even harmonics and guitar amps

I hope we bottomed out on the even harmonics being at
2, 4, 6, 8, etc times the fundamental and the odd harmonics
being 3, 5, 7, 9 etc... It should be pretty clear,

As I understood it, the tube amplifier distortion that was
prized was due to having tons of even harmonics. If I
remember properly, triangle and ramp waves are all odd
harmonics and have a somewhat nasal (read, not mellow)
sound. Summing even harmonics result in pulse waves which
are less nasal (read, more mellow) than triangles and ramps.

Your basic clipped signal is a square wave which is a
somewhat degenerate pulse, but transistor clipping "fuzz
box" sounds are certainly going to be very close to square
waves and real guitar weenies prize their Marshall distortion
over their "fuzzface" distortion.

Bob Valentine

Hi Bob

Thanks for your input. I see you have just joined this topic (forgive
me if I missed an earlier reply from you). You make an interesting
point.

I was told I should read about the Fourier Analysis which explains
this whole even-order and odd-order harmonic process. This I am doing
as I post this message.

What is the reason even harmonics sound warmer than Odd harmonics (in
ref. to tube amplifiers). Is it because the even harmonics contain
the octaves of the fundamental which simply make the sound more
full/bigger? Is that all there is to it?

Thanks
Walter

--- In tuning@yahoogroups.com, Bob Valentine <BVAL@I...> wrote:
>
> I hope we bottomed out on the even harmonics being at
> 2, 4, 6, 8, etc times the fundamental and the odd harmonics
> being 3, 5, 7, 9 etc... It should be pretty clear,
>
> As I understood it, the tube amplifier distortion that was
> prized was due to having tons of even harmonics. If I
> remember properly, triangle and ramp waves are all odd
> harmonics and have a somewhat nasal (read, not mellow)
> sound. Summing even harmonics result in pulse waves which
> are less nasal (read, more mellow) than triangles and ramps.
>
> Your basic clipped signal is a square wave which is a
> somewhat degenerate pulse, but transistor clipping "fuzz
> box" sounds are certainly going to be very close to square
> waves and real guitar weenies prize their Marshall distortion
> over their "fuzzface" distortion.
>
> Bob Valentine

----- Original Message -----
From: "Bob Valentine" <BVAL@IIL.INTEL.COM>

> I hope we bottomed out on the even harmonics being at
> 2, 4, 6, 8, etc times the fundamental and the odd harmonics
> being 3, 5, 7, 9 etc... It should be pretty clear,
>
> As I understood it, the tube amplifier distortion that was
> prized was due to having tons of even harmonics.

I thought it was odd harmonics.

* David Beardsley
* microtonal guitar
* http://biink.com/db

David Beardsley wrote:

>> I hope we bottomed out on the even harmonics being at
>> 2, 4, 6, 8, etc times the fundamental and the odd harmonics
>> being 3, 5, 7, 9 etc... It should be pretty clear,
>>
>> As I understood it, the tube amplifier distortion that was
>> prized was due to having tons of even harmonics.
>
>I thought it was odd harmonics.

As far as I remember, it depends on the kind of tube: tetrodes produce even harmonics, and pentodes produce odd harmonics.
It all depends on the way those tubes manage the direct flow of electrons and also the reflected electrons by the screening plates.
But don't ask more, I am not a specialist in this field.

Leonardo

Leonardo Perretti wrote:

> As far as I remember, it depends on the kind of tube: tetrodes > produce even harmonics, and pentodes produce odd harmonics.
> It all depends on the way those tubes manage the direct flow of > electrons and also the reflected electrons by the screening plates.
> But don't ask more, I am not a specialist in this field.

Here's a nice article:

http://www.spectrum.ieee.org/select/0898/tube.html

Graham

>What is the reason even harmonics sound warmer than Odd harmonics (in
>ref. to tube amplifiers). Is it because the even harmonics contain
>the octaves of the fundamental which simply make the sound more
>full/bigger? Is that all there is to it?

