After bass trapping.... 100 hz dip (28 dbs) HELP!!!!!!!!!

[josh2]

Hi all:

This is my 4th day trying to fix definitely acoustics problems in my room and everything is solved except a DIP of almost 30 db´s at 100 hz

The room was previously treated with corner superchunks (x4), acoustic panels in the ceiling ( ipakell), and some rockwool for first reflexions.


I have tried every posible combination of basstraps in corners wall- ceilling, wall- floor with rockwool in spades. Tried no basstraps. Tried rear wall with megatrap of 3´ depth (all the wall !!!!!!!!!!) and nothing .


The famous dip is in the mix position, 38% of the room, the best for the rest of the frecuencies and the only possible position for visibility of the tracking room. Other position is NOT POSSIBLE.

Plz, tell me any idea to try, I don´t want to live with this hole for the next years, I´m starting to get mixes for tv and some majors and i need confidence to work creatively


Thx

[wesarvin]

More Accurate Yet Less Bass?

Check out that thread. Some of the graphs aren't up anymore, but you still might get useful info out of it. I had sorta the same problem a while back. It might be SBIR.

[Glenn Kuras]

The famous dip is in the mix position, 38% of the room, the best for the rest of the frecuencies and the only possible position for visibility of the tracking room. Other position is NOT POSSIBLE.

Plz, tell me any idea to try, I don´t want to live with this hole for the next years, I´m starting to get mixes for tv and some majors and i need confidence to work creatively

38% is only a starting point. Try to move forward and back a little to see if the problem gets better.

Glenn

[nosebleedaudio]

Are your monitors on the meter bridge?
Are they rear ported?
Also where your speakers are with respect to the side and rear walls can have a HUGE influence on the response.
Try this: use a musical note that is as close to 100hz as you can get, going up and down the scale, does this ALSO cancel as much?
You will find a pure tone and a musical note at the same frequency produces different results...

[Weasel9992]

Are you running a sub? Can you give us some detail about how you built the traps? Did you really mean 3' (36") of depth? Can you post your room dimensions?

Frank

[avare]

Originally Posted by Weasel9992

Can you post your room dimensions?

+1 on the dimensions and are you ~5 ft away from a surface? that would cause a ~100 Hz dip in and of itself. that is it could be location dependent.

Andre

[josh2]

Originally Posted by Glenn Kuras

38% is only a starting point. Try to move forward and back a little to see if the problem gets better.

Glenn

I tried it, i need to move almost 2 feet forward or backward to avoid the problem. Too much.

[josh2]

Originally Posted by nosebleedaudio

Are your monitors on the meter bridge?
Are they rear ported?
Also where your speakers are with respect to the side and rear walls can have a HUGE influence on the response.
Try this: use a musical note that is as close to 100hz as you can get, going up and down the scale, does this ALSO cancel as much?
You will find a pure tone and a musical note at the same frequency produces different results...

- Monitors in stands
- Front ports - focal twin 6
- Monitors 5" from front wall ( this is the problem i think)
- Tried a musical note. but i need this hole to have a more rounded sound, i hear the hole clearly, more than 1/3 octave Q. The musical note have harmonics that are perfectly flat in my environment.

[josh2]

Originally Posted by guitarwes

More Accurate Yet Less Bass?

Check out that thread. Some of the graphs aren't up anymore, but you still might get useful info out of it. I had sorta the same problem a while back. It might be SBIR.

Hmmm, SBIR.... this afternoon put 4" of roock wool behind the speakers it helped a bit (2 or 3 db´s). More than nothing... thx

[josh2]

Originally Posted by Weasel9992

Are you running a sub? Can you give us some detail about how you built the traps? Did you really mean 3' (36") of depth? Can you post your room dimensions?

Frank

No subs, focal twins in heavy stands

How i build the bass traps? rockwool 70 kg or 90 kg superchunks in corners and panels also of rockwool similars to Giks or realtraps for first reflections.

Sorry, 1.2 feet of depth. I´m in europe and thought 1 feet was less. That trap was made with packs of rockwool 70 kg from floor to ceiling.

This trap is only usefull up to 2 feet high (2 or 3 db´s of success), the rest does nothing i removed it.

Tomorrow i´ll post room dimensions and ETF measurements, and i will try to make some 3d design for send you the best picture of the environment.

[josh2]

Well another day trying things, not much succeeded in the dip, the rest is even more flat than yesterday. 2 to 4 db´s in the whole range from 40 hz to 17.000 hz. And th f***ing hole starting in 70 hz with the maximum null in 93 hz and finishing in 130 hz.

Today i was experimenting with the position of monitors in relation with the front wall. This is the only variable that changes the dip clearly. the more i put the speakers far from the front wall the more the dip is decreasing in frequency:

5" = 93 hz dip
10" = 80 hz dip

This movements have side fx, the range 40 hz - 70 hz is disappearing more and more with every inch i separate the speakers from wall and my reference mixes sounds worse. tutt

[Glenn Kuras]

Originally Posted by josh2

I tried it, i need to move almost 2 feet forward or backward to avoid the problem. Too much.

why is it too much?

Glenn

[Glenn Kuras]

Originally Posted by josh2

Today i was experimenting with the position of monitors in relation with the front wall. This is the only variable that changes the dip clearly. the more i put the speakers far from the front wall the more the dip is decreasing in frequency:

5" = 93 hz dip
10" = 80 hz dip

Welcome to SBIR!!!!!!
Learn what is SBIR (Speaker Boundary Interface Response).

[nosebleedaudio]

Still have not seen your room layout or dimensions.
If your room is small then you sometimes have to choose which compromise is better.
Better sound or better room layout.
I assume your speakers are positioned symmetrically in the room..