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Huge dip in frequency response below 100hz
Old 3 weeks ago
  #1
Huge dip in frequency response below 100hz

Hi I've been experimenting a bit with speaker placement. Was wondering if anybody here could help me understand the problems I'm having in my room?

My room's 4,92m (L) x 3,02m (W) x 2,87m (H). I've setup on the front wall by the window (and alcove). The back wall's very uneven (it's a kitchen...). See photo.

My speakers are close to the front wall. They are Focal CMS 50's which have a frequency response of 55Hz - 28kHz (+-3dB). They are 110cm apart and tweeters are 128cm from the floor. I'm sitting approx 110cm away from my speakers.

As you can see on the SonarWorks graph, the frequency response of the speakers + room is pretty terrible with a huge dip around 75-100Hz...

I've experimented with moving the speakers away from the front wall and taking measurements with my SonarWorks reference mic. I'm using white noise this time and a spectrum analyzer for measuring to speed things up a bit (SonarWorks takes 20min). I only wanted to see how different speaker distances from the window would affect the low end.

Of course both graphs cannot be compared but I've noticed that the dip below 100hz seems to be a problem pretty much wherever I move my speakers to but around 1/3 away from the window is where I managed to get most bass/sub.

Just wondering if anybody on here can help me interpret those results a bit and perhaps suggest things to try out?

I know my room isn't ideal for mixing and unfortunately I cannot at this point add any kind of bass trapping or absorption so all I can do is play with speaker placement.

Even if I can't improve the situation much at least hopefully I'll learn something
Attached Thumbnails
Huge dip in frequency response below 100hz-img_2013.jpg   Huge dip in frequency response below 100hz-sonarworks2.png   Huge dip in frequency response below 100hz-speakers-away-windows.jpg  
Old 3 weeks ago
  #2
Gear Addict
 
uOpt's Avatar
To me it looks like that is where your speakers are at.
Old 3 weeks ago
  #3
Quote:
Originally Posted by Sexy Beast View Post
Hi I've been experimenting a bit with speaker placement. Was wondering if anybody here could help me understand the problems I'm having in my room?

My room's 4,92m (L) x 3,02m (W) x 2,87m (H). I've setup on the front wall by the window (and alcove). The back wall's very uneven (it's a kitchen...). See photo.

My speakers are close to the front wall. They are Focal CMS 50's which have a frequency response of 55Hz - 28kHz (+-3dB). They are 110cm apart and tweeters are 128cm from the floor. I'm sitting approx 110cm away from my speakers.

As you can see on the SonarWorks graph, the frequency response of the speakers + room is pretty terrible with a huge dip around 75-100Hz...

I've experimented with moving the speakers away from the front wall and taking measurements with my SonarWorks reference mic. I'm using white noise this time and a spectrum analyzer for measuring to speed things up a bit (SonarWorks takes 20min). I only wanted to see how different speaker distances from the window would affect the low end.

Of course both graphs cannot be compared but I've noticed that the dip below 100hz seems to be a problem pretty much wherever I move my speakers to but around 1/3 away from the window is where I managed to get most bass/sub.

Just wondering if anybody on here can help me interpret those results a bit and perhaps suggest things to try out?

I know my room isn't ideal for mixing and unfortunately I cannot at this point add any kind of bass trapping or absorption so all I can do is play with speaker placement.

Even if I can't improve the situation much at least hopefully I'll learn something
You have 2 dimensions that are almost the same (W & H).
This will produce wide nulls without the modal support from the space which are very difficult to impossible to fix unless you change one of the dimensions.

If you want to analyze your room further download REW. Measure your space and post the MDAT result here and we can try to help.
Old 3 weeks ago
  #4
Quote:
Originally Posted by thethrillfactor View Post
You have 2 dimensions that are almost the same (W & H).
This will produce wide nulls without the modal support from the space which are very difficult to impossible to fix unless you change one of the dimensions
Thanks! I've thought about that. Just wasn't sure how similar the 2 dimensions have to be before it starts being a problem.

Quote:
Originally Posted by thethrillfactor View Post
If you want to analyze your room further download REW. Measure your space and post the MDAT result here and we can try to help.
I've tried to use REW. Looks like a powerful piece of software but unfortunately haven't had much success with it. Watched many tutorials but still can't seem to make it work so I bought sonarworks which is so much easier to use
Old 2 weeks ago
  #5
Here for the gear
 

The graphs in Sonarworks are smoothed out quite a lot though (1/3 octave?), which can be useful as a general guideline but can also be a hindrance if you want to properly analyze the room. Sonarworks is EQ correction software (and very good at that imo), but it's not really a room analysis tool.

Sonarworks will only give you smoothed information of the transfer function (frequency response) from speaker to microphone. When analyzing room acoustics the decay times for different frequencies are a key parameter to look at to identify issues in the room. No amount of EQ correction will fix time domain issues which are present in all untreated smaller rooms. So I'll echo what someone else has said already, try to get REW to work and do some measurements in that. Then it's easier to see what's going on in your room and what can possibly be done to help it.
Old 2 weeks ago
  #6
Quote:
Originally Posted by B36arin View Post
The graphs in Sonarworks are smoothed out quite a lot though (1/3 octave?)
No idea but you're probably right!

Quote:
Originally Posted by B36arin View Post
try to get REW to work and do some measurements in that. Then it's easier to see what's going on in your room and what can possibly be done to help it.
I'll see if I can get somebody to help me with REW. Looked so easy when I was watching the tutorials in YouTube but not so much when trying to make it work myself. Couldn't even get the RTA to work
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