I am replacing my factory subwoofer in my 98 XK8 Coupe to get some more bass.

Could you please tell me what ohm the replacement subwoofer should be? Worded another way, what impedance is the factory 4 ohm dual voice coil sub-woofer wired to? Is it wired in parallel for a 2 ohm load on the amp or wired in series for an 8 ohm load?

Do you have any subwoofer recommendations? What is the best 8" shallow depth free air sub.

 

The Subwoofer is a Dual Voicecoil, 4 ohms each winding. One winding is connected to one channel and the other winding to the other channel (R&L). So, a Dual Coil unit should be used as a replacement.

Also, The factory unit is a odd size (About 9.5 in). A 10" unit is too big and a 8" is too small without a adaptor plate. You might be able to adapt a 10" unit to fit by slightly enlarging the opening in the package shelf.

 

I did not realize that I had to get a dual voice coil sub or that I could fit a 10". Thanks so much!

I just bought a MBQUART RLP254. It had the best reviews for a shallow mount sub. It works in a sealed box of only .4 cubic ft.

Any ideas how I can make a sealed enclosure for it? I bought some polyfill to make the enclosure sound larger.
Can I use expanding foam to make a sub box or will it just absorb all the sound?

 

If it were me, I would have purchased a 'free-air' (aka infinitie baffle) subwoofer to replace the similarly designed unit on the shelf. JL Audio makes one specifically for that use. Since you already bought a different one, it appears your only option now is to install it into a box and remove the old subwoofer from the rear deck, using that opening now as a pseudo 'port'. Instead of making one, I'd just order a prebuilt/carpeted unit and affix it to the floor...be careful of the fuel tank's location, as I think in the coupe it also is partially between the rear seats and the boot.

Making a box, then mounting it to the underside of the shelf is another option, but that sounds like much more custom work.

You may also be surprised to learn the old amplifier output just doesn't do justice to your new woofer...a little beefier amplifier may be desired following your project.

 

Matt, I see you are quite the audiophile.

I haven't done much of this lately, but used to be a real nut case. I cut my teeth at a time when an especially cool project was to try to approach zero tracking force on a turntable stylus. We always walked as lightly as possible around such systems since they would go crazy with the slightest provocation.

 

Thanks so much for the help guys.

I took your advice and ordered a speaker level amplifier.

Here it is: http://www.crutchfield.com/p_161LC2I...iocontrol+LC2i

I have a big subwoofer amp and two 12" subs laying around so I will just return the new sub I bought to fit in the factory location. It has a low sensitivity which will most likely need more power to compensate.

I love bass and also like how the subs weight lowers my rear suspension to match the wheel well gap in the front. I just hope it will not be too distorted and the bass will make its way to the front of the car. Which way should I face the subs?

 

If you're serious about the weight of this gear lowering the car, the bass should make it not just to the front of the car, but to the next zip code.

Sub's are by nature non-directional, so the way you face them probably won't matter much. Maybe experiment a little before you bolt everything down.

 

I agree with what "Dennis07" says about the Subs. Got a couple pics in my profil pics.

 

I love me a good audio and video show.

I have no idea what that is, and if it is difficult or not. Sounds tough!

 

Ancient history for you, I think. Vinyl LPs actually WORE OUT over time. So you wanted the least amount of weight possible on that needle riding in the groove while still having it stay in the groove. All sorts of tricks were employed, but they mostly boiled down to isolating the whole arrangement from any source of shock or vibration.

Still, there was something really fun about the "machine-ness" of gear like that, if you know what I mean.

 

I don't much rate free air subs, but they do fit a purpose if you don't want a large box taking up most of the trunk space.


Then again you could always make one of these




And once fitted

 

I am jealous. That is a work of art. I am simply going to throw some massive subs in the trunk and rattle everything to pieces.


Thanks everyone!