wyo_vr4

Disclaimer: I am by no means an expert. This is just a write up of what I did. Hopefully it will help some people.

Stereo Install on 2002 Trans Am Convertible (w/Monsoon)

Unplug the negative battery cable before messing with your car’s electrical wiring.

Remove Monsoon head unit. Pop the trim ring off from around the stereo and climate controls. Use a screwdriver or just do it by hand. Unscrew the mounting screws and partially pull out the stereo so you can get to the back of it. Make sure you don’t have a CD in there, unless it’s Celine Dion or some other sissy crap, in which case leave it in. Disconnect the wiring harnesses and antenna cable. Remove head unit. Easy.

Getting new head unit ready for install. I installed a Sony MP-80 ($249.99 when I bought it) head unit I used to have in my VR-4. I used Scosche’s GM1503 install kit, GM02 wiring harness and antenna adaptor. Leave the speaker wires exposed on the wiring harness provided by the stereo or cap them, depending on whether you are going to hook up the pre-outs to separate amp(s) or not. Either way, I’m rewiring the whole car. You can use adaptors and factory amp bypasses and whatnot but that’s for lazy people. Running all new speaker wire is higher quality, more reliable and really not all that difficult. You’ll thank yourself later. Anyways, follow the included instructions and get your stereo ready to install in your house rather than in your car. I soldered and heat-shrank plastic on the necessary wiring harness connections. Plug it in to your car to check it powers up, operates the power antenna and all the functions work. Obviously, you won’t hear any sounds yet. Disconnect and set aside for later.

Remove rear seat speakers. Unlike the door speakers, the plastic grills do not pop off and on. Remove the whole panel by unscrewing and removing the plastic part that covers the seat belt assembly and unscrewing the panel down on the door sill by the base of the seat. Then take a allen wrench and unscrew the part that the upright of the rear seats clips in to. You will need to unclip the wiring harness that powers the light then remove the panel. Unscrew the speaker and remove, first disconnecting the wiring harness by pressing the button or using your screwdriver to press it and pull away from the speaker to disconnect.

Remove door panels and speakers. Look around the door panel and unscrew all the screws. There’s one smaller one, next to the door handle that holds the plastic trim piece in place, and 4 larger ones dotted around. Unscrew and remove the triangular panel that sticks up towards the front of the car. Remove the locking switch (the part that moves back and forth when you operate the power locks and has a visible red part when the door is unlocked) by pulling it towards you (away from the door). It may be stiff. You’ve just got to wiggle it and work it out of there. Next, pull off the small panel that surrounds the handle. You’ll need to pull the handle a little bit. Pry up the panel with the door locking and window switches up. There are two wiring harnesses and a lightbulb around the back. Pull the wiring harnesses out and unscrew the lightbulb. Work your fingers around the edge of the main door panel and pull the whole thing up and towards you. If it doesn’t want to move, maybe you forgot a screw. Compared with some other cars I’ve worked on, this was remarkably easy. Just a couple more things: you’ll need to unclip the tweeter’s harness before completely removing the door panel. Unscrew and pull out the plastic thing the woofer is mounted on. Don’t make the mistake of trying to remove the speaker itself at this point as you will most likely end up breaking off the speaker wiring harness. Reach back there and unclip the wiring harness after unscrewing the plastic mounting bracket. Then you can put the whole thing on a table and unscrew the speaker itself.

Front component speaker install. I used Sony’s XS-D170SI (currently $98 shipped from www.hookedontronics.com ). Unscrew and remove the factory tweeter from the door panel if you have not already done so. Replacing it with your aftermarket tweeter should just be a matter of popping it in the hole and screwing it in, running the wire out back. Likewise the woofer mounts easily into the plastic bracket, using the existing screws and holes. Make sure the old wiring is either out of the way or removed. Unscrew and remove the kick panels/door sill plastic trim. Thoroughly clean the metal of dust and black sticky crap and Install Dynamat Xtreme or other sound deadening product in the door at this point. With the door wide open, pull off the flexible rubber grommet that goes around the wiring from the inside the car to the door. You should be able to reach from each side and touch your fingers together. That’s where you’ll run the new speaker wire. Run wire from the speakers inside the car and tuck it away in preparation for crossover mounting. Optional: Hook up the stereo and test speaker operation. Reinstall door panel and kick panel by reversing the above directions. It can be a pain to line back up but keep trying – you’ll get it!

Rear speaker install. I used Sony’s XS-S160CX (currently $74.06 shipped from www.6ave.com ) Run speaker wire first. You shouldn’t need to remove any further parts than you already have. Use appropriate (3/4” thick 6 ½” wide, in this case) spacer and Dynamat between the speakers and the mounting surface for convertible top clearance. If you were dumb and broke off the rear speaker plastic covers like I did, use the new covers you got with the component set or rear set in their place. Et voila! Check operation before putting car back together.

Crossover mounting. There are a number of spots you can mount them. I chose to remove the dash panel under the steering wheel and affixed them to the inside of it using Velcro. There’s plenty of room, they’re out of the way and it’s relatively easy to run the speaker wire from the head unit (or amp) and the doors.

CD Changer install. The factory changer won’t work with your aftermarket unit so remove it by unscrewing the brackets and unplugging the wiring harness. Install your new changer in its place. I bought a Sony CDX-757MX (around $110 shipped from an eBay seller). Along with Pioneer and Alpine, Sony offers changers that are fully compatible and controllable with their brand of head unit. The 757 is a 10-disc unit with CD-R/CD-RW/MP3 capability. 10 CDs full of MP3s is roughly 50 hours of music, give or take a few! After mounting the changer, run the supplied audio wires and power/control wire to the head unit while you’ve got your car torn apart anyway.

Factory Monsoon amp removal. The amp is located near the power antenna, a little bit further towards the front of the car in the wheel well. Remove this dead weight by first removing the spare tire and the plastic trim panel that conceals the amp mounting bracket. Unscrew the mounting bracket, unplug the large wiring harness and work it all out of there.

Sell all the **** you removed on eBay! Don’t bother keeping it to maybe one day reinstall when you sell the car. It’ll gather dust and unless you have far too much time on your hands, you’ll end up tossing all of it. Make some cash now to help pay for everything and look good in the eyes of your significant other. I’m betting they’ll prefer you spending less cash on new **** and not clogging up their garage with old ****.
I got $150 for the changer, $85 for the head unit, $25 for the amp, $23 for the front woofers (one of which was broken), $10 each for the tweeters and rear speakers for a grand total of over $300!
The install cost me $98 for the front components, $74 for the rear speakers, $110 for the changer, $20 for a good deal on some Dynamat Xtreme, and maybe $30 for wires, wiring harness, head unit mounting, speaker spacers, miscellaneous supplies, etc. I had the head unit already, that I paid $250 for. So, that’s about $330 in new purchases and $580 total. Net total cost = $280. Yes, I’m a cheapskate bargain hunter. And yes, I know Sony is not exactly the best out there but it’s good enough for me.
There’s still a lack of bass but the sound quality vastly improved. Next up: amp + subs! (when I have the time, money and inclination…)

todddchi

iTrader: (3)

I chose to keep the factory head unit to avoid theft temptation. If you go this route, it is possible to bi-amp certain aftermarket 4 ohm co-axials.

In convertibles... the front speakers are bi-amped with the head unit driving the tweeters and the amp driving the woofers. With some soldering time you can duplicate this wiring arrangement with aftermarkets.

By doing this, you won't pick up any major volume, but you can greatly increase sound quality. Given the compromises inherent in a convertible, I think this is a pretty strong upgrade. I for one didn't want an aftermarket deck visible, nor did I want to go through the hassle of trying to get subs into the system and rewiring everything for aftermarket amps.

So for me, this path combined with an AUX input made for a nice-sounding, factory integrated system. It's really a no brainer if you have blown factory speakers.

1LoudTA

iTrader: (11)

cant you just hook up an amplifier that can also work with low frequency speaker wires to power subs in the stock system???

i kind've wanted to pull out the 6.5 subs in the back seat, put in my kenwood 800 amp and my 2 12" subs....

todddchi

iTrader: (3)

wyo_vr4

Yes, if his factory amp is totally gone, then someone would have had to rewired the entire system. It really isn't too difficult to run speaker wires from the h/u to all four speakers. Someone very realistically could have done this. I am not aware of any sort of "jumper harness" that would allow removal of the amp, but this is in theory also possible.

1LoudTA

You could splice into any full-range high or low level wires and drive a dedicated sub amp/tube. No problem there. Just have to pick the right ones, since there are both high level from the h/u and higher level from the amp, and filtered and unfiltered wires in the oem setup.

And 12" subs just in a box in your trunk will just rattle the deck lid with the top down. It won't work like in a coupe when the top is down.

todddchi

iTrader: (3)

I just noticed there is no mention to be careful with the length of the screws you use with the back speakers. The top drops down in this area - you not only have to worry about the linkage hitting the speaker magnet, but also the top getting snagged on the screws. Be careful to trim them to just long enough, if they are too long.

I also sold my 4x stock speakers on the bay for over $150. Specifically showed the PN and usage, maybe vert ones cost more or something, I dunno.

todddchi

iTrader: (3)

This will be updated from time to time using suggestions from this thread - and including links to other images. Not all of the images are mine, and I will try to credit them to the owner when possible.

Introduction:

Although people tend to ignore sticky posts and FAQ posts, asking the same questions over and over again, I am going to try to pull together a basic overview of stereo options and generally good / bad ideas when working on a system for a 98+ 4th gen convertible.

I'm doing this because I made quite a few costly mistakes working with my convertible. I've put systems in several cars and trucks - and going off of that experience wasn't the most efficient path to take. Many of my mistakes could have been easily avoided with a good reference to work from. I hope to make this thread such a reference.

The thread will be divided into several main topics in the following posts:

- Factory monsoon overview
- Overall upgrade paths
- Deck
- Factory speaker locations
- Subwoofer options and amps

Much of the information applies to coupe guys and general practices, but this thread is made for us vert owners.

todddchi

iTrader: (3)

Factory Monsoon Setup and a brief note about the base V6 setup:

The factory monsoon system is the same for all 98+ convertibles. There are no real wiring / setup differences between Firebirds & Camaros like there are in coupes, though the front speakers are different due to the door panel design.

There is a base system that was standard on V6 vehicles (and some have said early V8's). If you have that system, it is just a plain 4 speaker, 4 ohm system driven off the head unit. Upgrades are actually easier with the base system, but nearly all V8's have the monsoon. Either way is fully workable with incremental upgrades so long as you realize how things are set up. Don't listen to CC or BB jerkies that try to tell you something special requires you replace and rewire the whole car.

Finally, some marketing literature refers to both a 300 and 500 watt system for Camaros. They are all the same. They use the same amp. It's just marketing interpretations of the power ratings.

Monsoon Head Unit:

The head unit is a standard GM/Delco head unit. You can't tell from the head unit if you have the monsoon, because they don't all have the logo. The easiest way is to check for the amp in the tire well. You got that amp, you got a monsoon.

There is nothing special about the head unit in any way, it sends 4 normal high level (8-12 rms watts, maybe) speaker outputs to the monsoon amplifier which is located in the spare tire well. That's it. No special power levels, no low level RCA type outputs, nothing.

2000 and higher model year CD units have provisions for a trunk mounted 6 disc changer. Earlier tape decks also had this provision, but earlier CD units did not. It was introduced on some 1999's - but sincee it was a mid-cycle introduction you can only be sure the AUX will work on your CD deck if you have a 2000.

This aux input can be used with a number of adapters to allow the use of an ipod or other aux source. There are also aftermarket CD changers, but one of them (the Neochanger) is junk. Trust me, this was my first mistake... they are JUNK. It'll look tempting as a stealth solution, but you'll be buying a paperwieght. The aux is best used if you want to hook up an ipod, a portable mp3 disc player, or a mp3 capable cd changer with its own controls. All of those would be nice functional upgrades to a stock system, that could be well hidden.

In extreme climates the monsoon head units are prone to fail due to thermal expansion of the board, made worse by our cars being top-down all the time. Usually the lights will go first, or things will start acting inconsistently. It is typically a fairly simple repair but it may or may not be worth it to you to deal with, because it will probably require some soldering work. Some shops will know exactly what to do and therefore won't charge you much. Some won't, and will. Check out an example here:

Monsoon deck repair thread

The head unit is the 2nd weakest piece of the monsoon setup. It cannot provide a clean enough full-range signal to drive the monsoon amp at full output. So effectively the gain of the monsoon amp is set too low. Believe it - the amp is actually held back by the head unit. Therefore just a head unit upgrade can actually provide a sound quality boost, but dollar for dollar you'd be better off starting with the speakers. Most of your benefit in a head unit is for features, like MP3's.

The Humble Monsoon Amplifier

The amplifier is the same 8 channel unit used in coupes (all 98+ carry the same PN), but it is wired differently. In convertibles two amp channels are used at each corner speaker, one for the woofer and one for the tweeter. To my knowledge there is no special equalization in place, though there may be some slight crossovers built-in – it will not be apparent if you wire up an appropriate woofer and tweeter to each channel. The amp is the best part of the monsoon system. I estimate it provides roughly 20-25 watts rms to the 2 ohm bass channels, about the same for the others as well. Properly biamped to aftermarket speakers it can provide much better power levels than common (15-20rms rating) head unit amplifiers. Factor in the 8 channel operation and the monsoon amp is a significant upgrade vs. a integrated deck amp, but it must be wired appropriately.

The amplifier is turned on by the speaker level inputs, so there is no turn on wire to work with already ran for you. It doesn't matter anyways because the factory power wire isn't sufficient to use with an aftermarket amp. It is also possible to simply unhook both wiring harnesses at the amp and put jumpers in place to bridge around it. This would be something to do if you just want to run your speakers off of head unit power. But since we know the monsoon amp is actually pretty solid vs. a deck amp... we won't bother with that. Should you want to use that wiring, pinouts can be found on the net.

The Monsoon Speakers

The monsoon front monsoon speakers are the same as in coupes, using a 2 ohm woofer and a tweeter in each door, which is coaxially mounted in Camaros and separate in Firebirds. The rear speakers are a distinct driver, not the same as the door speakers, or the sail panel speakers used in coupes. It is a free air driver with virtually no travel or capacity for bass. The driver has no enclosure so it is not made to produce bass, but it is otherwise a normal 4 ohm coaxial speaker, again with 2 amp channels each feeding the woofer and tweeter. The monsoon speakers are the weak point of the system, with 100% of your bass and most of your sound quality coming from the front door speakers. They should be the first target on a budget upgrade path.

