“Q Spruce” refers to high-performance guitar soundboards supplied by our wood vendor, Pacific Rim Tonewoods, that have been sonically graded using advanced acoustic science. While traditional wood grading (A, AA, AAA) focuses on aesthetics, Q Spruce is graded based on its physical and musical properties, specifically its damping coefficient, known in physics as the “Q factor.”
What is Q Spruce?
Q Spruce is typically Sitka or Lutz spruce that has been analyzed using a technology called BING (Beam Identification for Non-destructive Grading). Developed in partnership with European wood laboratories, this process involves striking a wood billet with a standardized impulse (a steel ball) and using high-precision microphones and software to measure its vibration.
The most critical metric is “Q,” which is the inverse of damping. In simple terms:
- Low Q (High Damping): The wood “soaks up” the energy of a vibrating string, causing the note to die out quickly.
- High Q (Low Damping): The wood resists internal friction, allowing sound to radiate efficiently and sustain for much longer.
The Benefits of Q-Graded Tops
There are several benefits of Q Spruce from a player and collector perspective, including resonance, responsiveness, sustain, volume, and consistency. Since high-Q wood does not “swallow” the vibration of the strings, the guitar is more responsive to a light touch and more powerful when driven hard.
The process also provides our head luthier, Steve Nall, with even more information for wood selection and voicing of individual instruments.
Finally, as Q-graded tops are increasingly recognized as premium offerings, knowing a guitar was built with “High Q” spruce also provides a technical pedigree that complements the aesthetic beauty of our instruments.
Availability on Collings Guitars
We are pleased to offer Q tops as a custom option on all of our flat top models (except for our CW and Hill Country instruments, which come standard with Adirondack spruce tops). Please contact an authorized Collings dealer to inquire about a custom build using a Q Spruce top.