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Help analyze room graph and acoustic design
Old 28th September 2012
  #31
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1 Review written
🎧 15 years
Ceiling

The sine test suggests that you treat the ceiling corners. Or all the way across if the high level is all the way across. i.e. A horizontal SuperChunk or at least straddling panels as Glenn suggested.
Absorbing the energy where it is highest will reduce the reflection back into the room. This will help the null a lot.
DD
Old 29th September 2012 | Show parent
  #32
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sl4zhz's Avatar
 
🎧 10 years
Quote:
Originally Posted by DanDan ➑️
The sine test suggests that you treat the ceiling corners. Or all the way across if the high level is all the way across. i.e. A horizontal SuperChunk or at least straddling panels as Glenn suggested.
Absorbing the energy where it is highest will reduce the reflection back into the room. This will help the null a lot.
DD
got it... what about the 700hz ? how I can test that part? is it the same by playing sine wave?
Old 1st October 2012 | Show parent
  #33
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Sine

I meant to add check with the sines up and down the vertical front corners also. Vertical SuperChunks or Soffit variations like GIK make are the most frequently used treatment.
700Hz is a bit high. Try it. You will probably find peaks and nulls every few inches. Standing near the measurement mic can cause false measurements around that frequency range. Move away from the mic 1.5M or more.
DD
Old 2nd October 2012 | Show parent
  #34
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🎧 10 years
Quote:
Originally Posted by DanDan ➑️
I meant to add check with the sines up and down the vertical front corners also. Vertical SuperChunks or Soffit variations like GIK make are the most frequently used treatment.
700Hz is a bit high. Try it. You will probably find peaks and nulls every few inches. Standing near the measurement mic can cause false measurements around that frequency range. Move away from the mic 1.5M or more.
DD
I see.. I tried 700hz waves, but its very hard to find the spot.. low freq tends to congregate on the corner, so I can easily move around that spot and find the peaks. where is the common spot of 700hz freq ?

yeah I'm looking to add a vertical super chunk on the rear wall. planing to use a 120 x 60 cm rockwool and cut it into 8 pieces. so I get roughly 30x30 cm Triangle shape. and I'll stack it up through the ceiling 260cm. what do you think?
Old 2nd October 2012
  #35
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🎧 10 years
30x30cm triangles are too small, cut the 120x60 panels in 4 not in 8
Old 2nd October 2012 | Show parent
  #36
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🎧 10 years
Sorry my directness, but unless new placement of the speakers will change the response dramatically you need to get new monitors. The response is so bad, that I seriously doubt treatment will solve enough. And no one can mix anything with accuracy with a response like that.

A pair of Behringer Truth B2031A/P are much better and also very cheap. Shoud be combined with subs though.
Attached Images
File Type: png b2031phorizontal.png (84.4 KB, 490 views)
Old 3rd October 2012 | Show parent
  #37
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🎧 10 years
Quote:
Originally Posted by bwo ➑️
Sorry my directness, but unless new placement of the speakers will change the response dramatically you need to get new monitors. The response is so bad, that I seriously doubt treatment will solve enough. And no one can mix anything with accuracy with a response like that.

A pair of Behringer Truth B2031A/P are much better and also very cheap. Shoud be combined with subs though.
So the response of my room is pretty bad ?
I'm open to any suggestion.. yeah I'm trying to put some pads bellow the speaker like auralex modpad and see if it works or get a speaker stand.

what is that graph about anyway?
Old 3rd October 2012
  #38
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🎧 10 years
The two cancellations you have are so deep and wide that I would think it's monitor related.
Old 3rd October 2012 | Show parent
  #39
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🎧 10 years
Quote:
Originally Posted by bwo ➑️
The two cancellations you have are so deep and wide that I would think it's monitor related.
I have a big cabinet if you see my room scheme.
do you think its possible because of big cabinet there causing the low freq response not right in my room?
Old 3rd October 2012 | Show parent
  #40
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Bjorn Omholt's Avatar
 
🎧 10 years
Quote:
Originally Posted by sl4zhz ➑️
I have a big cabinet if you see my room scheme.
do you think its possible because of big cabinet there causing the low freq response not right in my room?
No. You're sitting in nearfield, so your response should have been much better.
Try out what Jens suggested here and report back with new measurements:
https://gearspace.com/board/8281819-post2.html

Last edited by Bjorn Omholt; 3rd October 2012 at 10:59 AM.. Reason: spelling
Old 3rd October 2012 | Show parent
  #41
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🎧 10 years
Quote:
Originally Posted by bwo ➑️
No. You're sitting in nearfield, so your response should have been much better.
Try out what Jens suggested here and report back with new measurements:
https://gearspace.com/board/8281819-post2.html
I see. so the cabinet is not a big deal ?
will Auralex Mopad Help significantly in this case?

