Total Harmonic Distortion

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Total Harmonic Distortion

Postby Christian LeBlanc » Fri Oct 29, 2010 1:33 pm

I just finished reading a fascinating article on total harmonic distortion ("the amount of extra sound generated by the electronics in the piece of equipment itself"), and thought I'd share it here.

Now, I did a search through our archives and didn't find anything, but I'm sure we've already talked a great deal about it already under different names and situations. What I like the best about this article is how 'user-friendly' the explanation is, as he compares layers of harmonic distortion to layers of varnish. He even goes on to describe how it's useful for different types of music, be it lo-fi, techno, black metal, etc.

While I myself might not be able to hear the THD that a single piece of gear might impart, I can definitely tell when it's not there. I find home recordings are notorious for missing this bit of character (mine definitely included), and I'd recommend this article to beginners primarily, but I think it makes a good read for anyone.

Anyone here have any thoughts/comments on the article/concept?

Edit: I just noticed a helpful follow-up post in the comments section that discusses 'sonic varnish' in terms of DAWs: http://timothyshrout.wordpress.com/2010 ... c-varnish/
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Postby Cryptowen » Fri Oct 29, 2010 2:55 pm

I find the trick for getting good digital grit is to make a whole bunch of decisions that don't make sense. I don't mean just hitting the "randomize" button a whole bunch, but walking the line between total chaos & being some sort of clinical sound producing robot.
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Postby Christian LeBlanc » Fri Oct 29, 2010 3:26 pm

Understanding what rules you're breaking, in other words?

EDIT: (note to self - Friday afternoons seem to be the perfect time for wresting the coveted 'triple crown' of last post in all three forums away from Drumwaiter)
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Postby Cryptowen » Fri Oct 29, 2010 4:22 pm

^Either that, or following a set of rules that don't really follow conventional production logic, and following them for a good reason (besides that they don't follow conventional production logic).
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Postby Malcolm Boyce » Fri Oct 29, 2010 10:44 pm

I remember learning very early on the wonderful smearing quality of harmonic distortion. Bouncing tracks on analog tape machines and realizing that the more it was degraded, the "better" it sounded.

This was especially true when combining early MIDI instruments with guitars, bass and vocals. It really helped everything blend in the end.

...and of course to nitpick a little. "THD" is a measurement of harmonic distortion, but the "effect" is just harmonic distortion.
"Once again, it is NEVER the gear that makes a good record.
It just fills Forum pages..." --compasspnt

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Postby Scott DeVarenne » Sat Oct 30, 2010 2:30 am

Very interesting essay. Thanks for passing that on, Christain.
I very quickly did some pricing. I gotta say, that's a very rich signal path:

Layer 1: Vintage Telefunken U47 (tube microphone) $8,495
Layer 2: Chandler TG2 mic preamp $2,182
Layer 3: Tube Tech CL-1B Compressor $3,150
Layer 4: Cranesong HEDD converter (a touch of its Pentode processing) $3,620
INDIVIDUAL TRACK PROCESSING DURING MIXING
Layer 5: Sound Toys Decapacitator plug-in (emulates the sound of vintage consoles)
Layer 6: Tube Tech CL-1B hardware compressor
FULL MIX PROCESSING
Layer 7: API 2500 stereo bus compressor $2,545
Layer 8: Dangerous Audio BAX EQ
Layer 9: Studer A-80 1/2″ tape recorder Appr $1,000,000,000
ANALOG TO DIGITAL PROCESSING
Layer 10: Studer output stage
Layer 11: Cranesong HEDD A-D conversion (with a touch of Pentode processing)

The author acknowledges this. In his own words "Yes, the signal path I describe above costs thousands of dollars, and I don’t expect everyone to have access to that kind of gear".
He goes on to offer approaches for those of us using "consumer grade" gear.


I loved the "What about Honest Recordings?" section.

Yes, Guided By Voices is some cool shit, but I feel some of the recordings of their more brilliant works were undermined by a harsh sonic quality.

In the Comments section there is a link to this sight:
http://shunyata.com/
Am I just being cynical or does this smell a little like Audiophilia Nervosa?
http://www.audiophilia.com/features/aptest.htm
If I don't get a Shunyata approved electrician to come and rewire my studio, will all my mixes be doomed to suckage?

Also, in the Comments section there is a link to this article, which offers a purely digital approach to the concept of audio varnish:
http://timothyshrout.wordpress.com/2010 ... c-varnish/

Remember Dana Carvey as Grumpy Old Man (Vintage SNL)? I'm thinking something along the lines of "Sonic Varnish? Bah!! They should call it Sonic Tarnish! Back in my day it was consumer grade mic pre to A/D converter to hard drive, one instance of compression, and Bang, there was your mix... and we liked it."
Yeah, yea? No? I thought not. Sorry.

P.S.
I will undoubtedly apply this concept to my next recording session/mix.
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Postby Christian LeBlanc » Sat Oct 30, 2010 10:30 am

Thank you for nitpicking, Malcolm :)

Scott: you're welcome! Thanks for adding up that signal path; I think it's important that the follow-up article be read for anyone (me) who has no access to any of that professional gear.

I'll also be keeping this in mind for my future mixes, and re-evaluate my old ones; this might make me rethink (or at least experiment with) recording through my amps instead of recording direct. Previously, I considered my amps to be used only if I were performing somewhere, but now methinks I should play around a bit more.
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Postby Malcolm Boyce » Sat Oct 30, 2010 12:22 pm

For those working "in the box" it's important to remember that there are many plugins designed to add harmonic distortion as part of their function. This is usually not just a side effect of their process, but purposely added in to emulate "analog" distortion.
"Once again, it is NEVER the gear that makes a good record.
It just fills Forum pages..." --compasspnt

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