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First measure with rew
Old 6th July 2016
  #1
Here for the gear
 

First measure with rew

So I got my behringer ecm8000 today and started to make some measurements in rew. Somehow i could only use one monitor at each measurement so what I did was I used "java" driver to actually use both monitors through windows. (dunno what delays and stuff that have been made through windows)

I don't know how "accurate" it will be with the java drivers, but i haven't find a fix for this yet.

This is like I said, my first measurement in my untreated room (just to see the difference later) and to know what kind of treatment I need!

Now, i don't really know alot about what rew is showing me, but I understand it to a tiny bit.

My room is 90% concrete and i have windows behind my monitors so it's not "something you would choose" to mix in.

So it would be awesome if someone could help me explain these graphs, and if there's something more I need to do!

Mdat is attached
Attached Thumbnails
First measure with rew-rew.jpg  
Attached Files
File Type: mdat rew.mdat (8.58 MB, 51 views)
Old 6th July 2016
  #2
Gear Guru
 
Glenn Kuras's Avatar
For sure the one test with both speakers is not correct. Over all the left and right measurement looks typical of a non treated room.
1)30db from the lowest dip to the highest peak. This should be more like 15db to 10db.
2)LOOOOOOOOOOOOOOOOOOOG decay in the low end.
Understanding Decay Time and Waterfall Graphs - GIK Acoustics

The solution........
1)Make sure you have the speakers and seating spot facing the correct wall (generally the short wall).
2)Proper bass trapping in as many corners as possible.
3)Absorption for early reflection points.
4)THICK absorption and or diffusion for the wall behind you.
See the following to give you a hand with the above things.
Basics of Room Setup -
Old 6th July 2016
  #3
Here for the gear
 

Quote:
Originally Posted by Glenn Kuras View Post
For sure the one test with both speakers is not correct. Over all the left and right measurement looks typical of a non treated room.
1)30db from the lowest dip to the highest peak. This should be more like 15db to 10db.
2)LOOOOOOOOOOOOOOOOOOOG decay in the low end.
Understanding Decay Time and Waterfall Graphs - GIK Acoustics

The solution........
1)Make sure you have the speakers and seating spot facing the correct wall (generally the short wall).
2)Proper bass trapping in as many corners as possible.
3)Absorption for early reflection points.
4)THICK absorption and or diffusion for the wall behind you.
See the following to give you a hand with the above things.
Basics of Room Setup -
Haha yeah okeyokey, yeah I thought so too about the measurement with the both speakers.

Yeah im gonna go with DIY 10cm thick broadband absorbers(?) with a space of 10cm behind. And for the bass I was thinking of porous Superchunks. Read about a guy here with the same glassfiber as i have and he used them for superchunks which i think you said in his post that it was had good results.

The only problem now is that half the wall behind me is open to the hallway, no door, nothing. But i think i asked that here on gearslutz and that people said it will work like a kinda "bass-trap" thingy. The only thing im a bit worried of is that it will "bounce" uneven behind me.

Correct me if I'm wrong, im no expert on this!
Old 7th July 2016
  #4
Here for the gear
 

I'm gonna build my broadband + bass traps in a couple of days, so I'm gonna update you guys as soon as I can with new tests!
Old 7th July 2016
  #5
Gear Guru
 
Glenn Kuras's Avatar
Quote:
The only problem now is that half the wall behind me is open to the hallway, no door, nothing. But i think i asked that here on gearslutz and that people said it will work like a kinda "bass-trap" thingy. The only thing im a bit worried of is that it will "bounce" uneven behind me.
Yes the opening can actually help as it lets low end out and hopefully it will not come back. As far as throwing things off, you would need to test with REW to find that out.
Room EQ Wizard Tutorial - GIK Acoustics
Old 7th July 2016
  #6
Here for the gear
 

Quote:
Originally Posted by Glenn Kuras View Post
Yes the opening can actually help as it lets low end out and hopefully it will not come back. As far as throwing things off, you would need to test with REW to find that out.
Room EQ Wizard Tutorial - GIK Acoustics
Just standard test or something advanced?

Yeah I'm abit worried bout the opening, its 3 more meters on the opening to the "back" wall. So don't know if these difference would make any problems.
Right now with nothing on my walls, i can't really say if im noticing it, but yeah who knows. Can it be making like nulls/peaks? beacuse of the difference in the distant on the backwall?