The monsoon speakers have a rough life. They aren't very good to start with, our doors do not protect them from moisture, and our verts subject them to even more moisture. The monsoon amp can send them too much power, and the monsoon deck means those high levels are accompanies by lots of distortion. In the end, they not only suck but are also doomed to fail under hard use. Remember even the newest vert has 4 year old monsoon speakers in it.

Here are pictures of the front and backs of my original (2000) Z28 vert speakers. I sold them on ebay for almost $150 shipped. Yup, that's right... $150. So be careful taking them out! Notice the 4 wire connections for bi-amping, and the different construction of the fronts and rears.

todddchi

iTrader: (3)

Overall upgrade paths:

For convertible systems it is very important to sketch out your budget and overall goals at day one. I didn’t do this and it cost me a lot of extra time, money, and disappointment. There are some things to consider at day one:

1.) Bass is expensive. You can toss a 10” sub in a shoebox, feed it 100 watts, and get good bass in a coupe. Kiss that goodbye in a vert, it isn’t happening. Reasonable bass in a vert is going to cost as much as killer bass in a coupe, and killer bass in a vert is going to cost a small fortune.

2.) Top down is what creates the bass challenge. If you are not interested in top-down bass, then your life just got a lot simpler.

3.) Simple head units should be used to limit theft temptation. This is 100% my opinion, yours may vary.

4.) All of my assumptions are based upon a clean, professional level installation. If you are ok with tossing a bandpass box in your trunk and losing your trunk, my recommendations won’t fit you. Things can always be cheaper but my recommendations are based upon a clean install with minimal impact to the vehicle’s usability, at the best value for your money. I realize there are many opinions here, and would appreciate flaming be reserved for other threads. I’m not here to fight about brand and price preferences.

Option 1: If your needs are modest, and you just want good sound quality at a decent price, then I recommend my budget plan. I had my car setup like this for some time and it will play rock type music very well. Great highs, clear mids, and accurate bass. You won't be booming but you'll be rockin'.

1.) Replace the monsoon deck with an aftermarket deck of your choice. Opinions vary greatly but in my findings ~$150-200 is a good price range for the best value. Budget an extra $40-60 for a PAC steering wheel control adapter (Froogle search for PAC SWI-X ) so you can keep your steering wheel controls. Pick a unit that has the features you want, paying close attention to the display, which is important in a vert. It also needs to be remote-compatible (steering wheel controls) and if you are planning on using subs I highly recommend a model with 3 pairs of RCA outputs as the independent sub control is critical for verts (top up/top down). Don’t skimp too much, the deck needs to give good sound quality and have a true 15-20 watt rms amp. Note that some very high end head units don't have built in amps, and you need one in this budget setup since the monsoon amp uses high level inputs. So about $200 here total, and don't forget to consider the price of installation stuff (wiring harness, antenna adapter, and mounting kit) when comparison shopping. Some places include these for free, some don't.

2.) Pick a premium pair of front coaxials (~$100) or a modest set of components. Imho components are overkill for this budget setup, but adjust as you like. 2 ohm drivers ARE NOT NECESSARY, but they are ok if you can find them. 4 ohm drivers will work just fine, the aftermarket deck will drive the monsoon amp to full capability and you will be good to go.

Both front and rear speakers MUST support biamping. All components do, but only some coaxials do. You need to be able to wire up the woofer and tweeter separately, and not all co-axials support this. Search in electronics for 5000 threads about this, you want a co-axial that runs the tweeter wire through the center post, not through the woofer cone.

Look at the picture of the factory monsoon speakers above, see how the tweeter wire runs through epoxy spots in the woofer cone? That's what you don't want.

Rear drivers are not critical, but if you like rear fill, then add a lower priced pair of coaxials from the same product line, so they are tone matched. On a budget I'd honestly just unhook the stockers. Recall the rear drivers are free air so it doesn’t make sense to put a beefy high power driver back there. You can’t anyways as the top mechanism limits how deep they can be, too deep and the top will come down and whack your new speaker (). Most specifically shallow mount drivers will work, most normal speakers will work with a spacer. Use Crutchfield to study up, and carefully check all your fits at the install. You'll really hose things up if your top mechanism whacks that speaker, it needs to be a good 10mm or so clear. Remember, you just want them to be tone matched to the fronts, and they should be 4 ohm following the factory drivers.

3.) Install your head unit and speakers, taking care to biamp the speakers. That’s it, you’re done. You now have a nice featured head unit and roughly 40 watts going to each 6.5” speaker (20+20). If you hooked it up right the sound will be very good, only lacking bottom end bass that the 6.5” drivers can’t provide. It will be capable of playing very loud with great clarity. This ~$300-400 solution is all I recommend to casual users that are anywhere close to being ok with the factory setup.

