REW/External Measurement Signal?

[miklorsmith]

First post, sort of. I joined a while back but have been away long enough to start over. I searched but didn't find this topic . . .

I'm a music guy over HT, but have used the REW software to get my mains+subs setup dialed in on the bass, it's amazing software. I'm fairly acquainted with at least the basic functions and use it in combination with my bass EQ to killer effect.

I have a system in my garage (don't laugh, it's actually quite good) that has a Squeezebox server with a software plugin for semi-parametric EQ. This setup is quite simple - the SB goes to a Peachtree Nova, with built-in DAC, to the speaks. They're single-driver and display the rising mid-to-upper common to the breed. When corrected, they actually make decent bass.

Yesterday I brushed up on REW and got some meaningful measurements. My normal process, probably like everyone, is measure, apply corrections in the EQ, measure, etc. However, this process requires that the measurement signal passes through the EQ applying correction.

In my garage setup, the EQ is completely separated, it's 'at the source', being fed to the amp, where the measurement signal is a different amplifier input. The two never cross, so I can measure, apply some guesstimate corrections to the EQ but that's the end of it, I can't re-measure and optimize.

I'd like to use something, Audacity maybe, to generate a test signal to feed through the SB for REW to evaluate and display, somewhat similarly to what it does with a self-generated signal.

Or, as an alternative, is there some way to do something similar with Audacity or another software suite? I have a Behringer microphone and USB preamp, so ready to party!

Thanks in advance,

Mike

[JohnM]

Easiest thing for your garage system is probably to use the REW signal generator in its Pink PN mode, save the PN signal to a wave file using the button on the generator and play that back over your garage system. You can then use the REW RTA (with rectangular window and the same FFT length as you used when saving the PN signal) to adjust your Squeezebox eq plug-in live while you view the effect on the RTA.

[Wayne A. Pflughaupt]

Hi Mike,

When you say you "brushed up" on REW, that suggests to me that perhaps you have an older version. If so you should download the current version, to avail yourself of the RTA feature John mentioned, that wasn't available in previous versions. Unlike the "sweep, EQ and check" method you mentioned, the RTA (real time analyzer) generates a steady broadband pink noise tone that shows in-room response on the screen, and EQ changes to response are instantly seen in "real time" as you tweak the filters.

Here's a post with more details on the RTA function and how to use it.

Regards,
Wayne

[miklorsmith]

Awesome! I'll give that a shot guys. Should be a piece of cake (yeah, I always say that).

I'll post back when I get it done.

Thanks,

Mike