Thread: Suggestions/information for new GT owner with Monsoon

Greetings all. New to the site, but seems like we have some very knowledgeable people around here so I'd like to ask for some suggestions and/or information. Firstly, I have an '06 GT with the Monsoon system. I used to be fairly heavy into car audio so please feel free to talk techie if need be. Since getting my GP, I have found that I miss my "loud music" as my son calls it so I am wanting to explore options to upgrade the sound a bit.

First question - is it possible to upgrade the deck and retain the steering wheel controls? I thought that I heard some GPs came with a touchscreen but have not found any evidence of this. I used to be all out with the 24-bit Burr-Browns and high V pre-outs, but no need for all that, I just want to make certain I have a clean, quality signal being sent.

Second question - I see that the stock speaker sizes are 3.5" (dash), 6.75" (front door), and 6x9" (rear deck). Taking into consideration that proper impedance is observed, is it simply plug-and-play with aftermarket speakers? Are all the stock speakers coax, or true components?

Third question - I would like to add some low end to the system through subs (potentially a couple of 10s or a ported 12). Are there any setups that have worked well in the GP (ported, sealed firing up)? Should I be aware of anything if I were to simply upgrade speakers and add this to the setup?

Thanks, in advance, to anyone taking the time to help an old man trying to recapture a little youth.

Thanks for taking the time to respond. A few more questions if I may.

So, with the proper PAC equipment, I can essentially upgrade to any aftermarket deck I want and retain all my controls?

Good point on the stock EQ, though if I upgrade the deck this should be a moot point, no?

Are the existing speakers in the front doors coax or component?

Do you, or anyone else, have experience with podded, sealed enclosures on the side of the trunk (I would like to retain as much trunk space as possible)?

Originally Posted by setshot50

Thanks for taking the time to respond. A few more questions if I may.

So, with the proper PAC equipment, I can essentially upgrade to any aftermarket deck I want and retain all my controls?

Yup.

Originally Posted by setshot50

Good point on the stock EQ, though if I upgrade the deck this should be a moot point, no?

Correct.

Originally Posted by setshot50

Are the existing speakers in the front doors coax or component?

I'm not familiar with the 04+ grand prix's sound systems unfortunately.

Originally Posted by setshot50

Do you, or anyone else, have experience with podded, sealed enclosures on the side of the trunk (I would like to retain as much trunk space as possible)?

I800 aka Rob has one of those.

http://www.grandprixforums.net/members/i800c0llect.html

Hopefully someone will chime in with some experience with this particular model. I like that trunk set up. Very clean install. Any idea on how it sounds?

Thanks for posting my links(also in my sig). I really enjoy my setup!! The toughest part is getting your doors done right to keep the vibration transfer down. I'm going to add some foam to get some separation. You also want a higher Qt, ~.55 or higher, in your mids if you decide to use them in stock locations. My speakers are border line so the mid-bass can't take a lot of power but I time alignement, attenuation, and my rear 6x9's to help. Mids and rears are crossed with 18db slope @80hz. It sounds GREAT when crossed with 24db slope @63hz but that's when I pick up a lot of vibration in the door card.

I'm not a basshead so I've tuned my system to be natural. In the current location I'm sure my sub could get somewhat loud but you'd definitely want to build out the opposing side for an additional sub. Unfortunately, that's where my XM module was located on a bracket and the area didn't look condusive for the size magnets on my subs. So now I just have a replacement "in case". My sub is crossed with 36db slope @63hz.

Everybody thinks my mids are creating all the bass. The bass is in front of my windshield. It has a few odd cues because of the dash layout but I'm very happy with the results.

One more thing...with all the leather and glass in my car it makes my speakers seem "bright" due to reflections. Phase and cross over points are crucial in controlling run away reflections. Throw a fat kid in the passenger seat and that fixes a lot too Diffraction is a b and reflections don't help in our vehicles.

Existing speakers for stock 04 grand prix are 6.75" mids and a 3/4" tweeter. These are components with basic filters on the stock wiring. However, not all 6.75" mids work. I had some Pioneer 720prs mids I wanted to use but didn't feel like fiddilng with the factory speaker pod/mount.

