Better EQ Through Software

Wednesday, November 29th, 2006

Recording acoustic guitar with a pickup is an extremely appealing idea. It eliminates the expense and hassle of microphones, soundproofing, and room treatment. The biggest problem is the sound quality – not usually that great in my experience. But recently I’ve run across some ideas that might make pickup recording a more useable alternative.

Over at the Acoustic Players Forum a Dutch fingerstyle player and Taylor enthusiast named Eltjo Haselhoff started a thread describing his technique for EQing various pickup systems to make them sound more like a guitar recorded using a microphone. He developed a piece of software that compares a piece of music recorded using a mic and a pickup at the same time. The software then defines settings to use with a graphic EQ to make the pickup recording sound more like the miked recording. His results are pretty impressive to many of us.

In the meantime, Doug Young has been demonstrating Har-Bal in some of our sessions together. This is a piece of software that the creator describes as the “worlds first visual mastering software.” One of the features of Har-Bal 2.2 is a quick tool to EQ one file so it resembles another tonally. I decided to experiment with Har-Bal and some pickup and microphone recordings.

I pulled out my Kathy Wingert Model E (You can see pics of it here.) This guitar has a B-Band AST 1470 soundboard transducer pickup system installed, and I’ve been told that it sounds pretty good in amplified situations. I set up a pair of EV RE16 mics in an X/Y configuration, pointing at the bridge at a 45 degree angle, and about 12″ from the guitar. I ran the mics through a John Hardy M-1 preamp, into my LynxTwo-C soundcard, and into Adobe Audition 1.5. I plugged the pickup into a Baggs Para Acoustic DI (PADI), took the XLR out and connected to Channel A of an FMR RNP preamp. This fed another channel on the LynxTwo-C, and I configured Adobe Audition to record this single channel on both sides of a stereo track.

I played a simple Hawaiian vamp and recorded both sources. I kept the recording short because I wanted to present the material as a .wav file instead of a compressed MP3 file. I normalized both files to -2 db so their peak levels match.

The pickup recording: PEQT-PUP.wav
The microphone recording: PEQT-RE16.wav

I don’t think it’s very hard to hear the difference, and I think most people would prefer the microphone recording.

Now what can Har-Bal do for us? I loaded the microphone track as a reference, then loaded the pickup track as the active file. I chose the IntuitMatch cursor and passed it over the pickup track. Har-Bal computed an EQ set that would bring the pickup closer to the tonal balance of the microphone track. The result was not identical, but much closer. And to my ear the result was pretty impressive.

The Har-Bal adjusted track: PEQT-PUP-EQ.wav

I still prefer the microphone track, but I could certainly live with the adjusted pickup track. Perhaps a little tweaking with reverb or delay might add a little of the “air” and “body” that are still missing. It certainly seems worth exploring further.

This entry was posted on Wednesday, November 29th, 2006 at 10:55 am and is filed under Audio. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.


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About the Blog

    Howdy, my name is Fran Guidry and this is my Homebrewed Music blog.

    I play Hawaiian slack key guitar and recorded my solo acoustic CD at home. Most of the recording information I find on the internet seems focused on bands, drums, multitracking, and so on but my main focus is recording solo acoustic guitar. Lately I’ve been enjoying video recording along with audio, so that shows up in the blog as well.

    I’m also a guitar nut. I love big ones and little ones, handmades and factory guitars, cheap ones and expensive ones. So I’ll be sharing the fun of exploring guitars as well, along with the challenges of amplifying acoustic guitars for live performance.

    Welcome!

Philosophy

    My recording philosophy is pragmatic, skeptical, not super critical. After all, the performance is by far the most important component of a track, and every aspect of any recording is a matter of taste.

    But I do like to know “about stuff.” Back in hifi days I learned about double blind testing. I learned that we humans can easily hear differences that don’t really exist. The more I’ve learned about our human auditory system, the more I’m skeptical of what people say they hear, especially if they claim that a particular microphone or preamp or cable has some magical property.

    I’ve only been recording since 2001, and when I started I found the usual places on the internet. I sought advice and accepted it, thought I would improve my recordings by using more expensive equipment. It didn’t work.

    Two things that did seem to lead to better recordings were experience and room treatment. Getting an appealing sound is the combination of many small details, and learning those details only comes from experience. Amd the sound of the recording space is obviously a big factor.

    I’ve only recorded seriously using digital technology, but I remember trying to record rehearsals and gigs back in analog days. I don’t have any nostalgia for analog recording and playback systems at all. I think even low end digital systems can capture marvelous recordings. So when I look at gear, I look for good specs: low noise, broad flat frequency response, wide dynamic range, low distortion. I’m not interested in colorful components, mics and preamps with a sound, I want the sound to be the sound of my guitar.

    But the last word is that I’m just learning and I hope you find something useful in my posts.