Impious

Someone pushing their equipment beyond realistic limits is the fault of the owner, not the amplifier. There's not much inherent to an amplifier that would cause an audible difference like you describe. There's something more to the story.

Fuck. Can someone please fix the rep on this post? It was a -1, I went to hit the +1 as I didn't see a sensible reason for a negative rep but instead accidentally hit the negative again so now it's at -2

How do you "know" this? I ask because the word "underrated" seems to be thrown around a lot regarding most of these amps, but I've never seen a properly conducted bench test of any of the amplifiers posted or released. It seems most of the time people are basing this on nothing but clamp tests, which are useless for determining if an amplifier is "underrated".

I missed the part where he was specifically referencing HT crossover designs for his midranges. As Ryan said.....most of what happens in HT isn't going to transfer to car audio as our environment and other constraints are so much more challenging and so much further from ideal.

Ah ha! Do you see a huge difference between a tweeter/midbass at 88db 1w/1m and a midrange at 91db 1w/1m? I see 3db of difference Audible difference is something that you can't determine just from looking at the listed sensitivity specifications. It's going to have a lot to do with the installation (driver location, aiming, etc) and the actual FR of the speakers a long with their operating bandwidth. I wouldn't worry about a 3db difference in sensitivity, that's easily enough corrected for if necessary.

Why haven't I EVER seen a build log or even mention of an l-pad for car audio? Because most people doing the build logs are either using a prebuilt passive crossover (which either has an L-pad/attenuation or it doesn't), or they are running active (where a passive L-pad isn't really necessary). Over in Europe there are some SQ competition formats which are 100% passive crossovers........those competitors probably use L-pads as they custom build all of their passives.

If you are running active you have no need for an L-pad. Adjust the gains on the necessary amplifier channels or adjust the level settings on the active crossover to properly level match the drivers.. 91db 1w/1m sensitivity is 91db 1w/1m sensitivity regardless of the impedance of the driver because it's a proper 1w/1m measurement. The only time you need to "correct" the sensitivity rating is if it's a 2.83V rating, because 2.83V results in different wattages depending on the impedance of the driver. But if it's measured at 1w, then 1w is 1w regardless of the driver's impedance.

We bought our house from an estate and the old lady who lived here died in the family room. We've had other sort of weird stuff happen, so we've always sort of joked about her ghost being here. But this is the first time something "helpful" happened. I've lived in this house since '03 and I've never had that door move from just walking through the room, and the magnetic latch is actually fairly strong. You've got to give it a solid tug to get it to pop open, much less unlatch and swing fully open.

My wife was carrying an arm full of towels into the bathroom. Once she got in there she realized her arms were full and she couldn't open our linen closet doors (which have magnetic latches). As she was standing there deciding where to sit the towels down, the door unlatched and opened all of the way. She said thank you and put the towels away. Now if we could just figure out how to train it to fold the laundry too we would be all set.

Clamp results are pretty useless. Typically the only people impressed by clamp results are those too ignorant to know what they are actually looking at (which is normally not their fault, they just don't know any better).

They are very good subs. You won't be disappointed.

Noise Troubleshooting Guide

i like the hybrid-audio stage III and stage IV they look good have you used them at all? You aren't going to be able to get Hybrid for your budget.

A friend of mine needs to fix 6 of them for his pro audio system. He loved those subs originally, but he is afraid to buy the recone kits. He doesn't know if they're worth the cost. I bought 4 midbass speakers for his car, on that site. They seems to be very good. With the small motor (neodymium or somehing). He has only installed 2 of them, but he plans to use all 4. He likes them a lot. He managed to make them blend very well with the rest of his Davis Acoustics door speakers. I'll take a look at their amp quick ! Do you know what's wrong with the subs? Those NRT motors used a coating/plating that isn't very heat tolerant and can peel. It might be as simple as removing the motor and cleaning the gap.

If nothing changed and you are not over driving your speakers it sounds like you have a bad amp.

In it's most basic form a subwoofer is nothing but an air pump. The more air that it moves, the more pressure is produced, the louder it will be. If one moves more air than the other, the one moving the most air will be loudest. It's more complicated than that, but if you are asking simply in terms of output then yes, if two speakers have the same cone area and are playing the same frequency (and are in the same enclosure alignment) but one speaker is louder than the other......then the louder speaker would necessarily have more excursion (which is why it's louder). Now the question of why one may have more excursion at a given frequency in a given enclosure than another speaker is a lot more complicated to actually answer. There are a lot of things that make two subwoofers different and why they behave the way they do. There are literally entire books written on the topic, so trying to narrow it down to a single post or thread would be difficult. If you can narrow down your question some we might be able to answer it more directly.

Been around for a long time, they got out of car audio several years ago but have continued in the OEM speaker market. Their NRT motor topology is rather famous. They are more well known in the home audio realm for their NS series of subwoofers and small diameter wide band speakers, both of which use the NRT motor. Oh, and their other well known product is the "bass shaker". Overall a good company that makes quality products. Obviously they design to a price point though so I honestly have no idea how good the comp speakers are....they did have a set of comps that were fairly popular, the MR series I believe, not the speakers on blow out on PE. Their amps should be solid. http://www.aurasound.com/

Need to know budget, atleast

To add to what was said, keep in mind that a barrier such as mass loaded vinyl is most effective with a decoupling layer between the barrier (the MLV) and the vehicle body. I believe it's mentioned on the SDS website but hasn't been in this thread, so I thought it was worth a mention. Ideally you would have a layer of closed cell foam or a similar product underneath the MLV.

Might be a loose solder joint or poor connection somewhere. For giggles you can try testing the impedance at different points, such as right at the tinsel leads instead of at the connectors. See if the readings change any.

They should read nearly identical. Make sure the batteries in your DMM aren't low to start with.

So you're not very savvy with car audio yet, but still decided to buy a frankenwoofer with thrown together soft parts on a motor and no specifications? Doesn't sound like a very rational decision to make. Without atleast having T/S specs you are not going to be able to build a proper enclosure for the subwoofer. You're not going to be able to research making a box....there's nothing to research, it's a pile of parts thrown together to create a functioning subwoofer.

What parameters do you have for the XL ? Depending on what parameters you have it might be possible to calculate out the Vas & sensitivity.

That's my job here.

The company itself ran by a jackass so I would not recommend their products. As Denim mentioned you would be substantially better off by contacting Sound Deadener Showdown. High quality products sold by an individual who actually understands sound deadening and will be extremely helpful in helping you achieve your goals.