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MLS and Newells sequence
Old 24th March 2014
  #1
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🎧 15 years
MLS and Newells sequence

Could someone explain the differences between Boggys MLS and Newells sequence??

When each of these is appropriate??

Also would someone post the link to Boggy's sequence??

cheers…….
Old 25th March 2014
  #2
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🎧 10 years
Yiannis,

I'm sure Boggy will comment here, but I'll say this: There is a big difference between the Binary / MLS sequence and Philip Newell's 3-4-5 slat sequence.

The Newell slat sequence is simply a pseudo-random shuffling of x3 - x4 - x5 width boards calculated to provide a certain percentage of reflection vs absorption. (At least that is my take on it)

The Binary / MLS sequence is also a pseudo-random calculation, but it works very well as sequences go... see Acoustic Absorbers and Diffusers by Trevor J Cox & Peter D'Antonio. and https://gearspace.com/board/9971677-post94.html

See attached

Cheers,
John
Attached Files
File Type: txt MLS sequence 1 through 126.txt (2.3 KB, 1110 views)
Old 25th March 2014 | Show parent
  #3
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avare's Avatar
 
🎧 15 years
Quote:
Originally Posted by jhbrandt ➡️
I'm sure Boggy will comment here, but I'll say this: There is a big difference between the Binary / MLS sequence and Philip Newell's 3-4-5 slat sequence.

The Newell slat sequence is simply a pseudo-random shuffling of x3 - x4 - x5 width boards calculated to provide a certain percentage of reflection vs absorption. (At least that is my take on it)
+1.

I do not know how the Gearslutz community has gotten stuck at Newell for the x3 x4 x5 sequence origin. (The great) Michael Rettinger described it in Acoustic Design and Noise Control ,published in 1973, as a pattern that yields approximately 50% open area.

Well spaced and documented,
Andre
Old 25th March 2014
  #4
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Thank you for your answers.

Here is the wall I would like to treat.

Width is about 1.8m so if I use MLS sequence with 5cm (W) x 2,5 (D) slats I could use about first 36 numbers of the sequence.

If I use 3cm slats I could use 60 numbers of the sequence, if I have understand the concept correctly.

I can see that the sequence is in parts of 15.

1)Could I use random parts or I have to follow the sequence?

2) What's the difference between 0.5 and 1cm slat spacing...…

3)Between 3cm and 5cm slats??

4) Should I follow a sequence for half the wall and then do a mirror image for the other half or I should just follow a continues sequence?

so position 43-56 will give me

01_10101_101_1001


Is this correct?
Attached Thumbnails
MLS and Newells sequence-180410_1592881263800_4401462_n.jpg  
Old 27th March 2014
  #5
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Finally I have build it using the MLS sequence (19-56) using 5cm wide x 2.5 thick slats.These are not permanent for the moment and not yet painted as I will check what is the effect of these in a recording session.
Attached Thumbnails
MLS and Newells sequence-p3260120.jpg  
Old 29th March 2014
  #6
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🎧 10 years
Yiannis,

You'll like it, I'm sure.

Cheers,
John
Old 29th March 2014
  #7
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Quote:
Originally Posted by jhbrandt ➡️
Yiannis,

You'll like it, I'm sure.

Cheers,
John
Thank you very much John.

Here is one of the 1D panels for my CR rear wall 20cm absorbers.

First photo is the 1D and second is temporary attached to the panel…..
Attached Thumbnails
MLS and Newells sequence-2.jpg   MLS and Newells sequence-1..jpg  
Old 3rd April 2014
  #8
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I have make a classic guitar and a vocal recording in the room.

Sound is more live ,at last,and for some reason those hi mid resonances I had before ,especially on vocals just...gone.

Now I have a wall to make with two SC on the sides.

Could I use vertical slats on the SuperChunks and horizontal on the wall between?
Old 3rd April 2014 | Show parent
  #9
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Quote:
Originally Posted by Yiannis ➡️
.....Could I use vertical slats on the SuperChunks and horizontal on the wall between?
Personally, I would keep the slats running vertically. The reason for this is that we have two ears. One on each side of our head and not on the top and bottom. And, we move about in the room side to side - horizontally and experience more of the sound field that spreads horizontally.
Additionally, it may be the reason why a speaker system's horizontal dispersion is more important than its vertical dispersion.

With vertical slats you can create a more meaningful (acoustically useful) dispersion field.

