Justin Phelps has been mastering albums since 1997. His involvement in this mysterious art was ramped up in 2009 when he moved from San Fransisco to Portland. At that point he received some final training from legendary engineers John Cuniberti at The Plant Mastering in Sausalito CA and Rick McMillen at Super Digital in Portland OR. Since then he has mastered approximately 400 projects for regional, national and international artists.

Justin’s mastering credits include:

Emily Wells, Everyone Orchestra, Fruition, Rich Kids On LSD, Amanda Richards, March Fourth, All Classical FM, Jet Boy, Lynx, MDC, Dead Kennedys, DOA, Robin Jackson, Sassparilla, Lila Rose, Logan Lynn, Ryan Lewis, The Dandy Warhols, Tiffany, Double Plus Good, Moon Museum, Volume Bomb Records, Rise Records, Fat Wreck Chords, Cartesian Binary Records and Hallowed Halls Presents live concert documentary series among many others.

Explore some of Justin’s other credits here:   https://www.discogs.com/artist/360056-Justin-Phelps?type=Credits&filter_anv=0

Duggan Backhouse-Prentiss

Duggan (they/them), also known by their producer/DJ name sea_wraith, first began studying audio mastering at the Hallowed Halls studio under chief engineer Justin Phelps in 2019 while finishing their degree in sonic arts at PSU. They are now working at the studio and taking clients. Duggan is also a full time DJ and Twitch streamer, and loves working with electronic and hip hop artists. Follow: @sea_wraith 

Duggan’s mastering credits include:

Giant Killer Bats – Giant Killer Bats EP (Terrible Records) 

JHNN – StereoTYP (album, Dem Modest Kids) 

Volume Bomb the Cops (compilation, Volume Bomb Records) 

Liila – Soundness of Mind (album) 

CD 3K – Sleeptown (album) 

voix in the dark – New Body (single) 

HorrorScene – Redwood Forest (album)

Marceline – D.O.O.M.

Full list of credits:



Mastering is an essential but frequently overlooked and misunderstood part of making a great-sounding record. Mastering is the process of transferring audio from your mix master (analog tape, digital file, audio CD, DAT, cassette, etc.) to a medium that can be used for mass duplication and/or distrubution (such as a lacquer disc for a vinyl release, a DDP image or Redbook Standard audio CD for a CD release, or a digital distribution file set for a digital/streaming release). In the course of this process, numerous enhancements, edits and alterations can be made, as dictated by the nature of the project and the client’s wishes.

A Fresh Perspective

The opportunity to have a pair of seasoned, experienced ears analyze your mixes on exceptional playback equipment in a well-tuned room. A mastering studio's accurate monitoring can expose flaws in your mixes that had previously not been apparent.

Mixing First Aid

The opportunity to fix problems detected when it's too late to remix (remove clicks and pops, adjust levels, correct frequency imbalances, reduce noise, etc.).

An Album with Flow

The opportunity to fine-tune the sequencing of your master, including adjusting or adding fade-ins and fade-outs, crossfades, and space between tracks... even adding tracks from multiple recording sessions in multiple formats to the final album program.


Use world-class processing (EQ, compression, limiting, stereo field adjustment, etc.) to enhance your mixes making them even better than the already great mixes you left the studio with. Often it is the work done in this phase that helps the recording stack up to other commercial recordings.

6 min and under

$ 50
  • 1 Round Revisions
  • Meta Data Entry
  • DDP File Creation

6 - 10 minutes

$ 70
  • 1 Round Revisions
  • Meta Data Entry
  • DDP File Creation

10 min and over

$ 100
  • 1 Round Revisions
  • Meta Data Entry
  • DDP FIle Creation