In a sense, this is exact; even harmonics contain all octaves, and a few fifths, thirds and so on. The first "not-so-consonant" harmonic is the 14th. If you consider that high harmonics gradually diminish their intensity (at least for acoustic instruments), and, for middle-high fundamentals, to exceed the human hearing perception, you will see that adding even harmonics brings a reinforcement of the harmonics corresponding to the consonances we feel pleasant, then the "warm" sound.

On the contrary, let us consider odd harmonics.
First of all, we don't have octaves; the first harmonic (3) is a fifth (the fifth of the octave), the second (5) is a third (the third of the octave of the octave), the third (7) begins to be far from what we feel as consonant intervals, and so on.
Comparing even vs. odd, you see the difference.
The "hardness" of odd harmonics has been profited by a certain kind of music, see, for an example, the success of Marshall amplifiers in rock music, but some kinds of organ stops and other instruments (clarinet) use this feature for obtaining typical sounds.

Regards
Leonardo

--- In tuning@yahoogroups.com, Graham Breed <graham@m...> wrote:

/tuning/topicId_43050.html#43056

>> Here's a nice article:
>
> http://www.spectrum.ieee.org/select/0898/tube.html
>

***Well, this is a neat article, particularly about the guitar
stuff. I had no idea that people were still using *tubes* in guitar
amps. I guess I haven't looked inside a guitar amp of late... :)

J. Pehrson

Hi Leonardo

Thanks for the definition of a "warm" sound as a result of even
harmonics. Very well presented.

Thanks
Walter

--- In tuning@yahoogroups.com, Leonardo Perretti <dombedos@t...>
wrote:
> >What is the reason even harmonics sound warmer than Odd harmonics
(in
> >ref. to tube amplifiers). Is it because the even harmonics contain
> >the octaves of the fundamental which simply make the sound more
> >full/bigger? Is that all there is to it?
>
> In a sense, this is exact; even harmonics contain all octaves, and
a
> few fifths, thirds and so on. The first "not-so-consonant" harmonic
> is the 14th. If you consider that high harmonics gradually diminish
> their intensity (at least for acoustic instruments), and, for
> middle-high fundamentals, to exceed the human hearing perception,
you
> will see that adding even harmonics brings a reinforcement of the
> harmonics corresponding to the consonances we feel pleasant, then
the
> "warm" sound.
>
> On the contrary, let us consider odd harmonics.
> First of all, we don't have octaves; the first harmonic (3) is a
> fifth (the fifth of the octave), the second (5) is a third (the
third
> of the octave of the octave), the third (7) begins to be far from
> what we feel as consonant intervals, and so on.
> Comparing even vs. odd, you see the difference.
> The "hardness" of odd harmonics has been profited by a certain kind
> of music, see, for an example, the success of Marshall amplifiers
in
> rock music, but some kinds of organ stops and other instruments
> (clarinet) use this feature for obtaining typical sounds.
>
> Regards
> Leonardo

>I had no idea that people were still using *tubes* in guitar
> amps. I guess I haven't looked inside a guitar amp of late... :)

> J. Pehrson

Hi Joe

Tubes are "BIG TIME" these days (and in the past)when it comes to
guitar amplifiers.

See the links below for some of the "custom" builders.

http://www.matchlessamplifiers.com/match00.html
http://www.mavenpeal.com/
http://www.hoffmanamps.com/index.html
http://www.hollandamps.com/
http://www.ginelleamps.com/index.html
http://www.fuchsaudiotechnology.com/index.html
http://www.alessandro-products.com/main.html
http://www.allenamps.com/
http://home.planet.nl/~dht_rob/
http://www.edwardamp.com/

