Topic: Need help with EQ and/or HPF in Audacity (samples linked in)

[terabyte23]

Hello,

I don't really know what I'm doing, but I'm having a lot of fun :-)  I taped a couple of great shows recently on my new R-09.  One of them has very boomy low end that I would like to reduce in post-processing.  I have been experimenting with Audacity.  My source files are 24/44.1 WAV.  So far I have tried this:

Import to Audacity WAV > Select 30 sec portion > Normalize to 0db > HPF @ 100Hz > Amplify
Import to Audacity WAV > Select 30 sec portion > Normalize to 0db > Apply EQ curve > Amplify

I read that often the really boomy parts are somewhere within 100-180Hz.  If I apply an HPF of 180Hz it seems like it will remove too much info, but 100Hz still leaves some boominess.  So, I tried making my own EQ curve to keep some of the low-end and cut out a bit more above 100Hz (see screenshot of curve in the zip file linked below).  But I don't know if the curve I made is appropriate.

I think both of these 30-sec clips sound better than the raw file, but I'm guessing I can improve upon them.  So what tricks can I use to achieve even better results?

Included in the 2.9MB zip file: raw.mp3, eq1.mp3, hpf100.mp3, eq.png (mp3's are 256 kbit, exported from Audacity).
http://www.mediafire.com/?vdshajkmcto (edit - fixed download link)

[easy jim]

I have not checked out your clip, but I do have a couple suggestions from just reading your post.

'Normalize' (I assume you mean rms normalization) and 'amplify' are similar processes to boost your levels to maximize the loudness of your source to digital full scale (dBFS).  I would choose one or the other, preferrable only 'amplify,' if we're talking about a 2 track audience recording from microphones; and, make it your last step.

So, I would do it more like this...

Import -> Apply EQ curve or HPF -> Amplify (to 0 dBFS, or -0.2 dBFS)

Boominess may live in the ~ 60-250 Hz range, but it is usually enough with room recordings to simply eliminate the low-end rumble/mud that resides below 60 Hz.  If the room in which you recorded has resonance issues with bass frequencies above 80 Hz or so, you're probably going to be better off isolating the frequency or frequencies that are resonant and then reducing them with a notch filter.