This may be a good sticky thread if it hasn't already been posted yet.
I have been trying to find out the specs on the factory Pioneer system for our cars and I found some info on it finally! Hopefully this helps.
Pioneer Electronics and Chevy Cobalt Team Up!
The Cobalt audio system was professionally designed and sound tuned by Pioneer audio engineers. The goal is to have bass you can feel (output down to 30Hz) and high output with low distortion.
The Pioneer system consists of 7 speakers and an amplifier:
Shark Fin 0.75" Tweeters
Front Door 6" HSS Speakers
Rear Shelf 6x9 ERS Speakers
Dual Voice Coil 10" Subwoofer
6 Channel Analog Amplifier
1" Tweeters: The location of these tweeters is on the a-pillar "shark fin". This location was chosen due to its perfect alignment with the driver's ear level.
6.5" ERS, Extended Range Speakers in the front doors offer extended frequency response. This provides smoother high frequency response, adds clarity, and enhances the vocal portion of your music source.
10" Dual Voice Coil High Excursion Subwoofer for higher output and less distortion. This subwoofer operates using a dual voice coil in a 2-Ohm load, to produce clean deep bass response for all types of music. The woofer also incorporates the latest speaker cone technology called Pioneer IMPP (Injection Molded Poly Propylene) to prevent the speaker cone from flexing or breaking up. This results in smoother output. In addition it has a bumped back plate for longer woofer movement. The subwoofer will not bottom out, and has higher output capabilities compared to standard subwoofers.
Enclosure for subwoofer is located in the left rear section of the Cobalt's trunk. This 18 liter size molded enclosure was specially designed and accurately sound tuned to work with the woofer and provide extended smooth deep bass response. This allows subwoofer to play low frequencies.
6-Channel High Power Amplifier
270 watt peak output power
2-Channels front tweeters
2-Channels front door speakers
2-Channels for 6 x 9" speakers with bridged mono channel for the 10" subwoofer
Low distortion output