REW Measurement in Stereo?

[bmx]

Is it possible to measure with REW in Stereo?

REW BETA 22 has support for the miniDSP EARS, which is a product for measuring headphones. Additionally it says that it can be useful for creating binaural recordings. So, it does seem suitable for measurements.

I have often wished to figure out how to measure in stereo. For instance: to experiment with acoustic panel placement to "Symmetricize" an Asymmetrical room. But also for tuning DIY studio gear like EQ's and mic preamps for stereo matching.

Is it fair to ask for this feature request?

And if not, how does one check for listening room Symmetry?

Many thanks!
BMX

 

[Wayne A. Pflughaupt]

Stereo requires two discrete signals. For example, a keyboard in one channel and saxophone in the other. Or maybe two different saxophones, one played in each channel. The same keyboard (or sax) in both channels is obviously not stereo but a split mono signal.

Of course, any split mono signal can be converted to stereo by adding a slight time delay to one channel. Then you now have two discrete signals.

How exactly is “stereo” accomplished with a mono test signal, such as the sweep sine wave tone that REW generates? Well, as mentioned you could split the output and add a slight delay to one of the signals.

It should be obvious that the resulting stereo signal would wreck havoc on any in-room measurements using the sine-wave sweep: At any given moment, the two speakers would be reproducing different frequencies. What kind of useful frequency response measurement are you going to get from that?

Of course, the situation is different with measurements for headphones, as the two signals would be fully isolated. But in that case the “stereo” time delay is irrelevant. The end result will be no different than if a split mono signal were used. Or of you ran a mono measurement in one channel, followed by one on the second channel after the first was finished.

It should be obvious that you can't achieve "stereo matching" unless both channels are a perfect match. You can't hope to accomplish that with discrete (read mismatched) test signals.

If I’ve misunderstood your objectives, please elaborate!

Regards,
Wayne

 

[bmx]

Hi Wayne,
Thank you for your response. I think that makes sense. Maybe my question is wrong. I want to output a mono test signal, but measure with the miniDSP EARS. I'm thinking that the two graphs would allow me to treat my asymmetrical room for a more symmetrical response.

For Stereo matching outboard gear, I do use a mono signal. I run two passes, each time swapping cables. Then I compare them in the "Overlays" window" It never goes into the acoustical domain. I guess what I would like to do is have Right/Left measurement signal in the same window. I'm a home recording enthusiast, so my wants may just be out in left field.

Best wishes ,
Ethan