Are you listening from the front seat? There's a pair of seats between you and the speakers. Try sitting in back..

You might want to check and see if the dealer programmed your radio correctly.

The radio has a setting to tell it what model of car its in. They may have not set it. I think you turn the key to on, and with radio off your hold the menu key until it turns on then scrool through the menu's for the model setting.

I'm not sure thats applicable to all the radios though.good luck

Thanks, Shancopp. I picked Blackberry Crush. I had to order the 5-sp man. with no options except the alarm and it took 2 weeks.

Frostwolf, I already checked the setting before posting here. It was already set at xB. I played around with the different car-model settings. It didn't make a difference as far as front speakers/rear speakers sound quality.

I made some recordings with Olympus DS-30 to illustrate the condition.

Front is front speakers only with recorder held at the height of the head unit between the two front speakers.
Rear is rear speakers only with recorder held at the height of the head unit between the two rear speakers.
Front Right is recorder held at about 12 inches in front of front right speaker.
Rear Right is recorder held at about 12 inches in front of rear right speaker.

Volume level (35), Bass level (0), Treble level (5), and SSP (Feel) settings are all the same during the four conditions. Fade is all the way front during front speaker recordings and all the way rear during rear speaker recordings.

From listening to and comparing these recordings, I think the rear speakers lack the bass and the 'boom' feeling and a bit too much mid-range compared to front right speaker. And I think the rear speakers are positioned too low. The sound quality sitting at the middle of rear seat is nowhere near the sound quality sitting at either the front seat.

I don't know why Scion makes front speakers sound so much better than the rear speakers. That was why I posted the question in the first place, wondering if there was something wrong with my rear speakers.

Make sure you turn down your treble level when you listen to these recordings, treble is very sharp. I have also included a clip of the actual mp3 music file for reference.

Front Speakers
Rear Speakers
Front Right Speaker
Rear Right Speaker
The actual mp3

I know my stereo sounds good if I have the settings to xB and the SSP to the "FEEL" option. Anyhting else I have found does not sound that good.

"Feel" distorts the EQ way too much.  I use "hear" since it fixes the phase problem in the default setting and cut the treble and bass a little so I can "hear" the mids.  And I have a 12" sub to fill out the bottom.

I've had my xB since August and never knew it was set to tC  sound until I joined this forum and read this post!  THANK YOU!!!!   

Did you read the 5th post?  Make sure you set the SSP Car type to xB... it comes set to tC from the factory which doesn't have the same rear speaker setup as us.