Jump to content

Odd and Even Order harmonics


murky69nz

Recommended Posts

  • Members

Yo yo

 

Been looking at some amp reviews, and have noticed that some people tend to go on about odd and even order harmonics. One guy said that the Matchless DC 30 being class A ment you didn't have to hear odd order harmonics.

 

I understand that this is generally the harmonic distortion that you hear when you crank, but can anyone shed some light as to what amps fall into each category, and better still, has anyone got clips highlighting the difference?

 

Thanks!

Link to comment
Share on other sites

  • Members

 

Yo yo


Been looking at some amp reviews, and have noticed that some people tend to go on about odd and even order harmonics. One guy said that the Matchless DC 30 being class A ment you didn't have to hear odd order harmonics.


I understand that this is generally the harmonic distortion that you hear when you crank, but can anyone shed some light as to what amps fall into each category, and better still, has anyone got clips highlighting the difference?


Thanks!

 

 

hm.. that'd be difficult, as anything generating sound with a string is creating those harmonics anyhow, IIRC. tube amps are know for ACCENTUATING odd order hamonics... but they'd still be there.

 

i wouldn't get hung up on amp classes, honestly... you have to listen to them, and a lot of companies will throw 'class a' as a marketing term anyhow and not substantiate it. most preamps, to my knowledge, are class A anyhow by virtue of design-- so they're not lying.. but inasfar as i know, real class a amps are fairly rare, and not necessarily practical.

Link to comment
Share on other sites

  • Members

 

hm.. that'd be difficult, as anything generating sound with a string is creating those harmonics anyhow, IIRC. tube amps are know for ACCENTUATING even order hamonics... but they'd still be there.


i wouldn't get hung up on amp classes, honestly... you have to listen to them, and a lot of companies will throw 'class a' as a marketing term anyhow and not substantiate it. most preamps, to my knowledge, are class A anyhow by virtue of design-- so they're not lying.. but inasfar as i know, real class a amps are fairly rare, and not necessarily practical.

 

 

you're missing the point.

 

the deal is for a single test frequency, which additional frequencies are generated not that they are already present.

 

for a 1kHz sine wave, if the added frequencies are 2k, 4k, 6k, 8k... then even order harmonics are generated and if 3k, 5k, 7k, 9k... are generated then odd order harmonics are generated.

 

yes, the amp design matters.

Link to comment
Share on other sites

  • Members

my limited understanding of harmonics is this- odds are percieved of as 'pleasant and soft', evens are considered 'angular and unpleasant' due to the ways in which the waveform of a note 'aligns' with itself-- that being that any plucked note will have the fundamental-- plus, as it vibrates, have proportional amounts of other notes within it as it moves. both tube and solid state amps reproduce both equally until they start cutting the 'edges' of the waveform (i.e. distorting).. when clipping occurs, it become painfully obvious, as the solid state clips and makes the evens stick out more, and it get more harsh. tubes clip softly, and when it does-- it's naturally accentuated odd order harmonics are amplified, sounding warmer.

 

it's actually pretty interesting stuff as you look at 'sinusoidal patterns' of strings and see how it's all based on proportions. i don't fully understand its implications as it's math of a higher order than i can process..

Link to comment
Share on other sites

  • Members

 

you're missing the point.


the deal is for a single test frequency, which additional frequencies are generated not that they are already present.


for a 1kHz sine wave, if the added frequencies are 2k, 4k, 6k, 8k... then even order harmonics are generated and if 3k, 5k, 7k, 9k... are generated then odd order harmonics are generated.


yes, the amp design matters.

 

 

i'm not sure what point i'm missing? i know the amp design matters-- but my point was that it isn't just the CLASS of the amp that matters in terms of sound-- and that marketing terms can really blur the picture.

Link to comment
Share on other sites

  • Members

 

the deal is for a single test frequency, which additional frequencies are generated not that they are already present.


for a 1kHz sine wave, if the added frequencies are 2k, 4k, 6k, 8k... .

 

 

I'm not sure that the 6K would qualify as an even order harmonic - I think it has to be a whole octave above the fundamental to qualify as 'even order'....here's an explanation someone gave me in the lesson loft forum:

 

 

Originally Posted by Leo Plumtree

Only 'even order' harmonics with only binary factors produce octaves. 6:1 is two octaves plus a pure fifth, for example.


1:1 unison

2:1 octave

3:1 octave and pure fifth

4:1 two octaves

5:1 two octaves plus 5-limit Just major third

6:1 two octaves plus pure fifth

7:1 two octaves plus septimal m7

8:1 three octaves

9:1 three octaves plus Just major second

10:1 three octaves plus 5-limit Just major third

11:1 three octaves plus...um, something between a 4th and aug 4th

12:1 three octaves plus a pure fifth

 

Link to comment
Share on other sites

  • Members

 

I'm not sure that the 6K would qualify as an even order harmonic - I think it has to be a whole octave above the fundamental to qualify as 'even order'....here's an explanation someone gave me in the lesson loft forum:

 

 

IIRC, an octave is typically 2x the frequency-- i.e. 1000hz octave up is 2000, an octave down is 500hz.

Link to comment
Share on other sites

  • Members

If you take a sine wave and keep adding odd harmonics to it it looks more and more like a square wave.

If you keep adding even harmonics to it it approaches a triangle wave.

 

Go listen to a pure square wave and a pure triangle wave and see which you prefer. ;)

 

 

 

 

 

 

 

 

 

 

 

 

Or just go and try out the amps and see which you like the sound of. :poke:

Link to comment
Share on other sites

  • Members

This is a classic case of "class" warfare perpetrated by misguided liberal socialists trying to take over the country. Oh, wait...this damned political election season crap is getting to me. ;)

 

Here are the facts:

 

Even-order harmonics generated in the output stage are canceled out in push-pull output stages. This does *not* mean that even-order harmonics generated in the previous stages are canceled - they are passed right through, so a push-pull amplifier will have both even and odd order harmonics, just less even-order harmonics than a single-ended amplifier.

 

Amplifier class has nothing to do with it - a class A or class AB push-pull stage will both cancel the even-order harmonics. In fact, it can be argued that a true class A push-pull output stage will actually cancel *more* even-order harmonics than a class-AB amp because they are likely more symmetrically balanced.

 

The real answer is that a *single-ended* output stage will not cancel even-order harmonics generated in the output stage, while a *push-pull* output stage will cancel them. Again, only the harmonics generated in the output stage will be canceled. Therefore, the output stage distortion generated by a single-ended amp will be predominantly even-order, while the output stage distortion generated by a push-pull amp will be predominantly odd-order.

 

So, if by your definition, even harmonics = good, odd harmonics = bad, then you'd best only play single-ended amps, like Fender Champs, and throw away all your push-pull amps, like Marshalls, Matchless, higher-power Fenders, and almost every other amp over 10W ever made because they cancel your even harmonics in their output stages.

 

The problem here is that people don't know what they are talking about (even amp builders). They think "single-ended" and "class A" are the same thing (they aren't), and then extrapolate that to: "Matchless claims to be class A, so it must not cancel even-order harmonics" (which is isn't, it is cathode-biased, not class A, and they are not the same thing).

 

Listen to the *amps*, not to the misguided "experts" and reviewers who don't have a clue...

 

Randall Aiken

Link to comment
Share on other sites

  • Members

The "Class" thing is just about how the amp processes the power coming into the amp, how the power valves work.

 

"Class A, B, D etc." is just a label, NOT a rank. A Class A amp is not better than Class B etc.

 

In a rough nutshell, Class A amps run the power 100% of the time. Class A/B amps run two valves in tandem, with the signal split so one valve amplifies one half of the signal, and another valve amplifies the other- the "push-pull" you hear about.

 

 

"Class A" doesn't mean that it's a better amp than "Class B", not at all.

 

In fact, the bad thing about "Class A" is that it is very inefficient about handling power. Amplifiers used for radio frequency carriers etc. are "Class H" I think- very extremely efficient.

 

Of course they'd probably sound crap for guitar ;) .

Link to comment
Share on other sites

  • Members

This is a classic case of "class" warfare perpetrated by misguided liberal socialists trying to take over the country. Oh, wait...this damned political election season crap is getting to me.
;)

Here are the facts:


Even-order harmonics generated in the output stage are canceled out in push-pull output stages. This does *not* mean that even-order harmonics generated in the previous stages are canceled - they are passed right through, so a push-pull amplifier will have both even and odd order harmonics, just less even-order harmonics than a single-ended amplifier.


