FRK facing used on the rear of fiberglass bass traps - Gearspace.com
The No.1 Website for Pro Audio
FRK facing used on the rear of fiberglass bass traps
Old 19th June 2009
Gear Nut
🎧 10 years
FRK facing used on the rear of fiberglass bass traps

I've seen the advice mentioned numerous times about having FRK facing only to the outside of fiberglass bass traps and removing it from the layers closer to the wall. I understand the definite advantages here with the high frequencies being bounced back into the room, but I haven't been able to find an explanation for why to not keep it on the back?

From my understanding, the air gap is present in porous bass traps because they work on sound wave velocity, which is 0 at the wall surface and higher further away from the wall. Then helmholtz and membrane traps work best near a wall since they rely on sound pressure instead of velocity, which is highest directly at the surface of the wall.

So, if the FRK facing acts as a limp mass membrane, then why would having that closer to the wall not help absorb more bass?

Old 20th June 2009
Gear Guru
Ethan Winer's Avatar
🎧 15 years

The only way to know for sure is to measure with and without FRK on the rear at varying distances from a surface. As far as I know nobody has done that. FRK on the rear with an air gap should give more bass absorption. But another advantage of an air gap is the rear of the panel can absorb sound that gets back there. And with FRK on the back side of the panel, that will reduce mid/high frequency absorption. So if I were treating a reflection point I'd probably leave off the FRK, even on the rear. But I admit I'm mostly guessing.

📝 Reply
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.

Slide to join now Processing…

Forum Jump
Forum Jump