Cheers,
John
Old 3rd April 2014
  #10
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Thank you John……..


I forgot to mention that this wall is behind my speakers……..

1) Should I use vertical slats there too?

2)MLS sequence-slat the entire wall or use your way (5cm slats with 2cm gap between)?
Old 4th April 2014
  #11
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🎧 15 years
I would love to have an answer as I am going to start the construction today ….
Old 4th April 2014
  #12
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🎧 10 years
1. yes.
2. do it 'my way'.

That's my opinion, anyway.

Cheers,
John
Old 4th April 2014 | Show parent
  #13
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Quote:
Originally Posted by jhbrandt ➡️
1. yes.
2. do it 'my way'.

That's my opinion, anyway.

Cheers,
John
Thanks John,

I will do it as you say…….5cm slats with 2cm gaps……vertical…….

I guess "your way" will reflect more……than the MLS.
Old 5th April 2014
  #14
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🎧 15 years
SuperChunk almost finished......

the rockwool behind and even the fabric do not touch the slats!!

Could that be a problem ????
Attached Thumbnails
MLS and Newells sequence-imageedit_2_5092187643.jpg  
Old 6th April 2014
  #15
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🎧 10 years
Most likely not a problem... Testing will confirm.

Make sure that you don't have any reflective surfaces in the first reflection zone/area.

The slats in the front of the room are for YOU, not the sound source from the speakers. These create a diffractive surface for the room occupants so they have a sense of the 'room' - so that it doesn't seem 'dead'. But to the source, they do nothing and you will be presented with 'the source and only the source' without reflections, interference, or comb filtering.

Cheers,
John
Old 6th April 2014
  #16
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🎧 10 years
More discussion here: DIY Binary Amplitude Diffuser anyone?
Old 7th April 2014
  #17
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+1

I use MatLab for finding an optimum sequence...

But for the CR front wall I recommend using the 70% / 30% slat/gap sequence to optimize the reflective area and still have bass trapping.

I will post a new (very long) MLS sequence that I have found to work very well on the above mentioned thread.

Cheers,
John
Old 9th April 2014 | Show parent
  #18
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🎧 10 years
Quote:
Originally Posted by jhbrandt ➡️
+1

I use MatLab for finding an optimum sequence...

But for the CR front wall I recommend using the 70% / 30% slat/gap sequence to optimize the reflective area and still have bass trapping.

I will post a new (very long) MLS sequence that I have found to work very well on the above mentioned thread.

Cheers,
John
For the slats on the front wall or front corners, what is the advantage of using 2.5cm thick slats (like the OP has done) over using thinner, say 0.5 cm ones? More/less lower end absorption?
Old 9th April 2014
  #19
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🎧 10 years
Deeper slats = better edge diffraction. That's all.

Cheers,
John
Old 29th April 2014 | Show parent
  #20
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ciro's Avatar
 
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Quote:
Originally Posted by jhbrandt ➡️
But for the CR front wall I recommend using the 70% / 30% slat/gap sequence to optimize the reflective area and still have bass trapping.
Cheers,
John
Just posting to say that I did it in my front corners, with 5cm slat/ 2cm gap (1,5 cm thick mdf) and it makes a big difference vs the rockwool superchunks with "magazine paper" I had before.
I was a bit afraid with FR but it remains basically the same . The sense of depth as John saids, and image improved a lot.


Ciro
Old 30th April 2014 | Show parent
  #21
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🎧 10 years
Quote:
Originally Posted by ciro ➡️
Just posting to say that I did it in my front corners, with 5cm slat/ 2cm gap (1,5 cm thick mdf) and it makes a big difference vs the rockwool superchunks with "magazine paper" I had before.
I was a bit afraid with FR but it remains basically the same . The sense of depth as John saids, and image improved a lot.



Ciro
How wide are the super chunks?
Old 30th April 2014
  #22
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Hi Jolida, they are the 17 X 17 x 24 .As I felt they where not enough, I put a 4" panel in front (the one with the slats).

I have a similar configuration in the rear wall ceiling corners , but these have the "minichunks" behind the panel. Also in the front wall / ceiling, but this is a massive, very thick panel with low density rockwool. All have slats in front.

Ciro
Old 1st May 2014 | Show parent
  #23
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🎧 10 years
Quote:
Originally Posted by ciro ➡️
Hi Jolida, they are the 17 X 17 x 24 .As I felt they where not enough, I put a 4" panel in front (the one with the slats).

