Add fiberglass to a cab which already has foam?

Discussion in 'Amps and Cabs [BG]' started by GlennW, Jul 27, 2013.

  1. GlennW


    Sep 6, 2006
    My DIY cab (pic) is lined with foam, and disassembled for painting (for obvious reasons).

    I have an empty Peavey 1x15, and it's lined with white insulation like stuff that's about 1.5" thick.

    Would it be a good idea to add a layer of the Peavey stuff over the existing foam?
  2. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Yes you can mix different types of damping materials. How effective it will be can only be determined by trying it.

    I've lined ported cabinets, then added additional layers and noticed a difference. At some point additional material doesn't result in any noticable changes. So you have to experiment.
  3. Foz


    Jul 26, 2008
    Jax FL USA probably standard fiberglass insulation - best to use un-faced batts [no paper or foil] - attach with staples through 1" squares of heavy card stock.

    I'd probably rip that stuff out and start over [looks way to thin to do any good] but looking at the pics it doesn't look like it weighs much or uses up much volume = doubt it hurts anything, so if its glued-in or for some other reason a giant PITA to remove I guess I'd leave it.
  4. GlennW


    Sep 6, 2006
    The foam is about 1" thick. The cab has 1x1 (full 1", not 3/4") fir for inside corners, seen in the left side in the pic for reference.

    The Peavey stuff isn't like house insulation, not the itchy kind, might even be nylon or something, not sure.

    I like the cardboard washer idea, but will use 2" or 2.5" screws since I have some and my staples are too short.

    No ill effects from crowding the ports with the extra stuff?

  5. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    If it isn't the itchy glass material, I could be a spun polyester batting that is in your cab. Material like this is available in rolls at a fabric store. It comes in different densities.

    Best to avoid blocking a port with it but otherwise, just use common sense when lining the cab.
  6. GlennW


    Sep 6, 2006
    Thanks. I wasn't going to block the port, but I think the specs said the ports need to be x" from the sides, and wasn't sure if that includes batting.