Amplifier class has nothing to do with it - a class A or class AB push-pull stage will both cancel the even-order harmonics. In fact, it can be argued that a true class A push-pull output stage will actually cancel *more* even-order harmonics than a class-AB amp because they are likely more symmetrically balanced.


The real answer is that a *single-ended* output stage will not cancel even-order harmonics generated in the output stage, while a *push-pull* output stage will cancel them. Again, only the harmonics generated in the output stage will be canceled. Therefore, the output stage distortion generated by a single-ended amp will be predominantly even-order, while the output stage distortion generated by a push-pull amp will be predominantly odd-order.


So, if by your definition, even harmonics = good, odd harmonics = bad, then you'd best only play single-ended amps, like Fender Champs, and throw away all your push-pull amps, like Marshalls, Matchless, higher-power Fenders, and almost every other amp over 10W ever made because they cancel your even harmonics in their output stages.


The problem here is that people don't know what they are talking about (even amp builders). They think "single-ended" and "class A" are the same thing (they aren't), and then extrapolate that to: "Matchless claims to be class A, so it must not cancel even-order harmonics" (which is isn't, it is cathode-biased, not class A, and they are not the same thing).


Listen to the *amps*, not to the misguided "experts" and reviewers who don't have a clue...


Randall Aiken

 

Great info.

 

Can you talk a little about the theory that some "old" amps sound "sweeter" because their output tubes are NOT matched and biased perfectly, thus lending to them not completely attenuating some harmonics as much as if they were perfectly biased and matched?

 

-W

Link to comment
Share on other sites

  • Members

 

IIRC, an octave is typically 2x the frequency-- i.e. 1000hz octave up is 2000, an octave down is 500hz.

 

 

Well yes, one octave up is two times the frequency, but the next octave up is four times the fundamental frequency ( 2 x 2, which gives you the second even order harmonic) not what you'd expect really, it's a little bit like compound interest.

 

+1 to the comments about using your ears when you're deciding which amp you want to buy.

Link to comment
Share on other sites

  • Members

WOMAN:

Oh, there you go bringing class into it again.

DENNIS:

That's what it's all about. If only people would hear of--

ARTHUR:

Please! Please, good people. I am in haste. Who lives in that castle?

WOMAN:

No one lives there.

ARTHUR:

Then who is your lord?

WOMAN:

We don't have a lord.

ARTHUR:

What?

DENNIS:

I told you. We're an anarcho-syndicalist commune. We take it in turns to act as a sort of executive officer for the week,...

ARTHUR:

Yes.

DENNIS:

...but all the decisions of that officer have to be ratified at a special bi-weekly meeting...

 

ARTHUR:

Yes, I see.

DENNIS:

...by a simple majority in the case of purely internal affairs,...

ARTHUR:

Be quiet!

DENNIS:

...but by a two-thirds majority in the case of more major--

ARTHUR:

Be quiet! I order you to be quiet!

 

WOMAN:

Order, eh? Who does he think he is? Heh.

ARTHUR:

I am your king!

WOMAN:

Well, I didn't vote for you.

ARTHUR:

You don't vote for kings.

WOMAN:

Well, how did you become King, then?

ARTHUR:

The Lady of the Lake,...

[angels sing]

...her arm clad in the purest shimmering samite, held aloft Excalibur from the bosom of the water signifying by Divine Providence that I, Arthur, was to carry Excalibur.

[singing stops]

That is why I am your king!

DENNIS:

Listen. Strange women lying in ponds distributing swords is no basis for a system of government. Supreme executive power derives from a mandate from the masses, not from some farcical aquatic ceremony.

ARTHUR:

Be quiet!

DENNIS:

Well, but you can't expect to wield supreme executive power just 'cause some watery tart threw a sword at you!

ARTHUR:

Shut up!

DENNIS:

I mean, if I went 'round saying I was an emperor just because some moistened bint had lobbed a scimitar at me, they'd put me away!

ARTHUR:

Shut up, will you? Shut up!

DENNIS:

Ah, now we see the violence inherent in the system.

ARTHUR:

Shut up!

DENNIS:

Oh! Come and see the violence inherent in the system! Help! Help! I'm being repressed!

ARTHUR:

Bloody peasant!

 

DENNIS:

Oh, what a give-away. Did you hear that? Did you hear that, eh? That's what I'm on about. Did you see him repressing me? You saw it, didn't you?