I have a similar configuration in the rear wall ceiling corners , but these have the "minichunks" behind the panel. Also in the front wall / ceiling, but this is a massive, very thick panel with low density rockwool. All have slats in front.

Ciro
Minichunks as in???
This is my rear wall / ceiling corner done as u have described..
Attached Thumbnails
MLS and Newells sequence-1398875994392.jpg  
Old 1st May 2014
  #24
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All my superchunks are "hidden", behind a 4" panel. Some are the 17"X17"x24' type , and some are "minichunks" (I mean the smaller ones - a panel cutted in 16 very little triangles)

If I had chosen the big ones (32" x 24"), the 4" panel in front would probably not be necessary.

Ciro
Old 1st May 2014 | Show parent
  #25
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🎧 10 years
Quote:
Originally Posted by ciro ➡️
All my superchunks are "hidden", behind a 4" panel. Some are the 17"X17"x24' type , and some are "minichunks" (I mean the smaller ones - a panel cutted in 16 very little triangles)

If I had chosen the big ones (32" x 24"), the 4" panel in front would probably not be necessary.

Ciro
U mean u have 4 inch rigid fibreglass panels straddled at wall/ceiling junctions filled with fluffy behind them?
The panel on your front corner is the first u have done with the 5cm/2cm slat/gap configuration? U mentioned slats on wall/ceiling panels too. Slats in what sequence?
Old 1st May 2014 | Show parent
  #26
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🎧 10 years
Quote:
Originally Posted by Jolida ➡️
U mean u have 4 inch rigid fibreglass panels straddled at wall/ceiling junctions filled with fluffy behind them?
Yes

Quote:
The panel on your front corner is the first u have done with the 5cm/2cm slat/gap configuration? U mentioned slats on wall/ceiling panels too. Slats in what sequence?
Yes, the 5cm/2cm slat/slots are the ones I did 2 weeks ago.
I have a "mix" of slat / slots configuration in the other corner traps.Rear wall/ceiling have different width slats (~65% slat/ 35 %slot) and in the front wall/ceiling I used the 3-4-5 pattern (50% / 50% )

If I had to do it again, probably I would make them much more reflective (like 90/10, I see corner traps made this way) . My guess is that it would help (?) to keep the 200/1000 hz energy , which is easy to over absorbs if you have too much broadband traps (like in my small room)

Ciro
Old 1st May 2014 | Show parent
  #27
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🎧 10 years
Quote:
Originally Posted by ciro ➡️
Yes



Yes, the 5cm/2cm slat/slots are the ones I did 2 weeks ago.
I have a "mix" of slat / slots configuration in the other corner traps.Rear wall/ceiling have different width slats (~65% slat/ 35 %slot) and in the front wall/ceiling I used the 3-4-5 pattern (50% / 50% )

If I had to do it again, probably I would make them much more reflective (like 90/10, I see corner traps made this way) . My guess is that it would help (?) to keep the 200/1000 hz energy , which is easy to over absorbs if you have too much broadband traps (like in my small room)

Ciro
Pics would be appreciated...
Old 3rd May 2014 | Show parent
  #28
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🎧 10 years
Quote:
Originally Posted by ciro ➡️
Just posting to say that I did it in my front corners, with 5cm slat/ 2cm gap (1,5 cm thick mdf) and it makes a big difference vs the rockwool superchunks with "magazine paper" I had before.
I was a bit afraid with FR but it remains basically the same . The sense of depth as John saids, and image improved a lot.


Ciro
I tried that last evening & am in total agreement with u. It made things sound so much more focussed & imaging/layering & depth is now more defined. As always, what John Brandt says never goes wrong !
Old 15th May 2014
  #29
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🎧 15 years
Constructions almost finished..... it took some time due to unavailable spare time...

Tracking room side wall

Tracking room SC

CR front wall using John Brandt design.

Thanks John...
Attached Thumbnails
MLS and Newells sequence-2014-05-15-023.jpg   MLS and Newells sequence-2014-05-15-022.jpg   MLS and Newells sequence-2014-05-15-020.jpg  
Old 16th May 2014
  #30
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Finished Cr front wall.

I hear tighter bass and a better stereo image…...
Attached Thumbnails
MLS and Newells sequence-p5150184.jpg  
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