Is all speaker fill created equal?

[JimA84]

I have always wondered about this in general.

It might have made sense in very old speakers where open back tweeter and midrange drivers were put in an open enclosure.

Fiberglas (tm), etc. typically only damp high frequencies.

Particularly in terms of bass response it seems like stuffing the enclosure with anything is only going to reduce the volume and raise the resonant frequency.

 

[fineMen]

Currently at the build stage of making my enclosure, but I’m struggling to determine what a good sound dampening material is for the box.

Some people say the cheap poly fill that’s in your pillows is enough, but i also just watched a video by audio judgement on how sound dampening material affects a speakers frequency. He also made a comment that “denser fills will be better for absorbing lower frequencies”.

This makes me wonder what is a good brand or good material to use? Have studies been done between plain Jane poly fil vs a more hifi specific brand? What’s recommended?

BASF's Basotect is extremely effective against resonances, but quite expensive. For increasing the effective volume polyfill suffices. Two tasks, two materials.

 

[spiral scratch]

When I was looking into various speaker fill options, i read that melamine foam (Magic Eraser) will off gas formaldehyde. That and the cost made me decide not to use it. I picked up recycled denim insulation instead.