**Brief description:** This project uses spectrotemporal modulation filtering and cross-validated spectrotemporal receptive field (STRF) modeling to identify brain regions that respond differentially during recognition of speech with two simultaneous talkers when those talkers utter identical phrases ("Unison" condition) versus when those talkers utter phrases with different key words ("Competing" condition). We identify three such cortical networks that differ in terms of their STRF responses in the Unison vs. Competing conditions and in terms of their contributions to speech recognition performance across conditions. **Brief methods:** Twenty-five listeners performed a 3-AFC variant of the Coordinate Response Measure task in the Unison and Competing conditions during fMRI scanning. Spectrotemporal modulation filtering was performed on two-talker mixtures using the Bubbles procedure (Venezia et al., 2020) and STRF models were estimated from the filter patterns using a fully cross-validated implementation of the "boosting" procedure (https://github.com/christianbrodbeck/Eelbrain). STRF model predictions (R2) were compared across conditions (Unison, Competing) at the second level. Regions showing a significant difference in STRF model predictive accuracy between conditions were decomposed into networks using agglomerative clustering applied to the fitted STRFs. Brain-behavior modeling was then performed within those networks using a hierarchical Bayesian procedure, which we refer to as 'neurometric function' modeling. **Manuscript pre-print** at https://psyarxiv.com/vea5y/ **Code and Data:** The Files repository included with this project contains all code used for stimulus generation, presentation and data analysis. Example stimuli from one participant are also included. Results of second-level fMRI analyses are included in cortical surface format (text files to be mapped to the surface files in 'Template' using SUMA) as well as results of neurometric function analyses (R data files). Please see the README.txt file for a description of the included code/data. **Contact:** jonathan.venezia@va.gov, christian.herreraortiz@va.gov Venezia, Jonathan H., Marjorie R. Leek, and Michael P. Lindeman. "Suprathreshold differences in competing speech perception in older listeners with normal and impaired hearing." Journal of Speech, Language, and Hearing Research 63.7 (2020): 2141-2161.