Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

How do i create second harmonic distortion?
How do i create second harmonic distortion?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 5th November 2017, 12:17 AM   #1
filthyone is offline filthyone
diyAudio Member
Join Date: Oct 2015
Question How do i create second harmonic distortion?

Hi everyone,
as the title suggests, i want to create (on purpose) second harmonic distortion, preferably on a line signal level.

What would be an easy way to accomplish this? I would also very much like to be able to control the amount of the effect (the percentage of the 2nd harmonic).

I thought of using something like a misbiased emitter follower or something similar. Can anyone think of an easier way to do it?

The reason for this weird quest, is that i would like to "study" the effects of 2nd harmonic distortion on real music, to listen and learn what it sounds like, and hopefully understand why some people kind of like it, or at least don't get bothered by it (choob lovers etc...).

Also, could this be done in audacity? (i'm a little lazy)

Thanks very much for any info.
  Reply With Quote
Old 5th November 2017, 01:22 AM   #2
PeteMcK is offline PeteMcK
diyAudio Member
Join Date: Feb 2002
Location: Western Sydney
maybe worth a read:
Soft Clipping
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 5th November 2017, 01:51 AM   #3
filthyone is offline filthyone
diyAudio Member
Join Date: Oct 2015
Originally Posted by PeteMcK View Post
maybe worth a read:
Soft Clipping
I have read this article, but soft clippers produce predominantly odd harmonics. Are you suggesting a single diode soft clipper?
  Reply With Quote
Old 5th November 2017, 02:16 AM   #4
JMFahey is offline JMFahey  Argentina
diyAudio Member
JMFahey's Avatar
Join Date: Mar 2009
Location: Buenos Aires - Argentina
Symmetrical clippers produce mainly odd harmonics.
Unsymmetrical clippers produced mainly even harmonics.
Sharp clipping produces high order harmonics.
Soft/rounded clipping or curve nonlinearity produce lower order harmonics.

So in a nutshell, you will not produce just second harmonic and nothing else, but with careful selection of parameters you can produce relatively soft and "musical" lower order even harmonics.

That´s the generic recipe, now you will have to shake your lazyness , and read and experiment a lot
Design/make/service musical stuff in Buenos Aires, Argentina, since 1969.
  Reply With Quote
Old 5th November 2017, 03:51 AM   #5
bwaslo is offline bwaslo  United States
Old guy with soldering iron
diyAudio Member
bwaslo's Avatar
Join Date: May 2006
Location: Portland, Oregon!
How do i create second harmonic distortion?
A JFET grounded source stage that has no source degeneration (bypass the source bias drop resistor with a big cap) and running relatively low current is pretty good at doing 2nd harmonic distortion.
[W9MJE] Horn spreadsheet SynergyCalc/; SmallSyns SmallSyns;
Crossover design Xsim; Depot diffusor super-easy diffusors
  Reply With Quote
Old 5th November 2017, 05:26 AM   #6
mt490 is offline mt490
diyAudio Member
Join Date: Jun 2010
If you are designing an experiment I would probably tend to digital synthesis methods as these provide the greatest possible flexibility and opportunity to isolate desired parameters.
  Reply With Quote
Old 5th November 2017, 05:30 AM   #7
tomchr is offline tomchr  Canada
diyAudio Member
tomchr's Avatar
Join Date: Feb 2009
Location: Calgary
If you only clip one half of the sine wave, you get second order harmonic distortion.

MOD686: Up to 240W/8Ω, <0.00025% THD. MOD86: 40W/8Ω, 0.000054% THD. HP-1: 3W/20Ω, -130dBc THD, 128dB DNR.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
  Reply With Quote
Old 5th November 2017, 08:14 AM   #8
AndrewT is offline AndrewT  Scotland
Join Date: Jul 2004
Location: Scottish Borders
A single ended stage with resistor loading, that is driven to near the supply rails will produce a very distorted sinewave. Most of that distortion is 2nd harmonic.
At low levels the distortion is very low, at medium levels the distortion is just about audible.
At high level the distortion is gross.

Is there a circuit that adds a nearly constant proportion of 2nd harmonic?
regards Andrew T.
  Reply With Quote
Old 5th November 2017, 08:43 AM   #9
Elvee is offline Elvee  Belgium
diyAudio Member
Elvee's Avatar
Join Date: Sep 2006
You can insert this halfwave/soft clipper in the signal line: it is almost passive, just requiring a static bias requiring no current (a battery or a big cap), produces ~90% second harmonic, and has many parameters to play with, to adjust the distortion profile:
-The values of R1 R2
-The tap ratio if you use a potentiometer
-The negative bias voltage
Attached Images
File Type: png Distorter.png (173.6 KB, 259 views)
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophoneİ ♫♪
  Reply With Quote
Old 5th November 2017, 08:50 AM   #10
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
Mooly's Avatar
Join Date: Sep 2007
How do i create second harmonic distortion?
You can play around with this in Audacity. Try 3 or 6db for a start, save your file under another name and then compare using an ABX comparator such as Foobar.

For a real circuit I would go with a JFET as in post #5.

You can even try that for real by simulating it in LTSpice (make a stereo pair) and applying a .wav file to the sim and then capturing the output.
Attached Images
File Type: jpg Capture.JPG (195.3 KB, 253 views)
  Reply With Quote


How do i create second harmonic distortion?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Harmonic Distortion Profiles MagicBox Solid State 3 16th May 2013 07:48 PM
harmonic distortion vitalstates Tubes / Valves 13 15th June 2010 08:17 PM
Why is distortion harmonic? dsavitsk Tubes / Valves 48 12th March 2008 02:49 AM
second harmonic distortion tenderland Tubes / Valves 5 5th August 2004 11:29 AM
Non Linear Distortion testing - Harmonic Distortion JMB Multi-Way 0 20th July 2004 02:54 PM

New To Site? Need Help?

All times are GMT. The time now is 11:58 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio