R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2  All   Go Down

Author Topic: Free EQ room correction in a small room, Room EQ Wizard Rocks!  (Read 13173 times)

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114

This is a mac only tutorial:

my room is 11x14. I have posted previously about trying to tame a null at 70hz. I had twelve  4" panels placed mostly near the front wall.  Fran and Ethan and others recommended placing more absorption on the rear wall.  

I moved my desk forward to the front wall so the speakers were about 6" from the front wall/window. I placed 1 panel on each front corner and 1 on each side and 2 above me. Then I placed the remaining 6 panels on the rear wall corners. Scoped the room with EQ Wizard and it fixed the 70hz mode. Now I had a more usable roll off below 100 down to 30 with no deep nulls.

I have seen so many talks about people using the audyssey eq. Ethan has done an excellent write up on how it just doesn't work. There are also so many products on the market as well. Ergo, ARC, and the JBL 4300 series etc. Do they work? I set out to find out. Following Ethan's Advice I downloaded Room EQ Wizard and looked into the Behringer eq's etc, but I had a problem with that. I use Adams and an apogee converter. I certainly didn't want to go through another stage of low end conversion and DSP. I also didn't want to drop money on a suitable parametric and be limited to 4 or 5 bands.

I thought what can I use to be able to insert plug-ins into my bus and be able to use the same eq plug-in to listen to my Itunes library and other media sources?
I would also need to be able to send Room EQ Wizard into logic and then back into the built in line input.

ARC ($500) does this inside of Logic or other DAW, but what if you want to hear your bounce or other media through it?

The trick would be then to get my systems output into Logic and then to my apogee.

Solution (Free):

1 Download Soundflower from cycling 74.
2. Set the System preferences to output to Soundflower 2ch. Set the input to Built in Line Input.  
3. Go to Audio Midi and create an aggregate device and add Soundflower to it after your sound card. Make sure the built in lines are not used in the aggregate.
4. set the default input to built-in line input and the default output to soundflower 2ch and the system output to soundflower 2ch
5. open logic set the i/o to aggregate device.
6. create a stereo audio track and set the input to the soundflower channels. they will be the ones right after you main I/o on my symphony system 1-32 are for that and ch33-34 are for soundflower.
7. connect your measurement mic to your preamp and then output the pre to the built-in line input on the back of your mac. I use a xlr to 1/8 cable I had to buy.
8. open room eq wizard and go to the preferences. under soundcard set the output to default device and input to built-in line input. back in logic insert 3 linear phase plug-ins on the master bus and lower the fader to about -4.
10. open soundflower. it does not have a GUI but a flower will be up on the top task bar with a drop down list. set its output to none.
9. go back to logic. on the sound flower channel hit the "I" when it lights up yellow/orange the audio from your system including itunes will input here.    

you now have your system setup so that all sound is routed through logic. This will allow you to measure your room. enter your eq settings into the Linear phase eq's and re-measure. this will also allow you to monitor all of your other media through logic so you can take advantage of the EQ Correction.

I was able to dial in an almost flawless low end response curve in my room with 12 bands of eq and a low shelf boost of 6db. All this was free and it works, in my opinion better than adding additional conversion.

I would like to point out that I did not eq anything over 500hz. will post more on my mixing results and graphs later.

Regards,
Brett
Logged

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #1 on: August 29, 2010, 09:57:42 pm »

room with all panels in the front of the room.index.php/fa/15331/0/
Logged

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #2 on: August 29, 2010, 10:01:42 pm »

room after moving half the panels (6) to the rear of the room. notice the null at 70hz is gone. But now there is a mode between 100-200.index.php/fa/15332/0/
Logged

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #3 on: August 29, 2010, 10:04:00 pm »

room after applying EQ. index.php/fa/15333/0/
Logged

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #4 on: August 29, 2010, 10:23:10 pm »

 
As could be seen, the biggest improvement was evenly placing the acoustic panels in the room first. Then the eq allowed me to shape the low end from there with subtle cuts and boosts. Its not perfect but its pretty good considering the size of my room.  I am happy with the results.

Hope this will be helpful to some of you.

-Brett
Logged

Thomas Jouanjean

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #5 on: August 30, 2010, 06:24:18 am »

"You can't fix a time domain problem in the frequency domain"

There is just no way around it. I have never heard good results from EQing a room and using DSP correction.

