SJD Posted March 12, 2008 Report Share Posted March 12, 2008 If you have a harmon kardon set up in your Ci then you'll have more than likely heard of the tennis ball mod. If you haven't and have the dreaded 'rattle' here is a brief overview taken from someone who has done the mod an their M3. (not me, I read it and re-worded it LOL) Needed: 3 tennis balls (and an extra pair of hands is nice too!) flat head screwdriver and 8mm (iirc) socket. Unplug the sub to avoid damage to the wire. Undo the bolts with the 8mm socket - there are 4 to undo. Use the flathead screwdriver to help pop the 2 white plugs. (insert it next to the white stud to avoid damage) With the sub removed the first tennis ball sits on the centre strut then the other two go either side. Tucked into the corners. They should sit in the ridge pretty well. Replace the sub, etc. The idea is, of course, that they stop the vibration between sub and parcel shelf. I have only ever heard positive reviews of this mod. Hope it is of interest. Link to comment Share on other sites More sharing options...
Steviejay Posted March 12, 2008 Report Share Posted March 12, 2008 MOD WITH PICTURES!!! Link to comment Share on other sites More sharing options...
SJD Posted March 13, 2008 Author Report Share Posted March 13, 2008 Cool. Link to comment Share on other sites More sharing options...
Steviejay Posted March 13, 2008 Report Share Posted March 13, 2008 Link to comment Share on other sites More sharing options...
Lee131 Posted March 17, 2008 Report Share Posted March 17, 2008 ive retrofitted my own sub in my shelf and this idea is aamazing, i love this site as its in plain english Link to comment Share on other sites More sharing options...
Steviejay Posted March 18, 2008 Report Share Posted March 18, 2008 ive retrofitted my own sub in my shelf and this idea is aamazing, i love this site as its in plain english Haha......To true!! Link to comment Share on other sites More sharing options...
DAVE.F Posted April 19, 2008 Report Share Posted April 19, 2008 Haha......To true!! The Harmon Kardon sub in my Convertible also vibrates badly at times, would it be the same approach for a convertible set up as it is for the coupe.?? Link to comment Share on other sites More sharing options...
Steviejay Posted April 19, 2008 Report Share Posted April 19, 2008 The Harmon Kardon sub in my Convertible also vibrates badly at times, would it be the same approach for a convertible set up as it is for the coupe.?? Dave as long you look under your shelf and none of the mechanicals of your roof move a out under there (which I doubt) then you should just be able to puncture them and squeeze them under there. It just puts preassure on the outer shelf and the metal plate under it that you can see from the boot. I've not actually seen an convertible buddy, but I dare say it would be exactly the same principle. Stevo! Link to comment Share on other sites More sharing options...
SJD Posted June 10, 2008 Author Report Share Posted June 10, 2008 Been meaning to post for ages to say I did this mod and it works a treat btw! Plus I followed the way I typed up - none of that putting holes in the tennis balls with a screwdriver - just undo the sub and there is plenty of room to feed them in So for the about £1.50 in tennis balls (I went for Salzenger btw ) I have an option that cost £650 now working properly! Link to comment Share on other sites More sharing options...
V321TY Posted June 16, 2008 Report Share Posted June 16, 2008 The Harmon Kardon sub in my Convertible also vibrates badly at times, would it be the same approach for a convertible set up as it is for the coupe.?? And where exactly would I find the aforementioned sub in a vert? Link to comment Share on other sites More sharing options...
Dicky Posted June 16, 2008 Report Share Posted June 16, 2008 The sub is only on the Harmon Kardon set up It is in the ski hatch in the middle of the rear seat back http://www.realoem.com/bmw/showparts.do?mo...hg=65&fg=20 Link to comment Share on other sites More sharing options...
V321TY Posted June 16, 2008 Report Share Posted June 16, 2008 The sub is only on the Harmon Kardon set up It is in the ski hatch in the middle of the rear seat back http://www.realoem.com/bmw/showparts.do?mo...hg=65&fg=20 Thanks, mine is Harmon Kardon Link to comment Share on other sites More sharing options...
joey_d Posted June 18, 2008 Report Share Posted June 18, 2008 So these tennis balls squeeze in tight enough to not go rolling around with serious driving? That would be most frustrating to end up with three 'thuds' in the boot every time you braked/accelerated/cornered hard!! I will try this tennis ball mod when I remember to buy some tennis balls - I am most forgetful at work!! Get home... ... ... aaaaah crap I forgot XYZ. But the HK rattle is getting on my nerves. Certain songs hit it just right to make it sound awful. I used to be very much into my car audio (I still have a lot I need to get round to selling from my Puma) and used to custom make enclosures and false floors etc... but I think the HK stuff is OK. While it's far from high end car audio, it is certainly very listen-to-able! I also don't want to go digging around my new BM with a screwdriver replacing what was originally a £650 optional extra! But three tennis balls I can manage. Link to comment Share on other sites More sharing options...
