REW smoothing functions and settings

[Bigdaddy999]

In trying to get myself up the learning curve on BFD and REW, I ended up doing some measurements that included application of a 1/1 smoothing function to the resulting curves. Got some wonderfully smooth response curves of course, but they also sounded pretty good.

after bfd.jpg




But it's been suggested by brucek that I shouldn't have applied that 1/1 smoothing function when setting my BFD filters. So a couple of questions about REW.

Can anyone describe how or "where" REW applies those curves? Does it affect the actual measurement data on the input side? Or is it simply applied to the measured data after receipt, but BEFORE the filtering algorithms?

I'm guessing its between measurement and filter application since I can change the smoothing for the curve and then get different filter suggestions and graphs after the measurement data is collected.

What's the optimal smoothing setting to use for Sub eq? 1/3? 1/6?

Thanks!

[Otto]

You're right -- it's after the measurement, basically just an algorithm applied to the measured data.

I don't think you should use any smoothing for sub EQ. Just use the raw data, allow REW to apply filters and them assign those to your BFD. Only use smoothing for your own viewing after filtering and remeasuring and for higher frequency measurements (most of us don't even measure higher frequencies because we're not going to EQ them, the meters aren't accurate and the reflections in the room make the measurement very erratic).

I don't use smoothing much at all. I just go with the raw data.

[brucek]

Read through this thread and you will see why smoothing is such a bad idea at subwoofer frequencies. Turn the smoothing to none before creating REW filters or the filters won't match the room modes properly. You may get a smooth looking frequency response but if you examine the waterfalls you may not like what you see.

brucek