So normally I just use small 6" bass cannons or at most an 8" sub in a small box stuffed up inside the passenger foot well.  However I got an offer from an ex Fiero Stereo nut.  He had a custom Fiero sub box that was fiber glassed and shaped to fit the entire passenger side foot well and sits flush even with the bottom of the dashboard.  Its not HUGE airspace but is made for a 12" sub.  Now 12's are not normally something I fiddle with as I leave those to the competition guys and Rice Burners.  However with my new 4.9 car being so modified already. I decided why not have a little extra boom.  We have a family car now and 2 kids so its not like I'll be taking the wife out in the Fiero much anymore.

     My questions are.    Its a 12" rated for 1000w "PEAK"  500w RMS continuous.  My Current Kicker Amp behind the passenger seat is 300w RMS 500w peak.  I know under driving a speaker is almost as bad as overdriving one, but will that amp be enough to be safe?    If not, what should I look for in a new amp.  My amp is Old School probably been using it for the better part of 10 years.  I have thought about upgrading it, but its one of those, "if it ain't broke don't fix it" type of deals.   My head unit has 5 channel pre-outs 1 for the sub and 2 sets for the front and rear, however I just use the sub and run head unit power to the dash and pillar speakers, as I don't need them to do anything more than mids and tweets.  I have 2 dedicated tweets in the dash pointing at the driver and passenger and good quality 4x10 dash speakers and good pillar speakers.  I can't remember the brand off the top of my head. JVC IIRC.  

      The box is a sealed box and not a ported box, would I be better off adding a port to it.

         Should I add Poly fill to the box, I am not looking for the hard BANG punchy bass I am looking more for the low tones that my 8" subs and Cannons could not produce?

   Any suggestions from the Stereo guys are welcome.

Here are some pics of the new sub.  I don't have pics of the enclosure, as I have not gone and picked it up yet. 

well. the Rms is 0.707 of the peak watts.

looks like your current amp is too low in power. i would definately swap in an am with more power than you need and underdrive it a bit to get the cleanest power from the amp.

don't lose sight of the ohms. you have a 4 ohm speaker and that will overdrive an amp that is optimized to run at 8 ohms. check out the specs on your current amp and your new one (what ever that one is). make sure it can run a 4 ohm speaker (there may be a switch on the amp). a resistor can be added to the speaker as a last resort (a big one). 

with that kind of power, size up the wiring and dont go too small.

-food for thought.. the size (length) of a low frequency wave is huge. this is why the little old lady, 5 cars away can here you coming but it sounds normal in the car (minus the car's shaking). by selecting a smaller cone, or under driving the sub, you may end up enjoying the sound more (in the car). something you can test and play with.

:-D

Gary

Thank You Snow Man and Gary, yes Snow Man I do have a few amps, but the largest is only 500w Peak, 300rms.  Its an older Kicker Amp that I used to run on an ADS A8S Sub. Which was good for an amazing 132db (it was a really high end competition sub, and a lot of other gear to make the most of the sub, proper active crossover)

   Gary, I have 0/3 er 3/0 or 3 ought wire that I run for my remote mount battery and I usually use 8g high strand copper wire for power to the amp/amps.  Do you think I'll need to go to 4g high strand copper for this setup.  I know the 8g is enough for  my  current amp, I run the power direct to the battery and ground it to the passenger seat stud. 

     If I actually do go with a much bigger Amp I'll look at a Class D Monoblock amp to power it.  I might even give Brian a call he used to have a really high end amp I believe it was a 5.1 channel amp in his car.  Now that he is racing it and possibly selling it this time, he might want to let his amps go reasonably.  However IIRC he paid a fair chunk when amps were still rather expensive to buy and recently with the changes in electronics and  improvements in design the amps have gotten inexpensive.  (200 bucks will get you a Decent amp no a days)  Now don't get me wrong, I place anything one level over Pyramid to be decent.    I am also going to get in touch with Arun and Zander for the inside track on Amps and this new sub. 

