[How To] Flatten your FRFR-Monitors

cobhc999

Member
Because of some request, I decided to write a little tutorial about flattening your FRFR-monitors.
My english isnt the best one, maybe a mod can correct it afterwards?!

Some pictures I post here are made by "Black_Bender" of the recording.de-Forum.

Part I

First of all, what you need:

-Room EQ Wizard V5:
1906f766b7c29a6e2f6fa0e1b6cc30d7.jpg


You can get it from here:
REW - Room EQ Wizard Home Page

Registration is required. For executing the REW, Java has to be installed. java.com: Java + You

-A reference microphone

An example of a cheap reference mic is the Behringer ECM8000. An advantage of the ECM8000 is, you can download a calibration file from it on the REW page. I'll return to this later.
View attachment 198155

- A audio interface

It dosent have to be the really best one, but you also shouldn't use the onboard soundcard. Phantom power is required for the Behringer ECM8000.



The positioning
:

Its very important to position your mic in the middle of the axis of the 15" driver and the tweeter. (The 15" are only an example, it depens on your monitor)

Firstly start messuring with a distance of 20cm. Then make 10cm-steps up to 100cm.

Connect the reference mic with your soundcard to input Left and enable the phantom power.
Messur_posittion.jpg


Installation and default preferences

Install REW V5 on your computer. Maybe in the default path: "C:\program files\Room EQ Wizard V5"

Run REW V5 and click "Preferences"
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Set the samplerate of your audio interface to 48kHz. Then transfer the preferences like on the picture below: (Of corse choose your soundcard and I/O. Set the samplerate to 48kHz too, not like in the picture!!!
0fcf90447abee443a5112b1aaebea1a5.JPG


If your using the Behringer ECM8000, choose the Calibrationfile on "Mic/Meter":
da56567d2ec640e4ece4db116091293e.JPG
 

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Part II

Part II

Levelling

To avoid a shock of the calibration noise turn the volume of your monitor to zero.

Now click on SPL Meter:
a13833bae9f07b3736ed912b12dd0aeb.jpg




Now transfer the settings of the SPL Meter like below:
03b15280c0bf131b3cf9e900cc74aeb6.jpg


Click on calibrate. Now raise the volume of your monitor up to the loudness how you normally use it. I recommend wearing ear protection, because the calibration sound and the sweeps are relly nasty.

Now dial in the mic gain of your preamp until you reach -20dB, then press Finish.


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The measurement


Click on Messure:
a6636ac1e2d47154e338dca68dd5a0cc.jpg


Take these settings:

Start freq.: 20Hz
End freq.: 20000Hz
Level: -6dB
Length: 1M
Sweeps: 1

Then press Start Measuring. Now you have to be really cuiet and stay away of your monitor and mic.
Now rename your first measurement (20cm) and do this again until you reached the 100cm.

Thats my measurement with a distance of 70cm (the blue graph)

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The missing parts will follow, I've run out of time...:mad:
 

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There was some time left ;-)

Part III:

Select your first Measurment (20cm) and click on "EQ"
image.jpg



Overtake the settings on the right side. Press the red circled buttons in the marked order.

EQ2.jpg


Now export the corrected Filter:

Export.jpg


Now do this with every measurement you made from 20cm to 100cm.

Now you should have all filters from 20cm up to 100cm in a .wav format.
Now convert these into a .syx file. I prefer Ownhammers tool:
OwnHammer.com - Axe-O-Matic

Download-button is at the bottom of the page.



Next step:
Upload all these new .syx-Files into your AxeFx Cabinet-Slots.

Now you have to redo all your measurements but with the corrected filter in your chain. Dont start a new project in REW. Make them in your existing project, where your original measurements are made.
That signal chain should look like this:

Audio interface L -> AxeFx -> Monitor -> Reference Mix -> Mic In of preamp

The preset in your AxeFx should only contain one Cabinet, loaded with the corresponding .syx.
For example: If the distance of the mic is 20cm, load the Cabinet with the "20cm"-.syx. If the distance is 50cm, load the cabinet with the "50cm"-.syx. etc.

If you finished the new measurments, compare them all together and choose the distance, which has the flattest result in our opinion. The best one is your "correction-filter". In my measurement it was 70cm. I placed this "70cm"-.syx in every preset of my AxeFx at the end of the signal chain.
After i was done with the measurments it looked like in the picture below. Select "All SPL" and change the Smoothing to 1/48. Because there are to many graphs, you can deselect the not necessary at the bottom.
Alle_Messungen.jpg


The result of this 1-Day-Taking-Measurment-Making-Exercise is a much flatter monitor: (Blue graph: Before || Yellow graph: After)
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PDF of the whole Tutorial: File-Upload.net - How-To-flatten-your-FRFRmonitor.pdf


If you use the Db Opera M12-4 Plus too, maybe you want to use my corrective filters: http://www.file-upload.net/download-3876025/DB-Opera-Frequenzkorrektur.rar.html
 

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Last edited:
Cool!

It might be interesting to try a similar approach with a set of studio monitors and a DAW convolution plug-in, although I assume the tool has a different approach to handling the more general home studio setting.

Thanks again cobhc999. :)

Terry.
 
This is what makes THIS FORUM so awesome! People taking the time to put together informative posts to help others. It's not an easy task and the OP could have just tossed out a few sentences with the software and mic recommendations and been done with it. Kudos for taking the time to walk us through it.

~tip of the hat~
 
Thats what i made at home with my studio montiors. Its nearly the same thing.

For flattening your studio monitors:

You only have to place the mic on your listening position and not on several distances like in this tutorial.
You have to measure the left and the right monitors separately. Afterwards you can export the corrected filters in stereo and load it into a convolver programm like SIR2 or leCab.
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Pictures from Black_Bender of recording.de

If the pictures are enough for you, or you understand some german, check this tutorial for your studio monitors:
http://recording.de/Community/Forum...akustik_und_Dämmung/147164/Post_1504318.html#

Thanks alot for this praises!
 
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Great post. Thank you for sharing.

One quick question, shouldn't the ref mic be positioned in about the same place of the player (or the player's ears) ? I believe this is the spot you'd like to flatten.
 
Cool!

It might be interesting to try a similar approach with a set of studio monitors and a DAW convolution plug-in, although I assume the tool has a different approach to handling the more general home studio setting.

Thanks again cobhc999. :)

Terry.

this approach is quite popular, but in reality you just can't fix problems in the time domain (the room) within the frequency domain (filters)

the tool is very handy to see what kind of treatment your room needs, tho.
even tho it's almost always basstraps ;)
 
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Wow, thanks for putting in this effort!

I think this is worthy of being 'stickied'???

(Moderators....what do you think?)
 
this approach is quite popular, but in reality you just can't fix problems in the time domain (the room) within the frequency domain (filters)

the tool is very handy to see what kind of treatment your room needs, tho.
even tho it's almost always basstraps ;)
There's no substitute for a good room, is there! :)

I moved my studio to a different room and I hear an "edgy-ness" that was not there before. I was able to move my near-fields about 16" away from the wall they sit in front of, which has helped. I also put them on some acoustic foam so they are not directly coupled to my desk. This has also helped. However, I have not treated the room at all. When I clap my hands I can hear a more pronounced reflection in this space than the one I came from, so I know there's work to be done!

Terry.
 
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