infinity sound system replacing speakers

[DesertRunner]

so i bought a 97 sport with the infinity sound system and it sounds horrible sounds like the speakers are blown. i went to buy some replacements today and the stereo shop said that i needed a head unit or a bigger under seat amp to run "aftermarket speakers" he said the stock speakers were 8 ohms and aftermarket were 4 ohms and wont work....

so do i really need a amp and speakers? or?

im speaker stupid and searching got me alot of for sale add and no real answers.

thanks,
chad

 

[summitlt]

Ive got regular pioneers with a infinity equipped 99 XJ for years. No problems

 

[Talyn]

Depends what speakers you get. For instance, the Infinity Happas like more power, where the Infinity Refrence series will work fine with stock power.

 

[camarors8992]

I'm prolly wrong, but if the stocks run at 8ohm, and the replacements run at 4ohms then why would you need more power ? That's half the reisistance of the stockers.

 

[srimes]

what are you looking for? Fix what's broken or upgrade to hifi sound? You don't need an amp for door speakers, that shop's just trying to sell you more.

 

[SleeperXJ]

You'll need an amp if you're trying to drive 4 ohm speakers. Stick with 8 ohm and you won't need the amp. If we do a little arithmatic...
P = V*I and V = I*R then p=I*I*R
Lets say you have 50 watts of power through 8 ohms
I*I =50/8, I=2.5
For 4 ohms
I*I =50/4, I=3.54
So, I guess a 4 ohm speaker draws more current at 50 watts then an 8 ohm speaker.

 

[DesertRunner]

what are you looking for? Fix what's broken or upgrade to hifi sound? You don't need an amp for door speakers, that shop's just trying to sell you more.

just looking to get it working not trying to blow out my ear drums i would assume it sounded great when it was new and thats all i need... i will be adding a 10inch sub when i get around to making a box for the rear cubby (if it ever makes it to the top of the list...

 

[DesertRunner]

You'll need an amp if you're trying to drive 4 ohm speakers. Stick with 8 ohm and you won't need the amp. If we do a little arithmatic...
P = V*I and V = I*R then p=I*I*R
Lets say you have 50 watts of power through 8 ohms
I*I =50/8, I=2.5
For 4 ohms
I*I =50/4, I=3.54
So, I guess a 4 ohm speaker draws more current at 50 watts then an 8 ohm speaker.

you lost me at arithmatic... but where do i get 8 ohm speakers? apperantly there hard to get?

 

[SleeperXJ]

Haha, I'm good at arithmetic, I'm not good with sound components. I'm in the same boat trying to find speakers for my wife's tj. Crutchfield.com has an automated search engine that can help you pick speakers for a stock head unit, that's what I'm going to use. You'll probably be buying an amp anyway for that sub.

 

[srimes]

just looking to get it working not trying to blow out my ear drums i would assume it sounded great when it was new and thats all i need... i will be adding a 10inch sub when i get around to making a box for the rear cubby (if it ever makes it to the top of the list...

Ok, then you don't need an amp for your door speakers (you will for the sub). Just a working head unit, working speakers, and working wiring to connect them. I can't tell you what's wrong with what you have now, but I'd suggest looking for a better shop, or a friend with some basic audio (car and home aren't that different) and troubleshooting skills.