i've heard nothing but good things about O2 speakers. This seems like a good upgrade
http://cgi.ebay.com/NEW-O2-AUDIO-8-MIDBASS-FREE-AIR-SPEAKER-MID-BASS-SUB-/350384171069?pt=Car_Subwoofers_Enclosures

 

No.

Two really big reasons not to get it:

1) That's a midrange *speaker*, not a subwoofer. It's frequency response is 100 HZ - 9 kHZ, a 8" subwoofer typically goes about 25hz - 250hz.

2) It's 8ohm, the bose is somewhere between 2 and 4, if I recall correctly.

If you're looking an 8" subwoofer for something near that price that won't ruin your amp and is actually a subwoofer, try any of these instead.

http://www.crutchfield.com/S-tteS4pr...o-8W1v2-4.html
http://www.crutchfield.com/p_20610C8...84.html?tp=111
http://www.crutchfield.com/p_107DB84...40.html?tp=111

 

^ thanks. What about to use for loud competition speakers on a fiberglass enclosure in the trunk lid. I'm looking for really loud vocals like EV (electro voice speakers) is that what this speakers are for?
http://cgi.ebay.com/2-O2-AUDIO-8-MIDBASS-FREE-AIR-SPEAKERS-MID-BASS-SUBS-/390212160352?pt=Car_Subwoofers_Enclosuressomething similar to this i'm doing on the trunk lid but with a tweeter below each speaker

 

If you're doing anything like what's in the picture, you definitely started this thread with the wrong question.

Take the picture to a custom fabricator and tell them you want something similar, and they'll discuss recommended components for your budget, and tweak the enclosure based on the specifications of the components.

Asking anything futher from this board won't help much.

Now if you get all your components and a price quote and want to ask the board if you're getting taken for a ride, we can probably help with that.

 

I was just wondering if those speakers are meant for high vocals since you said they're not subs. But I already talked to a shop for the fiberglass enclosure and labor. And they said around 400-600$ with me bringing my own stuff. components around $180 for pair. Tweeters 90$ pair, samsung flatscreen $150, 4 channel amp 800w or more $150-250. Thanks for the links on the sub replacement.

 

Human voice is usually between 100hz to 1.1khz (source Wikipedia), but high vocals and "s" sounds can reach upwards of the 6khz range, so the 2.5khz listed frequency response on those O2s would cover most of that, but just because it can produce sound in that range doesn't mean it can do it well. Harmonics on high singing voices can reach upwards of 15khz even!

You'd need its frequency response charted out properly to really say how good it is, but it would probably reproduce vocals, just no idea how clearly.

I would really question the need for tweeters if your system is meant to project that sound out away from the car any distance, since they are much more dependent on distance to and direct sight of the listener than mid-range and subs are.

Here's a good discussion on DIYaudio.com that kinda talks about getting a good vocal setup.
http://www.diyaudio.com/forums/multi...-speakers.html