Tuesday, June 23, 2009

Comparing apEQ to Eqium 2.0

Ever since Paul Jacobson pointed Nature Recordist list readers to apEQ, I've been wanting to compare it to Eqium 2.0 . The later plug is currently sold as UNIQUEL-IZER for considerably more than ApEQ. A question posed by Justin on the Nature Recordist group prompted me into action.

To conduct an A/B test, I made a recording of the dusk interactions in a rural setting including car traffic and hubbub from a village a mile away in order to create a sample of a recording that would likely benefit from EQ.

As I've mentioned on the topic of field recording equalization before, "I never met a lower octave I did not like." I rarely use "roll-off" filtering of the type Justin is experimenting with because I feel that I can better address the most exaggerated frequencies, individually, with narrow-ish parametric EQ "curves." Its time-consuming, but I feel this technique preserves more of the fundamentals of the sound waves that are helpful in recreating useful overtones in the lower mid-range.

Here's the comparison as a 7mb QuickTime movie. The soundtrack is full resolution (16 bit/48K). Here's screen shot of the curves used.

A few observations:

(1) I'm really surprised at how differently the two EQ plugins affect the recording-- especially within the range of 80 Hz to 500 Hz. The result of attenuation made with a single apEQ "peak" curve has more impact. Even with very careful "Q" or width settings, apEQ tended
to remove a little more of the "body" and adjacent tones than I'd prefer at times. However, the difference is subtle and only shows up after a more complex curve is in effect. With a wider boost/cut range of 40 dB, its easier to use a + dB "peak" in apEQ to audibly locate an offensive tone or bandwidth than with Eqium. Recordists who like to attempt to "remove" man-made drone sounds as might like the greater expediency of apEQ. I found that I could get impressive improvement in the field recordings I experimented with as few as 5 to 8 curves. apEQ might be preferable when needing to quickly but effectively equalize a recording. I'll probably stick with Eqium when I'm trying to coax "space" out of an ambience recording, but the sound quality differences are curious and worth more experimentation for sure.

(2) The controls of apEQ are fantastic. After you create a Peak EQ curve by clicking anywhere on the master curve, you can click on one control variable in the floating box to drag-change that setting without affecting the others. This is very handy for fine tuning Q and the Gain after you find the frequency. I also like the "bypass" button for A/B comparing just one setting. I didn't find a "B" buffer option for comparing two sets of EQ's; maybe I missed this.

(3) The superimposed FFT display of apEQ is also fantastic-- I found that I referred to it a lot. (I have to open a separate FFT window when I used Eqium and this clutters the screen and is not as visually efficient.)

(4) I could not find a master gain knob in apEQ. Also, I couldn't find a global balance setting. Stereo mic pairs usly need some tweaking. Of course, both of these corrections can be achieved with other plugs and time line settings, but I missed having these basic adjustments saved with the plug setting document. Or, maybe I missing them too?

(5) I'm not sure how many bands of EQ one can create with apEQ but it seems like plenty. (One can create 99 bands with Eqium.) apEQ probably taxes the CPU more than Eqium but the preview audition mode seemed very responsive on my 2004 model 2GHz Dual G5 PowerPC Mac.

I would definitely give the free demo of apEQ a try if you are contemplating spending some money on EQ. Rob D.