8 ohm speakers?

[CO318is]

I am starting to look at building a diy set of components and was wondering if you can use 8 ohm speakers in car audio builds? It looks like most car audio speakers run at 4 ohms, and most amps are rated at 8 ohms. I am kind of a noob when it comes to this but after looking at the diymobileaudio forum, and bmwman91's build I think diy is the way to go for quality sound.

[KenC]

Most car audio amps are rated at 4 ohms

[george graves]

Yep - what he said

(most) amps are made to work with 4 ohm. And in some cases lover. Stick with 4 ohm for everything unless you know what you are doing, or (depending on the amp) you'll have trouble driving them - they won't be loud enough is the issue.

[StereoInstaller1]

Do you understand impedance and how it affects the amplifier?

When you lower the impedance (from say 8 ohm to 4 ohm), everything doubles: heat, distortion, and power. So, lower impedance (numerically lower) is a heavier "load", so the amplifier (deck power is an amplifier too) makes more power...unless you load it too much, then it lets out smoke.

It is all a balancing act: load vs. Sound quality vs. money vs. SPL.

I know I want no less than about 50 watts RMS to achieve the SPL I require, so that means if I want an 8 ohm speaker (there are LOTS of choices) I want to find an amp that makes at least 100 watts RMS rated, so it can have a chance of hitting the SPL goal I have.

Unless I can find a more sensitive driver, or build more efficient enclosures.

It is all about the trade-offs.

Luke

[Jean]

Or just double up on the drivers lol :)

[CO318is]

Sounds like I would be better off just using a 4 ohm speaker like these

https://www.madisound.com/store/product_info.php?cPath=45_228_254&products_id=8707

I don't think there are many 100 watt per channel amps out there...

[Jean]

Seas makes car specific drivers, look into those as well :)

Half of the work after you select the drivers will be crossover design, testing, re-design, testing and so on.

I love SS drivers, I currently use them for my diy speakers but I would never put them in a car environment myself.

[StereoInstaller1]

Sounds like I would be better off just using a 4 ohm speaker like these

https://www.madisound.com/store/product_info.php?cPath=45_228_254&products_id=8707

I don't think there are many 100 watt per channel amps out there...

Those pretty much require a small ported box or they will flap and fart like a dog trying to shit out a newspaper.