Contour Enthusiasts Group Archives Forums Modifications Audio Rear Deck free-air Sub question.

I believe I probably said a free air mounted 8" would the best choice for an easy free air mounting. Jazzman says that his car doesn't have the factory hole that Aaron (APT CSVT) and others have on their car. To be honest I thought all of our cars had it, but I trust that Brian knows what he is looking at. He didn't have a jig saw to open it up, so I thought that maybe a small (.4 cubic foot) box suspended underneath might be a good compromise of sound and space.

Aaron, is using a free air 8" sub on the rear deck with good results as well as Colin (cthomp21).

I have an mb quart free air 8" in my rear deck. It's mountd under the rear deck and it shakes the hell out of the rear deck. For optimal performance for the free air sub is to top mount it on the rear deck that way nothing will rattle. Also dynomat the entire rear deck.

What is the difference between top and bottom mounting with regards to rattling?

I would venture to guess that the result of the cutout diameter being less than the diameter of the 8 inch driver's actual moving cone probably 7.3 inches the waveform coming from the driver will rattle or move the rear deck carpet or board causing vibration like sounds.

Anyway I have succumbed for the need for some more bass and midbass via the front doors. Currently I have pioneer's 6X8 plate tsp682
installed there and am looking to put not some real 6X8 there which exists in the back doors which did not satisfy my bass needs (reasoning for adding a rear deck mounted woofer) but possibly to put some 6X9 there using an 1.5 adaptor for magnet space.

Though we are talking enclosures here has anyone installed a small enclosure in the OEM cutout space for a 5.25 sized driver sort of like a q-form for the door area instead of the door kick or foot well area?

yeah I did for the back of a blown focal component i had just to see how to do it..

all I did was find a cardboard tube big enough to fit the area..then I fiberglassed it and then flared/spread or whatever you want to call it the edges enough with glass to screwn through it.

looked good..how effective was it? no idea speaker was blown..ill let you know when I do the same for my orion components.

I don't know what you mean by that. But, anyway, I believe that Aaron measured the factory hole at ~7" which is about equal to the diameter of the piston on a typical 8". Even if it were slightly smaller, I don't believe that the negative effects would be noticeable.

I still don't believe that any 5.25 or even 6.5" driver is going to give you the bass you are looking for, even if mounted in an enclosure.

I rememmber the factory hole at 6.5" which means that a 6.5" speaker would fall through as the mounting diameter is ~5 7/8". A 6.5" driver is cable of some bass, but I don't know of any 6.5" drivers that have more than 5mm of excursion so they don't move much air. There are some 8" drivers capable of 9+mm xmax which is a vast improvement over most affordable 6.5" drivers.

Top vs. bottom mount - do whatever is easier. I think either way you'll need an adapter plate.

On the contrary let us not forget Ralph's comments 'I have an mb quart free air 8" in my rear deck. It's mounted under the rear deck and it shakes the hell out of the rear deck. For optimal performance for the free air sub is to top mount it on the rear deck that way nothing will rattle. Also dynomat the entire rear deck. '

for experience is worth more than guesses.

So what have you experienced?

And sorry to make you repeat but what then is a good way to get some mid bass in the front of the car? I saw some competition contours (95 my year in particular) in a car sound mag with some speakers actually molded on the front deck. I can only assume the passenger side airbag was disconnected and the extreme left right vents were removed.

Tell me more tell me more "APT SVT" what are the names of those 8" 8"xmax drivers. The 6.5 inch I am currently using is the AudioBahn AMD60 if I remember correctly and lots of bass I get only when the source material contains it in the frequency in which it is boosted 50HZ. Ohh I am also thinking of adding another line driver for greater bass boost only this time with a volume boost control near the head unit so that I may adjust when the tunes requires it.

I agree which is why I speak, from my own experiences. Ralph didn't tell us what was actually shaking. In my case, the only thing I notice is the carpeted package tray cover which should easily be fixed by using a thick foam pad or insulation between the carpet covered cardbard and the metal of the deck. Dynamat will not do it becasue it's not thick enough. And it's far more expensive a solution.



A good 6x8 or 6.5" speaker should be fine in the stock door locations, with some immitation dynamat. I don't have much front mid-bass, but I'm pretty sure it's my crossovers which are not easily adjustable.