Huge (-10 dB) dip between 200Hz and 300Hz in my room.

[flipflop]

for me full range dirac correction sounds better than limited one

It could be because your room is acoustically well-behaved or it could be the biased conclusion of sighted listening observations.
In any case, correcting dips in the in-room response that don't exist in the anechoic response will create problematic resonances.

 

[abdo123]

now measure the other

It's in both speakers.

 

[abdo123]

Absorption panel just behind the speakers, at these frequencies the GIK Acoustic Alpha series 4A should work, or at least help.

would a double folded towel show any improvement? I don't want to invest without a proof of concept at least first.

 

[Eetu]

I was wondering if you have other hard surfaces within 30-40cm from the woofer center (sides, up/down). That will multiply the SBIR effect.

Basically the only thing to get rid of it completely is pull your speakers out in the room and cross over to a sub.

would a double folded towel show any improvement? I don't want to invest without a proof of concept at least first.

Give it a go, nothing to lose. I would try to leave an air gap of 5cm or so between the towel and bookcase/wall, should help it absorb lower.

 

[vavan]

It could be because

Tbh do not really care about the reasons. See also https://www.audiosciencereview.com/...ave-digital-room-correction.18707/post-612462

 

[abdo123]

@Eetu @oursmagenta

folded towels didn't really do anything, so I tried pillows. It definitely completely removed the dip. Not without fucking shit up the rest of the way up to 2KHz but nothing EQ wouldn't manage.

However, the bookcase dimensions are set in stone, so i can't really buy just any acoustic panel.

Do you know a company that sells accoustic carpets or accoustic wall paper that would absorb in the frequency range I need? or at least custom sized acoustic panels?

 

[oursmagenta]

@Eetu @oursmagenta

folded towels didn't really do anything, so I tried pillows. It definitely completely removed the dip. Not without fucking shit up the rest of the way up to 2KHz but nothing EQ wouldn't manage.

View attachment 122907

However, the bookcase dimensions are set in stone, so i can't really buy just any acoustic panel.

Do you know a company that sells accoustic carpets or accoustic wall paper that would absorb in the frequency range I need? or at least custom sized acoustic panels?

First of all, this is nice ! It seems that the suspect was indeed guilty. Now for solutions, I know that GIK acoustic sells 60cmx60cm panels is it too big ?

 

[abdo123]

First of all, this is nice ! It seems that the suspect was indeed guilty. Now for solutions, I know that GIK acoustic sells 60cmx60cm panels is too big ?

Apparently you can inquire them directly to get custom sized panels. great.

I'm just not sure if i would need 1D diffraction or 2D diffraction. They would probably upsell me the 2D version lol.

 

[Eetu]

@Eetu @oursmagenta

folded towels didn't really do anything, so I tried pillows. It definitely completely removed the dip. Not without fucking shit up the rest of the way up to 2KHz but nothing EQ wouldn't manage.

View attachment 122907

However, the bookcase dimensions are set in stone, so i can't really buy just any acoustic panel.

Do you know a company that sells accoustic carpets or accoustic wall paper that would absorb in the frequency range I need? or at least custom sized acoustic panels?

Great, always nice to see theory working in practice.

Yeah, you can inquire custom sizes from GIK. Looking at this graph the 242 or Alpha should do a decent job. Not sure about the methodology, if the ratings are measured with an air gap behind etc. though.

It's up to you if you want to use a panel that's only absorption or with a scattering/diffusion plate since the freq you're dealing with is not affected by that. If it's behind the speaker there should be only little treble energy radiating backwards.

You could also go DIY route and for example cut several layers of felt that fit perfectly inside the bookcase and stack them behind the speakers. Should work

 

[abdo123]

Great, always nice to see theory working in practice.

View attachment 122910
Yeah, you can inquire custom sizes from GIK. Looking at this graph the 242 or Alpha should do a decent job. Not sure about the methodology, if the ratings are measured with an air gap behind etc. though.

It's up to you if you want to use a panel that's only absorption or with a scattering/diffusion plate since the freq you're dealing with is not affected by that. If it's behind the speaker there should be only little treble energy radiating backwards.

You could also go DIY route and for example cut several layers of felt that fit perfectly inside the bookcase and stack them behind the speakers. Should work

the absorption coefficient is the least of my problems, the most important factor is the partner appreciation coefficient.

I will ask for the 'GIK free advice' and see how much money will i pay for foam to fix this.

 

[headshake]

Are there books in the bookcase?

Build the speakers into a wall of books. I bet things will go away when there is a larger surface,

 

[abdo123]

Are there books in the bookcase?

Build the speakers into a wall of books. I bet things will go away when there is a larger surface,

Can you explain this better?

 

[headshake]

Can you explain this better?

Inwall speakers will have fewer room issues. Studios put speakers in walls. You could come close to that if your case lets you make a flush wall. I have no idea what your case looks like. In my mind, it is the width of the room.

 

[abdo123]

A little update, I followed @headshake 's advice and I tried to 'trick' the speaker to think it's flush mounted and that pretty much cleared all the problems.

it wasn't straight forward and each speaker behaved differently, but I'm very very happy with the results!

 

[oursmagenta]

A little update, I followed @headshake 's advice and I tried to 'trick' the speaker to think it's flush mounted and that pretty much cleared all the problems.

it wasn't straight forward and each speaker behaved differently, but I'm very very happy with the results!

View attachment 123587

View attachment 123588

Glad that you solved your problem! And kudos to @headshake for the clever trick!

 

[JasonC331]

Absorption panel just behind the speakers, at these frequencies the GIK Acoustic Alpha series 4A should work, or at least help.

Yep until you get this email: I ordered quite a bit over a month ago.


Hey Jason,

That is correct. Our current lead time is approximately 8-10 weeks due to a large influx of orders and some minor production delays brought on by difficulty acquiring select materials.

Best regards,

 

[JasonC331]

If you are handy with some tools.....https://www.atsacoustics.com/cat--DIY-Acoustic-Materials--102.html

I ordered a few from GIK a few from ATS, a friend is making the rest, shit gets expensive.

 

[Stefano_Milano]

A little update, I followed @headshake 's advice and I tried to 'trick' the speaker to think it's flush mounted and that pretty much cleared all the problems.

it wasn't straight forward and each speaker behaved differently, but I'm very very happy with the results!

View attachment 123587

View attachment 123588

Hello,
I realized I have the same problem.
How did you do? Did you surround the speakers with books above and to the side?
Thanks
Stefano

 

[abdo123]

Hello,
I realized I have the same problem.
How did you do? Did you surround the speakers with books above and to the side?
Thanks
Stefano

I ended up pushing the Speakers closer to the wall (pushing the dip to 300-400Hz range) then surround it with Basotec foam.

 

[Stefano_Milano]

I ended up pushing the Speakers closer to the wall (pushing the dip to 300-400Hz range) then surround it with Basotec foam.

Thanks
I will try.