But if the results made a positive impact on your work, then it's all good.
Logged
Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

bruno putzeys

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1078
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #6 on: August 30, 2010, 07:30:34 am »

Thomas Jouanjean wrote on Mon, 30 August 2010 12:24

"You can't fix a time domain problem in the frequency domain"

Of course you can. Time and frequency domain are the same thing seen from different angles. One reason why people don't believe it is because traditionally EQ's are minimum phase whereas acoustical problems are not, meaning that after correction you still have a smeared impulse response. If the EQ is a full FIR correction you can, in principle, correct everything...

BUT ONLY...

...in one spot in the room. Or n spots if you have n speakers. The issue has nothing to do with time vs frequency domain but with the fact that the room is a space and you have only two points (a pair of speakers) to control it by. If you have a dip at a certain frequency / spot, you will have a bump at the same frequency elsewhere. Correct the dip and the bump elsewhere gets worse. Room correction restricts you to sitting in one exact spot. That is why it doesn't work practically. However, if you are happy to have your head nailed down in one precise location you can remove everything. Echos, everything. Just don't move your head.
Logged
Warp Drive. Tractor Beam. Room Correction. Whatever.

Affiliations: Hypex, Grimm Audio.

Thomas Jouanjean

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #7 on: August 30, 2010, 07:53:12 am »

bruno putzeys wrote on Mon, 30 August 2010 06:30

Thomas Jouanjean wrote on Mon, 30 August 2010 12:24

"You can't fix a time domain problem in the frequency domain"

Of course you can. Time and frequency domain are the same thing seen from different angles. One reason why people don't believe it is because traditionally EQ's are minimum phase whereas acoustical problems are not, meaning that after correction you still have a smeared impulse response. If the EQ is a full FIR correction you can, in principle, correct everything...

BUT ONLY...

...in one spot in the room. Or n spots if you have n speakers. The issue has nothing to do with time vs frequency domain but with the fact that the room is a space and you have only two points (a pair of speakers) to control it by. If you have a dip at a certain frequency / spot, you will have a bump at the same frequency elsewhere. Correct the dip and the bump elsewhere gets worse. Room correction restricts you to sitting in one exact spot. That is why it doesn't work practically. However, if you are happy to have your head nailed down in one precise location you can remove everything. Echos, everything. Just don't move your head.


And thus, in my book it doesn't work in practice and has no real interest in studios. A good room should be quasi isotropic. Not a mediocre nail head sized sweet spot with everything even worse everywhere else.

I've also noticed severe degradation (in order of importance) of depth, "timbre" and stereo. Sound gets ghost like too.

Though I will recognize that the Trinnov guys etc, are all good engineers with excellent technique and deep knowledge of their field.

I've also good hope that these systems can compensate for some particular problematic speaker behaviours (phase issues etc). But I leave this discussion to speaker designers though.

Sorry I always sound like an old grumpy grandpa when these systems pop out Very Happy
Logged
Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

bruno putzeys

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1078
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #8 on: August 30, 2010, 10:35:51 am »

Thomas Jouanjean wrote on Mon, 30 August 2010 13:53

And thus, in my book it doesn't work in practice and has no real interest in studios. A good room should be quasi isotropic. Not a mediocre nail head sized sweet spot with everything even worse everywhere else.

Indeed, I only wanted to point out that time vs frequency domain is not what lies at the root of this. Which doesn't mean that it works, unfortunately! (sorry for the hordes who hawk these things, and even sorrier for those who buy them).
Thomas Jouanjean wrote on Mon, 30 August 2010 13:53

Sorry I always sound like an old grumpy grandpa when these systems pop out Very Happy

No worries mon vieux, you're not alone. *waves cane*
Logged
Warp Drive. Tractor Beam. Room Correction. Whatever.

Affiliations: Hypex, Grimm Audio.

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #9 on: August 30, 2010, 11:09:40 am »

I notice no weird modes anywhere when I walk around the room. As I said the low end was pretty evenly rolling off after acoustic treatment. The only real issue was a mode at 100-160 in the upper bass low mids. Using a some minor cuts and boosts it fixed the problem. In a small home studio my work space is only between my monitors and they are only 3 feet apart. So where else would I be making decisions but here in the small area where I know it is accurate?  