Talk about bang for your buck, but I am kinda worried about quality for that price, wonder if it would blow up the first time I cranked it up.  (amp blowing up, not the sub)

2400w peak, 650w RMS for 80 bucks.

http://www.ebay.ca/itm/NEW-BOSS-R2400D-2400W-CLASS-D-MONO-BLOCK-CAR-AUDIO-AMPLIFIER-AMP-2400-WATT-/271001080160?pt=Car_Amplifiers&hash=item3f18ec5160 - http://www.ebay.ca/itm/NEW-BOSS-R2400D-2400W-CLASS-D-MONO-BL OCK-CAR-AUDIO-AMPLIFIER-AMP-2400-WATT-/271001080160?pt=Car_A mplifiers&hash=item3f18ec5160

Holy Crap, maybe this one,  http://www.ebay.ca/itm/NEW-BOSS-NXD4500-4500W-CLASS-D-MONO-BLOCK-CAR-AUDIO-AMPLIFIER-AMP-4500-WATT-/281027656578?pt=Car_Amplifiers&hash=item416e8dbb82 - http://www.ebay.ca/itm/NEW-BOSS-NXD4500-4500W-CLASS-D-MONO-B LOCK-CAR-AUDIO-AMPLIFIER-AMP-4500-WATT-/281027656578?pt=Car_ Amplifiers&hash=item416e8dbb82  

I found some as high as 13,000 watt car stereo amps.  Good Gawd what in the heck would someone do with a 13,000w stereo system aside from blow the windows from their cars, and the cars next door and the windows in the buildings around them.  I thought Aruns 2000w system was Huge.   Some of the prices on these amps are down right reasonable thought, couple hundred bucks for 4500w amp. I realize that is peak numbers but they still make 2000w plus RMS.

my expierence with car amps has shown me to look beyond the claims on the box an dig a little deeper into the instruction manual..

so i took a look.. http://images.bossaudio.com/manuals/NXD4500_DOWNLOAD_1.PDF - http://images.bossaudio.com/manuals/NXD4500_DOWNLOAD_1.PDF

the calims on the carton and the instructions sometimes differ and the wire gauge they recommend is often a tell tale sign. in this case, the brand you have here so seems to be the real thing.

the fusing is high and the amps use Mosfet technology.. nice. the amp should give you some serious power.

the next bit you need to look at is enclosures. with the fiero, space is at a premium. somewhere out there on the net, there must be some volume tables for 12" cones and that will give you an idea of how big the enclosure needs to be. you may find out that you need a really large enclosure and i would assume that you would simply make do with the space you have or follow what others have done. adding a baffle to the enclosure, or sealing it up will also affect the speakers resopnse. i would expect the maker of the cone would have some data on what is best there.

consider, that some other guy with the same stuff and has a large car and can get the volume sizing he needs may end up with a different sounding system. so you will need to be prepared to accept the result you get, given the cars size.

i am assuming that you have a crossover in the input (from the stereo).

sounds exciting.

Gary

Yes my stereo has a really nice crossover, so nice in fact that I can't figure out all the settings, I am going to have to take it to a stereo guy to tune it for me. 

  Now as to the box, the speaker has an optimal air space of 3.5 cu ft which is the size of a bar fridge so obviously I can't do that.  I am getting a box from Fire451 that he ran in his Fiero, its a custom fiberglass box molded to the shape of the passenger side foot well and turns the entire foot well flush with the dash into a giant box.  Its a sealed box and I'll be putting roughly 1lb of Polyfill in the enclosure to make it act like a larger enclosure.  He had fairly good luck with the box but is now into VW's so its not of much use to him.   He actually helped me pick out this sub.  However at the time we thought that might current amp would be able to run the sub, maybe not drive it to full excursion, but still make it sound good.  However after seeing what my current amp actually produces (290w RMS at 14.4v) I am going to have to get a new amp.  

