Hi All,

Sorry for my ignorance, just a quick question regarding the stereo speaker in my car. There are ten speakers in my car are they all speakers or are some tweeters? I am in the process of replacing the sound system and I don't know much about car stereos.


Regards Dan 1990 928GT

 

Tweeters & Mids. Adding a small bass tube to the new system will do the system justice. Just my .02

 

Hi Ron

when you say mids are they just regular speakers? how many of each will I need?

Regards

Dan 1990 928GT

 

Long time no see, hows HK?

The 10 speaker system in a 928 has:

4 each Tweeter speakers.
4 each Mid-Range speaker.
2 each Mid-bass speakers.

You can run the new speakers off the stock amplifer as long as you don't run the Ohm load <up> past 2 Ohms per channel. It's been a long while since I played around with this stuff, so if I made a mistake in the load, please speak up.

Like others have said, if you want to bump or if you like hearing the low, lows, you will need a liitle Sub-Woofer. Size is up to the individuals own taste.

Edited 2 Ohms, not 4 Ohms!

 

Hi Dan,

Not really sure if your speakers in you '90 GT are the same is in my '89 S4. I drew out the speakers some time ago to determine appropriate replacements. This drawing is on nichols' site:
http://www.nichols.nu/speakers89.jpg

When replacing them, keep in mind that the system splits up the speakers. Therefore the impendance is different then the current 4Ohm speakers speakers (See impendance of the old speakers on the drawing). If you have multiple outputs and/or an amp. this should not be an issue. The speakers behind the rear seats are combined and have integrated filters.

 

Hi Curtis

How have you been? I am preparing to bring the shark to Vancouver Canada I'll PM you later today.

Regards Dan

P.S. thanks for the info guys

 

Dan,
If you're in Vancouver, why don't you check in with some of the local Brotherhood?
Glenn

 

Replacing the speakers in your '90 GT is not a simple process. In addition to the normal size constraints, you have some electrical problems...

The midrange and tweeter speakers are normal four-Ohm speakers, and can be replaced fairly easily with any of several high-quality types.

The two larger bass speakers are two-Ohm units, and are part of the housings - not eay to replace!

The existing 928 stereo amp is set up specifically for the two-Ohm speakers, and the system will sound like crap with anything other than the two-Ohm speakers.

To get good sound, you will need to either use the existing speakers (reconing as required), or you will need to do some custom work. You can cut the existing speakers from the housings, and then glue new speakers in the housings. If you do that, you must also get rid of the existing amplifier and do some rewiring.

If you do a search on the Forum, you should find several threads with suggestions and solutions.

 

I will do Glen. I am looking forward to driving the Shark on some of those great B.C. mountain roads.
Does anyone else in B.C. have a RHD 928GT?

Regards Dan 1990 928GT

 

I take it its not feasible to change a 4 ohm speaker to run at 2 ohms?

 

Nope. You could change the filter to get the desired impendance, but then the frequencies probably would be off.
When connecting the speakers parallel, the impendance approximately divides into half. When connecting them in series, the impendance doubles. The several (lower) impendances in the 928 are used because there are several speakers on 1 output. This way they can compensate the number of connections and filters to a total of 4 Ohms per input.

So connecting the 4 Ohm speaker to the circuit, can cause damage to the amplifier. To upgrade the installation with the equal amount of speakers, you have to do some serious calculating. Not only the impendance, but also the filters. The filters should filter out the frequencies the speaker isn't built for and also filter out the resonance frequency.

It would be easier to just use 4 Ohm speakers (as they almost all are for car-audio) and use more outputs. A normal head unit these days have a pretty descent 4 way outputs and 1 or more extra outputs for an additional amplifier. This way you can separately feed all speakers. I replaced the old Blaupunkt amplifier with small up to date amp. which fits in the passenger side console.
If you don't filter off the speakers, it is recommended to use a cross-over filter. This electrically filters out (and can be adjusted) the unwanted frequencies. These ar also integrated in a lot of boosters you can buy these days.

All in all I was reasonably happy with the way the audio sounded in high- and midrange. But the bass didn't do much. In addition I added a sony-xs-aw200 subwoofer. It has it's own amp. so no extra amp. needed. It really sounds great for it's size. (Its just fits under the edge of the rear seats).
And it's always possible to go overboard of course. The audio shops are most happy to help you out...

 

Here's what I did to get passed the depth limitation on the rear Mid-range speakers.

Pictured is a JL Audio Mid-bass speaker with the Porsche factory grill.

Spacer made from a piece of PVC pipe, Plexi and texured paint.

 

Here is a few pictures of a test run I did on a concept system. It produced concert quality sound even the neighbors could enjoy

Did it ever make it as a perm. install? Nope! But it was a fun project

 

It took me a while to find it, but here it is!

For those of you who may wonder how you can run 4 Ohm speakers on a two Ohm amp! Basic Car Audio is a very good source for information.

Enjoy!

 

Thanks Curtis


Dan 1990 928GT