The 2nd upgrade path, the big dog, is for people with bigger budgets that want subwoofers, and some boom boom boom.

1.) Same guidance as above for the head unit. $200

2.) Go rock solid on front speakers, the best you can stand buying, noting that price doesn't necessarily mean quality. You want components or coaxials with strong midbass output and power handling, and some very expensive component systems aren't designed with these goals in mind. Budget to use at least a speaker kit of dynamat or other sound deadener on the doors.

Same recommendation as on the cheap setup for rears, modest coaxials matched to the fronts. It never makes sense to put expensive speakers in the back locations. Let’s say $250 on up.

3.) You’ll be using an amp. For moderate systems I think 5 channel amps are a good solution, one of my favorites being the smaller Memphis which is 75x4+400x1(classD). The stock charging system will support amplifiers with roughly 75-90 amp fuse ratings very well. Beyond that you'll creep into lights flickering and then into charging system upgrades and big systems beyond the scope of this thread. Regardless of what you do, you want 75-100 watts going to each corner location (again the fronts are most critical) and I would recommend at least 100-200 watts per subwoofer. The minimum useful sub arrangement I’d recommend is 200watts fed to two 8” subs. If you go with separate amps go class D for your sub amp. Let’s say $300 on up for the amp, and this is a good place to buy used. Don't forget the cost of wiring and fusing.

4.) Subs – this is the big problem and will be covered in the last topic header. $300 on the low end, on up, and up, and up. Very usable dual 8" solutions can be had for about $350 or so. Less if you build yourself.

5.) So you can see you’re now looking at a minimum of probably $1,000. How much is that bass worth to you? Is it really worth $600+ and 50 extra lbs.? Decide now, and realize you'll always be a step behind the coupe guys. Unless you love bass it's probably better advice to use that money towards go fast upgrades to smack the coupe guys in place.

For both options:

1.) Don’t skimp on wiring. Use a distinct fuse block or circuit breaker mounted close to the battery for your amp, and use nice 8 gauge or bigger hot and ground wiring. Fuse should be one step above your total amp fuse rating.

2.) There is a nice rubber grommet in the firewall, under the PCM (you’ll have to pull the PCM) to run your hot wire through. It’ll be clearly visible poking into the passenger compartment if you pull the passenger lower dash panel and look up. If you can't handle this you might want to quit while you are ahead.

3.) The PAC steering wheel control unit is basically a universal remote that reads the control outputs and sends out a remote signal to your head unit. So you’ll need to mount the ir output sensor, and it needs a line of sight to your head unit. Search in electronics and you’ll find what you need. Some people report being able to mount the sensor right in their head unit mounting kit. It depends on the sensitivity of your deck's remote sensor. Keep in mind where people and things will commonly sit in your car, and check it in sunlight. The emitter needs a line of sight to your radio's sensor. I mounted mine on the angled portion of the cupholder cutout, glue the sensor in the mounting ring or it will be easy to push it through with an accidental elbow swipe.



4.) Put at least a speaker kit of dynamat or similar on the front doors if you are using an aftermarket amp for the door speakers. They’ll need it, the doors get buzzy fast if you are driving 75-100watts in there. As SSpeedracer suggested, this is also a good time to felt up or epoxy the factory grill in place. It isn't well connected and will rattle on the door panel fairly easily. Finally, if you went with components - there are dips in the door shell to line up (use clay) that will allow flush mounting of the tweeters. Personally I get plenty of treble from my coaxials (Infinities with a swivel tweeter), but no doubt component mounting could be better, particularly for big guys whose leg will block the drivers side speaker.

todddchi

iTrader: (3)

Deck:

There’s not a whole lot left to cover here not mentioned above. Aftermarket head units are generally grouped by price (online prices are used here…). Most stuff under $100 is fairly junky/lacking features/not reliable. $100-200 tends to be a nice sweet spot, giving you decent quality and features. Once you start getting over $200 you start paying for very specific features like full color displays or ipod flexibility. There is nothing wrong with this but know what you need and only pay for what you need. There are some key options that should be considered mandatory, but the more expensive it gets, the more tempting of a target for theft it becomes, and the more of a tip-off that something else is in the trunk.

Things you need in a deck:

1.) Wireless remote control or at least compatibility if one is not included. This allows the use of the PAC module to keep your steering wheel controls.

2.) A good quality, big display. Not many displays are good in the sun, but some are better than others. Simpler displays with larger fonts tend to fend better than the fancy graphical, small font displays.

3.) 3 pairs or RCA outputs. Allows for proper front/rear fading, and independent control of the subwoofers should you use them. Putting the top down kills at least 10db of bass response, so you’ll want that subwoofer control. You can could also use a separate amp level **** but if your deck can handle this it is cleaner imho, and you’ll have one less visual clue of the install.

