Stereo and Speakers Upgraded

i thought I would have a go at doing a better job than Porsche in upgrading my stereo. Bought a Becker Grand Prix 7990 which is an excellent unit and looks OEM. Also bought 4 Infinity Kappa 42.7i speakers to replace the paper Nokia units. I must say, the sound difference with the new head unit between the old Nokia speakers and the new Infinity speakers is very different, but unusually it is the Nokia speakers that sounded better. I have installed the crossovers that come with them and ensured that the connections are consistent on all four speakers (i.e, terminals connected the same way on each speaker). Not sure what is positive or negative on the cable from the infinity crossovers but as long as they are consistently connected on each speaker that should not make a difference. Now I get no bass at all ! All I get is an annoying pop. Head unit is 4 x 30W the speakers are 150W peak with 50W RMS so powerful enough for the head unit. One thing I have noticed is the speakers are 2ohm where the head unit is 4ohm (or it could be the other way around). Would that make a difference? Really need to include some sort of sub but with no pre out on the head unit (which is strange for such an upmarket piece of kit) an amp will need lots of filters to stop engine noise coming through the sub and as i have a 1998 996 there is nowhere to hide a sub that I can find. anyone have any suggestions? Not looking for an audiophile setup but one that at least makes a nice enough sound. As I've destroyed the speaker brackets to place the infinities I'm thinkling of just buying some Nokia speakers to go back in as the infinities sound crap (unless I've done something wrong). Any help would be appreciated. Does anyone know the + or - wires on a 996 standard speaker wiring loom? Cheers, LeeRoy

The wire colours for a 1998 996 without the M490 (Harman) Sound Package are: LF+ Yellow LF- Yellow/Brown LR+ White LR- Brown/White RF+ Red RF- Red/Brown RR+ Blue RR- Brown/Blue My 98 C2 had just the dash and rear side speakers. I fitted a Pioneer AVIC double DIN head unit, and replaced the dash speakers with Pioneer eMotion 10cm units. I got pretty much the same result that you have - ie no bass at all. I don't think you will get any from a 10cm unit anyway. I then disconnected the rear side speakers, and fitted a pair of Pioneer 6"x9" eMotion ellipticals to a 'parcel shelf' I made myself. The difference was unbelievable, and the whole system just came alive. I'm no audiophile, but it sounded brilliant. My Turbo came with a snazzy Kenwood Nav/TV/DVD/Tuner, 6 speaker setup, which sounded dead as a dodo by comparison. So I changed the dash speakers, door speakers, and fitted another pair of 6x9's to a home-made speaker box. All eMotion speakers again. It's quite an improvement, but nothing like as good as it was in the C2. I reckon the sound quality of the head unit isn't that good. For the dash speakers, you can buy blank grilles and fit your own speakers to them. Much easier, and it saves hacking up the old speakers. They are about £17 each. Part number 996.649.045.02.01C. Only available in black. If you happen to have a Savannah interior, I have a pair of Nokia dash speakers if you really want to go back..... HTH

Wow, that shelf looks excellent. How dod you make it and secure it? Does it rattle at all? That would be a perfect solution for my car. I have the teracotta interior so getting a colour match has been difficult. Thanks for the kind offer of the speakers. I will pursue the shelf route it is an excellent solution. I did hear someone mention that you can fir 6 x 9's in the rear quarter panels but have to remove the rear quarter panel and secure the speakers to the inner wing. Doing this means the panel goes back in place with the grille but the speaker attached to the actual body and not the grille. May pop the panel off and have a look at that solution too. You should sell those shelves, every 911 owner in the country would fit one ! !

It originally started as a storage box. Mine was made in 6mm MDF with a leatherette covering. Here it is before fitting the speakers, and another one covered in carpet. I did a DIY for the PCGB forum. If you'd like a copy drop me a PM with your email address. In the Turbo I made a speaker box which fits behind the seats (where the Bose box goes), and coverered it in black faux suede. No pics yet, I'm afraid.

Have you got any ics of your dash? I'd like to see what the AVIC unit looks like in place. Thanks

I'm going to try and source the carpet in the colour of my interior. Any ideas on where I could source it? Also how have you secured the shelf inside the car? Does it rattle at all? Do you have a template for the shelf? I'd gladly pay you for it.

The carpet shelf was done by one of the guys on PCGB and he got the carpet from a place called Trimmania in Reading. The shelf slides under the rear panel, and is held down at the front by a couple of straps to the side trim. The DIY shows it all. No, it doesn't rattle or squeak - or at least mind didn't. Sorry, I don't have a template any more. I just cut a cardboard one to size first, and transferred it onto the MDF.

You have inspired me ! ! I'm going to go for it ! ! # Just been to my ICE place. Very knowledgeable. Ex 911 owner himself. Here is why I have the popping issues. 1, the head unit is a Becker Grand Prix 7990. 4 x 30W peak but only 4 x 18W RMS. 2, the infinity kapp 42.7i's are 2 ohm, 150W peak and 50W RMS. As they are 2 ohm they are drawing double from the head unit. 3, when the volume is up you can see the screen on the head unit flickering so too much is being drawn from it, hence the popping. What we are going to do. 1, loop the front speakers creating a 4 ohm ring, do the same for the rear. This will create the capacity for a 100WRMS feed. 2, install a T1 Audio LS 1100.4 amp and run the loop from one side of the amp. Adjust the gains on the channels and bring in some bass once the hpf is configured correctly. 3. wait for some sub woofers to arrive in the post, build a shelf, conceal the woofers and run them from the other channels on the amp. Adjust the hpf again through the 4 x 100W channels and feed the sub woofers with a lpf increased gain configuration which should push the low range frequency at the right level that it works in sync with the hpf. Doing it this way means I can get better sound from the Infinity speakers which they should produce. Right now they are drawing too much from the head unit which is affecting the sound. There aree some more technical bits that the ICE man is taking care of (like wiring loom, gain filters and the like. He's also fitting the iPod cable to run to the centre consolve so I can fasten the iPod to the inside of it and retain space for bits. All getting done on October 6th (with exception to the sub, need to locate materials for shelf), but will all be sub ready for me anyway. Looking forward to my journey to work from Tuesday the 7th ! ! I will take pics and post them.

:thumb: Looking forward to the pic's !

If you are going to this sort of install why are you choosing 2-ways rather than going with components? I'm running MB Quart components front and rear giving the headunit a 4 ohm load.

Just in case it's of interest, here's the speaker box on the Turbo. Also provides a useful cubby hole to hide those little bits and bobs out of sight.