Impious

Then you don't understand the relationship between amplifier power and acoustic output.

Then you'll need to either physically secure the panel or again place foam between the panel that is vibrating and whatever it's vibrating against.

And always ignore anyone's "estimation" of power output. It's crap, every single time.

Check to make sure the subs are wired to 1ohm. It sounds to me like the amp is seeing too low of an impedance.

Okay but What about all of the people i've seen whos' door have something crazy like eight mid range drivers and pillars loaded with tweeters? This is one of my pet peeves with these systems. Aside from the fact they are acoustically a terrible idea, because it's done so frequently people look at them and assume it must be a good idea or sound great because so many people have done it, including many "influential" people in the hobby. It's a terrible idea. From a sound perspective adding more speakers would be a terrible idea if the goal was to both increase output and retain sound quality. What is your budget, what specifically are your goals, and how much fabrication are you willing/able to perform?

You'll want some CLD to help reduce the vibrations and some foam to place between the rear deck cover and the metal of the rear deck itself. Contact Don at www.sounddeadenershowdown.com, he's got what you'll need

The market is flooded with knock-off/straight rebadged drivers or drivers stolen from other companies and taken to China where production costs are cheaper, which drives down the cost of products across the board in order to be competitive in the market. This makes any real innovation cost prohibitive as the end product will simply be too expensive compared to the knock-off/Chinese products in the market. The only realistic difference between subwoofers now and subwoofers in 5 years is that the market will continue to be dragged down towards cheaper and lower quality products. That was a long winded way of saying: Agreed. No idea who that is. The number of "internet companies" springing up is simply outrageous. It's actually sad to see that the "internet company" genre has gone from a provider of quality built, well performing and differentiated products priced below mass-market competition to any random kid (literally) with a user account on a popular internet forum and enough $$ (typically from mommy and daddy) to meet minimum order quantities from an overseas build house and buy ad space on the major forums. I've stopped trying to keep track of or care about any "internet company" started within the past 5 years. There's too many to keep track of, they go under far too quickly to remember who's still in business, and their products are such cheap overseas lack-luster carbon copies to even give a shit about them to begin with. It's unfortunately more about who can generate the most nuthuggers and who has the most friends modding forums to delete negative comments/reviews/issues rather than quality, performance and product differentiation. This isn't just subwoofers, but every car audio product from wiring to deadening to amplifiers and everything in between. That is another long winded way of saying: Agreed.

I'm sorry, but they are the worst tool for measuring. This is exactly what I am talking about in the previous posts. You see it acting differently and pick arbitrary numbers out of the air , insert, and bam. See what I'm getting at? Isn't that how you measure all the time. You measure with your eyes when you need to stop your car so you don't wreck. How far to step so you don't fall down the stairs. What size a bolt is so you can get the right size wrench. I don't carry a fucking ruler in my back pocket nor do I care too. See what I'm getting at? I noticed a very audible difference as well. At full tilt my truck is quiet as shit on the outside with the windows up. I don't think anyone is saying AT does absolutely nothing. At the very least it's adding some measurable amount of mass to a panel, and potentially adding some minor but probably measurable amount of stiffening to the panel. Same goes for products like Peel N Seal. But those two attributes don't necessarily make it an effect constrained layer damper, which is the primary job it's supposed to be performing.

You need new friends.

........

How exactly are they damaged? Is the coil frying?

That's the trade off with something that's hand crafted in the USA rather than mass produced overseas.

Mine stopped asking a long time ago.

In my previous installs the auto tune actually did pretty good, that's both with a 2-way front stage using door mounted mids and a kick mounted 3-way. It provides good imaging and tonality without major deficiencies. Some minor tweaks to personal liking, but generally overall good results. Took care of a major midbass peak I had with the 3-ways in the kicks. It took a little bit of "edge" out of the midrange, an edge or aggressiveness that I sort of enjoyed, but it improved the tonality a little by doing so so it was a trade off I could live with. I could probably do just as good if not better myself with a quality processor and measurement equipment, but it probably would take me an entire weekend or two (if not more) compared to the couple hours I spent with the MS8 to get generally the same results. I've always used aftermarket HU's so I've never used the unit to EQ the incoming signal. It's not quite as plug-n-play as advertised. The first few auto-tunes I did with it were shit. Once I figured out what was going wrong and why I was able to get the issues corrected and get some good tunes going. For example, level matching. The subbass was either non-existent or overwhelming. I followed all of the suggestions from other users (level match prior to auto tune, auto tune at a low volume level, etc) and couldn't get it right. So finally I just left all of the amp gains at minimum during the auto tune and then went back and level matched via the gains to my preference after the fact. Another issue was the xover for the midbass. With the xover set any lower than 80hz, the MS8 applied way too much boost to the midbass and tried to make their cones jump out of their baskets. It's just stuff like that where you need to run it a few times, figure out what you didn't like and how to fix it. Once you start getting it sorted, results get better and better. I've got my qualms with it. I wish you could leave the processing off to try different xover points before auto-tuning instead of having to do the entire process every time. I wish you could kill processing to individual channels so you could compare different drivers or aiming without losing the auto-tune to the entire system, but you can't. Having the 31 band EQ at your disposal still is a nice feature though. The xovers are very flexible. Overall I like it, but I'm also fidgety and like having control over things, so there are times I miss a normal processor.

