Broadband absorbers not doing much

[javamad]

Hello,

I have a studio in Dublin, Ireland and I built out the treatment a couple of years ago.

Its a single room facility and I have to record and mix in the same space.

The room dimensions are: Length 6.6m, Width 5.5m and Height goes from 2.7m at one end to 3.2m at the other as the ceiling is slanted.

Its a small industrial building in a lane behind some houses and the walls are 4inch block, space and another 4 inch block so soundproofing is pretty good. When we leased it we had a ceiling put in below the industrial thin ceiling that is 2 x 9 beams, filled with fluffy insulation and with 2 layers of plasterboard with green glue between them.

I have my mixing desk at the low ceiling end as I wanted the higher ceiling for the drums.

I went with a kind of LEDE style and I have 3 superchunks in corners (unfortunately there is a door in the 4th corner)

When I designed what I was going to do, I decided to make my own broadband absorber panels and I made 18 of them (as per the pics).

There are 4 on the left wall for first reflections and 4 on the right
3 above the mix position as a cloud
3 above the drums as a cloud
2 across the back wall and ceiling corner
I also have 1 behind each speaker (one narrow due to a door to the back room and toilet.

Photos attached to show the room a bit.

I am also attaching a REW graph with a before and after of removing all the broadband panels from the room .. and I was surprised to see that basically nothing changed below 2k! ... and not only that it seems the highs are actually lower in the room without the panels (green line)
REW screenshot key:
RED line: No EQ, panels all present
Blue line: DSP EQ (26Hz -10db, 66Hz -15db) , all panels present
Green line: DSP EQ (26Hz -10db, 66Hz -15db) and having removed 10 panels (8 from sides and 2 behind the speakers)

The construction of the broadband panels is a firm piece of rockwool (100mm Rockwool flexi-slab 1.2m x 600mm SKU: SPE\RWFS100 ) with a wood frame and a cloth covering as per photos

MY QUESTIONS:
1. Did I make the panels wrong that they are not really affecting anything
2. Is there anything I can do with the existing panels to tame those nodes or do I have to build
3. Does anyone have any experience with the AVAA active bass trap product that came out a couple of years ago? Would they work as node-tamers? (I could cut out a space in my superchunks and put them behind the cloth)

Thanks

[DanDan]

Up Cork. Howdy. Nice big space. You did nothing wrong I reckon. The 100x600x1200 Semirigid fibre trap is a useful 'standard'. Just checking, are those frames open, i.e. no solid back panel?
Generally such traps have greatly amplified LF absorption when straddling corners, but this peaks around 70-80Hz.
Conversely, an isolated trap in the middle of a wall may kill flutter echo but not much more.
Traps behind speakers similarly do little to nothing as there is no MF/HF back there.

When treatment is introduced, Frequency Response can often show little improvement, but your Room Decay may be improved. Look at the Waterfalls, RT60
Those corner traps, how wide, what fibre?

[javamad]

Up Cork. Howdy. Nice big space. You did nothing wrong I reckon. The 100x600x1200 Semirigid fibre trap is a useful 'standard'. Just checking, are those frames open, i.e. no solid back panel?
Generally such traps have greatly amplified LF absorption when straddling corners, but this peaks around 70-80Hz.
Conversely, an isolated trap in the middle of a wall may kill flutter echo but not much more.
Traps behind speakers similarly do little to nothing as there is no MF/HF back there.

When treatment is introduced, Frequency Response can often show little improvement, but your Room Decay may be improved. Look at the Waterfalls, RT60
Those corner traps, how wide, what fibre?

Hey Dan

Just checking, are those frames open, i.e. no solid back panel? ?

Correct .. just a frame around the side and cloth on the front only

Conversely, an isolated trap in the middle of a wall may kill flutter echo but not much more.

So my 8 panels on the sides and 2 behind the monitors are flutter-killers and not much more? Great!

Those corner traps, how wide, what fibre?

They are the same material as the panels .. I just cut each one in half then diagonal to make triangles and stacked floor to ceiling and covered with cloth



I can't attach the mdat ... but I have put it in google drive: https://drive.google.com/file/d/1gNjjIE ... sp=sharing

There is a small difference in the waterfall but neither is pretty.

I have been managing to mix with Sonarworks and walking to the corners where the bass builds up .. but I think I need some serious bass trapping but don't want to give up floor space .. the usual challenge I suppose.

[DanDan]

So my 8 panels on the sides and 2 behind the monitors are flutter-killers and not much more? Great!

LOL probably not. The Cloud and Side absorbers create a Reflection Free Zone for High and Medium frequencies at least.
We want the first 20mS to be without any reflections above -20mS, or better. Anechoic, Big Headphones.

The 84cm wide Studiotips Superchunk is a fine thing. But a square trap would have twice the amount of fibre, and more of it projecting further from the boundaries. These can be faced with pegboard or hardboard if you want some HF bounceback plus a possible LF absorption boost.
Courtesy of Acoustician Jeff Hedback....

KIWI GRAPH.jpg

[DanDan]

This might encourage you.

Dub 2.png

Dub 1.png

[DanDan]

D1.png

D2.png

[javamad]

The 84cm wide Studiotips Superchunk is a fine thing. But a square trap would have twice the amount of fibre, and more of it projecting further from the boundaries. These can be faced with pegboard or hardboard if you want some HF bounceback plus a possible LF absorption boost.

I think a square trap in the front two corners is something I could try without much fuss and not losing too much floorspace.

Thanks for the suggestion.

[DanDan]

You are welcome. Doesn't have to be square, could be rectangular or even have an angled side. These deep traps need framing, but luckily when deep, the very cheap low density fibre used in Attics or Partition Rolls works way better than the expensive dense stuff.