Matthew Langford is a sound artist, composer, trumpet player, and improviser. His work has been featured in the Denver Film Festival, the Denver Digerati Experimental Media Festival, the Arvada Center for the Arts and Humanities, the Supernova World on Fire Festival, and the OME Festival. His collaborators include visual artist Jeremy Grant, sound artists Tatsuya Nakatani, Jim Ruberto, Ryan Seward, and Andrew Weathers, caves, canyons, an empty pool, various objects, memories, and a 400 gallon tank of water placed in the center of the Tank Center for Sonic Arts.

In one morning recording session subtle vessel was recorded live in the seven-story aquatic space known as the Tank Center for Sonic Arts in Rangely, Colorado. This is the culmination of a two-year-long recording project by Matthew Langford that began as a voice memo he made at a piano in Lakewood, Colorado on July 26th, 2022.

Mirroring and adding to Alvin Lucier's process for »I Am Sitting in a Room«, he made live re-recordings of the original voice memo on July 26th, 2023 while adding layers with trumpet, flügelhorn, and simple delay effects. Bringing a body of water into the Tank for the first time, on the morning of July 26th, 2024 Langford began by soaking for thirty minutes in a 400-gallon tank of water while the recordings he had made on the same day one and two years in the past were played into the Tank and re-recorded once more. While standing in the tank of water, he then made five more re-recordings while continuing to add layers with trumpet and flügelhorn to complete this full-length album.