Acoustic panel air gap/stand off wall question

[vespiz]

The airgap doesn't affect specific frequencies as such, it lowers the effective range of the panel by about an octave, if spaced off the surface by an equal amount or more its depth (2"+2"). That's the simplified version. How much bass frequencies is affected is dependent on the depth of the panel, material used and location. 2" panels don't reach that low, if you want to tame bass frequencies. If you can, go with 4" or deeper.

If you can only do a couple of panels, I'd start with the corners first OR, more likely if the panels are shallow (2" or so), the surfaces between you and the speakers. Bass "gathers" in corners and panels there help most, but for more accurate imaging (stereo field) the panels in the first reflection zone (speakers - listener) are important. So basically, it's all important! :D Don't forget, basic rooms have 12 corners and then there's also the ceiling..

OK. All the information you require is in here. Read the stickies, the contain most of the useful info. Read them and then if you have some specifics, come back and ask again.

I'm still studying this stuff, so if I'm wrong in any way, please correct me folks!

[kasmira]

Originally Posted by vespiz

The airgap doesn't affect specific frequencies as such, it lowers the effective range of the panel by about an octave, if spaced off the surface by an equal amount or more its depth (2"+2").

Not really true. Your main point is correct though, and that is an air gap doesn't absorb everything better - it just lowers the effective frequency by some. But doubling the size of the panel by air gap does not increase it by an octave, only in some configurations. I understand you were just trying to be brief, but there are ways to be brief without misinformation (this is how this information spreads in the first place). For example, Andre (Avare) gets quoted often saying things like this, and most people don't realize a lot of his small, quick posts are specific to that thread, and not general answers.

Originally Posted by vespiz

How much bass frequencies is affected is dependent on the depth of the panel, material used and location. 2" panels don't reach that low, if you want to tame bass frequencies.

Originally Posted by vespiz

If you can only do a couple of panels, I'd start with the corners first OR, more likely if the panels are shallow (2" or so), the surfaces between you and the speakers. Bass "gathers" in corners and panels there help most, but for more accurate imaging (stereo field) the panels in the first reflection zone (speakers - listener) are important. So basically, it's all important! :D Don't forget, basic rooms have 12 corners and then there's also the ceiling..

That's the ticket!

To the OP:

I understand your flutter echo problems. Before I even realized I had bass problems, flutter echo completely annoyed me, and I always heard it.

However!

If you do plan on treating the bass frequencies I would do that first. Adding bass traps and first reflection panels will easily kill a ton, if not most of your flutter echo. If you treat flutter echo first, you will have unnecessary 2" panels everywhere making your high end very dead..

[vespiz]

Thanks Kasmira! Learning all the time.

[Ethan Winer]

Originally Posted by Old School

I will be adding some panels (2" depth) to my front wall behind the speakers to help address the issue.

You're already getting good advice, so I'll just add that the front wall behind your speakers is one of the last places to consider because your speakers face the other way. This article explains the issues in depth:

Front Wall Absorption

Also, an air gap always helps, no matter what problem the panel is intended to improve.

--Ethan

The Acoustic Treatment Experts