Could you elaborate on the why part? The years of R&D that went into the driver, to the custom designing and tooling nearly every part on the driver, to the increased overhead of a larger company and marketing costs for a company that actually spends money advertising.....there are a multitude of reasons. It's been a decade since the driver was released and it's still in the top tier of overall performance, which says a lot about the quality of the engineering and design of the driver.

And I'm really failing to see the benefit to that, especially once you understand the relationship between the wavelengths involved and the dimensions we deal with in car audio/subwoofer enclosures. M5 brought up wavelength earlier, and your defensive response was to link to an article that had zero relevance to the topic at hand. You need to revisit his earlier post and think about it a little harder rather having a kneejerk reaction. If he was doing this with subwoofers then he was doing nothing but wasting his time. There is absolutely zero possibility that it made any audible difference, much less a 5-8db difference. Zero. There were other factors at play.

They can be mind-numbingly boring at times, but if you want to learn it's the best way to go about it. 95Honda mentioned a couple good sources.

There are entire books written on the subject of enclosure design. If you are wanting that detailed of an answer, I would suggest purchasing one of those books as no single post is going to be comprehensive enough to cover all of the necessary aspects without, well, turning into a book. Trying narrowing down your question to something more specific, unless I'm reading too much into your question. Or download WinISD or something equivalent and spend an afternoon modeling different enclosures and comparing differences.

I'm not sure how or why you gathered that from the site, but I fail to see any real objective information that seems to substantiate that judgment. Hell, they guess at the Xmax of the Z based on nothing more than mechanical noise.......LOL. It simply looks to me like they took more time to subjectively review the Z than they did the Xcon. I'm not saying the Xcon is the best choice or a better sub, just suggesting that your interpretation of that site and it's information is a little inaccurate, IMO.

Fi recommends .6 - 1.2cuft for ported, so .9cuft ported is smack in the middle of that range. I haven't ran the #'s myself yet so for now I'll go with the Fi recommended range. For sealed even with the high Qts a net volume of .9cuft gives a Qtc of .574 (according to WinISD), which isn't too low but it's on the lower side. For the normal Qts sub .9cuft each gives a Qtc of .471 (according to WinISD), which again is pretty low and some people might like a slightly higher Qtc. A higher Qtc gives a little more bump in the mid-subbass region with less low frequency extension but due to the lower damping a response some people might call a little more "lively". It's really a matter of preference. I personally seem to like lower Qtc systems, my last system was a sub with a Qts of .4 running IB, but some people might like higher Qtc's a little more. Either way .9cuft is definitely on the larger end of things for a sealed enclosure. Whether or not you'll like that response most is really up to you. Luckily for you it's a lot easier to decrease enclosure volume than it is to increase it The other benefit is slightly better low frequency extension with the larger enclosure, which sealed with those sub is probably going to come in handy. EDIT: Didn't see the link to the enclosure before I responded. Don't bother trying to port that sucker. If the time comes where you can go ported (I'd recommend it) you'll be better off custom building the enclosure.

Honestly the differences between the normal Qts and the high Qts aren't huge according to WinISD. If you think you might be going ported at some point in the future go with the normal Qts drivers. If you think you will be strictly running them sealed then go with the high Qts. That sealed enclosure is a tad large, but would "work". In that sealed enclosure you'd be a bit better off with the high Qts option. But again, the differences are relatively mild between the two options and if switching to ported at some point in the future is a possibility I'd probably go with the normal Qts and run it sealed until the time to go ported comes. Those drivers would come alive ported. They are geared more towards ported than they are sealed, especially with being smaller diameter drivers which means limited displacement potential....the low end would really come alive ported. Sealed the low end might be a bit on the weaker side of things. Honestly if you could figure out how to do an external port in that enclosure, that volume would work out pretty well for a ported enclosure as well. And while I don't know Fi's sales figures I would also imagine the normal Qts option probably carries a bit more resale value and would probably more a little quicker.

A DMM and ~100hz test tone would be a very simple method of determining if the LPF was working correctly or not

I understand that much, but how and why? What changes about the subwoofer? I just want to know more about High Qts. "How and why" isn't a simple short answer. But basically, they machine the gap a little wider to reduce the motor force some. The change in Qts changes how the subwoofer responds to a given enclosure volume and the enclosure volume needed to achieve a specific Qtc. In a similar alignment (same Qtc) the high Qts option will have slightly more output and slightly more extended low frequency response throughout most of the passband, although it will require a larger enclosure to obtain a given Qtc. If instead of keeping alignment the same we keep the enclosure volume the same, the high Qts option will have a higher Qtc and the associated differences that comes from having a higher Qtc (slightly more peak output, less damping, less mechanical power handling, slightly less low frequency extension, etc).

If jumping it from the power wire fixed the problem, then the remote input on the amp wouldn't be the problem.....the wire itself or remote output on the HU would be.