Have some more questions actually if its ok,

Im thinking of 10cm thick broadband absorbers for a start, if I remember correctly, theyr 20kg/m3. And I'm gonna go with a air-gap of 10cm too!

For bass trap, I thought superchunks with 50cm on each side, and like something with 2m of height. And for the wall/ceiling, maybe straddle? Because it's alot easier, but I dont really know if its good for the lower end.

For the "half back wall" how thick would you say? is 10cm with that 10cm gap ok?

Aaaand like how much treatment would you guess on concrete walls? Like you said, the decay is looooooooooooooooong, and i guess thats because of the concrete walls?

If there's something I can do with rew to get more info, just tell me what to do!
Old 7th July 2016
  #7
Gear Guru
 
Glenn Kuras's Avatar
No just the standard test is fine and looking at your test things look pretty even left and right so you may be ok.

Quote:
For bass trap, I thought superchunks with 50cm on each side, and like something with 2m of height. And for the wall/ceiling, maybe straddle? Because it's alot easier, but I dont really know if its good for the lower end.

For the "half back wall" how thick would you say? is 10cm with that 10cm gap ok?


That all seems good. For the back wall though I like to go as thick as you can afford/stand.

Quote:
Aaaand like how much treatment would you guess on concrete walls? Like you said, the decay is looooooooooooooooong, and i guess thats because of the concrete walls?
Concrete walls can for sure keep a lot of the low end inside of the room, which causes longer decay times.
Old 7th July 2016
  #8
Here for the gear
 

Quote:
Originally Posted by Glenn Kuras View Post
No just the standard test is fine and looking at your test things look pretty even left and right so you may be ok.





That all seems good. For the back wall though I like to go as thick as you can afford/stand.



Concrete walls can for sure keep a lot of the low end inside of the room, which causes longer decay times.

Yeah i can't really hear any strange at all.


I could stack two panels so its getting twice the thickness (20cm), but I don't know if i could double the air gap tho, it would be 40cm in total out of the wall in my living room!

If i clap my hands or someone talking in here, i can really really feel the echo, but, yeah I guess im gonna need alot of treatment.

How about the superchunks btw? Do they feel alright?
Old 8th July 2016
  #9
Here for the gear
 

Oh i forgot to mention, is 100x50x10 "in cm" broadband absorbers with 10cm air-gap for the rest of the room okay? because they'r pretty cheap, I think I payed 35 usd for 10 pieces. And I can manage to get 20 cm thickness for the back wall, but with only 10cm air-gap.

I think that's all
Old 8th July 2016
  #10
Gear Maniac
 

In REW's Mic/Meter preferences select "Mic or Z weighted SPL meter", you currently have "C-weighted SPL meter" selected so your measurements have inverse C weighting applied to them. You can fix that on existing measurements by using the "Change Cal" button on each measurement and un-checking the C weighted SPL meter box.
Old 8th July 2016
  #11
Here for the gear
 

Quote:
Originally Posted by JohnPM View Post
In REW's Mic/Meter preferences select "Mic or Z weighted SPL meter", you currently have "C-weighted SPL meter" selected so your measurements have inverse C weighting applied to them. You can fix that on existing measurements by using the "Change Cal" button on each measurement and un-checking the C weighted SPL meter box.
Oh okay! Thanks man! Do I need to reupload it or something?
Old 10th July 2016
  #12
Here for the gear
 

Built the first absorber today. It's 14cm deep, 120cm long and 55cm wide. Gonna put in 2x 7cm thick Isover 35 (european) with a 18kg/m3 density. There's also an air-gap of 14cm with the spacers.

Maybe not the prettiest yet but it will look better.

For the top "spacer" I'm gonna put on a red tape/moulding/shelf edge moulding (what you wanna call it) and something nice to hide the plywood (had it at home so I used it to get rid of it).

It's all wood, pretty light weight actually, would guess somewhere between 5-8 kilograms.

The fabric is the same fabric as in sheets, its breathable for sure.

Gonna use these ones for early reflection points and for the wall/ceiling "straddle" basstraps (if its ok?). Don't know it they're good for the back wall though.
Attached Thumbnails
First measure with rew-thumbnail_snapchat-5041006336962988960.jpg   First measure with rew-thumbnail_snapchat-7202857782257658559.jpg   First measure with rew-thumbnail_snapchat-7260927624859144834.jpg   First measure with rew-thumbnail_snapchat-948509770845253554.jpg  
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