building my first stereo system

first off, this post is going to be a compilation of a bunch of questions. second off, i don't have mad cash to blow on a system but i want something that will it pretty good.

i'm building my first system by myself. i have an alpine head unit (cda-9827) and 2 12" infinity subs that are currently running off a bazooka el2100 amp (from an older system). i just bought a new car so i want to customize it and still keep these parts of my old system.

first off, the subs recommend amping them to 300 watts rms. the amp i'm running right now is 330 bridged for one channel. is this ok even though i'm running two subs off it? i was thinking about getting a new amp, probably alpine or something that would pump about 340 bridged.  any suggestions here?

second, i'm going to replace the interior speakers and am looking at infinity reference series. how do these compare to the alpine type-s series? any other suggestions here. i'll probably amp the speakers to using an amp that puts out about 40 per channel, will this be sufficient (mainly concerned about power to the rear 6x9)?  i would also be getting a cap. i've been told to use these so your headlights don't dim. is this true and if so would a one farad cap work? i was planning on running 4 guage wire from the battery to the cap, then 4 guage from the cap to a distribution block, the 8 guage from the block to both amps. this sound alright or should i do something else?

thirdly, i'm going to be building a box for my subs. my friend suggested using ALL plexiglass so it is completely see through. has anyone ever seen one of these or heard of one or even think it would be ok to build one like that? i've been doing some research, mostly on www.automotiveforums.com and have learned some stuff. when the sheet that came with the woofers talks about the volume of the box i'm assuming that is the interior volume or the air space the sub needs. is this correct? i have drawn up a plan for a box that i really like and it fits the box volume requirements (assuming that i need 2.5 cubic feet since one sub requires 1.25 cubic feet?) and i really like the plan. i do not know if i need to take into account the theile-small parameters on the sheet or what other numbers i need to consider when building my box. so far the closest i have come to building it is drawing it on paper. i want to make sure i know what i'm doing first of all.

once again, sorry for all the questions but i want to make sure i make this all right the first time. i don't have the money to go out and buy the best of the best but i don't want it to sound real shatty either. feel free to say i'm full of it in my ideas or to say something i haven't considered. i'm wide open for suggestions.

You are going about this the right way, and I congragulate you for it.  You're working everything out on paper first.  This is the order in which to go: 

Select your interior speakers by comparing the two models you mentioned here.  You do this in a showroom.  If you're not thrilled with the highs of either one, keep shopping.  The front soundstage is the most important.  The rears work best by attenuating them to the point where they are just pulling the front sounds back toward you more.  So, the four interiors should be powered by a 4 channel amp.  You'll see a great selection of 4x50RMS at 4 ohm.

Read the info carefully for your subs.  Some manufacturer's will give you the air space you need and also the air space after the sub is installed.  If they don't particularly say both, then you will deduct the sub displacement.  Use 3/4" MDF for your enclosure, and make it double-chambered.  And sealed.  You can go on to plexiglass and ported boxes and fiberglass and whatever after you get a good system done for the first time.  Do what is easiest and most likely to sound the best.  Use the manufacturer's recommendation for a sealed enclosure, because they have already figured all the T/S parameters.

If the subs are single voice coil 4 ohms, you can run them to stereo channels of that amp, but not bridged.  Post up what they are in impedance and coils.  The amp will underpower them if the subs are rated at 300 RMS each, so continue to look for a better amp for the subs in the future.  With this amp, be very careful to set the gains properly, so that you are not sending clipped signals to the subs ( a danger of underpowering).

Shop for and install sound deadening in the front doors on both skins, if that is where the front speakers are, and on the rear deck and the trunk lid metal.  At a minimum.  Sound deadening is a priority of expense way before a cap is.  Leave the cap out of it until you have the system complete and sounding as good as it can get.  There are other power upgrades that would be chosen before adding a cap, and you very well might not need to go there with this system.

You're wiring ideas sound fine, and shop for a good value on the amp kit.  KnuKonceptz has quality for a fair price.  And, if the rear 6x9's are stock, get rid of them.

1.  Yes    2.  Yes, for your benefit.   3.  My best guess is that the Bazooka amp is stable to 4 ohms bridged, but if you wire two single coil 4 ohm subs together in parallel you get a 2 ohm load, which cannot be bridged onto the amp.  If they were wired in series the load would be 8 ohms bridged which is the same as wiring each sub to a channel.  You would take the latter as first choice.  And I did say you should continue to look for a more powerful amp for those subs.  

4.  I'm not familiar with those web retailers.    5.  Sound deadening is a must if subwoofers are used.  You will certainly be rattling metal.  You don't want that.  Everything improves with damped sheet metal.

Your sub manual shows specs of 1.25 cu.ft per chamber, and they tell you that they have already determined the displacement of the sub.  So you don't have to subtract for it.  Just be sure each air space is 1.25 before putting in the sub.  And also they account for 1" of batting or polyfil glued to the insides of the box with the air space given.

Read the fine print shown under the sealed enclosure volume specs in the manual.  They have allowed for the 1" box lining with the recommended 1.25 total cu ft air space.  Make each space 1.25 cu ft, line with batting, and drop the woofer into it.  Take note, you have the most leeway in air space with a sealed enclosure over other types.  That alone makes it the easiest type to build.  So some variation of the recommended air space is usually alright.  Take into consideration the space you have in the vehicle, and try to get the air space within 10% of specs.

Multiple outputs on a mono amp allows for easier connection to multiple speakers.  When you see two rights, they are connected internally.  You can use one or both, it doesn't matter.  Amp owner's manuals will show diagrams for wiring.

There are a lot of mono amps that will push 500 watts at a 2 ohm load.  Ideally, you have a total of 600 watts RMS with those two subs, but 500 watts will push them just fine and you'll have the most choices.  Here is one.