with 13' x 15', the C1 is your ideal speaker. it has bass down in the low 30s for you. try them out, several pairs on a'gon. if not enough, go further up the pipeline.
but C4s are definitely out of the question for you---refer to stereophile review for more information.
but C4s are definitely out of the question for you---refer to stereophile review for more information.