Regards
Walter

--- In tuning@yahoogroups.com, "Joseph Pehrson" <jpehrson@r...> wrote:
> --- In tuning@yahoogroups.com, Graham Breed <graham@m...> wrote:
>
> /tuning/topicId_43050.html#43056
>
> >> Here's a nice article:
> >
> > http://www.spectrum.ieee.org/select/0898/tube.html
> >
>
> ***Well, this is a neat article, particularly about the guitar
> stuff. I had no idea that people were still using *tubes* in
guitar
> amps. I guess I haven't looked inside a guitar amp of late... :)
>
> J. Pehrson

--- In tuning@yahoogroups.com, Bob Valentine <BVAL@I...>
wrote:
>
> I hope we bottomed out on the even harmonics being at
> 2, 4, 6, 8, etc times the fundamental and the odd harmonics
> being 3, 5, 7, 9 etc... It should be pretty clear,
>
> As I understood it, the tube amplifier distortion that was
> prized was due to having tons of even harmonics. If I
> remember properly, triangle and ramp waves

i think you mean triangle and square waves.

> are all odd
> harmonics and have a somewhat nasal (read, not mellow)
> sound. Summing even harmonics result in pulse waves which
> are less nasal (read, more mellow) than triangles and ramps.

ditto.

> Your basic clipped signal is a square wave which is a
> somewhat degenerate pulse, but transistor clipping "fuzz
> box" sounds are certainly going to be very close to square
> waves and real guitar weenies prize their Marshall distortion
> over their "fuzzface" distortion.
>
> Bob Valentine

not sure what your point is . . . ?

--- In tuning@yahoogroups.com, David Beardsley
<davidbeardsley@b...> wrote:
> ----- Original Message -----
> From: "Bob Valentine" <BVAL@I...>
>
> > I hope we bottomed out on the even harmonics being at
> > 2, 4, 6, 8, etc times the fundamental and the odd harmonics
> > being 3, 5, 7, 9 etc... It should be pretty clear,
> >
> > As I understood it, the tube amplifier distortion that was
> > prized was due to having tons of even harmonics.
>
> I thought it was odd harmonics.

hello from atlanta. it's the evens.

----- Original Message -----
From: "wallyesterpaulrus" <wallyesterpaulrus@yahoo.com>
To: <tuning@yahoogroups.com>
Sent: Friday, March 28, 2003 8:10 PM
Subject: [tuning] Re: even harmonics and guitar amps

> --- In tuning@yahoogroups.com, David Beardsley
> <davidbeardsley@b...> wrote:
> > ----- Original Message -----
> > From: "Bob Valentine" <BVAL@I...>
> >
> > > I hope we bottomed out on the even harmonics being at
> > > 2, 4, 6, 8, etc times the fundamental and the odd harmonics
> > > being 3, 5, 7, 9 etc... It should be pretty clear,
> > >
> > > As I understood it, the tube amplifier distortion that was
> > > prized was due to having tons of even harmonics.
> >
> > I thought it was odd harmonics.
>
> hello from atlanta. it's the evens.

I've been thinking about this today.
It's not very important to me, I just play guitar.

I do know that my tube amps sound great to me
(and apparently my audience likes them as well).
I also know I don't understand the whole odd/even harmonics debate.

The tuning list turns into the Larry King show.
"Hello Reykjavik, Iceland'

* David Beardsley
* microtonal guitar
* http://biink.com/db

--- In tuning@yahoogroups.com, David Beardsley
<davidbeardsley@b...> wrote:

> I do know that my tube amps sound great to me
> (and apparently my audience likes them as well).

likewise. i got to play through a bunch of nice tube amps this
weekend, at some cajun gigs and blues gigs and at the warrior
guitar/bass factory. tomorrow it's back home to my two tube
amps.

> I also know I don't understand the whole odd/even harmonics
>debate.

the good old fuzzbox only produces odd-order distortion products
(including harmonics, and also combinational tones).
something like a mesa-boogie rectifier gives you gops of
even-order stuff, which is why it sounds so much more "natural"
and "alive" than a fuzzbox. but i love fuzzbox distortion too!

