Carpet Underlay or Acoustic Foam

[Fraggy]

which works better, proper acoustic foam or is multiple layers of carpet underlay just as adequate?

keeping in mind you can get off cuts of underlays for free.

[Moseph]

1) You didin't specify what you want this for. You also didn't specify the type of acoustic foam. Absorption is different than reducing transmission. It's also different than diffusion, mode control, reflection, and room tuning.

2) One is free, and the other is not. Why not start with what's free and then try the other thing if you're dissatisfied? Actually, you've been asking these sorts of questions for about a year, and based on what I recall from those questions, I'm pretty sure you're just gonna do this anyway.

[Motleyguy]

Yeah, Moseph's right. In order for us to tell you what is going to adequate for your needs, we need to know what you're using it for.

[Fraggy]

1) You didin't specify what you want this for. You also didn't specify the type of acoustic foam. Absorption is different than reducing transmission. It's also different than diffusion, mode control, reflection, and room tuning.

2) One is free, and the other is not. Why not start with what's free and then try the other thing if you're dissatisfied? Actually, you've been asking these sorts of questions for about a year, and based on what I recall from those questions, I'm pretty sure you're just gonna do this anyway.
lol moseph, i only ask questions because i trust the opinion on here.

this is for an guitar cab iso box. stick the quadbox in and shut the door. not supposed to be fully soundproof but it isnt supposed to quiet it down.

[Motleyguy]

so you're building an iso booth of sorts? If you want a completely dead sound, you'll need some acoustic foam (the eggshell stuff works well) but underlay would probably work in some places. Try it with the underlay, and then if you need to, add the acoustic foam.

[Fraggy]

Yeh fair enough. i'll do that.

[Aus_rock_god]

In short, Underlay will deaden the sound, Acoustic foam will quieten the reverb, but keep the frequencies that sound nice.

I personally find (depending on what you want to do) that sticking a guitar amp in a warm room (hallways are good), using a 57 up close and a condencer at a distance sounds really nice, rather than using a dead room that makes the guitar sound cold.

[Fraggy]

no im worried about my neighbours hearing it...

[Aus_rock_god]

Just don't fu*k up a lot and they won't complain, haha.

[Aaron]

haha.