SJD Posted June 18, 2008 Author Report Share Posted June 18, 2008 They lodge in tight enough so no rolling around or thuds. Really does work a treat mate. Link to comment Share on other sites More sharing options...
joey_d Posted June 29, 2008 Report Share Posted June 29, 2008 I have now tennis balled my parcel shelf up! I found that you can do it without removing the sub, but you need to do that piercing of the tennis balls business. Much easier with the sub out. I have the HK subs and they seem to be cardboard 6x9s. I was thinking it may be worth replacing these with some better new 6x9s if they are indeed that size and not some crazy BMW size which is similar but not the same. Can anyone confirm that they are in fact 6x9s? I used to be very much into my ICE and still have about £1500 of kit in my house, but I don't want to go cutting up my BMW just yet, so I will be using that small HK amp. I know that changing the cones won't make THAT much difference, but every little helps. I do want to change all the speakers at some point (I'll keep the amps) but I figured I'd start with the easiest (the "subs"). I wonder why they didn't use 6" round cones, or even 8". Or perhaps 32" Anyway - I just thought I'd say that the 3 tennis ball mod did work for me (so far). The hardest part was getting myself into the boot to begin with! Link to comment Share on other sites More sharing options...
ccfj1 Posted June 30, 2008 Report Share Posted June 30, 2008 I have the HK subs and they seem to be cardboard 6x9s. I was thinking it may be worth replacing these with some better new 6x9s if they are indeed that size and not some crazy BMW size which is similar but not the same. Can anyone confirm that they are in fact 6x9s? Yes they are standard 6x9, however, they are very shallow in size, there are very few speakers that will fit the HK sub enclosure, the only ones I've seen that will fit the enclosure are the Kenwood KFC-WDA69RC - 6x9, http://tinyurl.com/5zuljv they are not cheap and come with it's own amp. Normal sized 6x9's are too big (depth) and don't fit without spacers to the enclosure. Updating the sub alone may upset the sound of the cabin speakers as these will now be the weak link. I used to be very much into my ICE and still have about £1500 of kit in my house, but I don't want to go cutting up my BMW just yet, so I will be using that small HK amp. I know that changing the cones won't make THAT much difference, but every little helps. I do want to change all the speakers at some point (I'll keep the amps) but I figured I'd start with the easiest (the "subs"). You may need to dump the main amp as well as this pushes out 3-Ohms not the normal 4-Ohms. HTH Link to comment Share on other sites More sharing options...
Keith Posted May 16, 2009 Report Share Posted May 16, 2009 Forgive my asking, but why does the HK speaker unit need to be removed? Does it cover a a hole that needs to be 'plugged'? Please help me asap - I'm about to go down to Brighton for a night out, and I'm the driver; so some tunes on the way down without rattle would be spot on Cheers Link to comment Share on other sites More sharing options...
SJD Posted May 16, 2009 Author Report Share Posted May 16, 2009 Easier access. That way the tennis balls remain in tact and therefore more solid so do the job even better (IMHO). Link to comment Share on other sites More sharing options...
Keith Posted May 16, 2009 Report Share Posted May 16, 2009 Thanks for the prompt reply mate. In tact where though? I just got in there, rammed a tennis ball in either corner and dug my fingers in to arrange them solidly between the sponge stuff and the parcel shelf. Wasn't sure where to put the third, but I cranked up a bassy tune that used to give a terrible rattle (Skream Rmx of La Roux ) and seems to be fine, even with just 2 in! Much better. Would the third go into the centremost hole that you can see with the HK unit still intact? Link to comment Share on other sites More sharing options...
Dicky Posted May 16, 2009 Report Share Posted May 16, 2009 I forgot about this mod I am so doing it asap because my JL's are rattling my shelf, cheers for digging this one up Marsden Link to comment Share on other sites More sharing options...
///Marty Posted May 16, 2009 Report Share Posted May 16, 2009 Did it on mine last week... not driven it since to test it out though. Link to comment Share on other sites More sharing options...
Keith Posted May 18, 2009 Report Share Posted May 18, 2009 Recommended mod for sure. The drive down to Brighton was consumed by chat and conversation, so didnt really have much of a chance to test it out. The journey back home yesterday though was an awesome test. Me and my mate were both feeling a little rough still, so the tunes went on, loud, and the sound was vastly improved - no more embarrasing rattle. The only thing I need to do now is get some low-density foam to sit underneath my disc changer - bumps in the road around town (and even some on the motorway) seriously upset the player and it skips badly - a bit of a design fault really, being located just above the rear wheel. I trialed this with a soft towel underneath and it did improve it somewhat, so I'm sure some foam will be even better. Link to comment Share on other sites More sharing options...
simonlpearce Posted May 18, 2009 Report Share Posted May 18, 2009 Just a thought but i have the electric rear blind which my sub tends to make rattle, other than putting it up is there any other way to stop this? Link to comment Share on other sites More sharing options...
bigbaz Posted May 19, 2009 Report Share Posted May 19, 2009 Reminds me of a story about a tennis ball mod I read some time ago involving a Kawasaki two stroke triple. A guy bought one that had a misfire on the middle cylinder which was not uncommon on those and the similar Suzuki two stroke triples of the era. He changed the spark plug, no better, changed the ignition coil, no better, then did a compression test and found the middle pot was way down compared to the other two so decided to take the cylinder head off to investigate. He was amazed to find that the piston had been removed from the con rod by the previous owner who apparently couldn't source another one and needed to shift the bike quickly so he'd carefully cut a tennis ball and slotted it over the gudgeon pin to stop the con rod rattling against the side of the bore as the crank turned.!!!!!!!!!!!!!!!!!!! Link to comment Share on other sites More sharing options...
Dicky Posted May 19, 2009 Report Share Posted May 19, 2009 ^^^That is brilliant but I think our method is not so drastic Link to comment Share on other sites More sharing options...