>
> The tuning list turns into the Larry King show.
> "Hello Reykjavik, Iceland'

john de laubenfels is coming over for dinner soon!

I'm moving lists because this doesn't have much to do with tuning any more.

wallyesterpaulrus wrote:
> the good old fuzzbox only produces odd-order distortion products > (including harmonics, and also combinational tones). > something like a mesa-boogie rectifier gives you gops of > even-order stuff, which is why it sounds so much more "natural" > and "alive" than a fuzzbox. but i love fuzzbox distortion too!

What fuzzbox would that be? The oldest of note seems to be the Fuzz Face, which is described in details here:

http://www.geofex.com/Article_Folders/fuzzface/fffram.htm

and says "The voltage swing in the other direction, when the input is trying to turn the first transistor off, is not as constrained as the swing towards saturation. Fuzz Faces naturally tend to bias with only about half a volt on the collector of the first transistor, so there is a lot of room upwards. The input stage will first hit mushy saturation on one polarity of signal and then if driven hard enough, hit cutoff on the other polarity. The Fuzz Face has asymetrical[sic] clipping designed into it!"

If it has asymmetric clipping, it will give even-order harmonics. Along with pretty much anything designed for guitar distortion.

Here's a link I found along the way:

http://www.geofex.com/effxfaq/distn101.htm

which is good, and explains some things I had to work out for myself when I originally looked at this. And here's the classic pro-tube paper:

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

It says "The guess that this is white noise is due to the fact that many of the edge harmonics like the seventh and ninth are not musically related to the fundamental." which I could use to bring the subject on topic if I hadn't already given up.

Graham

I wrote:

> It says "The guess that this is white noise is due to the fact that many > of the edge harmonics like the seventh and ninth are not musically > related to the fundamental." which I could use to bring the subject on > topic if I hadn't already given up.

Oops! I forgot to change the "to" address, so I'd better bring this on topic.

If you're using a clean distortion with fine-tuned 9-limit (or higher) harmony, these components will probably be less objectionable. Along with the fact that intermodulation distortion will tend to reinforce an otonal chord, it may be that op-amp clipping is more appropriate in some microtonal contexts.

That said, I still prefer to avoid harsh distortion with chords.

Mats Oljare said once that intermodulation distortion also works with phi timbres, and tunings based on them. I did experiment with this (until then I'd been avoiding distortion, thinking it would veer towards harmonic timbres) and it sounded quite good. Although not good enough to distract me from those "classic" harmonic timbres long enough to record an example, which is why I didn't mention it before. And I don't know if it worked because of the theory, but it did work. For inharmonic timbres.

Graham

--- In tuning@yahoogroups.com, Graham Breed <graham@m...> wrote:
> I'm moving lists because this doesn't have much to do with tuning
any more.
>
> wallyesterpaulrus wrote:
> > the good old fuzzbox only produces odd-order distortion products
> > (including harmonics, and also combinational tones).
> > something like a mesa-boogie rectifier gives you gops of
> > even-order stuff, which is why it sounds so much more "natural"
> > and "alive" than a fuzzbox. but i love fuzzbox distortion too!
>
> What fuzzbox would that be?

i believe the big muff pi, and some of the heavy metal ones mentioned
in this link you posted:

> http://www.geofex.com/effxfaq/distn101.htm

> Mats Oljare said once that intermodulation distortion also works with
> phi timbres, and tunings based on them. I did experiment with this
> (until then I'd been avoiding distortion, thinking it would veer

Incorrect. In fact i said that wave shaping produces difference tones,
which isn't entirely true either. In most cases it will produce a
strong feeling of the fundamental of whatever harmonic series the
intervals happen to be part of. So if the interval played is
5/4,6/5,7/5 or whatever, the "1" of the theoretical harmonic series
(and all the other harmonics of it) will be clearly heard. As for
_non-just intervals though_ , such as 12-tet major and minor thirds,
it is far more complex and probably involves difference tones as well
as the "fundamental note" in some way.

/Mats Öljare