Fostex T40RP mkII - Modified

Sounds like you're having a sub-woofer party in a closet.

See the mod here - https://www.head-fi.org/threads/fostex-t50rp-incremental-mods-and-measurements.618659/post-16356751

Updated mod - https://www.head-fi.org/threads/fostex-t50rp-incremental-mods-and-measurements.618659/post-16376166