Say what you want about the Bose components, but the subwoofer box is well engineered. They just used price point components inside. The Morel drivers, wired in parallel fit the box well and provide tight bass for the 986 cockpit.

I think that you really want to find a Bose box and then gut it.

Based on internet researching, I believe the 987 BOSE subwoofer box will fit a 986. The port design looks slightly different though. The 987 unit is more angular to match the changes interior styling.

Some might not care about this, but I hunted around for the 986 version to make sure it all looked period appropriate. The 987 version is far more common.

986 version:
https://uploads.tapatalk-cdn.com/202...414ca4cc4e.jpg

987 version:
https://uploads.tapatalk-cdn.com/202...0bbbf58ad5.jpg





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So do you think a thin mount 10” sub driver would fit in that bose deck box?

I’d say it would be pretty unlikely. Here’s what the internals of the BOSE box looks like. You might as well fabricate something from the ground up if you’re going to try to use a huge 10” driver.

https://uploads.tapatalk-cdn.com/202...5825b065ca.jpg


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Thanks yeah probably too tight. I modified a 996 cabriolet tunnel sub box for a shallow 8” kicker sub. Works well enough. Goes deep.

How deep are the Bose subs? 2.5"? 2.25"? Anyone know the Ohm load of the stock sub set up?

@azlvr - Thank you! I'm currently restoring / refinishing the door pieces which cracked due to age. If those turn out okay I will shift my focus to the other trim.

I've sanded down the cracks and used some UV stable surfboard epoxy. The first pieces I did turned out great. I'm in the final stages of sanding before I hit them with a buffing wheel. Hopeful to be able to keep these factory parts. They date the car back to the year 2000 for sure!

I was hasty and pulled the trigger on gray 987 bose box. (*sigh*) Patience is not my strong suit.

I only have front sound stage as well doors are mid woofer and sub. Use the pioneer as the control. Sounds great dont miss rear speakers.

Impedence
 

The Bose system is wired to 2 ohms. The rear box may be 1 ohm. That let them get away with a small 5 channel amp.

I'm back with another quick update.

I managed to score a pretty good deal on a 987 Bose rear sub. It's slightly different from the 986 version. The ports are more pronounced. Technically only one is a port. The other side is just cosmetic.

http://986forum.com/forums/uploads02...1581992948.jpg

I opened it up and found that the 987 version also had a small amp / combination crossover. I ditched that and rewired the 5.25" drivers to be 2 ohms. The little speakers in the corners are wired to deck power @ 55W each. They aren't too loud but they do provide a nice rear fill.

I added a mono amp and picked up signal right off of the DSP. I was able to adjust the 6" door speakers to handle all of the mid-bass. The rear box picks up all of the lower frequencies. I still have a big gap around 100hz. Rock music is just missing something. I may go back into the doors and seal up those vented boxes to try and get more from them.

http://986forum.com/forums/uploads02...1581992921.jpg


The blue coiled USB cable is for the DSP. I can quickly hook up the laptop and dial the sound in. Once I get the ACR-3 source changer for to quickly select / swap between settings I won't need to leave that hooked up. I may go back in and pull some thin black abs panels to hide the wires below the amps.


http://986forum.com/forums/uploads02...1581992934.jpg

http://986forum.com/forums/uploads02...1581992963.jpg



If I'm being 100% honest, the Bose box is okay. I kind of wish I had both the Bose box and the previous speaker box with the 4 3" drivers. I will be putting that box (complete with Haes speakers) up for sale soon.

Thanks for letting me share!

Your limitation is the Bose drivers. Not really high quality. In my 986 rear box, I replaced the drivers with Morel. Nice, tight bass. Also, changing the door speaker boxes from Bose to Nokia makes a difference. You can get them on Ebay.

I have the Nokia (HAES) door boxes. So that's good. Which Morel units did you go with?

Link to Bose rear speaker rework
 

Here's the article I found to gut the Bose box and add Morel drivers. I believe that CAI advocates for replacing the Bose door boxes with Nokia. It's a good upgrade as well.

https://www.diymobileaudio.com/threads/turning-a-boxster-bose-enclosure-into-a-real-sub.135149/

Morel CAW538 5" woofers

Thank you for the info on the Morels. Those appear to be 8ohm single voice coil drivers? Ideally I need a 4 ohm version so I can get them down to 2ohms. :(

TRP - where you are ending up with your car stereo overhaul and where I intend to take mine are moving closer and closer together.

My Boxster lacks door speakers so I’m looking at just overhauling the dash speakers plus the speakers present in the BOSE 986 subwoofer unit. All with a digital signal processor and an active crossover setup.

Looking at your amp installation, I’m considering a similar approach of using the factory CD changer and amp brackets to mount the aftermarket pieces. I’m planning on installing two amps as well (one to drive the front stage and the tweeters in the rear and the other to just drive the 5.25” “subwoofers”).

I too plan on swapping in the Morel CAW 538s as well. There are no 4 ohm versions of these out there so you’re best off wiring these two woofers in parallel for a 4 ohm and 300w RMS.

You might want to swap out that second AudioControl ACM 1.300 for a ACM 2.300. The 2.300 is the same size, can provide the required 300w RMS at 4 ohm when in a bridged configuration (the 1.300 only provides 175w RMS @ 4 ohms).

As for the lack of sound at 100 Hz, both the 1.300 and 2.300 can deliver full spectrum (20 Hz - 20 kHz) and the CAW 538 can perform from 35 to 3,500 Hz so you should be able to get the sound that you desire out of your existing setup. It may be that your cross over points in your DSP are off?

Also adding some of this to the inside of the rear woofer chambers might help improve performance at lower frequencies: https://www.parts-express.com/acousta-stuf-polyfill-1-lb-bag-speaker-cabinet-sound-damping-material--260-317


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Bah. I was afraid you would say that. Has anyone had success locating a close second to the Morel 8ohm drivers, but in 4 ohm?

Thank you for the info and best of luck with your install.

My Morel rear box is set up to 4 ohms (wired in parallel). The amp that I replaced the poor Bose model with is a Kenwood 50 wpmc x 4 and 200 w to the "subwoofer". The dash speakers are coaxial and the door speakers/rear box tweeters are component with off board crossovers. In this configuration, the bass is very good and the whole system gets plenty loud. I would add that the system is "musical" but not the overemphasized bass that is prevalent in most car audio today.

Good Morning Elmer,

I'm assuming you also have the Morel CAW 538 drivers? Does anyone know how they compare to the Morel Hybrid MW5? Is there a way to compare the two models specs side by side? Is there value in that?

TRP - I’m sure there are other viable options for replacement 5” woofers for the BOSE subwoofer box, but you have to look at the speaker ratings closely.

The reason why many folks have landed on using the Morel CAW 538 as a replacement speaker is because this speaker is optimized for a very small “vented” cabinet size. If you look on Parts-Express (https://www.parts-express.com/morel-caw-538-5-cast-frame-woofer--297-082), you’ll see the CAW 538 will perform optimally with a vented volume of 0.19 cubic ft. That works out to roughly 5.4 liters. The BOSE rear box has a volume of 11 liters. Since there are two 5” woofers you need double the optimal volume (5.4 L * 2 = 10.8 L).

So when considering other options look at their optimum vented volume measurements.


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