REW and home stereo setup

[eLko]

Hi guys,

I need some help,how to use REW with home stereo.I know,that REW was made for home cinema.But I think,that I can use it for stereo as well.

I have laptop,maudio mobilepre,ecm8000.I was reading this forum and find out,that I need to calibrate mic,soundcard and SPL meter in REW.Correct?
For mic,I use the cal file.For soundcard I have to do loop from input to ouput and calibrate response of the soundcard.Correct?
And for the SPL meter,I will need external analog or digital SPL meter and value set to the REW.Right?
Do I need to calibrate something else?

Than my external DAC has usb input.So I use my DAC as an output device and maudio as an input device.So I can make sweeps from REW and sound should come out from my speakers and mic should make measurement and I should find out where do I have peaks.Right?

Please,can somebody confirm,that it should work like this or do I have to do something else?
Thanks

[brucek]

I know,that REW was made for home cinema.

Not at all, it doesn't work for multi-channel actually. The receiver or processor must be used in stereo mode.

Please,can somebody confirm,that it should work like this

Yep............

For soundcard I have to do loop from input to ouput and calibrate response of the soundcard.Correct?.

Or simply hook a loopback to the left channel (line-out to line-in) of the soundcard. This acts as the calibration when the checkbox is ticked.

brucek

[eLko]

Thanks for the reply.

So.When I calibrate soundcard once,than I dont need to have that loopback when I do measurement?Because I am not going to use maudio as an output device for measurement.It will be my dac.Maudio as an output device will be used only for soundcard calibration.Right?

In settings,there is that checkbox for left channel reference calibration.I should check this only if i am using maudio as an output device for measurement and loopback is on.Right?

Thanks

[brucek]

When I calibrate soundcard once,than I dont need to have that loopback when I do measurement?

Yes, if the box is unticked you'll be using the soundcard cal file that you produced and stored (instead of using the left channel loopback).

But, here's the rub with your logic. You are including a piece of your UUT (unit under test) into your test equipment.

The standard method is that you calibrate your test equipment (usually a PC soundcard with analog line-out and analog line-in) with an external loopback cable, so that when the loopback is measured it returns a perfectly flat response.

Then when you hook this perfect test eqiupment up to the UUT (in most cases a preamp/amp or receiver with sub and or mains speakers and a room using a flat microphone) the response will be the UUT only.

Do you see what you're doing? You want to include the DAC in both the test equipment and the UUT. To do so, you'll have to accept the assumption that the DAC is perfect and so its influence will be a wash.

brucek

[glaufman]

brucek wrote:

To do so, you'll have to accept the assumption that the DAC is perfect and so its influence will be a wash.

I think more to the point, he won't be assuming the DAC is perfect, but that it perfectly matches the DAC internal to the m-audio... The internal DAC's response has already been included in the cal file he's producing, but then he's removing it from the test setup...

[brucek]

Yep................

[eLko]

So I calibrated my soundcard using loopback and created cal file.Response is perfectly flat.

Now what I want to say is,that I have stereo system made of cd transport,external dac,preamp,active monitors and active sub.

When the soundcard is calibrated,I can do some sweeps now.Questions is,how.

As I said before,my dac has usb input and I can select my dac as an output device in REW and testing sweeps will not go trough maudio,but directly from pc to dac.I can select only one output device in pc,so maudio output is disabled and dac is enabled.
Test tones go to dac and maudio will receive response from my speakers through the mic.Thats the first option.

Second.Output device will be maudio and I have to go from maudio to the preamp.But cd transport and dac wont be in my stereo chain.

Third.I can do cd with test tones and play those tones through cd transport.Than O dont know what should I setup for output device.Should I select maudio and use loopback?And I have to start meauserement simultaneously with meaeserement in REW.

Thanks

[m-fine]

Follow the second one. Any error from the CD transport and DAC are NOT what you want to correct with EQ anyway. You are looking for room resonances and using EQ to pull them out. Besides, any error from the DAC ought to be smaller than your measurement accuracy if it is a half decent DAC.

[brucek]

Second.Output device will be maudio and I have to go from maudio to the preamp.But cd transport and dac wont be in my stereo chain.

Yeah, go with this method.......

brucek