I built 14 ac. panels but it still sounds inaccurate

[djanogil]

I have eight 2" panels + six 4" ones, and I can still hear big dips and peaks when playing a chromatic sinewave in my speakers.

Here is what I think could be the reasons for the inefficiency of my treatment;

- I have one 4" panel in each corner, but they're only 4.5' high, which mean they don't reach the ceiling.

- I've got nothing on the ceiling/wall corners.

- Behind my speakers is a wall of windows , where I've put three 4" panels, one behind each speaker and one between them in the middle. Again the top part of the windows are not covered.

What do you think,
shall I place my panels differently?

I was thinking of covering more of the windows behind the speaker, using 6 panels put together to form a wall, would that be better?

I wish I could hear the bass accurately..

[matucha]

Yuu should fill the corners... that's one of the most effective treatments for bass.

Have you tried to move your speakers around? It takes some time to find a good spot, but it is very important to find it, no matter how much trapping you put in your room... moving your speakers 10cm (4") will definitely change the sound and the same monitor in the same room can sound very very differently when moved to a different spots.

[djanogil]

Originally Posted by matucha

Yuu should fill the corners... that's one of the most effective treatments for bass.

There are filled, except that the panels don't go to the top.

Have you tried to move your speakers around? It takes some time to find a good spot, but it is very important to find it, no matter how much trapping you put in your room... moving your speakers 10cm (4") will definitely change the sound and the same monitor in the same room can sound very very differently when moved to a different spots.

They are placed in exact simmetry to the side walls, and at a distance from the front wall that is based on the 38% of the length rule.

[Glenn Kuras]

djanogil,

4 panels straddling corners is a great start and sure it is helping, but most rooms need more. Also it sounds like you don't have anything on the back wall. I would place 4" to 6" panels on the back wall the space them the thickness of the panel. This will help with the direct null coming from the back wall area.

Glenn

[djanogil]

Originally Posted by Glenn Kuras

djanogil,

4 panels straddling corners is a great start and sure it is helping, but morst room need more. Also it sounds like you don't have anything on the back wall. I would place 4" to 6" panels on the back wall the space them the thickness of the panel. This will help with the direct null coming from the back wall area.

Glenn

Thanks for your replies,

on the back wall I have two 2" panels spaced 22" from each other, between them I have a cheap foam panel, and to the right next to the corner panels, there's a thick curtain hanging. The rest of the wall is bare plasterboard.

I've taken notes of the problematic frequencies ;

38hz= drastic differences in volume depending on where you stand in the room,
almost inexistant in the middle axis.
123hz = dip at the sweet spot, ( that's a problem..) and standing it's really loud!
392 hz also dip at the sweet spot and resonates in the centre of the room

etc..

[Glenn Kuras]

Originally Posted by djanogil

Thanks for your replies,

on the back wall I have two 2" panels spaced 22" from each other, between them I have a cheap foam panel, and to the right next to the corner panels, there's a thick curtain hanging. The rest of the wall is bare plasterboard.

I've taken notes of the problematic frequencies ;

38hz= drastic differences in volume depending on where you stand in the room,
almost inexistant in the middle axis.
123hz = dip at the sweet spot, ( that's a problem..) and standing it's really loud!
392 hz also dip at the sweet spot and resonates in the centre of the room

etc..

If the panels on the front wall are 4" then I would switch them and put 3 on the back wall. If nothing else try spacing the 2" panels off the wall 2 to 4". The foam is not really going to do to much of anything for the problem areas you are having.

Glenn

[djanogil]

Originally Posted by Glenn Kuras

If the panels on the front wall are 4" then I would switch them and put 3 on the back wall. If nothing else try spacing the 2" panels off the wall 2 to 4". The foam is not really going to do to much of anything for the problem areas you are having.

Glenn

Thanks,

I'll move things around and post the results.
One more thing to bear in mind, I have next to no ceiling treatment, only one 2" panel in the center of the room, what should I do about this?

Again thanks a lot for your help.

Jean

[Glenn Kuras]

Originally Posted by djanogil

Thanks,

I'll move things around and post the results.
One more thing to bear in mind, I have next to no ceiling treatment, only one 2" panel in the center of the room, what should I do about this?

Again thanks a lot for your help.

Jean

The ceiling treatment should be in the early reflection point at the mix spot. That would be between yourself and the monitors.

Glenn

[djanogil]

I have one corner at the back where the ceiling is at its highest point, I have put two 2" panels across that corner, is this too thin for bass absorption?

Should I move them elsewhere and use the thicker panels instead?

[jwl]

2" is a bit thin for bass absorption. I recommend 4" as a minimum, 6" is better for raw broadband absorption.

I agree that you will likely need more than the 4 bass trap panels you presently have. I'm sure your room is better than it was pre-treatment, but adding more bass traps can only help your low-end response.

