So it seems many of you are interested in sorting your Macintosh sub so I'll share my experience with you all.
Discussion on replacement options: viewtopic.php?f=22&t=14712
Installation Walkthrough: viewtopic.php?f=12&t=17131
Amp modification for Sub Gain: viewtopic.php?f=12&t=19926
SO the way I see it (and I'm basing this off reading every relevant audio forum post, but having limited personal knowledge) you have a few options based on how much you want to spend.
Inexpensive:
- Resealing/fixing Macintosh Sub (~$30-40)
- Sub Replacement only
(from my research the Kicker option I went with seemed one of the best matched options for the stock amp and can be had for cheap from Amazon right now
http://www.amazon.com/gp/product/B0035C ... ge_o00_s00
$110)
More Expensive:
- Sub and Amp replacement
(I think this is where the infamous Polk MM840 and DB840 options fit in as numerous posts I read found the Polks to be an upgrade but quite underpowered without a replacement amp - some have reported success with just the amp modification to power these Polks better however)
My Install
I bought my new Kicker sub off the Amazon link shown above and followed the above install guide to great success. My sub required a 20mm spacer to clear the torsion bars in the boot, I measured it out using the template provided in the box and used MDF which has worked well. Even with the spacer and bigger sub, the stock cover on the parcel shelf still fitted back over the top making it look stock.
Size of spacer, fitment in stock location, and sound issues will depend on the individual speaker but it seems this method of install works well with the Kicker and Polk options.
I also installed some sound deadening on the rear parcel shelf that I had lying around; this combined with having a better non-cracked sub has seen all vibration and rattle disappear from the system so far.
DISCLAIMER
This is just my experience based on the research and installation I did. I'm very happy with the Kicker upgrade over my broken Macintosh sub, and will update my build thread with impressions in a couple of weeks once my speaker has bed in and other bits for my car finally get back to me.
Refer to above forum links and other material if you want to consider other speaker options.
There is undoubtedly way more options out this, this is just based on my experience.