helotaxi

Best way is to build a Zobel filter into the crossover that will stabilize the impedance and make the crossover more predictable. You don't need a plot of the impedance curve. You do have to get measured values for the T/S parameters but that can be done with a voltmeter and a signal generator. I found a really good site on crossover design but I don't have the URL anymore. I found it via google so give searching a try. edit: Besel, Zobel, the memory is the first to go.

Yeah, I actually fly helos from the base for field security. Nothing other than our Huey's flying out of the base anymore. Tirefryr- The Pres's security detail is usually hauled around in a C-141 or C-5 if the airfield they are going to is big enough or multiple C-130s if it is a smaller airfield.

Now that I've had a chance to get my XXX broken in an listened to it for a while, all I can say is add that one to my list for sure. I can't see buying another sub other than the XXX.

Normally you want it set right around the tuning freq, there is no formula for figuring it out. Below tuning the enclosure will actually push and pull the speaker farther than it would travel on its own. This can lead to damage to the sub as the limits of the suspension are quickly reached at really low frequencies. The purpose of a susbsonic filter is to keep these frequencies from getting to the sub.

WTF does inverting the sub have to do with anything?

The "Digital Reference" amps were Gen 1 (there were two different logo designs on these and they were built in the late '80s, the original high current amp) and the Gen 2 which were basically the same as the Gen one but with one channel inverted so they could be bridged without the 400BDG bridging module that inverted the phase of one channel externally. The Gen3 had the removable top plates and the frequency cards underneath. They were marked "Competition Amplifier" and as I understand it had a higher current capability with more margin and current head room in the power supply. Gen4 included the R series and the G4. They had the integrated x-over and Intellibass added. I don't know what the distinction of the G5s are.

If I could get ahold of another one I would be making all the dB drag competitors here in town cry Bunch of hacks best I can tell. Think that the 13W7 is God's gift to SPL. Not saying that the XXX is, but I think I have a bit more of a clue as to how to go about getting loud. I so want to find anothr on of those amps. Gotta be of the "Competition Amplifier" rather than the "Digital Reference" breed though. Most SPL installs are not pretty but I can't abide non-matching amps.

It's amazing what you can do with a simple design, a table saw, two routers (one table mounted), a chop saw, a nice fresh sheet of MDF some PVC, a pound of #6 drywall screws, a free afternoon and a ton of patience. It was the second box I made in two days (I didn't like the first one and the prongs on a bunch of the t-nuts holding the sub in broke off so there were only 3 screws holding the sub in the box and that wasn't going to cut it. It was entirely glued together and I destroyed it getting the sub out.) and I had to cut two back panels to get it perfect. The box is sealed without the use of any glue or other sealant and in held together entirely by screws, none of which are on the front or rear face of the box. There is actually only one screw (other than those holding component down) visible in the whole install and it is right between the EQTs. All the rest are either on the sides and bottom of the box (the countersinks for the row closest to the front face were filled) or under components.

Fixed. Damn copy function truncated the link and mucked it all up.

and much more depends on the front stage than the sub.

Well I tried linking the pictures inline but I was getting red X's. Oh well.

What size are the screws that hold the mounting bracket on the amp?

If you're going to the trouble to cut up the back deck to install 8s why not just cut up the back deak to vent the bass from the trunk and use whatever subs you want?

I'm sorry. I regret to inform you that isn't big enough. Not planning on using the back of the truck, eh?

Steve- The first question that you should ask is has anyone on here actually heard a properly designed bandpass enclosure, cause I have only ever heard one or two myself, and not recently either.

They might want to tighten those bolts down hold that abomination into the enclosure. Nice publicity shots...or is there just no one in So IL man enough to pick that thing up and carry it in the door?

Sweat pant material IS fleece. Ramos- I always add a layer or two of mat or cloth over any form that I make out of t-shirt, so strength isn't much of an issue and the t-shirt is just soooo much easier to work with.

Cool. Just curious.

Well, the good news is we have answered one of the unanswerable Zen questions; "What is the look of two subs humping?" leaving the one hand clapping thing still unanswered...

This for 2 different cars or what? Just wondering about your reasoning behind going with 2 different sizes of subs and how you plan to deal with the cancellation issues that will arrise if they are in the same system and fed the same frequencies.

This the "quantitiy has a quality all its own" type of SQ or what?

"Cardiac" was a series made by Petras.

Does that "thing" use a 10" sub basket for the spider land or does it just look like two subs humping for no reason?

The gain is a tool meant to match the output level of the processor or headunit directly before the amp to the input level needed by the output stage of the amp for maximum unclipped power. Most amps have a range of around .2-5V within which the gain section can match the voltage to the output section. Most all HUs' outputs fall within that range. You want to set the gain so that at max volume (usually less than max on the volume scale on the HU) the gain setting corresponds to the voltage coming from the source. If the gain is set too high, the amp will clip, producing a ton of distortion and heat. If it is set too low, you will not get all the power it is capable of producing. You are better off setting it too low rather than too high. You could leave it set a max if you wanted, but the range of volume control that you had would be tiny. You would be able to adjust the volume from 0 to whatever volume corresponds with the minimum input voltage of the amp. Increasing the volume beyond that level would only increase distortion and heat, not sound level. The way an amp works is that the output stage takes an input signal and multiplies it a fixed number of times. The ouput section is limited by the power supply rail voltage (the amp power supply, not the car's 12V supply) as to what the maximum output voltage can be, after multiplication. If the signal to the output section times the multiplier exceeds this maximum voltage, any amount in excess is cut off or "clipped". Since there is no standard for the output voltage for car audio source components, there is no way to make a single input voltage for an amp that will allow the volume to be adjusted and the amp to make its max power without clipping. Enter the adjustable sensitivity control, commonly called the gain. All this is is a low current stage of amplification with an adjustable multiplier to convert the wide range of signal voltages to the voltage needed for the input to the output stage of the particular amp. As long as the signal voltage is within the adjustable range of the preamp stage of the amp, you will be able to adjust it so that you get maximum unclipped power from the amp. With modern HUs that have high-voltage outputs, the proper gain setting is generally somewhere just above minimum assuming that the input range is .2-5V. Bass boost or any other type of EQ boost has the effect of boosting the voltage at that frequency. If you have the gain set properly with the boost off and then turn it on, the volume at which the amp begins to clip will be lower as the boost sends the amp past its limit sooner. If you plan on using boost, you must account for it when setting the gains to keep the amp from clipping.

www.thezeb.com has all their a/d/s stuff on clearance. The top-shelf set is going for $329 IIRC. It is only a 5.25" set but they are some of the best speakers I have ever heard.