ACC 106 2x15: Insulate?

Discussion in 'Amps and Cabs [BG]' started by Count Bassie, Aug 30, 2020.

  1. I've got an Acoustic 106, loaded with EV 15-Ls. I'm wondering about lining it with some insulation, because after hearing a room mix of a jam it sounds heavily 'Boxy' in the low mids... there's some hollow-sounding resonance that's annoying there and I'd like to flatten that out.
    I've found a few walls-worth of good ol' 2" pink does a wonder. Anybody in the know about that, esp with this cab? It's low and wide, has never had insulation.

    Also, I'm mulling over trying to fit port tubes into the round vents in the baffle. The EVs are in good shape but I don't push then too hard... maybe I could get a little more at middling volumes if I tuned those vents?...
    Thanks for reading.
  2. Try it. 2" glass will be fine, you really only want to damp mid to high frequency reflections coming off the walls in your cab. But just make sure you wear a mask, gloves and a long sleeved shirt. You don't want to breathe it nor do you want it all over your skin. The nickname for that product in the construction industry is 'itch', or at least that's what we used to call it. I remember reading some place that JBL recommends one wall and one side. Try that first, and see if there's been enough change to get you where you want to be.

    You can tune the cab with Winisd pretty accurately with the 950 version.
    Count Bassie likes this.
  3. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Ime, the insulation needs to have a littlebut of density to it. 2" of batt type house insulation isn't going to be as effective as matted insulation or padding.

    It's also going to be more effective on the higher mids, so ymmv.
    Count Bassie likes this.
  4. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    Definitely lining the cab will remove alot of the boxy sound.

    But dealing with pink insulation is itchy and gross and not as effective.
    Recommend using poly batting
    or poly fill.

    This is not only more effective for reducing standing waves in the midrange frequencies
    but its not itchy or harmful to the lungs.
    fiberglass is itchy to install, also over time fiberglass will come out the ports.

    Poly bating sheets or polyfill is a non toxic fill.
    Used for stuffed animals as fill, or used as a sheet to make puffy comforter blankets.

    In a ported cab you cant use loose fill, so you use batting sheets for comforters.
    Sold at fabric stores or in Walmarts with craft/sewing sections, often super walmarts

    To understand the science of lining a cab. When the air or sound pressure passes through the batten.
    There is friction/ heat from passing along all the tiny hairs formed by the polyester.

    So basically its removing the reflected sound pressure by turning it into heat.

    This is why dense foam, mattress toppers or dense pink insulation is not as effective.
    the air cannot easily pass through it.
    You want the air to pass through so it can be essentially be dragged across the tiny fibers/hair like structure
    of the poly.

    Thick pink insulation with high R values isn't more effective like some believe.
    We aren't insulating a house lol, We are looking for a material air easily passes through
    and finds friction from passing through the material.

    Also poly usually comes in 6 ounce per yard and 10 ounce per yard.
    basically thinner material for blankets and thicker material for thick comforters.

    Usually use the thicker 10 ounce material since it is thicker has more fiber to create more friction
    to the air passing through it.

    You can also do a single layer on the sides/ top / bottom.
    and add a Extra layer on the back wall of the cabinet since this is where majority of the sound pressure hits
    and gets reflected.

    Its best to use 3M spray glue to attach the material.
    but temperature changes can make spray glues weak and eventually
    material can hang inside the cabinet or interfere with the speaker.

    So you use a combination of spray glue and very minimal staples.
    staples are there for reinforcement.
    Problem with stables
    is you need to make sure to use longer staples and that they sink into the wood well.
    Often times people use way too many stables and they dont sink into the wood, and will fall out.
    being attracted to the speakers magnets, a staple can damage the spider or cone of the speaker.
    also a problem with the pink insulation, more likely to have staples that dont sink well.
    Last edited: Aug 30, 2020
    Count Bassie likes this.
  5. Dig the poly-fill suggestion, I've got a link for that.
    Also yes, I've got 3/8" staples which, used sparingly and strategically, should do the gig ok.
    Thanks for the comprehensive and thorough reply! I'll be back with results...