Impious

It depends on the amount of power you are running, volume of your enclosure and things like your musical selection and listening habits. The purpose of a SSF is to limit the excursion of the driver at certain frequencies to decrease the possibility of damage to the driver. Of course this is a big problem for ported enclosures because of driver unloading below tuning. However exceeding the mechanical limits of the driver can also be a potential problem in sealed enclosures depending on the volume of the enclosure, amount of power, etc etc. To see if you are at risk, it's a simple matter to load the driver and enclosure into WinISD and look at the cone excursion graph. In a sealed enclosure excursion will always increase as frequency decreases, what's important to note is the frequencies at which you begin to exceed Xmax (although exceeding Xmax won't damage the driver, you don't know the Xmech of the driver so we'll use Xmax as an approximation to stay on the safe side). While it's probably pretty likely you won't really need an SSF, it is important to note where you might begin to run into problems. It helps keep you from doing stupid things like blasting a 20hz sine wave showing off for friends thinking you're "safe" because you have a sealed enclosure when it could in fact potentially damage the driver if excursion is too high in your enclosure volume with your power level. Or if you, for example, listen to a lot of classical music which can contain very low frequency reproductions. The other use for an SSF is to use it as an "equalizer" to smooth out a bloated bottom end

What exactly is your goal with the volt meters? I would agree with edouble that I don't see the point in having 2 meters. In most daily car audio installs I don't really see the point in having one. If you constantly run your system to the edge then the solution is to improve your electrical system, not install a volt meter.

Select an amp before you select an impedance. Which coil configuration you purchase depends on the amplifier you plan to run with them. No, completely unrelated.

How exactly do you plan to actively cross a 3-way active front stage + subwoofer with a 3-way active headunit? There are options, but none of them are really "good". IMO stick with 2-way.

I would disagree. The people who think you need a DMM or O-scope to "properly" set a gain make it overly complicated, especially since both methods are completely misused and misunderstood. It's something you can do satisfactorily with nothing but your ear. No need to pull out equipment and test tones only to end up with a gain that's still not necessarily properly set. As 95Honda said, a little bit of clipping isn't bad and running it into that range will allow you more dynamic room and average output compared to setting it with a conservative method and test tone. You are leaving power on the table with those methods and not really gaining anything in return.

In case the other 2 posts weren't enough, I would also not recommend using the o-scope to set the gain. It doesn't resolve enough information to really be of any use.

Fixed your post Sean

What level of test tone did you use? If it was 0db then that gain setting is overly conservative. Gain setting I usually do by ear. If you want to be on the safe side and use the DMM method you can, but I would recommend a -3db, -6db or -10db test tone depending on your usual music selection, listening habits, ability to discern driver stress, etc. The lower the recording level, the less conservative the gain setting. What frequency test tone did you use and what is your port tuned to? Assuming the frequency of your test tone was the frequency you wanted your SSF set to then yes, that is correct. I.E. if you wanted the SSF set to 35hz, you would have needed to use a 35hz test tone.

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Did they actually burn, or tear apart? Makes a difference if you were thermally or mechanically overpowering them.

No, as Ryan said the "Kick" version is supposed to have slightly better midbass output at the expense of some output at the top and bottom end of the spectrum.

My guess would be Hybrid Audio Technologies. HAT is owned by Scott Buwalda. Scott lives in (and hence HAT is headquartered in) Georgia. Headunit was a Panasonic "Bottlehead". They did make a US version of the headunit, although they are much more rare than the Japanese version. The tube is more looks than anything, it's barely in the audio path.

What exactly are your goals for the subbass? With that much volume you could do a ton of different things. And I wouldn't limit your options to the IB3.

In addition, need to know if there are any mounting depth restrictions and a more detailed description of what you are looking for performance wise out of a subwoofer. As Tirefryr said, there are hundreds of combinations and options. You need to narrow down that selection by giving us more details.

Even big e-retailers can sell fakes. Unknowingly, but it has happened. That's the risk of buying unauthorized. The price is cheaper, but that's because there are greater risks involved. That's the trade-off. What products are you looking at buying?

Hard to know for certain until installed. If it does once installed, consider a battery in addition to the big3. Pretty much sums it up. You need to install the system first and go from there. Too many factors to know before hand how the electrical will behave.

Just because it's a 2ohm load doesn't mean it will be any easier on the electrical system. It depends on the efficiency of the amplifier, not the impedance of the load.

As I said, you could make your own if you wanted to. Manual explains how. But your plan of leaving the amp full range & using the crossovers in the headunit is a much better option.

You would be pretty close to a volume equivalent to the VAS of the drivers, which without running the #'s to determine the resulting Qtc I can tell you that you would be pretty close to the lowest acceptable volume required to reasonably be considered "infinite baffle". That said, there's nothing inherently wrong with using them in a slightly smaller enclosure, you'll just experience a little raise on Qtc and a resulting shift in the frequency response. Any particular reason you are stuck on using such a large enclosure? Not that I have anything to say against IB, I run it myself. But most people running infinite baffle in their vehicles use their trunk/etc as an enclosure & don't actually have a 13cuft enclosure in their vehicle. If you don't have the space or layout to run car audio's version of infinite baffle, I think you might be better off saving some space & utilizing a ported enclosure.

Check ebay or make your own. They were simply a series of resistors. If you still have the manual, they have a graph & formula for determining the value of the resistors. The manual is on the website HERE, however the PDF on their website is a little hard to read in that section but might be legible enough to help you.

Around 1.25cuft per driver would be fine. 600w would be fine as well. No audible difference between 600w and 750w

As you can tell, I'm starting to get outside my area of expertise

Skip the DD-1. Gain match via DMM. SSF setting is pretty simple. The SSF is nothing more than a highpass filter, which means the frequency that the SSF is set to is the -3db point of the signal (presuming they use a basic Butterworth type filter for the SSF). Using your example; Play the 30hz test tone with the SSF knob turned all the way down (lowest frequency setting) or off. Measure the output voltage of the amplifier. The amount of voltage doesn't matter, literally doesn't matter, you just need to know what voltage you are starting at. Multiply the voltage you just measured by .707 and record your answer, this is your target voltage. Turn the SSF knob up until the voltage decreases to the target voltage. This means you've set the SSF so that 30hz is -3db, which means the SSF is set to 30hz. So, let's say you play your test tone and measure voltage at 2V. 2 * .707 = 1.414V Turn the SSF knob up until the voltage output from the amplifier decreases to 1.414V Your SSF is now set to 30hz. Repeat for 2nd amp. You don't have to start with the same initial voltage, just multiple the initial voltage by .707 and then set the SSF knob to that new target voltage. Now they are both set to the same frequency. Last, I don't know what you mean by "Eventually I'll use some sort of Bass eq to bring the voltage back up." There will be very minimal loss of preamp voltage using a y-splitter, very possibly there will be no measurable loss. No need for a "bass eq to bring the voltage back up".

That is true as well. Amps like LP did the significant underrating, other amps weren't underrated at 4ohm but would run at very low impedance.

I don't compete & SPL isn't my thing, but I thought the newer competition formats used actual power rather than rated power as they used to. I remember the Atomic's (or maybe it was American Bass, someone) being a huge controversy for that reason a few years ago....they output a lot more power than they were rated, so some people were trying to get the competitors using those amps bumped up in power class.