[Glenn Kuras]

Originally Posted by djanogil

I have one corner at the back where the ceiling is at its highest point, I have put two 2" panels across that corner, is this too thin for bass absorption?

Should I move them elsewhere and use the thicker panels instead?

Ah I think we just found part of the problem. Yes you still are going to need more bass trapping but those need to be twice the size to work. 2" or 3" fiberglass straddling corners just does not cut it as bass traps. Those panels you made for the back corners can be used for the early refections but not for bass trapping.

Hate to say this but you may need to double up on a lot of the panels you made.

Glenn

[djanogil]

Originally Posted by Glenn Kuras

Ah I think we just found part of the problem. Yes you still are going to need more bass trapping but those need to be twice the size to work. 2" or 3" fiberglass straddling corners just does not cut it as bass traps. Those panels you made for the back corners can be used for the early refections but not for bass trapping.

Hate to say this but you may need to double up on a lot of the panels you made.

Glenn

AArghh,

that takes so much time and energy..
I'll build another six 4" bass traps..

Can I get lower density for these (it's twice as cheap)?
for the first lot I used Rockwool 70kg/m3 in 50mm doubled.

Now another problem is to fix the wall to ceiling corner panels, because my ceiling is slanted..

Thanks,

Jean

[bpape]

Before you get too far here, let's clarify something. You say the bass changes a lot depending on where you are in the room. This is not unusual - especially in a smaller room. The fact is that it really only matters where you're sitting. If you get it right there, don't worry about what it is in places where you don't listen.

I'm quite sure that in the wall/ceiling corners for instance that the response is horrible - but you don't listen there.

The advice you've been given so far is all good - I just want you to be realistic and shooting for a realistic and practical goal.

Bryan

[Glenn Kuras]

Originally Posted by bpape

Before you get too far here, let's clarify something. You say the bass changes a lot depending on where you are in the room. This is not unusual - especially in a smaller room. The fact is that it really only matters where you're sitting. If you get it right there, don't worry about what it is in places where you don't listen.

I'm quite sure that in the wall/ceiling corners for instance that the response is horrible - but you don't listen there.

The advice you've been given so far is all good - I just want you to be realistic and shooting for a realistic and practical goal.

Bryan

Good point.. I did not read his post as he was moving around the room, but djanogil if you are then as Bryan said work on the mix spot.

Glenn

[djanogil]

Originally Posted by bpape

Before you get too far here, let's clarify something. You say the bass changes a lot depending on where you are in the room. This is not unusual - especially in a smaller room. The fact is that it really only matters where you're sitting. If you get it right there, don't worry about what it is in places where you don't listen.

I'm quite sure that in the wall/ceiling corners for instance that the response is horrible - but you don't listen there.

The advice you've been given so far is all good - I just want you to be realistic and shooting for a realistic and practical goal.

Bryan

Thanks,

No I'm not intending to climb up the corners to check my mixes..
but it was rather to illustrate the state of my room, but still, at the mixing spot I 've got nulls at 123hz and 392hz.. and probably more

Which I hope will be improved soon.

[Glenn Kuras]

Originally Posted by djanogil

AArghh,

that takes so much time and energy..
I'll build another six 4" bass traps..

Can I get lower density for these (it's twice as cheap)?
for the first lot I used Rockwool 70kg/m3 in 50mm doubled.

Now another problem is to fix the wall to ceiling corner panels, because my ceiling is slanted..

Thanks,

Jean

Yep that will work fine.

Glenn

[bpape]

Originally Posted by djanogil

Thanks,

No I'm not intending to climb up the corners to check my mixes..
but it was rather to illustrate the state of my room, but still, at the mixing spot I 've got nulls at 123hz and 392hz.. and probably more

Which I hope will be improved soon.

Understand - that was just kind of an over the top example as you said it was varying as you wandered around. In a larger room, we can potentially smooth things out considerably more as you move about. In a smaller space with limited options, we just do the best we can to optimize the mix position.

Bryan

[djanogil]

Originally Posted by bpape

Understand - that was just kind of an over the top example as you said it was varying as you wandered around. In a larger room, we can potentially smooth things out considerably more as you move about. In a smaller space with limited options, we just do the best we can to optimize the mix position.

Bryan

I know, I was just kidding, I'll focus on the mix spot.
BTW, any tips on how to distance the panels from the wall?

On my previous ones I had looped screws at the back of the panel hanging on a hook on the wall, but they can't get far enough from the wall..

[bpape]

The easiest way to space them out is to build the gap into the frame by making the frame deeper than the absorbtion. Short of that if they're already built is just to tack some 'feet' on each of the back corners.

Bryan

[kurt]

Originally Posted by djanogil

They are placed in exact simmetry to the side walls, and at a distance from the front wall that is based on the 38% of the length rule.

Have you placed your speakers at 38% or is this your listening position? (should be the last.)

[djanogil]

Originally Posted by kurt

Have you placed your speakers at 38% or is this your listening position? (should be the last.)

Yes it is my listening position