Reading the Runout
The "Deadwax"—the runout groove between the last track and the label—is the fingerprint of a record. It reveals who mastered it, where it was pressed, and often, how it will sound.
Anatomy of a Matrix
Every record has a matrix number etched into the runout. This alphanumeric code is the distinct ID for the metalwork used to press that specific disc.
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1.
Catalog Number Matches the spine/jacket (e.g., SD-7204).
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2.
Side Indicator Usually A/B or 1/2.
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3.
Lacquer Cut A letter/number suffix (e.g., -1A, -1B) indicating which specific lacquer was used. Earlier layouts often mean closer to the master tape.
Example: LED ZEPPELIN II
ST-A: Stereo, Atlantic Records
691671: Matrix ID
MO: Monarch Pressing (Los Angeles)
CC: Cut ID
"RL" (Robert Ludwig) - The Holy Grail
The "Hot" Signatures
RVG / VAN GELDER
Rudy Van Gelder
The sound of Blue Note. Known for a punchy, mid-forward piano sound and compressed dynamics that jump out of the speakers. Essential for 50s/60s jazz.
RL / STERLING
Robert Ludwig
Famous for deep, undistorted bass and massive dynamic range. His "hot cut" of Led Zeppelin II is legendary for making cheap needles jump out of the groove.
PORKY / PECKO
George Peckham
The king of UK rock/punk. Look for "A Porky Prime Cut" etched in the deadwax. Known for loudness, brightness, and energy.
KENDUN
Kent Duncan
70s funk, soul, and pop (Stevie Wonder, Fleetwod Mac). incredibly clean, spacious, and audiophile-grade bass response.
TML
The Mastering Lab
Doug Sax's facility. Look for TML-M (Master) or TML-S (Slave). Industry standard for natural, transparent sound (Pink Floyd's The Wall).
LH / STERLING
Lee Hulko
Another Sterling Sound legend. Often found on 70s rock. Balanced, powerful, but slightly more restrained than Ludwig.
The Groove Lab
Decode your deadwax with our AI-powered Matrix Decoder and Pressing Detective.