Okay, I'm a pretty low-tech guy when it comes to parametric equalization. I don't generally have a good ear for very specific frequencies, so I tend to grab the whole row of slides and manipulate them as if a spline, correcting the wide areas that sound like they need correcting, playing with it until it sounds right.

Now, with the empeg, I'm obviously unable to do that, what with the lack of physical slides and all, so I'm forced to actually try to do it in what's probably the ``right'' way. So does anyone have any suggestions as to a good objective paradigm for setting EQs?

It is extraordinarily difficult to set any equalizer just by listening. . . you may be able to get broad ranges of frequencies balanced, but that's it. What I do is play pink noise (ripped to mp3) from my Rio Car, then use RTA (real-time analyzer) software on my laptop with an external microphone to evaluate frequency response. I can visually see what frequency ranges need correction, and the beauty of a parametric equalizer is that I can adjust the freq, boost/cut, and Q. I don't own a calibrated microphone, so what I do is get a baseline freq vs. amplitude graph from a pair of reference speakers in my apartment first. The result is absolutely superb, but obviously not as good as my reference system. This method will work with any car system, but preferably if you have some quality aftermarket components installed. Alternatively, you can just take your system to a high-end roadshop and ask if you can play with their real time analyzer equipment (might cost you $$$, but worth it). Good luck!

It is extraordinarily difficult to set any equalizer just by listening. . .

It's not difficult, just time-consuming. It took me about a month of fiddling to get it close to where I wanted it, then much longer to fine-tune it. The trick is to make small changes and live with them for a while before moving on to other changes.

But I agree that a real time analysis would be much faster and much more accurate. I'm interested in knowing more details of how you went about doing this, because I've always wanted to try it. Is the RTA software freeware, is it something I can download?

As Tony says, make small changes at a time. Your aural memory is very short but you will quickly find out what you don't like to hear as your ears will get tired. Making lots of change quickly can confuse you too. People sill 'golden' ears can quickly identify what they want to hear and know how to tweak it. For the rest of us, just make gradual changes.

RTA shows you what you're changing but doesn't necessarily give you an indication of whether you will like that change. A 'flat' audio response is also pretty strange sounding.

Didn't someone have an excellent link to EQ basics?

I searched around and found about 5 package for Windows. The one I found that was about the best was a package called ST-X. Trouble is, I can't find the URL for the download site any more. I do have the install package still. I have had pretty good sucess using it in the car to flatten out the spectrum on a playback of an uncompressed (WAV) uncorrelated Pink noise track, but this was with an uncalibrated mike; you have to accept that this is only really a starting point.

I did start to look at how the loudness on the empeg worked using this, but didn't really have much time to take it very far.

What RTA software do you use?

What I do is play pink noise (ripped to mp3) from my Rio Car, then use RTA (real-time analyzer) software on my laptop with an external microphone to evaluate frequency response. I can visually see what frequency ranges need correction, and the beauty of a parametric equalizer is that I can adjust the freq, boost/cut, and Q.

This is EXACTLY what I want to do...I have a laptop, but I don't have a good reference system in my apartment to calibrate a mike with...maybe if I used your exact microphone and software and just used your graph, I could duplicate this technique?

What microphone/software do you use?

I'm using SpectraLab, but unfortunately, this is a commercial package and it costs money (or you can just use the free trial version)...I haven't found any freeware programs, but I'm sure they exist...maybe not. :-) I'm using the Radio Shack analog SPL meter which has an RCA output, going into the line-in jack on my laptop. Unfortunately, the signal-to-noise ratio is horrendous, and I'm only getting maybe 20dB of headroom above the noise floor...however, this solution is more accurate than just using your ears.

As far as whether or not you want a perfectly flat freq vs. amplitude, that's up to you...ideally, we'd match the freq response of the studio recording/mixing equipment, but different studios use different setups... perhaps some of you are capable of adjusting your eq's to compensate for aberrations that you hear...I am not. I can tell generally what range needs to be boost/cut, but the exact frequency range is difficult to pinpoint. This frustrated me so badly that I finally got a makeshift RTA system setup - in general, my adjustments were on the right track, but I could never match the improvement in SQ that I could using the RTA. In reality, I wasn't calibrating my car system to a flat response, but rather, to a home system that I know sounds good.

But the bottom line is that if whatever you have sounds good to you, then don't worry about it. NONE of my friends can tell the difference between a high-end setup and a mediocre setup, although they can "feel" differences in bass...maybe. If you're not anal retentive about sound reproduction (like me), then I say just enjoy the music. :-)

Valsalva