Fuse holder resistors

just removed the rear speakers from the rear panels and noticed there are fuse holders containing 2.7 ohm resisters, are these important?

Only if you still have the factory radio; they are load matching resistors. If an aftermarket radio and compatible with a 4ohm speaker load, they can be replaced with a fuse.

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Those aren’t resistors, but rather coils to provide impedance. They block high frequencies from the rear speakers. There’s a school of thinking that says people in cars wanna hear full range sound from in front but only bass notes from behind. If you wanna try hearing full range all around, just replace these coils with actual fuses (any rating, make sure there’s no coil inside).

Note that the OEM speakers don’t provide much in the way of high frequency response anyway. If you want good sound, you’ll want to add some tweeters.


I removed those things, and installed aftermarket stereo (aux in for smart phone!) And aftermarket speakers. No fuse.

I put two way speakers in back, and three way in front. I get a good deeper sound from rear.

No way! Have you seen a typical inductor in a crossover, Kirbert? They are physically large (mH range) and often wound on iron or ferrite cores. This is a wirewound resistor. It’s uH range inductance is suitable for megahertz frequencies, not audio, particularly in a low impedance circuit like a speaker. IMHO of course.

Believe me or don’t. Swap in some regular fuses and see if you can hear a difference.

The only difference you will hear will be volume; they are resistors. Adding a 2.7 ohm resistor in series with a 4 ohm speaker will reduce the volume by nearly half, which will be an audible difference.
Solid state audio output stages are sensitive to short circuits and a system designed for a 8 ohm load will run hot with a 4 ohm load.


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The factory speakers and sound system seem so crappy, you probably won’t even notice a difference.
I was trying to replace my speakers eventually with crossovers but didn’t want to cut any panels in order to keep the factory look. Which leads to does the factory head unit keep up. Seems to me on an old Motorweek review they said the unit was an Alpine system. Would like to keep it just can’t figure out why?

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They are totally crappy… actually unacceptable.
If you want good sound you have to replace the head unit.
Install Mid-Bass speakers in doors and rear, Mid-Range at the footwell panels and Tweeters where ever you fancy…

Actually they are quite good midrange speakers (Phillips, with a substantial magnet structure); just not a good application for them. A similar product was used in the Infinity Q series bookshelf speakers of the same period successfully.
You can get speakers of the same diameter that have an actual tweeter and a longer excursion main cone for a better full range; I used some Pioneer speakers of that type in the front doors and kept the OE in the rear; with an aftermarket Pioneer radio that has an equalizer function, it sounds pretty good.
Add a powered sub if you need more bass…

Do you know what model of Pioneer speakers you used in the front doors? 5" speakers that fit are hard to find.

They were Pioneer TS-G1045R; I also added a 11mm spacer ring so that the tweeter would clear the OE grille. The speakers are far enough forward that the extra depth doesn’t interfere with the window. By the way, the speakers were 4" in my '88 XJ-S (I just measured the ones I removed) as were the Pioneer replacements. I recall that I had to trim the black plastic watershield that mounts on the grille studs.

Bob ( @BobPhx ) posts here frequently and has a nice blog. One of the topics covered is the front speakers upgrade:

Speakers? With my modified exhaust (straight through to one small rear box) I don’ need no stinkin’ speakers.

I measured the cones on the stock speakers, and they are about 4.25". 5" db501 Polk speakers say the cone itself is 4". So much for standardization. Appreciate your input.

What standardization exists is in regard to the mounting holes, not the cone size.

The OE Phillips that I removed measure 4" for the actual cone diameter; I don’t recall any mounting issues.

Yes, it’s the hole and the common standard size is 5.25" but the Jaguar speakers are something like 5".
It’s quite problematic as the speaker is fastened via the studs that are part of the grill.
In my XJ I had to use aftermarket grills and make the hole bigger in order to fit 5.25" speakers.

I know that I used an 11mm spacer; perhaps I drilled a new pattern for the grille or speaker. I do know that I retained the OE grille and splash shield.