As said prior, I would not try and eq the highs, nor use eq to fix a null, but using eq to reduce energy that is omni directional does work, at least in this situation. You would be a fool if you thought a eq was going to make the entire room accurate.  But the measurement mic is located where it needs to be and that turned out outstanding in my opinion.
Logged

Thomas Jouanjean

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #10 on: August 30, 2010, 01:32:29 pm »

bruno putzeys wrote on Mon, 30 August 2010 09:35


Indeed, I only wanted to point out that time vs frequency domain is not what lies at the root of this. Which doesn't mean that it works, unfortunately! (sorry for the hordes who hawk these things, and even sorrier for those who buy them).


Non-minimum phase issues do, yes.



Hmmmm... Ok, so how should we word this and then make it an *internet rule*?   Rolling Eyes

And of course, have it ™ for when we write a book.

Then we can brag all over the place and claim we are gurus because we wrote a book.

Sweet.

[/Eric Cartman Voice]
Logged
Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

Ethan Winer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 571
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #11 on: August 30, 2010, 01:38:38 pm »

bruno putzeys wrote on Mon, 30 August 2010 07:30

BUT ONLY...
...in one spot in the room.


Exactly. Yet people often report positive results with these products. My guess is their room has a bad peak, so reducing that peak helped all over the room. In most small rooms the nulls are more damaging. But in a square room, or 2:1 such as 10 by 20 feet, resonant peaks can be worse than the nulls. It depends on so many things.

Of course I'm totally with you, and the main point is that EQ improvements that help in one place are made worse somewhere else. Even a few inches away in many cases.

--Ethan

Thomas Jouanjean

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #12 on: August 30, 2010, 01:40:58 pm »

brett wrote on Mon, 30 August 2010 10:09

 that turned out outstanding in my opinion.


And in fine that's what matters, period.

The issue is to know exactly what happens. There are so many possibilities as to why it can help a bit in a situation and not at all in another. The set of conditions in which you start are very important.

Then in the long run, how your work translate will tell the real extent of the improvement. (On a personal level, I always consider my job is done when after a period of 1 year+ of work in the new studio the client is still as happy as the first day).

Logged
Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

Thomas Jouanjean

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #13 on: August 30, 2010, 01:52:32 pm »

Ethan Winer wrote on Mon, 30 August 2010 12:38

 Exactly. Yet people often report positive results with these products.
--Ethan


Often, the better the room the more you can hear the overall damage done by these systems. In the really good rooms it can be pretty brutal. It's like your 24bit file became an MP3.

Logged
Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

brett

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1114
Re: Free EQ room correction in a small room, Room EQ Wizard Rocks!
« Reply #14 on: August 30, 2010, 07:30:02 pm »

Ethan Winer wrote on Mon, 30 August 2010 18:38

bruno putzeys wrote on Mon, 30 August 2010 07:30

BUT ONLY...
...in one spot in the room.


Of course I'm totally with you, and the main point is that EQ improvements that help in one place are made worse somewhere else. Even a few inches away in many cases.

--Ethan

not in this case. Not usually low end either in my experience. Highend yes where the wave lengths are smaller maybe. But low end response isn't drastic or noticible over an inch in my experience unless you are at the edge of a boundary. Eq in this case got rid of the boxy sound of the peak between 100-160. Bass tones don't sound so agressive anymore. And it helped all over. I turned off the eq and walked around. The peak could be heard everywhere evenly all over making the bass sound aggressive even on recording where the tone was smooth. The eq on and it was balanced all over.

important to point out that getting rid of nulls first is most important. a peak is more easily dealt with by eq as it removes energy from the room rather than add it like trying to boost a null which would add energy to the problem and is a losing battle.  

So, in this case it worked. Will it always? probably not. But the important thing to realize is that a balanced palcement of acoustic treatment is the best place to start as it got rid of the null. And I plan to add 12 more panels soon and reshoot the room. For now, the room is usuable and I didn't have to buy some gimic product with bad signal to noise issues or conversion or any expensive plug-in. Just smarter placement of panels I already had and some creative signal routing in my DAW.

Logged
Pages: [1] 2  All   Go Up