What do you think about my strange waterfall ?

[jloyer]

... Hello everybody !

Since six days i've made some basstrap i'm a bit confused about my waterfall . What do you think ?


Thus I've got a massive ringing @ 110 Hz , and this beast is a kind of difficult to tame.
I used 2 movable basstrap all around the control room with the help of a friend. The only positiv result was stradling them behind the desk floor to front wall.

Most of the walls are made of single plaster board screwed on vertical steel rail. I think it's not enough.
A 110 Hz sinus make the back celling and the back wall very vibrating.

- should i double the walls with an other plaster board ?
- ... or put some mega bass trap ( 6 unit of 135X60 cm, 15 cm thick ?)

If you could help me which direction should I take ?

Jerome

[Ethan Winer]

With no graph legends it's impossible to comment.

--Ethan

[Ethan Winer]

That helps, but it's much better if you change the Duration to 300 milliseconds or longer, to better see more of the decay.

--Ethan

[jloyer]

Hi Ethan,

my apologies ...

Is this correct now ?

[Ethan Winer]

That's better, and looks too good. Change the resolution from 1/12 octave to as high as possible, then you'll know the true response. But what you showed so far looks pretty good.

--Ethan

[jloyer]

Ethan,

Really ? I'm very surprised ... Did you take a look at my freq. response ?

Thanks I really appreciate your help !

Jerome

[jloyer]

( Ethan, Glenn or Andre ) do you have any advise here for my c.r setup ?
By the way, do i need diffusors ?

Thanks !
Jerome

[Glenn Kuras]

can you post a diagram of the room with the layout of the traps? Also how thick are they?
I want to say you need to treat that back wall with THICK absorption.

Glenn

[Ethan Winer]

Originally Posted by jloyer

Really ? I'm very surprised ... Did you take a look at my freq. response ?

I was commenting mostly on the evenness of the decay times. Usually a waterfall graph has a number of frequencies that extend for much longer than the rest.

--Ethan

[jloyer]

Hello,

All the bass trap are 135 by 60 cm with 10 cm thick. Glenn, I didn't complete all the measures (double angled celling) so I'll post asap.

All the basstrap are made with rock wool 135 by 60 cm - 100 mm thick.
As I ran out of purple fabrics the 100 mm acoustic panel period isn't finish yet.

Glenn when you say THICK I smiled because today i've made one big bass trap (see the 2 photos)

The thickness is 3 times 100 mm pannels layered (300 mm) . Is it too much ?

I put the mega bass strap on the floor, against the wall without screwing but the freq response didn't change a lot ...

What do you think about six like them on the back wall ?

Jerome

[Glenn Kuras]

What do you think about six like them on the back wall ?

I would try them back there and move them around. Maybe straddle one or 2 on the floor to wall corner and the rest on the wall itself. Without being in the room or having one on one conversation it is hard to pin point the problem but MORE (and thicker) is always better.

Glenn

[jloyer]

Thanks Glenn for reply.

More 5 to make ... ok ! I'll make some experiments with 4 . 2 basstrap stradling floor corners with two on the wall, then 4 on the wall.
I remind that the upper part of the back wall was ringing a lot,far more than the lower part specialy in that 105- 125 Hertz.

I'll come back with layout and new measures.

Regards

Jerome

[jloyer]

Hi gentlemen i'm back ...

after 5 days working , i'm quite proud of my 6 bass traps :




these are rockwool 16 cm thick with 14 cm gap . Density 70 kg/m3
I've built 3 more to test different position in the c.r

I've got 3 questions if you can help me ... i'm just don't know what to do now !



1 - After installing the 6 bass trap on the rear wall, the 110 Hz peak is still here ... and i see no improvemzent on the graph . I don't hear significant improvement in the bass at the sweet spot. Do you know why ?

2 - Putting a bass trap on the mezzanin make a little shift of the 110 Hz peak towards the lows. But the peak is still there .
I've found this after dozens of hour trying different placements .Is it a rigging mode problem ? How can i resolve that ?

Here are the layout and photo of the mezzanin :









- There's a alcove on the front right side of the desk (50 cm deep, 50 cm larg, 1.20 m high). If i cover it with a bass trap 12 cm thick, the response curve is quite different. Especialy from the Left speaker. What should i do with that alcove ? (here's a graph from the left speaker. Brown is with alcove uncovered. Red = covered





Here is photo of the alcove not covered :





... losing 6dB at 90 Hz with alcove covered. Could you explain me how this can happend ? Should i shut this alcove ?

I know i ask you so much things ... i'd appreciate your opinion about that !

Finally here are the waterfall and graph curve :





Hope i'm not annoying ...

Jerome

[jloyer]

... please read my last post , i've just upgrade this thread with lots of things (and questions) ...

thanks (Glenn / Ethan are you here ?)

[Ethan Winer]

Originally Posted by jloyer

I don't hear significant improvement in the bass at the sweet spot. Do you know why ?

No, I don't know why. Did you put the traps in corners?

I suggest you try using my weighted pink noise file to see where bass is building up in your room. Wherever the bass is loudest is where you should put more traps. Here's the link:

Pink noise aids placing bass traps

--Ethan

[jloyer]

Hi Ethan,

thanks for your advise. I suspect my audio interface is bad too. I will borrow a presonus firebox from a friend instead of my crappy adc powerbook . Maybe better and precise results.

come back soon ...

Jerome