I am setting up a small vocal/mixing recording studio in our workspace. The room measures 4.1m Long x 2.3m wide x 2.5m high. The roof cavity is causing issues as it is concrete and makes alot of flutter echo when you clap in the room. What is the beat way to eliminate the issue?
Like real estate, there are three attributes for the best acoustic value of small rooms: 1. Absorption, 2. Absorption, 3. Absorption. BTW Did you even bother to read Ethan's "PLEASE READ THIS FIRST"? All the answers are RIGHT THERE. This forum exists in part simply because we can't help repeating ourselves, over, and over, and over again.
Oh cheers Rock for the reply. Yes I did read Ethans post. Yes I did privately message him in regards to this and he mentioned to post it on here for advice. Yes I am new to this. Sadly in the "Please read this first" section there is no mention of the difference between Standard built/insulated walls to Concrete. Thus why I am asking as we have experimented with Absorption on the Walls, yet the concrete roof is where we have an issue. Understand you don't want to repeat yourselves. But I came here for advice, maybe a point in the right direction for shared knowledge rather than being dumbed down. We have had other engineers come in and offer advice that hasn't worked to our satisfaction. I prefer to ask many people to make an informed decision rather than spend a lot of money on something we never needed to. Cheers anyway Rock
So I don't consider myself an expert yet, but here are my 2 cents:
There probably isn't a lot of practical difference between standard vs concrete boundaries. I imagine that the concrete is less "giving", and thus reflects more sound energy back into the room, where the standard ceiling would allow some of that energy to escape. So if anything, you need that absorption even a little more than if it were a standard ceiling.
Keep in mind: it isn't really the boundaries that flutter and resonate -- it's the air mass in between them. Adding acoustic treatment to a boundary isn't intended to keep that boundary from moving (unless you're talking about stopping the sound from leaking into or out of the room), but rather, to damp the resonance of the air.
So unless there's something I'm misunderstanding about the cavity in your ceiling, or about interactions between your ceiling and floor: Ethan's advice in the "read me first" remains valid, as well as Rock's advice to study and follow Ethan's advice. At the risk of becoming a parrot, I advise the same.
And as long as I'm a parrot, I'll also repeat/paraphrase this: Flutter when you clap is probably not the worst issue you're facing with your floor and ceiling. I mean, flutter is bad and it's important to treat, but... Clapping doesn't generate bass frequencies, so it won't reveal how bass also reflects and resonates between your floor and ceiling boundaries. Peaks and nulls from bass resonance damage the sound too. What's worse, bass resonance is harder to treat than mids and highs, (but very doable - refer to "read me first"). The good news is that a velocity-based treatment which absorbs bass will also absorb mids and highs as well (unless it's specifically designed not to). So focus on the bass absorption, and the flutter will also go away.
You could look here: amcoustics.com/tools/amroc to see which bass frequencies will most likely resonate based on your room dimensions. And, you could measure your specific situation using Room EQ Wizard (REW). I doubt that these would change how you could use the answers given in the "read me first" thread, but it can help you to understand why they really are good answers.
hehe.. Rock's getting a little jaded, it would seem...
Right, this is very basic stuff and it's not Rocket Science. If you empty any small room with parallel walls of all the furniture, pictures, floor covering and window drapes and treatments, you'll have plenty of fluter echoes. Add enough absorption in the right places and like magic they disappear. If you locate the parallel surfaces that are causing the main offenders, mount your panels there but all parallel walls AND parallel ceiling and floor can cause flutter echoes. Did you try to mount absorbers on your ceiling? You may notice as you move around that the echoes are localized and depending on where you are, and where the sound source is, the echoes may seem worse or less at different places. For good measure, use 4" thick panels with a 4" space from the wall to improve LF performance. Like I said 1. Absorption, 2. Absorption, 3. Absorption. It's that simple.