Hi gearslutz,

this is my first post here, I'm Antonio, I'm from Italy and I'm a music lover / wannabe producer.
Since years I've always tried to improve the acoustics of my home studio by reading the forums and I was quite happy with what I had..but I think I made a big big mistake now so I really need some community help.
Before you start laughing: I can't speak english very well and I'm not an acoustics expert

Heres my situation:
a few days ago I had the chance to move into another room. (before I had the typical bedroom + homestudio situation).
My goal was to separate them, creating a semi-pro studio so I've copied the design of a pro studio I've worked in months ago that I really liked.
I got the measurements of that studio and reported them in my new room by building 2 plasterboard counter walls to match them. I've also built 4 corner traps with plasterboard and rock wool.
Now I just moved in and I'm really upset, I hear too much reverb + flutter echoes in some zones + the bass is louder at some frequencies. The only thing I like is the stereo imaging since I'm in a larger room.
Below theres a sketch of how my new room looks like.

Room size is 3,80 x 4,60 x 2,50h (meters). The corners traps sizes are 1,14mt each (front corners) and 0,57 (rear corners).
The listening position is at 38% of the room length.
By clapping my hands while moving around the room I can hear flutter echoes in the right half of the room. The closest I get to the pre-existing right wall, the more I can hear them. If I move to the left they disappear.
Also, I've placed a self built bass trap in the ceiling corner and it doesn't seems to help that much. In fact I have the sensation of being closed in a big guitar soundhole. Or maybe the soundhole is the space between the trap and the ceiling corner, I can't say it precisely its more like a sensation hahaha.

Not in the sketch: the door is completely covered with absorbers.
The floor is made of red bricks, should I put a rug under the listening position?

I'd like to enrich my post with some REW graphs but I spent all my damn money and I can't even afford 50 bucks to get a proper mic.
I got an old school sennheiser k3u with an me20 (omni) head tho. Reading the specs the frequency range starts at 50Hz. Should I use it anyway?

Thanks in advance guys

Hi Antonio, welcome to GS. First off, if you are using foam, stop buying that. You're going to want treatments that work at lower frequencies. Flutter is reasonably easy to get under control. Broadband absorbers staggered on your side walls plus a good cloud above the listening position should get them under control.

You can use the mic you have now to start learning to measure the room. When you can afford it, get a decent measurement mic and start over.

Please decscribe your corner traps in detail.

Thanks for the reply Syncamorea
It's nice to hear I've just spent something like 300eur on auralex foam just because they had it in that studio. Now I'm thinking I should've post here before doin all this

Anyways, the corner traps are built just like the walls: theres a metal structure supporting 10cm thick rockwool panels (75kg/m density) with plasterboard on it and foam on top. (look at the pictures attached)
I hope this is good because I can't destroy walls by then!

The way you built the corners is not recommend.. You would want to put fiberglass in the corners with fabric in front of that.

Hi Glenn, thank you too!

since I can't destroy the wall corners, should I just remove the foam and put some fabric on em?
I swear I read somewhere the rockwool is better than fiberglass when it comes to bass traps building :(

This is frustrating..I need HOPE

Both work the same so you did that part right. Putting the drywall over top of it is where you kind of messed up (if I understand you right).
removing the foam and putting fabric won't do much of anything besides not making it reflective. I would think about bass trapping in the upper corners where the ceiling/wall meet around the room. Those are corners also.

Wow. So I'll be okay by removing those plasterboard panels on top of the corners and covering em with fabric right? This is something I think I can do..plus I got some rockwool leftovers so I can start building a couple traps for the side wall-ceiling corners.

Also, do you think all this reverb (like if I'm in a bathroom) would go away once I fix the corners or it depends on something else?

Thanks again

If you are going to go through all of that trouble then also do a slat design over (or under) the fabric. It will help scatter/diffuse the upper frequencies in the room.
DIY Binary Amplitude Diffuser anyone?

Maybe some but most flutter comes from 2 parallel surfaces, like walls or ceiling/floor.

Thank you Glenn that looks really interesting. It seems like my journey into dust & tools wont finish soon

I've just finished measuring with REW following your tutorial on youtube tryin to do everything correctly. Here are the screenshots and the mdat file.
In the 1st screen I had 3 measurements. The red one shows both speakers, green is for the left one and blue for the right.
What would you do if you were me? (low budget + embarrassing waterfall graph)

mdat: https://dl.dropbox.com/u/979898/Anto...etti.mdat?dl=1

Hi Antonio,

I've attached a pic of your measurements. I've adjusted the viewing a bit to get somewhat of a better picture. This is showing both speakers playing. I cut off the frequency from under 60 Hz. Since your mic is only rated down to 50 Hz and your speakers around the same (and it looks like it from the measurements), I'm assuming that part of the measurement is useless. It may be better to measure with a different mic that is capable of correctly measuring lower frequencies to get a better idea of what its going on under 70 Hz.