4.) A good clean 15-20 watt rms amp. Nearly all of the $100+ head units have similar amp sections, but some higher end units don’t have an onboard amp. The monsoon amp needs the speaker level outputs so it has to be there if you are going with the budget setup. Remember to turn it off if you use full aftermarket amps.

5.) Removable face. It’s a convertible. Use it. They'll be able to see in well enough to see through the simple flip face or blackout designs.

todddchi

iTrader: (3)

Factory speaker locations:

Fronts:

In a convertible, your front speakers are your best buddy. They provide 90% of your sound. If at all possible, use beefy front speakers, install them properly, and feed them good power to avoid using subs. You are definitely limited by the 6.5” driver size but the fact of the matter is subs just cost a fortune. If you can live with a strong 6.5” setup then run with it and sit on a nice fat wallet instead of extra bass.

So regardless of our path - up front let’s make sure we put the nicest 6.5” we can stand buying, put at least a little sound deadener around the driver, shore up the door panel grille mounting, and feed the speaker a good 75-100 watts rms. With the top down these drivers are still going to be providing a good chunk of your bass, even if you do use subs. So do it up right, don't skimp here.

If your amplifier or deck supports it, use a high pass filter on your door speakers, but only trim the deepest bass the 6.5” cannot handle. I’d start somewhere in the range of 40-60Hz. This will keep the punchy bass in place but remove the steady state cruising bass the 6.5” can’t handle. You'll be pounding on these speakers and your speakers and doors will thank you for being so considerate.

Custom fabrication is out of the scope of this guide, but I would really like to see someone try a setup glassing in a pair of 8” subs down in the kick panel area. I have seen 8"s in the doors but I think it takes a lot of work shoring up our plastic doors to cope with that. I really think these are the most efficient paths to get good top-down bass, but it is out of my experience range, and what I am willing to do to my car. Two hard hitting 8” subs working in the footwell area would be more efficient than stuffing 2 12”s in the trunk, with the top down. I'd love to hear such a setup.

Rears

The rears must be shallow due to the top mechanism, and are mounted free air so it is pointless spending lots of money here. Have I said that yet? But if you like rear fill slap in a pair of speakers that are tone-matched to the fronts. A low cost coaxial from the same maker of your front components, for example. If your amplifier or deck supports it, use a high pass filter on these drivers to keep things clean. I would recommend 80-120Hz high pass, if not even higher. They just won't make any bass.

I will admit the rears do help to increase the overall volume of mids and highs, which helps out on the highway or if you use your car as a boombox. But they won’t improve or contribute to SQ.

Since you will probably be using a spacer, you’ll need new screws as well. Be very careful to look at how things work with the top. The mechanism needs to clear the magnet and the screws can’t poke through too far or you could tear your top! Take care in this area. I used the self-tapping screws that came with my coaxials, trimmed them to length, rounded the ends on a grinder, and then painted the ends after installation. Keep that speaker magnet a good 10mm or so away from the top mechanism. The mechanism has some slop in it side to side so if you cut it too close the top will probably hit if you use the top on an incline or tilt sometime in the future.

todddchi

iTrader: (3)

Subs:

This is the million dollar topic. Top-up, normal coupe methods are fine. With the top up the trunk cavity is similar to the hatch arrangement so a stealthbox or similar setup will work just fine, though it helps to remove the trunk divider panel. But if you are like me, you don’t care about that top-up stuff, you want bass with the top down.

Such is life, and of course this is a problem. When you drop the top, that heavy sound-insulated top folds up into a couple layers and basically seals your trunk off. So you are now effectively sitting in a tub (the passenger compartment) with your subwoofer behind you packed up inside a sealed enclosure. Obviously this is not good, and it is why getting good bass is expensive, and also is why I recommend people try making due with solid door speakers. You also can't just put something in place to keep the top off the floor, because in the full down position the glass is pushed rather firmly against the floor.

From what I gather, there are three options, in order of effectiveness:

The Battle-Ax Approach

1.) Damn the man and toss a normal monster of a bandpass, ported, or sealed enclosure in your trunk. Using brute force methods, you pound the bass out. Never mind that your subs are pretty much locked in a sealed chamber, you just keep pounding. The problem here is by the time you get enough bump going, you are rattling the hell out of your trunk and decklid, and pushing a ton of power and sub to get a minimal return outside of that trunk.

If you have big tower speakers at home, take them and lay them face down on the drivers, then cover them up with a heavy blanket. That is basically what you are dealing with putting subs in the trunk. Most people that do this realize later that the subs are essentially doing nothing for them with the top down, and either live disappointed or spend more money trying something else. So I’m hoping by reading this you’ll not take this path, if your desire is top-down bass.

If you still don't believe me, find someone with a sub box or even a home sub, and toss that in your trunk. Start your car, and pound that sub. You find out for free how well this doesn't work.

The Crafty Approach

2.) Using a small ported wedge box that sits on the shelf above the trunk cavity, we can obtain accurate bass extension at usable levels. Enough to annoy your neighboors and the fella in the lane beside you. This is my personal favorite solution, because you can get decent bass reinforcement out of it, with no impact to usability (trunk space).

What you want to do here is to use two, or maybe three, small 8” drivers in a ported enclosure. Opinions vary but most agree you want the subs firing into the trunk and the ports firing forward, as low as possible to the ground, and as close as possible to the outboard edges, at the edge of the glass or where the top is loose to the ground. If you build a proper enclosure to load two highly sensitive 8” subs, and feed them a healthy dollop of power (200watts rms or more), then you can get bass response that will fill out what is provided by your main 6.5” front drivers very nicely. The bass will have some feel to it, but you will not be booming. Plenty loud to grab attention but you won’t be shaking anyone else’s rear view mirror.

You'll want that sub level control here. It'll be much louder top up so adjustment is necessary. Make sure to setup your system so your subs and front speakers distort at the same time. You want to eek maximum bass out from your front drivers.

Tuning is also somewhat of a debate, 80-100Hz tuning offers the loudest punch and is good if you listen to mostly rock music. 40-60Hz tuning won’t sound nearly as loud but will do a better job at accurate bass reproduction.

I am currently locked in a bit of a mistake situation. My box uses four 8" drivers. I picked bad drivers (very low sensitivity), they don't have enough space (should have used two), and they don't have enough power (only 100rms each). Sooner or later I may decide to give a 1000 watt amp or more sensitive drivers a shot, but for now I am stuck. I bought on impulse, which is a mistake I usually don't make. Don't be me.

Here is a pic of my setup (first) and TA guy's wedge box (better):



When my wallet heals I may try to build my own box.

The All-In Approach

3.) If you want real bass with the top down, your only option is an in-cab in solution. There have been a few examples posted, a full blown rear seat delete type of box, a single seat box that replaces the lower seat cushion behind the driver, or some less than elegant solutions of just tossing a trunk box in the backseat, or a tube between them. It is my opinion that this is the only way you are going to get truly booming bass in a vert, but obviously making a professional looking solution is going to require major sacrifices to function, require a good bit of custom fabrication, lots of $$$, and pose a constant theft risk.

Whatever the in-cabin approach, you want the sound output set as low as possible physically in the cabin for maximum gain. This is why I would like to see someone try custom 8” fabs in the front footwells.

Amps

In the picture of my sub setup, you'll see my little memphis amp on the trunk floor. I made a very simple amp rack with a bottom plate, and a top U-plate that closes over the amp. This keeps the amp solidly in place and protects it when I toss stuff in the trunk. Other places to mount are the rear wall (watch your lamps and sealing), and the front wall (watch your gas tank!). I'm simple, I like the ground. There's still plenty of room to carry the tonnaue cover.

Since we have fairly modest needs for most vert systems, I really like 5 channel amps. My Memphis amp is capable of 75x4 at 2 ohms and 400x1 at 1 ohm, which is class D. Alternately I could bridge the 4 channels to give 150x2 to my fronts, and power my rears of the head unit. It has a total of 75 amps in fusing and can run full blast thumping without flickering the lights. For a decent midrange solution it is a very good fit, nice and small, as well. THere are many more options from Alpine, Kicker, Infinity, JBL, JL, etc. Using eBay can get you an amp of this grade for less than $200.

eBay or online is also a good place to get your wiring kits and fuse accessories for the amp. Local shops just mark up those products too much.

If your head unit doesn't have sub RCA outputs you can control at the deck, you want a remote level controller for the sub amp. There is too much difference top up to tup down to handle with just a bass level adjustment, imho.

We may be sending lots of power to subs, in a less than ideal enclosure. Therefore an amp with a subsonic filter, and/or a bandpass crossover mode for the subs is important.

If your system has more than 100 amps of fusing on the amplifiers, it's time to start thinking about charging system upgrades. Better wiring with a strong batttery may be good enough for 100 amps or so on the stock hardware, but much more than that and you just stepped into another level of costs due to charging system upgrades.

SSpeedracer

iTrader: (8)

Tips:
While your door panels are off, epoxy the plastic speaker grill to the surrounding panel. The unit is assembled by soldering/melting the tabs. These tabs are often loose and may vibrate.

There are a couple locations in the door panel where a tweeter could be mounted. Observe where the voides are in the door skin and align the tweeter there.

Now is the perfect time to swap in a power antenna (camaro) and connect it to the AMP/AUX switch from the head unit.

Tap into the speaker wires at the monsoon harness. No need to route new lines all the way into each door.

Two amps, or one big amp, will fit in the trunk floor and take up very little space. Covered with a sturdy panel and you'd never miss the space.

todddchi

iTrader: (3)

That's the first I've ever heard of that. There is a base system, but I thought it was reserved only for base (V6) convertibles.

