# REW for 5.1 Surround calibration



## CraigNZ (Apr 22, 2010)

I noticed that REW supports only 2 channel sound cards. I have an external 'sound card' (Echo Audiofire 12) which is configured in 'surround' mode providing 5.1 channels. Some questions:

1. What is the recommended method for calibrating a 5.1 system using REW?

2. I do have the option to 'reconfigure' the AF12 into 6 virtual sound cards (2 channels each, 12 channels total). My configuration would then be: 

Sound card 1: Left, Right Front speakers

Sound card 2: Center channel, LFE channel

Sound card 3: Left, Right Rear speakers

Should I then calibrate each sound card and then calibrate the speakers in the room individually? When completed I then reconfigure the AF12 back into surround mode.

3. Or, is there another software package that can work with 5.1 channel sound cards?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Welcome to the Forum, Craig!



> 1. What is the recommended method for calibrating a 5.1 system using REW?


Not sure if you’re asking about a 5.1 card there or a 5.1 surround sound system fronted by an AVR?

For the former, REW only needs to send a signal from a single channel, so if you can configure the sound card to do that you’re in good shape.

For the latter, REW only generates an analog signal from a single channel of a sound card to send to an AVR/ surround sound system. If you want measure center or rear speakers, you’ll need to plug them into either the left or right main front channel.

Regards,
Wayne


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## CraigNZ (Apr 22, 2010)

Hi Wayne,

Thank you for the welcome. Will find this forum most interesting as I get my system setup.

In answer to your question, the AF12 appears as a 5.1 surround sound card to Windows, and to applications. So what I am looking to do is calibrate the system through the sound card.

Reading your reply I think the best way is going to be configuring the surround sound card as 6 windows sound cards. REW can then work with each sound card to calibrate all of the speakers one at a time. When finished I can then reconfigure the sound card back to surround mode.

Craig


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## Wayne A. Pflughaupt (Apr 13, 2006)

> In answer to your question, the AF12 appears as a 5.1 surround sound card to Windows, and to applications. So what I am looking to do is calibrate the system through the sound card.


What system? Your home theater or your computer audio system?

Regards,
Wayne


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## CraigNZ (Apr 22, 2010)

Sorry, I meant the home theater. The AF12 is connected to multiple Crown ITX-2000 amplifiers. The amps in turn are connected to Klipsch THX speakers (Left, Center, Front, Surround Left, Surround Right). The AF12 also connects to the input of a Definitive Technology Supercube Trinity Signature sub for LFE. I have a Behringer mic for the tests. I will place the mic at the listening point in the theater room and use the REW software to measure the frequency response curve and the loudness level for each speaker. I'll use the integrated parametric equalizer in the Crown amps to correct all of the speakers but the sub. I'm doing this to move the DSP processing from the PC to the amplifiers to reduce PC requirements. Not sure yet on the sub. I think I can run the AF12 LFE channel to a crown amp, equalize there and then run the output (at line level) to the sub. Worse case I can drive the sub with speaker input from the Crown amp.

Craig


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## Wayne A. Pflughaupt (Apr 13, 2006)

A search for “audiofire” turned up this thread, so it looks like your interface can work with REW (the fact that he generated a viable graph proves that). 

You can use our generic calibration file for the Behringer mic (assuming you have the ECM8000), but since you intend to EQ the main speakers you really should get the mic calibrated. As you can see from the graph on our Calibration Files download page, there is substantial deviation in response from one ECM8000 sample to the next. You certainly don’t want to do any equalization based on inaccurate measurements. 

You are correct that each speaker should be measured independently. Your best bet for equalization will be to use REW’s RTA function.

Regards,
Wayne


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