2nd order vs 3rd order Harmonics?

[Alpha579]

Hi all,
I was just thinking about this, and im sure u have debated about this before, but my search came up with nothing in the archives...
  Alot of pedal builders promote an "Overdrive rich in 2nd order harmonics", and believe that 3rd order harmonics sound harsh and unrelated. These people also put down the early pedal using BJT's for fuzz, saying they sound harsh and 'fuzzy'(be that good or bad...). These early pedals are (i think) the ones that produced mainly even order harmonics, due to their assymetrical clipping. Also, alot of people believ that tubes produce only even harmonics. Not neccesarily true. the preamp tubes of vintage valve amps mainly contribute 2nd order harmonics (not always, but quite often), most of these amps (apart from class a'ers) used pushpull output stages, which produce more odd harmonics due to thier symmetry.
  Now i do not claim to be very knowledgeable in this area, so please correct me if any of the above is incorrect...
  When designing pedals/amps, do u prefer the sound of even or odd harmonics?

[Alpha579]

#b#u#m#p#

[Jered]

Let your ears decide, if it sounds good, then what else matters. I think this is quite a subjective topic, no right or wrong answer.
 Jered

[petemoore]

A real interesting subject, there are archives IIRC about ordered harmonics.
 However, I, like you don't understand it completely.
 I can visualize the waveforms assymetry, or symmetry, and the diodes or transistors clipping threshold on the neg and pos swing...and all the varied permutations as such.
 The vocabulary of it, and specific scenarios is what I don't particularly have a handle on.
 Even so, I believe I've been through it, beside it, over/under it, and around it...I just couldn't tell you about any of it without creating language.
 2nd order...3rd order...from what I'm trying to gather [so correct me pleez] third order is mathmatically more complex and will cause peaks in many more spots on a waveform, making the resulting output less related to the original tone...the more complex the input [say playing chords as opposed to single notes] the exponentially more complex the output becomes...to the point of sounding less musical [clear pitches] and more like noise.
 I would like to type more, about 2nd order harmonics, I think that's what I'm getting from the OA feedback loop clipper, [vocab?], and tends to find a particular harmonic content when allowed to sustain...
 I always kind of wondered about this stuff, dont really have the vocabulary definitions straight enough to type confidently about it yet though..

[Mark Hammer]

I would not summarily dismiss it as fluff.  At the same time, it is worth pointing out that everything people tell you about how good emphasis on these harmonics or those ones sounds is based on *listening*.  

So, uh, what exactly do they listen to?  Well, for starters, it goes to an amp, whose tone controls and gain settings are set up in a manner undisclosed to the casual observer, and then, depending on the type of amp, it goes through a transformer, and finally to a speaker or set of speakers, all of whom play a role in reconfiguring the balance of harmonics.  Personally, I find in many instances that the inherent lowpass filtering of sluggish 12" speaker cones does a whole lot to the harmonic balance.

So, again, I'm not going to dismiss the possibility, but I do wish to point out that there is just so much going on in between the pedal and your ears (only a small portion of which I outlined here), it ends up being a bit like asking whether sharper thresher blades make a better pie.

[toneman]

U can think of it as "even" and "odd" harmonics.
20+yr ago, in a galaxy far far away, i built
2 projects from the first Anderton book.
1 was a 4049type, *tube* distortion;
the other was the "standard" opamp fuzz.
I called them the "EVEN" and "ODD" Boxes.
They were pwred by plus/minus9VDC.
Now, i have *real* tubes!!
keepinthefuzzalive
tone

[WGTP]

The Blackstone Appliances' site has a nice discussion about harmonics and and a cool pic of the harmonics generated by a Tube Screamer, a 50w. Marshall and their device.  

Also, Geo has a nice article, Distortion 101.  

AMZ has good info too.

IMHO it takes both kinds for sonic bliss.  Too many even's and it gets too wooly, too many odds and it gets too thin or harsh.  After the initial attack, it's primaily the 2nd and 3rd that are being distortioned by your device.  It's about the combination of symmetry, ADSR envelope, Freq response, mojo, etc.  

[Ansil]

http://sansamp.com/Menu.html#warp


they have an interesting pic   a graphical display

[WGTP]

The Warp Control at AMZ is a good way to vary the even/odd ordered harmonic content of a distortion.  Varying bias or switching diodes also works.  

[Ge_Whiz]

Back in the early days of amplified music, dissonance was considered 'unmusical' and therefore a bad thing.

When you work through a series of both even and odd harmonics, all the harmonics are musically related to the fundamental note until you reach the seventh, which is not and therefore sounds dissonant. Thereafter, all the dissonant notes are always among the 'odd' harmonics. 'Even' harmonics are always consonant and hence 'musical'.

Hard clipping contains all harmonics and sounds 'fuzzy'. When bipolar transistors cause clipping, they produce both odd and even harmonics. Field effect transistors produce primarily even harmonics and sound more like the classical 'overdrive'.

[Paul Marossy]

Read this: http://www.dwfearn.com/tvst1.htm

It should give you a better idea about 2nd harmonic vs. 3rd harmonic.

But, like it has been said, it is a matter of personal preference. I think it is the higher order odd harmonics that most everyone would agree sound bad.

[PaulC]

To my ears a nice strong sym clipping gives a clear/strong/crisp sound.  It's great for playing full chords - notes come out with  clarity.  A strong even ordered/asym clipping has a fullness and body to it, but really puts some mud into chords.  I like it because it has that "woosh" attack sound that feels like some air is moving.  For myself the best sounds comes from a good strong sym clipping followed behind by a mild asym clip to thicken things up just a touch.    PaulC

[WGTP]

AMZ's article showing the harmonics from a guitar, shows that the 1, 2 and 3 harmonics are primary what is heard after the initial attack.  Each successive stage of distortion after the first is generating harmonics of the harmonics produced by the 1st stage.  The blend or balance of the harmonics at any point in the "note" is what determines the tone.  Different pickups at different places along the guitar string, with different body resonance, etc. determine this balance, in addition to the distortion.  The speaker EQ and resonance also effect this balance.  After a long sustain, about the only thing left is the fundamental and the harmonics produced by the distortion circuits.  Check out the fundamentals of physics stuff about harmonics, that's where its at.  Sinasoidal motion.   Man it's been a long time since we did the experiment with the string in lab class.  A defining moment until the quart jar of Mercury was dropped and we spent the rest of the time "herding" it back together, little realizing we were poisoning ourselves.   :roll: