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Treated small room issues
Old 3 weeks ago
  #1
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Treated small room issues

I recently treated a small room with broadband absorption, and now I notice a significant dip at 85 Hz. I'm not entirely sure what's contributing to this.

Attached are before and after frequency responses, including a waterfall graph.

Dimensions:
W = 3.24 m
L = 3.94 m
H = 2.83 m
Volume = 36.13 m3

What might be causing this dip and how would I be able to fix this?
(Please let me know if you need more information.)

Also, the room still has some flutter echo created between the side walls. I am wondering whether adding a large slanted board (with stands, like an idea board) near one wall might be a simple solution to treating flutter echo. Please let me know if I'm off on this prediction.

Thank you in advance to any helpful info, guidance.
Attached Thumbnails
Treated small room issues-before.jpg   Treated small room issues-after.jpg   Treated small room issues-waterfall.jpg  
Old 3 weeks ago
  #2
nms
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You really need to provide more detail on your room. Photos of the room and your treatment efforts would be a good place to start.

That said, it looks to me like you have your speakers pulled away from the front wall, perhaps due to the old misconception that it's best to do this?

Forget about the slanted board idea.

Also a note on flutter echo, if you're not recording mic'd instruments in the room, standing somewhere in the room and clapping may produce flutter echo, but that won't be of any critical importance in itself whatsoever. Your concern is with the sound coming out of your speakers and the path of that sound.
Old 3 weeks ago
  #3
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Quote:
Originally Posted by nms View Post
You really need to provide more detail on your room...


Also a note on flutter echo, if you're not recording mic'd instruments in the room, standing somewhere in the room and clapping may produce flutter echo, but that won't be of any critical importance in itself whatsoever. Your concern is with the sound coming out of your speakers and the path of that sound.
Thanks for offering to help. I attached here the drawn layout with all the measurements. One thing it doesn't mention is the speaker axis/listening position height, which is around 1.23 meters from the floor. And, I use Genelec 8050's on tripod stands, and I will soon build sand-filled sturdy stands for this which would allow me to push them further towards the wall.

The speakers are very close (about 5-8 cm) to those front absorbers which has about a 2" gap from the wall. This speaker orientation was recommended to me by Stuart/Soundman2020.

This room has some furniture and large 6" plastic pipes which were there before when the earlier measurements were taken (no dip at 85Hz). Only a couple of new furniture (small coffee tables) were introduced into the room in order to stand the side and back absorption panels since I had trouble finding proper mounts for them (so I decided to make stands). Since this dip is happening at such a low frequency and it's not present in the harmonics of this frequency, I am suspecting it is loose furniture or something absorbing energy. Then again, I assume it would affect a wider frequency range.

About the flutter echo. I don't record music in this room. But, I thought still audible flutter echo at the listening position would affect clarity.

Thanks again!
Attached Thumbnails
Treated small room issues-layout.png  
Old 3 weeks ago
  #4
nms
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Quote:
Originally Posted by mtsyas View Post
The speakers are very close (about 5-8 cm) to those front absorbers which has about a 2" gap from the wall.
Try some measurements with the speaker corners touching the absorbers. Then (if possible) try with the absorbers touching the wall and speakers touching the absorber (no gaps, in other words). I think you'll see better results here.
Quote:
About the flutter echo. I don't record music in this room. But, I thought still audible flutter echo at the listening position would affect clarity.
Depends what sort of clarity you're after. If you want maximum clarity for clapping your hands at the listening position, then treat the source of that flutter echo. On the other hand, if you're concerned with the clarity of what's coming out of your speakers and reaching your ears then perhaps you might try playing a clean clap sample through your speakers. I think you'll find the latter more relevant to your circumstances
Old 3 weeks ago
  #5
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Quote:
Originally Posted by nms View Post
Try some measurements with the speaker corners touching the absorbers. Then (if possible) try with the absorbers touching the wall and speakers touching the absorber (no gaps, in other words). I think you'll see better results here.
Depends what sort of clarity you're after. If you want maximum clarity for clapping your hands at the listening position, then treat the source of that flutter echo. On the other hand, if you're concerned with the clarity of what's coming out of your speakers and reaching your ears then perhaps you might try playing a clean clap sample through your speakers. I think you'll find the latter more relevant to your circumstances
I will wait for the new speaker stands to try this. Unfortunately, now, this is as far back as the tripods allow.
Thanks!
Old 3 weeks ago
  #6
Quote:
Originally Posted by mtsyas View Post
I recently treated a small room with broadband absorption, and now I notice a significant dip at 85 Hz.
The image of your frequence response reminds me of mine. Play with the REW Room Simulator and test different spots, closer to the front and further back.
Old 3 weeks ago
  #7
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Quote:
Originally Posted by johannburkard View Post
The image of your frequence response reminds me of mine. Play with the REW Room Simulator and test different spots, closer to the front and further back.
Thanks. I'll try this. Then, I guess the problem likely has to do with the speaker position.
Old 3 weeks ago
  #8
Quote:
Originally Posted by mtsyas View Post
Then, I guess the problem likely has to do with the speaker position.
Or with where you sit.
Old 2 weeks ago
  #9
Gear Head
 
Mark Alpine's Avatar
Quote:
Originally Posted by mtsyas View Post
Thanks for offering to help. I attached here the drawn layout with all the measurements. One thing it doesn't mention is the speaker axis/listening position height, which is around 1.23 meters from the floor. And, I use Genelec 8050's on tripod stands, and I will soon build sand-filled sturdy stands for this which would allow me to push them further towards the wall.

The speakers are very close (about 5-8 cm) to those front absorbers which has about a 2" gap from the wall. This speaker orientation was recommended to me by Stuart/Soundman2020.

This room has some furniture and large 6" plastic pipes which were there before when the earlier measurements were taken (no dip at 85Hz). Only a couple of new furniture (small coffee tables) were introduced into the room in order to stand the side and back absorption panels since I had trouble finding proper mounts for them (so I decided to make stands). Since this dip is happening at such a low frequency and it's not present in the harmonics of this frequency, I am suspecting it is loose furniture or something absorbing energy. Then again, I assume it would affect a wider frequency range.

About the flutter echo. I don't record music in this room. But, I thought still audible flutter echo at the listening position would affect clarity.

Thanks again!
What kind of insulation do you have in the super-chunks (triangular shaped corner bass traps)?
Old 1 week ago
  #10
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Quote:
Originally Posted by Mark Alpine View Post
What kind of insulation do you have in the super-chunks (triangular shaped corner bass traps)?
Yes. I mentioned the lengths of the sides around the right angle.
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