I'm wondering for all those that have added subwoofer(s) in their trunk space, has the added weight thrown off/changed the handling of the car noticeably compared to that of before?

 

I know it did in the Civic I owned before my RX-8.
When I ripped all the junk out of my car I was amazed how much of a handling difference it made, as well as noticeable acceleration.

You could always do a test. Put a couple bags of sand or kitty litter or something in the trunk to simulate the weight, and drive around for a few days.

 

I havent noticed a difference
but the car does look a bit lower in the back now

 

Depending on the size of the box, the difference in handling should be similar to driving with a full tank of gas versus driving with a half full tank of gas. (yes, the center of gravity is higher with subs).

The subs will actually probably make the car closer to true 50/50. Not to say that adding weight helps, but in the case of rear wheel drive car which is slightly front heaby , putting more weight at the rear probably won't hurt as bad as with a front wheel drive car.

No offense to present company, but I don't understand why people are putting big boxes with dual twelves. In this day and age of long throw speakers and inexpensive high wattage amplifiers, I can't imagine why a single JL 10W3v2 in a 1 cubic foot enclosure with 300 Watts behind it wouldn't be more bass than you could ever need. (unless you just want to go booming down the street with your head out the window)

That's what I plan to do and the total weight of everything shouldn't be more than 50 pounds and thus pretty insignificant from a handling perspective.

-Mr. Wigggles

 

I added a single 10" sub with a modest amp. It provides plenty of bass and really fills out the low-end of the Bose system nicely. It's not so heavy as to change the handling of the car and I still have a fair amount of trunk space to work with.

 

Mr Wigggles, you are right on. My single 12W3v2 is pretty much over kill. 1 long throw 10" with a lot of power will give you plenty of bass. The gain on my amp is only at 15% or so and I can easily over power the Bose sytem even at volume 30+.

Rememder, you are trying to supplement the bose system with what it currently lacks.

The reason I went with the 12" was because I really like ultra low frequency bass. A vented 10" would have required a box that just wouldn't fit how I wanted. So I put the 12" in with a PEQ centered and boosted 8 db around 40 cycles. I read in some thread that someone wanted to put a 15" in the trunk!! What???

Also, I had the spare tire kit and the enclosure and amp weighed about 15 lbs. more than the spare tire, I don't notice any difference. Keeping the weight lined up with the rear tires I think is more important.

Mr Wigggles, thanks again for those schematics!!

 

Ok, so I gather one 10 inch sub in the trunk isn't going to make the RX-8 handle like an SUV after all. :p That's a relief, now I feel a lot more comfortable about going through wih it. Thanks for all your responses!

 

haha, yea, that was me with the 15". That was before I did some research and found out how much better subs have gotten in just the last couple years. I now some 10 inchers will be sufficient, but I might just get a 12 for the hell of it. We'll see.

-JiM

 

I prefer 12's
I've had two 12's in my last 4 cars

 

I had 2 12's in my last car and when one of them blew I didn't notice! One day I popped the trunk while playing music and noticed it wasn't moving. The 1 twelve was plenty!

 

I had one 12 in my last car and thought the bass to be intrusive when I turned the volume up, so I figured I'd save some money and some space by going down to a 10. Pretty pleased with the results so far.

 

I would think that the overpowering of the bass would be less of an issue if the Audiopilot was turned on, as it should compensate by lowering frequencies that are being reproduced too loudly, and boost the quiet ones. Only problem would be if the Audiopilot's microphone can't pick up the lower frequencies. But all in all, this system should be a pleasure to add on to, since it would compensate for any slightly unmatched components, intelligently.

 

It is the opposite.

Especially at low volumes, the Bose Audiopilot thinks the extra bass is road-noise or whatever and boosts the bass to try and overcome it.

This offcoarse make more bass out of the woofers and thus further increases the positive feedback cycle.

-Mr. Wigggles

 

Ah, i thought the Audiopilot worked the other way around, that it listened to it's own output, and compared it to the microphone's input, and adjusted the output to make them match.

 

audiopilot has done its best work in the OFF position

 

The weight and location of the box in the car will determine if the car will handle differently. Both weight and location play an important part. The weight factor is an obvious one. Location isn't thought about very often in terms of handling but it plays a bigger affect than just static weight. The key to making sure it affects the handling the least is to keep the added weight as close to the center of the car as possible but definitely inside of the wheelbase. A 50 lb box sitting in the back seat will affect the cars cornering far less than a 50 lb box at the trunk door all the way at the back. In relation to the rotational center of the car the box in the very back of the car moves a greater distance in space due to being farther out in the radius of a circle. Draw a picture if you get confused. The same weight moved farther from the rotational center is being affected more by inertial forces and has more G forces exerted on it. The car thinks there is more weight than it would if the box were in the back seat. Get it? Go find a merry go round at a playground. Sit near the middle and spin around. Now sit at the outside at the same speed. Much more G-forces and therefore weight. The bigger the box you have, the more amplified the effect. The same rules apply for box height as well. A lower center of gravity has less of an effect so try to keep it short, forward, and light. Mazda understood these effects during the design of the car which is why everything important and heavy is inside the wheelbase, even the gas tank. This was not the case on even the 3rd gen RX-7 and is part of the RX-8's wonderful handling ability.

 

I was told I would get the best bass response when the sub was placed in the furthest rear position possible. Maybe I can get them to build an airtight box and fill it with Helium to compensate. :D

 

You probably will get the best response there. It was just a direct example to your question. The best option isn't always feasible. I plan on finding a way to mount 8's in the floor in the front of the cabin like I did on my 2nd gen RX-7. This is a longterm goal though.

 

I've seen that done on show cars before and it looks awesome IMO

 

i have a 8" subwoofer box lying around from my mr2.....i am very tempted to go buy a 8" and amp and see if i cant get some more 'bump in my trunk.'

 

that would suit the rx8 nicely