Link to comment
Share on other sites

  • Members

This is a classic case of "class" warfare perpetrated by misguided liberal socialists trying to take over the country. Oh, wait...this damned political election season crap is getting to me.
;)

Here are the facts:


Even-order harmonics generated in the output stage are canceled out in push-pull output stages. This does *not* mean that even-order harmonics generated in the previous stages are canceled - they are passed right through, so a push-pull amplifier will have both even and odd order harmonics, just less even-order harmonics than a single-ended amplifier.


Amplifier class has nothing to do with it - a class A or class AB push-pull stage will both cancel the even-order harmonics. In fact, it can be argued that a true class A push-pull output stage will actually cancel *more* even-order harmonics than a class-AB amp because they are likely more symmetrically balanced.


The real answer is that a *single-ended* output stage will not cancel even-order harmonics generated in the output stage, while a *push-pull* output stage will cancel them. Again, only the harmonics generated in the output stage will be canceled. Therefore, the output stage distortion generated by a single-ended amp will be predominantly even-order, while the output stage distortion generated by a push-pull amp will be predominantly odd-order.


So, if by your definition, even harmonics = good, odd harmonics = bad, then you'd best only play single-ended amps, like Fender Champs, and throw away all your push-pull amps, like Marshalls, Matchless, higher-power Fenders, and almost every other amp over 10W ever made because they cancel your even harmonics in their output stages.


The problem here is that people don't know what they are talking about (even amp builders). They think "single-ended" and "class A" are the same thing (they aren't), and then extrapolate that to: "Matchless claims to be class A, so it must not cancel even-order harmonics" (which is isn't, it is cathode-biased, not class A, and they are not the same thing).


Listen to the *amps*, not to the misguided "experts" and reviewers who don't have a clue...


Randall Aiken

 

Thanks for stopping by Randall, I always learn something when you post here.

 

:thu:

Link to comment
Share on other sites

  • Members

This is a classic case of "class" warfare perpetrated by misguided liberal socialists trying to take over the country. Oh, wait...this damned political election season crap is getting to me.
;)

Here are the facts:


Even-order harmonics generated in the output stage are canceled out in push-pull output stages. This does *not* mean that even-order harmonics generated in the previous stages are canceled - they are passed right through, so a push-pull amplifier will have both even and odd order harmonics, just less even-order harmonics than a single-ended amplifier.


Amplifier class has nothing to do with it - a class A or class AB push-pull stage will both cancel the even-order harmonics. In fact, it can be argued that a true class A push-pull output stage will actually cancel *more* even-order harmonics than a class-AB amp because they are likely more symmetrically balanced.


The real answer is that a *single-ended* output stage will not cancel even-order harmonics generated in the output stage, while a *push-pull* output stage will cancel them. Again, only the harmonics generated in the output stage will be canceled. Therefore, the output stage distortion generated by a single-ended amp will be predominantly even-order, while the output stage distortion generated by a push-pull amp will be predominantly odd-order.


So, if by your definition, even harmonics = good, odd harmonics = bad, then you'd best only play single-ended amps, like Fender Champs, and throw away all your push-pull amps, like Marshalls, Matchless, higher-power Fenders, and almost every other amp over 10W ever made because they cancel your even harmonics in their output stages.


The problem here is that people don't know what they are talking about (even amp builders). They think "single-ended" and "class A" are the same thing (they aren't), and then extrapolate that to: "Matchless claims to be class A, so it must not cancel even-order harmonics" (which is isn't, it is cathode-biased, not class A, and they are not the same thing).


Listen to the *amps*, not to the misguided "experts" and reviewers who don't have a clue...


Randall Aiken

 

See, I saw it as downward class warfare, trying to tell us those even harmonics were purer and more deserving of amplification than odd harmonics. :p

 

Thanks for the info man. :thu:

Link to comment
Share on other sites

  • Members

hehehe.... people think they want even order harms even though they dont know what they are.

 

even harms are very smooooooth and soft. Very... blues... oldies... fender champ cranked lulz.

 

odd harms are gritty, spikey, a metalhead's dream.

 

most guys who go on about odd vs even are dentists anyway.

 

Oh, and thankyou Mr. Aiken for the fill in, you're always amazing to read. I love your site. Its like a bible to me hahaha :):):)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...