White flag to standing waves

[yigitboy]

Hi all,

I am a 45years old ordinary music listener who wants a little better at 75db near field.
I do not have the opportunity to buy equipment after testing. I have a Presonus Temblor T8 sub and a couple of Edifier Mr4 located in my Cad design office as below. The long wall is 1mt behind me and i am 1,5mt to one corner. I tried some different locations for the sub but i think the biggest problem is the wall behind me and the corner . There is nearly 15db peak in 52Hz accoring to android spl meter app and i can definitely hear it. Eq mostly solves the peak but this time the subwoofer is nearly useless.
I do not a have a measurement mic. Even i had and made measurements, i will not be able to make a serious treatment to the office because i am only an employee.
Question is : If i give away the sub and Mr4s and buy a bigger set of active speakers like Kali Lp6, will i encounter same acoustic problem.
Or maybe there is an eq solution ?
I

 

[MAB]

You sit in the corner which is not ideal. You should try moving your sub.
This may help:

Are my bass traps reasonable or am i doing something wrong?

The measurements look plausible. Along the slab, GFR (gas flow resistivity) is usually less than in the perpendicular direction. WLG45 also suitable for 0,5 m basstraps. http://www.acousticmodelling.com/porous.php

www.audiosciencereview.com

Since you appear to be battling room modes, eq is of limited use and you need to not excite the resonance at you seating position, best option is to do the sub crawl to find a better placement. Second sub will potentially help smooth. New speakers may likely cause you to throw money away since the issue seems to be room mode and corner seating.
Can you move your seat and desk?

 

[yigitboy]

You sit in the corner which is not ideal. You should try moving your sub.
This may help:

Are my bass traps reasonable or am i doing something wrong?

The measurements look plausible. Along the slab, GFR (gas flow resistivity) is usually less than in the perpendicular direction. WLG45 also suitable for 0,5 m basstraps. http://www.acousticmodelling.com/porous.php

www.audiosciencereview.com

Since you appear to be battling room modes, eq is of limited use and you need to not excite the resonance at you seating position, best option is to do the sub crawl to find a better placement. Second sub will potentially help smooth. New speakers may likely cause you to throw money away since the issue seems to be room mode and corner seating.
Can you move your seat and desk?

On the left corner there is an empty desk i can use symetrically. That location's difference is the wall opposite is 3mt forward. I tried crawling but not helped much maybe 3db.
Floor is naked and the room is mostly empty. May a smaller sub help?

 

[MAB]

The corner is hard. It effectively doubles your problem (this is a simplified rough-estimate).
Second sub will potentially help. In my experience, the L-shaped room with corner seating could be a real zinger for bass resonance. Your observation that any eq that tames the 50Hz resonance essentially defeats your sub reinforces that.

 

[Willem]

Assuming you ar using a computer as a source in this office, you can upload precise REW equalization curves into Equalizer Apo (or Mac alternative if you are using a Mac). The problem with equalizing low frequencies from a sub is that without multiple subs this can only be done succesfully for one listening position. However, that is exactly what one has with a desktop system.

 

[yigitboy]

Assuming you ar using a computer as a source in this office, you can upload precise REW equalization curves into Equalizer Apo (or Mac alternative if you are using a Mac). The problem with equalizing low frequencies from a sub is that without multiple subs this can only be done succesfully for one listening position. However, that is exactly what one has with a desktop system.

Only listener is already myself You mean i can get rid of the 50hz problem if i exclude sub and use only speakers even they play 50hz

 

[Willem]

No I mean that even with a sub you can tame that peak. Measure in REW using a Umik-1 mic, create an equalisation curve in REW, upload that curve to the free Equalizer Apo software tbat you install on your PC, and enjoy. The only expense is the Umik-1.

 

[yigitboy]

No I mean that even with a sub you can tame that peak. Measure in REW using a Umik-1 mic, create an equalisation curve in REW, upload that curve to the free Equalizer Apo software tbat you install on your PC, and enjoy. The only expense is the Umik-1.

I found the resonant frequency to be 50hz. And dialed a negative gain to it but did not help. What can Rew do different to what i did. If you are sure it helps i will buy a behringer ecm8000 . I can not find umik in Turkey

 

[MAB]

I found the resonant frequency to be 50hz. And dialed a negative gain to it but did not help. What can Rew do different to what i did. If you are sure it helps i will buy a behringer ecm8000 . I can not find umik in Turkey

EQ can’t fix your issue given your description. It really appears to be a room mode at 50Hz. EQ if any kind will not address this issue. I have @sarumbear to thank for reinforcing this point to me (pun intended)! Your seat in the room’s corner makes EQ even less effective!

Since treatment is not an option at your workplace, experimenting with sub and seating position are the only options I think. Crazy idea: try the sub right in the corner with you. Then try moving it along the walls to each of the two adjacent corners. My guess is you will have OK sound at your seat with the sub in the corner with you, and will find that there are a couple of places along the walls where you will really excite that room mode. I don’t know the answer and am interested. But my guess is for a single sub the same corner as you are sitting in is the only good option. My other guess is that a second sub is needed to smooth the response at your seat. My last thought is that moving your seat away from the corner would improve things, but may not be feasible. In summary, you have a room mode and you are sitting in the area of highest reinforcement.

 

[NTK]

These are the 2D room modes based on your room dimensions. The number at the top is the mode frequency. Speakers placed at the white regions will not excite that particular room mode.

 

[ahofer]

These are the 2D room modes based on your room dimensions. The number at the top is the mode frequency. Speakers placed at the white regions will not excite that particular room mode.

View attachment 246133

Is that an available software package?

 

[NTK]

Is that an available software package?

I use Mathematica. I have an old thread on it.

Arbitrary Shape Room Mode Simulator

This opening post is to show how to simulate room modes using Mathematica. The other room mode calculators I could find on the web can only handle rectangular box shaped rooms. Mathematica can solve for arbitrarily shaped room. I only attempted 2D, but theoretically Mathematica should be able to...

www.audiosciencereview.com

I remember someone posted a link to a customized COMSOL app that does 3D arbitrary shape room modes. I am looking for it.

 

[ahofer]

I use Mathematica. I have an old thread on it.

Arbitrary Shape Room Mode Simulator

This opening post is to show how to simulate room modes using Mathematica. The other room mode calculators I could find on the web can only handle rectangular box shaped rooms. Mathematica can solve for arbitrarily shaped room. I only attempted 2D, but theoretically Mathematica should be able to...

www.audiosciencereview.com

I remember someone posted a link to a customized COMSOL app that does 3D arbitrary shape room modes. I am looking for it.

Pretty cool. I suppose, absent multi-subs, you‘d want to position in a peak-heavy place and knock them down, rather than null-heavy and…nuthin.

 

[NTK]

I use Mathematica. I have an old thread on it.

I remember someone posted a link to a customized COMSOL app that does 3D arbitrary shape room modes. I am looking for it.

Found the thread.

Room eigenmodes calculator

Hi all! I want to share this application to calculate and evaluate the natural frequencies of rooms modeled in 3D. At the moment, the application does not consider materials, only rigid surfaces, but it is a very useful tool to evaluate the eigenmodes in irregular rooms. It is recommended to...

www.audiosciencereview.com

 

[MAB]

Found the thread.

Room eigenmodes calculator

Hi all! I want to share this application to calculate and evaluate the natural frequencies of rooms modeled in 3D. At the moment, the application does not consider materials, only rigid surfaces, but it is a very useful tool to evaluate the eigenmodes in irregular rooms. It is recommended to...

www.audiosciencereview.com

Thanks for the link to your Mathematica thread and the Eigenmode calculator. Really great stuff, appreciated!!! Dusting off my Mathematica skill now…

 

[yigitboy]

These are the 2D room modes based on your room dimensions. The number at the top is the mode frequency. Speakers placed at the white regions will not excite that particular room mode.

View attachment 246133

Whites seems to be narrow but worth trying. Thanks for info

 

[MAB]

Whites seems to be narrow but worth trying. Thanks for info

Find those white stripes!!!
In reality they will be wider than the simulations I think. The simulation is done with perfectly rigid walls. Real walls and rooms are typically not rigid (unless your office is a hermetically sealed concrete bunker! Anything that Isn’t a perfect reflector will broaden the transitions and reduce the peaks.

 

[yigitboy]

After a few tryouts i located the subwoofer on top of the desk close to short wall. It is also more distant from the floor ( down firing sub ). Absolutely it is much better. 50 hz peak is flat now according to android spl meter. In fact there still is some according to my ears but i am happy enough. Thanks to all