      I am test fitting all this in my 88GT and will move it all into the V8 if I ever get it back.  (Shop has blown up 2 engines on the dyno and is installing the 3rd now)     I am looking for the deeper tones that my 8" subs simple could not make.  My 8's were good for fast hard punches but were horrible when cranked up to the max volume. IE when going down the highway with the windows down and some really good 80's track comes on and you just have to blare it. 

ya know, a bar fridge would be a nice addition to any Fiero!

any existing sub box is a good sub box.

post pictures when you get some.

Gary

Well I decided to go ahead and Go Big with the amp.  Its better to have more power and not need it, than to need it and not have it.

4500 watts peak, 2100w RMS, from what I have read 2g minimum power cable and recommended 0g.  Plus they also recommend taking power and ground directly from the battery.  Which in my case is going to kinda suck, as I have a front mount battery.

http://www.ebay.com/itm/NEW-BOSS-NXD4500-4500W-CLASS-D-MONO-BLOCK-CAR-AUDIO-AMPLIFIER-AMP-4500-WATT-/281027656578?ssPageName=ADME:L:OC:US:3160 - http://www.ebay.com/itm/NEW-BOSS-NXD4500-4500W-CLASS-D-MONO- BLOCK-CAR-AUDIO-AMPLIFIER-AMP-4500-WATT-/281027656578?ssPage Name=ADME:L:OC:US:3160

I'll run 0g for the power and ground as that is what they recommend.  I am running 3/0 (huge freaking welding cable) From the battery at the front all the way to the back of the car, which will give the alternator a bit of a cushion, and this is going into the 4.9 Fiero that has the Caddy Alternator that is IIRC 120amp alternator needed to run all the Caddy electronics. (that obviously the Fiero does not have)  I "might" get a big cap and install it between the amp and the battery, but this system is going being setup for competition class, I just want a bit of extra boom in my Stereo. I am not trying to rattle the mirrors off the car.  I have spent nearly as much on Spark Plugs rotor/cap as I have on this amp/sub combo.  Like I said in an earlier post I can't believe how cheap car audio has gotten. 

Sub through Parts Express was only $46 bucks amp from Ebay was 122 plus shipping and taxes came to 165, Head Unit from Fry's Electronics in Oregon was $204.  Granted if I were to buy those parts from a local Canadian retailer, I'll bet the sub would have been over 200, amp 500 and head unit priced at Future Shop was 419.  What's more kinda funny, I only paid $300 for the car when I bought it.

Ok I ran into a problem today!

     I was out doing Christmas shopping and browsing the electronics section, I came across speaker wire and realized that I didn't have any at home so I better grab some for the install.  Honestly I have no idea what gauge wire to buy.  They had 18g to 12g I went ahead and bought the 12g but not sure if that will be big enough or not.   Anyone have any idea what size speaker wire I should be running?

Ok so I got the sub box here, and took some measurements.  The interior airspace is well over 1 cubic foot, however when you take out the airspace from the sub. (I assume that’s what you do, rather than just quoting the air space of the box)  It’s probably just about 1 cubic foot useable.   I promised pics of the enclosure when I got it, so here they are.

Outside dimensions are 21 inches by 15 inches at the face and interior dimensions are 19 inches wide x 14 inches deep  at the largest area, and 14 inches tall. 

From the looks of it, he added wire mesh to make it stronger, it is formed to fit the exact footwell of the Fiero and sit flush even with the bottom of the dash. Leaving the passengers just enough area to cross their legs in front of it, at the same time getting a let massage when it turned on.

I forgot to post these here but here are the pics of the amp.

I was suprised with all the extra stuff that it came with, like the data link cable, the mounting hardware and the bass control knob for under the dash.  Also this sucker is HEAVY, which actully made me feel better about it.    The Subsonic filter is something I am going to have to read up on.  So far I have my sub, head unit, amp, box just no car to put it in.  Am still waiting for the car to be done from the shop.

I am so eager to test this stuff though I might install it in the 88 just to see how it sounds. 

The 88 already is wired for an amp, and the new head unit is already installed in the 88, as I was using the head unit during my travels around Oregon and Washington.