Rear parcel shelf Bose subwoofer: Guidance needed

[Britrover]

Hi, I have recently changed out the stock speakers and the head unit in my 98 986 Boxster. The sound quality and clarity is amazing, but the vehicle is lacking bass. I don't want to compromise leg room hence looking to add the OEM rear parcel Bose subwoofer.

Looking for feedback from those who have retrofitted it or have it in their vehicle with regards to the 'bass output' from this unit.

Also, am looking at three different ones (pictures attached) and not sure which model will be a proper fit for the 98 986. Would welcome some guidance here. Many thanks.

04 Porsche 911 996 Carrera Rear Bose Subwoofer Audio Sound Speaker Box



05 - 09 Porsche Boxster Cayman 987 Rear Deck Mounted Subwoofer



2011 Porsche 911 997 Boxster Cayman Subwoofer

[ike84]

I bought a speaker kit on amazon that fits into the stock shelf. Easy install physically, wiring was a bit difficult. I replaced the stock head unit with a double din a long time ago so I had to write directly to the amp. The problem there was that the stock amp is 4 channel, not 6. My solution was to purchase an aftermarketr 2 channel amp and ran rear inputs from the had unit to the second amp and then to the speakers. In terms of bass output it all depends on the setup and speakers used. This setup really wasnt designed for bass, it is meant to improve mid and high output (directly behind your head). You could theoretically use my setup and run those speakers through a low pass filter but I don't think that's what you're looking for. If you want thump then I would make a custom enclosure with two small subs mounted vertically between the seats against the firewall.

FWIW I'm going to completely redo this setup coming up. The double din is coming out, along with the door speakers, factory amp, and aftermarket amp. The front speakers and rear speakers will remain, powered by an aftermarket amp with bluetooth connectivity. I found that the double din is just taking up space and I can instead just use my phone for android auto, and the door subs aren't worth jack in terms of bass.

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[Radman]

I'm considering an under seat woofer. Just need to confirm if it would fit. Kenwood KSC-SW11 is what I'm looking at, there are others that are similar. I know that isn't exactly what you asked for, but wanted to offer another potential option.

[lskolnick]

I added the 987 Boxster Sub. You can find my thread here:

I added the 987 rear speaker with subwoofer to my 2000 Boxster S

I suggest adding to that thread if you go this route, so future people can benefit from it.

[Radman]

Originally Posted by lskolnick

I added the 987 Boxster Sub. You can find my thread here:

I added the 987 rear speaker with subwoofer to my 2000 Boxster S

I suggest adding to that thread if you go this route, so future people can benefit from it.

Yeah, that looks like the easiest route. Thanks!

[Elmer]

This is from a thread a couple of years old:

I recently replaced the entire factory Bose sound system for higher quality components. The Porsche/Becker/MOST system really limits the available options. Like you, I wanted Apple CarPlay and BT. There are lots of head units out there, but if you're wanting CarPlay, do your research, read reviews of head units to find a reliable, easy to use model. The factory amp is a five channel, under powered, MOST-only component. Amps are relatively inexpensive. You can interface with the factory speaker wiring and there are several websites that have the wiring diagrams. I think theRennTech site has posted several. The dash speakers, for the Hifi and Bose are component, 1 in tweeters and 3 in midrange drivers. The Car Audio Innovations website (cai-store.com) has adapters to mount 4 in coaxial speakers in that space. That's a great upgrade, and can be relatively inexpensive. The door speakers are 5 1/2 in.

If you have the Bose system, the wiring from amp to speakers is a bit wonky so that Porsche/Bose could use a cheap amp to get acceptable sound volume. The speaker drivers are fairly low quality, but can be made to sound good with a cleaner amp w/ a bit more power. But, they wired the door speakers to 2 ohm load and the rear "subwoofer" enclosure to a 1 or 2 ohm load.

Wanting Apple CarPlay in a double DIN configuration, I replaced the CDR 23 head unit and amp in my 03 Boxster S with a Kenwood HU and amp. That solved the MOST nonsense. The installer wired into the existing speakers. Sounded much better. CarPlay is wonderful. BT is handy. But, the Bose drivers are flat, bass is muddy, dash speakers not clear but very biased towards voice and "bright".

Next step, replace all speaker drivers. Rod at CAI Store helped with great advice and a few products. Some research online helped with other aspects. I ended up the CAI Store dash mount Hertz 4 in coax speakers. For the doors, I mounted Hertz 5 1/2 in woofers from the component set and put the tweeters in the rear deck speaker enclosure where the Bose tweeters were previously. The crossovers are mounted in the trunk next to the amp. The woofers in the rear box were replaced with Morel 5 1/2 in woofers. (I stumbled across this build plan on the DIY Audio website)

How does it sound? Wow!!! It's an amazing transformation. Certainly, the signal processing capabilities of a modern head unit help tremendously (Kenwood DDX 8905S and Kenwood XR 901-5 amp). The speakers are very clear and driven by an amp that has enough power to drive them efficiently. The rear deck subwoofer has "deep" tight bass. To say that I'm pleased would be an understatement.

I don't know if there's an easy way to get where you are wanting to go. The MOST bus is severely constricting to adding modern audio.

[amagalla]

The big question is do you have the factory BOSE/MOST system. If not, there are lots of options. The original factory system (not MOST) came with the subs in the door panels. This is what mine had and I decided to keep that configuration, but with all new components (HU, amp and all speakers). I modified the original door speakers housings to fit a 6.5 Kicker sub in each door. Then I put new speakers in the dash and in the rear parcel shelf storage compartment (again, not a BOSE unit). Here is the link to my process. I've since upgraded the HU to a Kenwood with AndroidAuto.
Build link