Is there anything else funny about your car? Was it a lot car, or was it build order?

I'll PM a mod for a possible sticky when the thread has pics and such in it. There's a lot of info right now but pictures will help make things nice clear.

JohnnyBs98WS6Rag

iTrader: (1)

I'll have to dig out my '98 Firebird Sales brochure, I remember there being a "*" near the Monsoon description saying it wasn't available in the 'verts (V6 or V8s). For all '98 'verts, (I'm pretty sure the same applied to '98 Camaro 'verts too) the standard HU was a non-Monsoon CD in-dash unit. The only options were to add the 12-disk trunk changer and to change the HU to a cassette (a "cash-back" option IIRC), which my car has both (it'd seem redundant to have a CD both in-dash AND a CD changer in the trunk and not be able to play cassettes).

My car was ordered by another individual, who apparently gave up waiting when delivery was delayed due to T56 constraints and a GM strike. Even the dealership didn't think they'd ever get the car as they were suprised when it finally showed up on a truck in late Aug '98 (my car went thru ASC on the 2nd-to last day of the '98 MY, early July). I was driving it home within 30 hours of their ad being published in the paper. I even paid under sticker since the '99s had just begun to be delivered to dealerships. I got one of the last '98s through the line.

JohnnyBs98WS6Rag

iTrader: (1)

I finally dug out my '98 Firebird sales brochure. It lists 4 different sound systems, 2 w/ 500W Monsoon and 2 without Monsoon. The "standard" of the 2 variations had the CD in-dash, w/ cassette being the optional version. Neither of the two Monsoon choices were available in either V6 (Firebird) or V8 (T/A) 'verts.

Both V6 and V8 'verts came standard w/ CD non-Monsoon system, w/ the cassette non-Monsoon optional.

The V6 coupe came standard w/ the CD non-Monsoon, and both the CD-Monsoon and Cassette Monsoon systems were optional.

The V8 coupes came standard w/ the CD Monsoon system, and the Cassette Monsoon system was optional.

Interestingly, neither CD system indicated remote CD changer pre-wiring was included in the description.

JohnnyBs98WS6Rag

iTrader: (1)

IMO, not having a Monsoon is an advantage, much simplier to integrate a sub or just upgrade the speakers or boost power w/ an amp. Currently all I've added was a sub (link in sig) which really helped the stock system. But eventually I plan on upgraded speakers in doors and rear seats (w/ a 4-sub box & larger amp). I'll add an amp for the doors, but the rear seat speakers, seeing as they don't produce bass anyway, act as mid/hi in a bi-amp setup w/ my sub. I plan on keeping the stock HU as thieft deterrent. For amps, I'll probably end up w/ a 4x75W for the doors / rear seats, and a BIG (600W+) one for the subs.

carman53

iTrader: (2)

With the top down, the rear glass is THE obstacle for sound waves to pass through with trunk mounted speakers (and ANY speaker aft of the glass). It's easy to test. Get a satellite speaker, attach it to the sound source of your choice and place it anywhere in the trunk area with the top up. Activate the speaker and then put the top down. The glass will block almost 100% of the sound.

Your speaker choices on a vert(if you are a top downer like me) must be within the cabin somewhere. I wired my 98 Z vert factory FM/CD head unit to a Sony Explode amp mounted on a flat piece of plex right behind the trunk divider. (I have two Muffin fans from radio shack blowing on it when it is powered up. I have 4 Polk speakers mounted in the factory locations and it has twice the sound of the factory unit and sounds much better than the monsoon factory units I have heard.

JohnnyBs98WS6Rag

iTrader: (1)

Well, that is a slight exaggeration. While it is true that having the top down attenuates any sound coming from the trunk, the top/glass acts like a low-pass filter, attenuating mid/highs much more than bass/sub-bass. But I don't think anyone was proposing putting a mid/high driver in the trunk either.

I've been planning on using my test CD and SPL meter to measure the effect of putting the top down, unfortunately it's packed away for moving. A good test will be with the car parked in a relatively "free field" environment, don't want any rattles / resonance from a garage structure or it's contents corrupting the measurements. However I seriously doubt that putting the top down attenuates bass from the trunk below 100Hz by more than 10dB.

Ragtop 99

iTrader: (7)

Interesting subwoofer option for verts post by "acarnut"
http://hewsoninc.ca/subwoofer.htm

JohnnyBs98WS6Rag

iTrader: (1)

FINALLY, I got around to making these measurements and getting the data plotted. Seems that putting the top down DOES attenuate the bass below 100Hz on average by ~10-12dB (depending on whether you have the boot on or off w/ the top down, and windows up or down w/ the top up). This is a little more than I was expecting. I also made a baseline measurement of the stock front speakers for comparison. FWIW, the plot is attached.