One time I had put together an enclosure made out of tubber ware sealed to the back and hardened with an expoxy. I forgot to measure the factory cut out and it didn't fit. I didn't feel like working any more on it so I trashed the setup.

Originally Posted by I800C0LLECT

The toughest part is getting your doors done right to keep the vibration transfer down. I'm going to add some foam to get some separation. You also want a higher Qt, ~.55 or higher, in your mids if you decide to use them in stock locations. My speakers are border line so the mid-bass can't take a lot of power but I time alignement, attenuation, and my rear 6x9's to help. Mids and rears are crossed with 18db slope @80hz. It sounds GREAT when crossed with 24db slope @63hz but that's when I pick up a lot of vibration in the door card.

I assume you've tried Dynamax (or a similar product) to help with vibration? This always seems to be one of the problem areas when upgrading sound systems. Thanks for the note on the Qt, a good piece of information to know. Though I would be a bit concerned of them getting bright (as you mentioned).

Originally Posted by I800C0LLECT

Unfortunately, that's where my XM module was located on a bracket and the area didn't look condusive for the size magnets on my subs.

Seeing that mine is set up for XM as well, I am wondering if my module is in the same location which would preclude a dual sub setup.

Originally Posted by I800C0LLECT

Everybody thinks my mids are creating all the bass. The bass is in front of my windshield. It has a few odd cues because of the dash layout but I'm very happy with the results.

Given the physical dynamics of the car, it does seem that there are some weird reflections going on. Have you found ways of accounting for this, aside of crossover points (type of tweeter, speaker direction)?

Originally Posted by I800C0LLECT

Existing speakers for stock 04 grand prix are 6.75" mids and a 3/4" tweeter. These are components with basic filters on the stock wiring. However, not all 6.75" mids work. I had some Pioneer 720prs mids I wanted to use but didn't feel like fiddilng with the factory speaker pod/mount.

Mine is an '06, but I assume it is the same? If I chose to go with a component set, I assume I could bore out the hole a bit more to fit a 1" tweeter?

My solution to the reflections was eventually to try and use them to my advantage. The closer you can get a speaker to the apex where windshield and dash meet, the better you are at mitigating diffraction. At that point you are able to use the windshield more like a wave guide.

There's a specific calculation that will specify where the diffraction break up occurs based on distance to the glass. So I ended up putting my tweeters in the A-pillars and then used PEQ at 8khz to help cancel out the breakup. If I can't hear it I don't care about it. But I'm sure if you measured it'll tell another story. I also messed with 16khz with EQ to help control the reflections too.

Long story short, unless you hit 100% on my volume majority of the reflections are dealt with. The down side is that the shape of our dash and angle of mids ends up skewing the stage a bit. I also think it has to do with whatever trick they used for "driving on center". I can move a little bit in my seat and the stage steers left and is damn near perfect. If I sit comfortably in my seat then the stage is to the right a bit.

The only other way to deal with reflections is to learn about psychoacoustics. If you go that route then you basically want everything to be point source and on axis. Kick panels work very well at mitigating issues with reflections due to psychoacoustics and their distance from glass. It is typically the best when trying to maximize your path length distance too. The down side is installing them so that your habits don't get in the way of the speaker. The same goes for the passenger.

ha

Quite true, reflections are an unavoidable variable in the sound stage equation. When you replaced your factory speakers, did you do so in the dash?

Rob, in building your enclosure do you recall the approximate mounting depth of the sub you used?

Originally Posted by setshot50

Rob, in building your enclosure do you recall the approximate mounting depth of the sub you used?

My mounting depth was based on the "pocket" that exists in our trunk already. I had measured out the depth and width of the magnet for the sub and it worked just fine. After the pocket was cut out we also "test" fitted the pocket as if it was the final product and again, it fit just fine. So then we used it as the mold for the fiberglass, by wrapping it in cardboard until we reached our final shape but test fitting it in the trunk prior to moving on.

Like yours, I would prefer a flush look with the upper curvature of the trunk. I assume your sub was a DIY, yes? Do you recall the actual mounting depth?