MBMB

On my '89 GT, the rear Blaupunkt woofers are marked 2Ω. The rear Blaupunkt mids are marked 4Ω. The rear tweeters are unmarked. As far as I know these are original equipment speakers.

Porsche appears not to have had a problem mixing 2Ω and 4Ω speakers. Why is this not a good practice?

The MB Quart mids that fit in the doors are too deep to fit in the wheel wells, so I'm inclined to refoam the original mids and stick with them. The woofers have built-in crossovers; can a 2Ω speaker be turned into a 4Ω speaker by soldering a 2Ω resistor in series?

Thanks,
Mark.

michaelathome

Here's a good read for you:

http://en.wikipedia.org/wiki/Electri...c_loudspeakers

I hadn't read about it in a while so I wanted to check

Michael

jleidel

MBMB, what size OEM speakers are in the 89's? Its tough to beat the sound of a set of MBQuarts with a clean signal. Diamond Audio used to make some a semi low profile reference speaker for just such applications.

Okv

This is not a really practical solution, because it will change the characteristiscs of the speaker (The electrical Q-factor will be much lower - not that important for a car stereo, this isn't exactly high-end audio..), and more important - the sound level from the speaker will be reduced by 6 dB.

Also, the series resistor would have to be L A R G E, because it must be able to dissipate the same power as the loudspeaker - a, say, 20W resistor may be sufficient - if the resistor gets too hot, it may set the interior of the car on fire before it fails.

And, if there is some kind of passive crossover attached between the amplifier and the speaker, this crossover will not function as intended anymore.
It does not matter if the resistor is put in front or after the crossover.

I think I would leave the speaker as it is, and just gamble that the new stereo unit can handle the 2 ohm load.

Or, you could try to replace the speakers, following advices which I am sure can be found in here - which reminds me, I must read about this now, as I may want to install a new, simple stereo in the shark, just to be able to have the radio in the background.

Car stereo is no fun, actually; too many wires going to unknown destinations, and in the shark there are speakers and amplifiers and god knows what all over the car.

MBMB

Thanks, Øyvind and Michael.

JLeidel, I'm not quite sure where the speakers are measured. The woofers are 5.5-ish inches, the mids are 4.25-ish.

I'm putting MB Quarts in the doors. I'm no audiophile and the shark cabin is not a concert hall, so I'll probably be content with the stock rear speakers.

David L. Lutz

Hey Mark, I notice the E55 in your signature. I have an S55 and yes your are so correct in saying "probably worth more to me..." I recently tried to sell mine and well still have it

But a blast to drive

I wouldn't worry about the unmatched speakers you will be OK.

Bill Ball

Refoam the stock speakers. Although MB Quarts and a lot of other speakers will fit the holes, you find yourself installing a subwoofer to get even modest bass. The stock speakers for all their faults, are pretty well balanced and work well if the cones have good foam and the voicecoils don't rattle. Leave the speaker impeadance alone.

RngTrtl

No offense to anyone, but the electrical information is so grossly inaccurate that it is funny. Posts #2 and #4 should be deleted so as not to give someone in the future that is using the search bad info. I swear that I am not trying to offend anyone.

hacker-pschorr

Rule of thumb, you can always go up in impedance, down depends on the amp.

An amp rated for 2 ohm's will run a 4 or 8 ohm speaker all day long without issues.
Running a 2 ohm speaker on an amp rated for 8 ohms can cause an issue.

This may not be ideal (that's open for debate) but it works.

Then we can get into wiring up stuff in series or parallel....

mj1pate

Yes....you can get audio resistors with sufficient wattage, so as to impedance match the load with the amplifier. That will make the amplifier output stage happy again. BUT, do you really want to dissipate half your power to particular speaker across a series power resistor? "Why is this speaker volume so subdued?"

Okv

And, that is?

RngTrtl

Shoot me a PM so we dont hijack the thread

Okv

I am sure the others would like to know as well, if faulty information is presented.
Which is always possible; I could be wrong, or, I may have presented the information so that it can be misunderstood.

Fogey1

Quote Originally Posted by RngTrtl : Shoot me a PM so we dont hijack the thread

QUOTE Originally Posted byOkv : I am sure the others would like to know as well, if faulty information is presented.
Which is always possible; I could be wrong, or, I may have presented the information so that it can be misunderstood.

+1. I was already hoping that Turtle would identify the errors he saw, explain and correct them.

MBMB

+1.