attic treatment

[bolero]

Hello there,

I´m trying to get a decent sound for Hifi and mixing in my attic.
I already made some measurements and a very rudimental sketchup file.
The only treatment so far is 8cm rockwool at the ceiling first reflection point.
I´ve already read through many threads but am not very sure which concept to choose for further treating, as the impulse response does not look that bad and the decay times are quite low already.
I was thinking of basstrapping the whole wall behind the speakers up to a height of 1,2m with fluffy, adding slats afterwards and covering as much area of the rest of the room as I can with qrd7.
Does it make sense?
Thank you very much for your advice in advance!

Cheers,

Daniel

[Jens Eklund]

Originally Posted by bolero

Hello there,

I´m trying to get a decent sound for Hifi and mixing in my attic.
I already made some measurements and a very rudimental sketchup file.
The only treatment so far is 8cm rockwool at the ceiling first reflection point.
I´ve already read through many threads but am not very sure which concept to choose for further treating, as the impulse response does not look that bad and the decay times are quite low already.
I was thinking of basstrapping the whole wall behind the speakers up to a height of 1,2m with fluffy, adding slats afterwards and covering as much area of the rest of the room as I can with qrd7.
Does it make sense?
Thank you very much for your advice in advance!

Cheers,

Daniel

Whatever you do, do not put up treatment just because you feel like it is needed. Measurements will tell you what is needed. If you want to use diffusers, make sure to use broadband absorption only where needed (at early reflection points) and use pressure based absorbers (membrane or perforated panels) at other areas where LF absorption is needed.

EDIT: In case you missed it:
Acoustics/Treatment Reference Guide - LOOK HERE!

[bolero]

somehow the zip-file with photo and measurement won´t upload.
I´ll try again

[bolero]

I hope it´s there now

[bolero]

Hi again,

Here´s for everybody without REW or Sketchup software.
I hope it´s ok like this.

@jens:
I´ve been reading about acoustics for months now, so yes, I have also read the linked thread.
I´m now asking for advice as I think that somebody with experience in this topic could prevent me from trial and error in the wrong direction.

thanks for the reply so far.

cheers,

Daniel

[Jens Eklund]

The first thing I would do is figuring out what causes the very early reflection showing up in your ETC.

http://www.gearslutz.com/board/5916321-post1.html

http://www.gearslutz.com/board/6397239-post80.html

[Glenn Kuras]

Jens is giving you some great advice, but to add I would think a lot of the reflections you are getting is coming from the wall behind you. If it is slatted like the front wall then the sound is coming right back on you. Also I would trap the upper peak in the ceiling with bass traps. Straddle broad band panels down the whole room.
Another thing you may want to try is placing the yourself so you are facing the window and run the speakers down the long wall.

[Jens Eklund]

Assuming the ETC is correct, I would try to absorb/redirect the first three of the five strongest reflections, and then possibly diffuse the remaining two.

In terms of modal/SBIR issues, you first need to find out what areas are involved in causing the problems before looking at treatment options.

[bolero]

Thank you for the replies, I´m really happy, that you answered!

The first thing I would do is figuring out what causes the very early reflection showing up in your ETC.

It´s from the back of the couch, which is close to the mic.

Jens is giving you some great advice, but to add I would think a lot of the reflections you are getting is coming from the wall behind you. If it is slatted like the front wall then the sound is coming right back on you. Also I would trap the upper peak in the ceiling with bass traps. Straddle broad band panels down the whole room.
Another thing you may want to try is placing the yourself so you are facing the window and run the speakers down the long wall.

I thought I already was running the speakers down the long wall. I once had the speakers as you mean, but without measuring. I will try that.
The room is 6,7mX5,2m and the 5,2m wall is the slatted wall behind and in front of the speakers.
Have you seen the attached .png ? there is no upper peak in the ceiling, as there has been made a new ceiling underneath.
I will try with some 10-15cm fluffy panels mounted removably to find out if there are strong back wall reflections.
From the listening position I could not see the loudspeakers putting a mirror on the back wall, but you never know...

In terms of modal/SBIR issues, you first need to find out what areas are involved in causing the problems before looking at treatment options.

Do I do this by making measurements with the microphone in different positions, for example corners?

Daniel

[DanDan]

Daniel, did you measure with one or two speakers running?
ETC would be very confusing with two! Which one is the source?
There would also be severe comb filtering at HF if you attempt to measure full range freq resp with two speakers.

http://www.gearslutz.com/board/studi...er-v2-1-a.html

Did you make those speakers your self? Nice.

When you do further measurements perhaps you could export them as WAV's. Strangely REW5 Mac currently can't open posted files, although it works very well apart from that.

There is a thread called SBIR

DD

[bolero]

Hello Dan,

yes, I made the mistake to post the results of both speakers driven simultaneously. Noob mistake, sorry.
I did a lot of measurements yesterday and will countinue to do so today or tomorrow until there is something worth posting (including wav).
I got myself 6 first reflection absorbers (100x65cm rockwool 10cm thick) and am experimenting with positions of speakers and panels.
I also tried to change the orientation of the speakers in the room as Glenn suggested but unfortunately it did not really improve things.

I will also read the recommended threads again.

Did you make those speakers your self? Nice.

Yes, they are self made and I really like them.
Eton chassis (er4 tweeter, 7"hex midrange, 11"hex woofer)
and they are active speakers.
The amps have some studio features (hi/low shelv, volume for each chassis, subsonic filter) as the guy who designed them used to do studio work in his early days.

closer look :

Duetta: Active modules , Die Homepage der Firma SAC, Special Audio Components.

By the way, the same guy designed this :

http://sac.de/sac/Files/Download/Tes...us_stp1188.pdf

and everything you find here :

SAC Products: Die Homepage der Firma SAC, Special Audio Components.

Thanks for the reply!


Cheers,

Daniel