With the current measurements, you can see some resonance at about 80 Hz, 95 Hz, and a large resonance at 115 Hz. The rest of the bass decay (up to 400 Hz at least) is still quite long. Bass traps, however, should affect all of these problems. At least 4" thick. Our 244 for example is 5.5" thick, but when straddling corners, has some really great absorption at 80 Hz. I would suggest similarly sized panels in other corners. Those front corners, if you have at least 4" of mineral wool, should do a good job at absorbing 80 Hz if the plasterboard is taken off. You can also stuff all of the open air behind the mineral wool with standard fluffy fiberglass or more mineral wool to get extra absorption at low frequencies, which you may or may not need depending on how much resonance you actually have under 70 Hz that we can't see in the measurement.

Perfect explanation..thats what I was looking for
I'll buy a behringer ecm8000 and repost the results again.
In the while I'll do the corners job and look out to get at least a couple of 244bass traps.
Thanks a lot for your help GIK (still Glenn?)

You don't necessarily need to buy a new mic just to test. In REW you can run the signal generator at low frequencies to get an idea of the problems under 70 Hz. And you can use the pink noise generator to assist in speaker placements, etc. Of course, a mic with a better low end response is best, just noting that I'm not trying to convince you to get a ECM8000, haha.

And no, I'm not Glenn. He was on a plane earlier when you posted the measurement results, so I figured I'd respond since he wouldn't have been able to for hours. My name's Alexander. Glenn posts under his own name. I'm much more awesome than Glenn so I post under the handle "GIK Acoustics"

Hahaha ok well thank you Alexander,
I know you werent tryin to convince me about the mic but I think I should get it to better understand what's goin on here. Seems like I need to seriously improve my knowledge about acoustics cause there's always something I don't like in the translation of my mixes and I'm sure a proper mic will be helpful.
Before I start to destroy my wall corners: do you think at least the room size is correct? (3,80 x 4,60 x 2,50h). As an ignorant I've tried to use a room modes calculator to get the best size without shrinking the room too much.
Please tell me I did it correctly, at least this one hahaha

Thanks again

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edit:

No more DIY for me. I took a look at your website and I'd like to know if the acoustical room advice service + planning to buy what's needed will solve all my problems. I got 3 headaches in the last 3 days so my conclusion is I need to focus on the music and let professionals do their job.

The Cloud is most effective above the speaker or the listening position????

If I was making a minimal cloud, it would be centered at the reflection point. But I like the idea of a huge cloud where you can add reflection and diffusion if its hugeosity is providing excessive deadness.

This GIK on GIK violence must end!

I'm destroying the corners right now. Ill put the fabric on top of the rockwool then Ill cover the borders with a wooden frame please someone tell me if this is ok

Forgot to say I've added another strate of rockwool now is 10cm thick

The thicker you make them the better.

Hey Glenn thanks for your suggestion. I've bought some more rockwool and filled the whole corners. Sounds a little better now but I can still hear some reverb while playing drums samples. I was thinking about the ceiling corner trap I've made before consulting the forums. Maybe there's something wrong with that? (pics attached)
It's made of a 2cm thick board of wood + 7cm thick rockwool, everything covered with thick fabric.

I'm planning to buy other broadband absorbers (no more diy), could you please tell me where I should put them?

Everyone else reply is welcome and really appreciated.
Thanks again to everybody

Without diving into this to deep it sounds like you just have some over all flutter in the room, which is either floor to ceiling or wall to wall (maybe the back of the room?). I would look at using more absorption but at this point as I said before I would use a slat design in front of them to help scatter/diffuse/retain the upper frequencies while still provide absorption below.
Sort of like this concept.
GIK Acoustics Scatter Plate Product Video

looks sweet. but I cant find it in the EU store

You were perfectly right. I put my double mattress on the back wall and I cant believe my ears. Now I just have to find something to replace it

We are in the middle of a redesign of the UK site, but we do have them in stock.. You can contact me on our website if you are interested in them.
Contact - GIK Acoustics
I am the ugly guy on the bottom right of the page.

+bookmark. You'll hear from me very soon
Thanks a lot for everything