UMC-200 calibration with REW

[neo20013]

Unfortunately, there isn't much information regarding the use of the best feature of the UMC-200, the PEQ.
I'm not a very advanced REW user, but i know the basics, so i will use this thread to seek advice, and, at the same time, document this process to be used as a reference for future users.

1 - First, and the most important, a description of the room :

The room is located in the last floor, and has a celling of plasterboard, with the shape of an inverted V. The floor to celling height is 2m in the center and 1m in the sides.
The dimensions of the room :



The room has a very rigid surface, and its almost empty. As such, it is a very lively room with many resonances.
At some frequencies, the celling reverbs, and it takes a few seconds for the reverberation to die.



2 - The Gear, in a 5.1 configuration

• UPA-700
• UMC-200
• LCR XTZ 99.26 89db
• MA BRFX
• SVS PB1000

[neo20013]

REW Measures

Gear

1. Silverline SPL Meter
2. behringer uca202

[neo20013]

Reserved 1

[neo20013]

Reserved 2

[neo20013]

Reserved 3

[neo20013]

Tomorrow i will connect the UPA-700 to the UMC-200.

As such, i'm planning to take the following measures:

1. Left Speaker
2. Right Speaker
3. Sub alone
4. Left Speaker + Sub
   
5. Right Speaker + Sub
   
6. Left + Right + Sub

Prior to taking this measures, i will need to configure the UMC-200.

Can anyone help me regarding the UMC-200 configuration, as i have several questions?
What should be the steps i need to take to configure the UMC-200?


   1. Configure speaker trims
   2. Configure speaker XO : I usually have a high XO, i can set it to 130Hz without locating the sub, so i will start with a high XO
        LRC        - 120 Hz
        SR/SL    - 150Hz
   3. Configuring Slopes - I have no idea what to use in this step !!!!
   4. Using a SPL meter, level all speakers to 75db. 
       Can i use the UMC-200 test tones to achieve this ? If not, what should i use ?

What do you think? Am i'm missing anything ?

[markusv2]

First step should be to get speaker levels into the ballpark.

Mount your SPL meter on a stand and place it at the main listening position where your head would be. Switch it to C-weighting and slow response.
In the UMC-200 set the crossover for each speaker to 250Hz. If your sub has a crossover control then set it to its highest value.

Play pink noise through the left speaker and sub. Use periodic pink noise from REW's "Generator":



Observe the frequency response with REW's "RTA". Use the following settings. Make sure the "FFT Length" in the RTA and Generator match. If they don't match the curve will wiggle around and prevent proper readings.



Adjust the subwoofer level so the 63Hz band matches the 1kHz band.
Play the pink noise signal through the next speaker and adjust its level so the 1kHz band matches the 1kHz band of the left speaker. Repeat for each and every speaker.

Measure the distance from each speaker to the listening position and set the UMC-200 accordingly.

Set crossovers to 80Hz and you're done with a very basic setup.

Optimizing the sub and crossover region should be the next step. A dramatic improvement in sound quality can be had.

[markusv2]

Dec 13, 2013 14:13:41 GMT -5 neo20013 said:

The dimensions of the room :

One of the most important requirements for good sound quality is acoustical symmetry. Virtually no amount of room treatments and signal processing can remove errors introduced by acoustical asymmetry.

[neo20013]

Markus, thank you very much for your help.
The procedure is more complicated that i used to do, but i will to follow your instructions

[neo20013]

Following Markus directions, i completed adjusting the levels for all speakers.

Some notes :

 1 - To be able to generate the pink noise for all speakers, i had to make the following configurations on UMC-200 :

    For measuring L/R
:
        Mode -> Stereo

        Playback Analog 2ch -> Stereo


    For measuring remaining speakers
:
        Mode -> All Stereo

        Playback Analog 2ch -> All Stereo

    The final trim settings were :

    Subwoofer : 0db  (I've used the subwoofer gain, and had to set it at approx 9 o'clock)
    L/R : 0 db
    Center : - 2.5 db
    RS/LS : +6 db


2 - The changes in trims aren't saved after i changed them? Is there a way to save them ?

[neo20013]

Default settings

• Crossover all channels : 80Hz
• Slope all channels except subwoofer : 12db
• Slope subwoofer : 24 db
• Phase : 0 degrees
  
  

This setting lead to the following SPL chart 

20 - 200 Hz



20 - 20000 Hz



Waterfall chart

[neo20013]

I find the null at the 67Hz very strange, as the sub is located in a corner.
I thought that this null was due to the subwoofer crossover setting on UMC-200 was at 80Hz, so i set it to 250Hz, measure again, and the SPL chart was exactly the same.

[neo20013]

Ok, i've found the cause, i was using direct. 
I've changed it to stereo and now its ok.

Default settings

• Crossover all channels : 80Hz
  
• Slope all channels except subwoofer : 12db
  
• Slope subwoofer : 24 db
  
• Phase : 0 degrees
• Mode : Stereo

SPL 20 - 200Hz



SPL 20 - 20000Hz




Waterfall

[markusv2]

Dec 14, 2013 13:20:08 GMT -5 neo20013 said:

Following Markus directions, i completed adjusting the levels for all speakers.

Some notes :

 1 - To be able to generate the pink noise for all speakers, i had to make the following configurations on UMC-200 :

    For measuring L/R
:
        Mode -> Stereo

        Playback Analog 2ch -> Stereo


    For measuring remaining speakers
:
        Mode -> All Stereo

        Playback Analog 2ch -> All Stereo

    The final trim settings were :

    Subwoofer : 0db  (I've used the subwoofer gain, and had to set it at approx 9 o'clock)
    L/R : 0 db
    Center : - 2.5 db
    RS/LS : +6 db

Not sure what you did there. You need to measure each speaker in isolation.

Dec 14, 2013 13:20:08 GMT -5 neo20013 said:

2 - The changes in trims aren't saved after i changed them? Is there a way to save them ?

You have to set speaker levels in "Setup > Speaker Setup > Test Tones". Make sure you reduce master volume before accessing that menu otherwise the UMC-200 will welcome you with very loud test tones.

[markusv2]

Regarding your measurements, measure each speaker in isolation. Why is there no output above 5kHz?

[neo20013]

Yes, i've measure each speaker in isolation.
But i think i've incorrectly used the trim levels to match the levels off all speakers ...

I've corrected the problem using the test tones to match the speakers.

[neo20013]

Dec 14, 2013 14:26:32 GMT -5 markusv2 said:

Regarding your measurements, measure each speaker in isolation. Why is there no output above 5kHz?

Dont know

[markusv2]

Dec 14, 2013 14:33:09 GMT -5 neo20013 said:

Yes, i've measure each speaker in isolation.

How do you measure each speaker in isolation when mode is set to "All Stereo"?

[markusv2]

Dec 14, 2013 14:34:19 GMT -5 neo20013 said:

Dec 14, 2013 14:26:32 GMT -5 markusv2 said:

Regarding your measurements, measure each speaker in isolation. Why is there no output above 5kHz?

Dont know

Connect UCA202 L out to L in and do a loop back measurement.

[neo20013]

I've removed the inputs from the power amp, switching only the speaker i wanted to measure