, particularly those of the monotheistic nature.

Have you guys seen any of the coverage where congress was arguing with Exxon today?

What do you mean by "power options"? You'll probably get your choice of coil configurations (d2 or d2) and that will be it, much like most subwoofers.

Good match between Man U and Chelsea in the Champions League final today. Lampard has pushed one off the woodwork twice. Shootout imminent....

A little background info for you, LB... When we say "4th order" or "6th order", this refers to the rate at which the response rolls off at its upper and lower "corner" frequencies. In other words, above a certain frequency (say, 60 Hz), response will rolloff (the driver/enclosure combo will be quieter). The same can be said for below a certain frequency (say, 30 Hz). So what are these rates of rolloff? Pretty simple: 1 order = 6 dB/octave rolloff. Extrapolating for a moment, you will see that a 4th order enclosure will have a rate of rolloff of 24 dB/octave, while a 6th order enclosure will have a rate of rolloff of 36 dB/octave. To understand that part, you need to know that an octave above a frequency is double that original frequency; an octave below is half that original frequency. Also, note that this is just referring to a type of mechanical filter that behaves in the same way as, say, your low-pass filter on your amplifier. To bring this all together, suppose a driver/enclosure combination that produces 100 dB from 30 Hz - 70 Hz. We'll say that the 30 Hz is the lower corner frequency (the frequency that the high-pass filter begins) and the upper corner frequency (the frequency that the low-pass filter begins) is 70 Hz. Suppose this enclosure is of the 4th order (24 dB/octave) variety. Looking at the low end of the spectrum, we will see that response is 100 dB at 30 Hz, 76 dB at 15 Hz, 52 dB at 7.5 Hz, etc (although it should be noted that at frequencies this low, your subwoofer will typically lack the throw to get much meaningful response). On the top end, we will see that response is 100 dB at 70 Hz, 76 dB at 140 Hz, 52 dB at 280 Hz, etc. Now to apply this to specific types of enclosures. One of the simplest enclosures (the sealed variety) usually demonstrates a rolloff of 12 dB/octave (aka 2nd order). Bass Reflex enclosures (usually called "ported") exhibit a 24 dB/octave rolloff (4th order). However, neither of these two types will rolloff on the top end (aka they do not make for a mechanical low-pass filter). Now bandpass is different. By definition, bandpass means you will see rolloff on the top end and on the bottom end (both low-pass and high-pass filters, respectively). So a 4th order bandpass exhibits the same rolloff as a ported enclosure, but this occurs below AND above the bandwidth it is used in. A 6th order bandpass also has rolloff below and above the bandwidth it is used in, although the rate of rolloff is obviously quicker (36 dB/octave). Why is this a good thing? Well, it isn't for many people as limiting the top end may be the opposite of what they want. For SPL competitors, however, this means that we gain more output in the bandwidth between these filters. In fact, the faster the rate of rolloff on the top and bottom end, and the smaller the bandwidth is, the more output at a central frequency you will see. Hopefully that makes sense and provides at least a cursory understanding of what these enclosures are about. The problem with bandpass enclosures is that they are typically quite large (especially those of the 6th order or 8th order variety as the ports consume a fair bit of a volume themselves). If you need to make a small step into understanding them further, you can simulate response with the spreadsheet on Brian Steele's website. If you want to visualize what some of these enclosures can look like, check out The12Volt.com. As mentioned above, many drivers require enclosures built specifically for them using the Thiele/Small parameters supplied. The higher the order, the more sensitive the enclosure is to miscalculation and poor building. Read for a little while and ask questions if any of this is unclear.

I think to call pretty much anything you've seen in a vehicle a "horn" (and in fact, what you've seen in houses) is a bit of a misnomer, especially in the lower frequencies a subwoofer typically covers. The size required to behave like a horn at these frequencies is enormous (particularly the size of the mouth). Most of Fitzmaurice's own measurements show this to be the case. If I ever have the money to do so, I will be building a horn in my truck. Mind you, this will require a blow-through and the enclosure will take up much of the space from the seats to the tailgate.

If you're going the "different" enclosure route, your best solution is likely a 6th order bandpass...still very big, but smaller than an 8th order and more practical than a horn or TL for your application. If well designed and well built, the limitation becomes how much current the coil can handle. Of course, it is even more complicated than the design of a 4th order, so you might be out of luck in that regard.

Happy Birthday, Scott.

That's my point: what does that mean?

The whole premise of SQ competition is flawed because it relies on the subjective interpretation of something very imprecise. For everything that I dislike about SPL competitions, at least a well-defined and easily identified method of judging is used.

If the proper accelerator is used with the proper kind of ca. The glue joint isn't harmed. Use the wrong stuff and it can have adverse effects on it. Many different kinds of ca glue's and almost as many accelerators Thanks for the clarification, Ramos.

Same difference. An accelerator is usually used with cyanoacrylates (CA glue) to speed up the curing (drying) process. I have heard from a few SPL competitors that the use of an accelerator will make the CA glue joint a little weaker but have never researched whether this is a attributable to a real scientific effect or is just one of those mystery myths the SPL world is full of.

Clean XP install coming up in about 30 minutes. Just finishing back-ups.... Would love to go to Ubuntu 100% but can't give up all the programs that are MS-only.

Ahem.... Infrasonic filter. Subsonic implies it is slower than the speed of sound.

Yeah, you'll be fine. The flares are the key to avoiding noise and keeping output. Sorry if I missed that stuff above.

4 keys on a key ring. A cell phone. My wallet. A lighter when I'll need it for the night. Nothing more, nothing less. They all go in the same pockets every time, too.

Either Excels, Revelators, or the SDX7. I really don't recommend the Extremis after my last few experiences with them...steer clear.

The future of AA is the exact opposite of down the drain...it's just that they're not what you, specifically, are looking for. Scott and Nick have been steadily building a reliable dealer network and strong products. Their online presence will be diminished going forward and that's a reality you'll have to live with. In terms of the properties of each material, carbon is a stiffer, lighter material. This offers increased efficiency, a more rigid piston (typically better detail), and less internal damping (typically a more pronounced peak up top). Each has their own advantages and disadvantages, although polypropylene is usually considered a pretty good "middle ground" cone material, with no huge benefits but no large detriments either. Carbon fiber cones, on the other hand, can offer some marked improvements (particularly at low frequencies where the cone is likely to flex); of course, it requires close attention to cone and surround geometry (and crossover design) to integrate it properly. This is not to say that either version of the 6.5" mid will exhibit any of these characteristics (a "sum of the parts" kinda thing).

Probably one of the best (and most common) motor platforms out there. Nothing wrong with an RL-p. 4 6" flared ports are plenty of port area for a pair of 18" RL-p's. The only problem is fitting the length in there.

He didn't declare bankruptcy: his incorporated business did. Totally different animals.

Word on the street is that Thilo got everything back except for one patent.

Depends on the coil geometry. But you can expect probably 600-1000 W for the most common coil/gap combinations.