because It's a bit too high and too far If I put it on a speaker stand behind my desk. as you can see, my desk have a 4U on left and right
the height measure from floor to top of my left right 4U rack is approx 110cm.
Old 4th October 2012 | Show parent
  #42
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🎧 10 years
do you think it's because of the speaker respose itself that made a 70hz deep ?
Old 4th October 2012 | Show parent
  #43
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GIK Acoustics's Avatar
 
🎧 5 years
Quote:
Originally Posted by sl4zhz ➑️
do you think it's because of the speaker respose itself that made a 70hz deep ?
I think he's suggesting that your monitors are defective (which, considering how often I've seen nulls like that I would not make an obvious assumption on that)

I would experiment with speaker placement to see if the null moves in frequency. Push the speakers farther back, test. Pull them farther forward, test. Bring them closer together, test. Farther apart, test. Lift them up (with some books just for testing), test. If the frequency changes you will know what is causing it. If moving them closer back towards the wall changes the frequency, try a trap behind the speakers. If moving them up changed the frequency of the null, then try a trap above the speakers (on ceiling), etc.

I would certainly try these things before declaring the speakers are defective. I know from experience HS80Ms don't randomly have some odd 70 Hz null.
Old 4th October 2012 | Show parent
  #44
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🎧 10 years
Quote:
Originally Posted by GIK Acoustics ➑️
I think he's suggesting that your monitors are defective (which, considering how often I've seen nulls like that I would not make an obvious assumption on that)

I would experiment with speaker placement to see if the null moves in frequency. Push the speakers farther back, test. Pull them farther forward, test. Bring them closer together, test. Farther apart, test. Lift them up (with some books just for testing), test. If the frequency changes you will know what is causing it. If moving them closer back towards the wall changes the frequency, try a trap behind the speakers. If moving them up changed the frequency of the null, then try a trap above the speakers (on ceiling), etc.

I would certainly try these things before declaring the speakers are defective. I know from experience HS80Ms don't randomly have some odd 70 Hz null.
I see.. I'll try it. thanks for you input
Old 4th October 2012
  #45
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Glenn Kuras's Avatar
 
🎧 15 years
Quote:
I would certainly try these things before declaring the speakers are defective. I know from experience HS80Ms don't randomly have some odd 70 Hz null.
I also own HS80ms and have done a lot of testing with them. There is not a odd 70hz null in them. If there was you would have not been the first to notice it.
Old 4th October 2012
  #46
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🎧 10 years
a 70hz null, even a deep one is kind of normal in a small room.
everything depend on the position of both monitors and the listening position, it's incredible how much it will change even with few cm of difference.
But, even if I didn't see the graphs because I can't open the pictures (strange) I guess that null have nothing to do with defective speakers.
10cm could rais a null of 15/20dB easily
Old 4th October 2012 | Show parent
  #47
DAH
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🎧 15 years
Quote:
Originally Posted by bwo ➑️
Sorry my directness, but unless new placement of the speakers will change the response dramatically you need to get new monitors. The response is so bad, that I seriously doubt treatment will solve enough. And no one can mix anything with accuracy with a response like that.

A pair of Behringer Truth B2031A/P are much better and also very cheap. Shoud be combined with subs though.
Sorry, that's pure bull.
I measured my HS80 at the woofer centre and it was like a flat line across 60 - 500+ Hz range. It is room. And all modern monitor brands are well within +-3 db across the working range.
Old 4th October 2012 | Show parent
  #48
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Bjorn Omholt's Avatar
 
🎧 10 years
Quote:
Originally Posted by DAH ➑️
Sorry, that's pure bull.
I measured my HS80 at the woofer centre and it was like a flat line across 60 - 500+ Hz range. It is room. And all modern monitor brands are well within +-3 db across the working range.
Read this again:
Quote:
Sorry my directness, but unless new placement of the speakers will change the response dramatically you need to get new monitors
So far the threadstarter hasn't gotten that far.
We're not getting anyway here unless he can experiment with placements, measure and report back.
Old 4th October 2012 | Show parent
  #49
DAH
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🎧 15 years
Quote:
Originally Posted by bwo ➑️
Read this again:

So far the threadstarter hasn't gotten that far.
We're not getting anyway here unless he can experiment with placements, measure and report back.
What the heck do NEW monitors have to do with the ROOM non-linearities?
Let's assume the OP will get some new monitors, WHAT WILL THIS CHANGE?
If you mean those particular speakers are faulty, then
1) the simplest test to check it is to measure the response very close to the woofer center
2) why recommend another brand?
Old 5th October 2012 | Show parent
  #50
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sl4zhz's Avatar
 
🎧 10 years
Quote:
Originally Posted by bwo ➑️
Read this again:

So far the threadstarter hasn't gotten that far.
We're not getting anyway here unless he can experiment with placements, measure and report back.
I Just try to decouple the speaker from the desk with 2 ply of hard rubber mat and 4 big bolt nut in between the bolt.

heres the respon before and after


waterfall graph AFTER


What do you think?
I'll they to move around the speaker possition and see how it works.

After I decouple one of the speaker, I feel that the bass response is much softer than the other one, but its sounds much cleaner with the speaker decouple from the desk
Old 22nd October 2012
  #51
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🎧 10 years
any suggestion anyone to the Deep Null at 70-80hz ?
I just renovate my studio a little bit too.

1. remove the big closet
2. added 2 super chunk on the rear corner (one 30x30cm due to space restriction, another one is 42x42cm)
3. front basstrap is covered from floor to ceiling (previously only in the middle)
4. put some vinly flooring
5. added a small decoupling to the speaker. with big bolt nut and a 1cm thick mat stack like a sandwiches.

and I the null still there.
tried to move the speaker position, add decoupling below the speaker, try to put the speaker further back on a tall wooded chair temporarily to check whether it works.
none helps.

and also what I notice is, when I turn only just One monitor, I feels something bouncing back, it feels like phasing when I sit in mix position with just one speaker turn on. is it because interference of the low freq ? is this normal?
Old 22nd October 2012
  #52
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Glenn Kuras's Avatar
 
🎧 15 years
Any time I have viewed 1/3 smoothing it look much more "smoothed" out, which tells me something is funky with your tests. Like there is some kind of noise going on.
Old 23rd October 2012 | Show parent
  #53
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sl4zhz's Avatar
 
🎧 10 years
Quote:
Originally Posted by Glenn Kuras ➑️
Any time I have viewed 1/3 smoothing it look much more "smoothed" out, which tells me something is funky with your tests. Like there is some kind of noise going on.
what do you mean something funky here? Something wrong with my graph?
Old 23rd October 2012 | Show parent
  #54
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Bjorn Omholt's Avatar
 
🎧 10 years
Yes. Something is seriously wrong which I've indicated before. Either with the measurements or speakers. Your graph is much too uneven and there's way too little energy below 130 Hz.
Old 23rd October 2012 | Show parent
  #55
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sl4zhz's Avatar
 
🎧 10 years
Quote:
Originally Posted by bwo ➑️
Yes. Something is seriously wrong which I've indicated before. Either with the measurements or speakers. Your graph is much too uneven and there's way too little energy below 130 Hz.
how the graph should be ?
I'm using behringer ECM8000 through saffire pro 40 on board pre. set the gain at 8 no cliping. is that right?
Old 23rd October 2012 | Show parent
  #56
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Bjorn Omholt's Avatar
 
🎧 10 years
If you had a decent response it should look something like the ones below or preferable better. The red one which is flatter would probably be the best one for mixing. Within +/-5 with 1/24 octave would be considered excellent. Your graph is not near within +/-5 even with 1/3 resolution.
Attached Thumbnails
Help analyze room graph and acoustic design-average-freq-response-2.jpg   Help analyze room graph and acoustic design-average-freq-response.jpg  
Old 23rd October 2012 | Show parent
  #57
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sl4zhz's Avatar
 
🎧 10 years
Quote:
Originally Posted by bwo ➑️
If you had a decent response it should look something like the ones below or preferable better. The red one which is flatter would probably be the best one for mixing. Within +/-5 with 1/24 octave would be considered excellent. Your graph is not near within +/-5 even with 1/3 resolution.
hmmm I'm using fuzz measure with this setting:
PLAYBACK: Channel 1 - which is my main out of studio monitor 1-2
Recording Setting: Channel 1 - interface input channel 1

is that something wrong here?
Attached Images
Old 23rd October 2012
  #58
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🎧 10 years
I don't know, but at least increase the length of your measurement to 10-15 seconds.
Old 23rd October 2012 | Show parent
  #59
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echoRausch's Avatar
 
🎧 10 years
1/3 octave smoothing doesn't lead you anywhere...
Old 23rd October 2012 | Show parent
  #60
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Glenn Kuras's Avatar
 
🎧 15 years
Quote:
Originally Posted by echoRausch ➑️
1/3 octave smoothing doesn't lead you anywhere...
Agreed, but I was just pointing out that his graphs should look like a smooth line more that the gagged one.. Needless to say I don't think it is the speakers unless there are totally distorting.
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