electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » MusicFromOuterSpace.com designs by Ray Wilson
Filter White Noise to get Pink Noise
Post new topic   Reply to topic Moderators: dnny, Uncle Krunkus, v-un-v
Page 1 of 1 [7 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
roglok



Joined: Aug 28, 2010
Posts: 156
Location: uptown

PostPosted: Mon Jan 02, 2012 10:59 am    Post subject: Filter White Noise to get Pink Noise Reply with quote  Mark this post and the followings unread

Hi all,

After lurking around for years I finally got around to writing my first post - and of course it's a question Smile

Although I'm no electronics expert, I have started to build a +/-12V modular synth and already finished a few modules. I am planning to build Ken Stone's Real Ring Modulator and want to add a really simple noise source to fill up the remaining panel space.

Ray Wilson's simple transistor based circuit caught my eye, but I would like to add an additional noise colour (preferably pink). How complex is it to derive pink from white noise? I have considered a simple RC low pass filter to create brown noise, too...

Here's the original schematic:
Posted Image, might have been reduced in size. Click Image to view fullscreen.

Any suggestions and, if possible, schematics are appreciated!
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 156
Location: uptown

PostPosted: Mon Jan 02, 2012 1:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

I found something. According to this article, pink noise is produced by applying a -3dB filter to a white noise source:
http://www.decodesystems.com/pink-noise.html

Would it work to tap pin 7 of the op-amp in Ray's schematics and simply add this circuit?

Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message
Blue Hell
Site Admin


Joined: Apr 03, 2004
Posts: 20269
Location: The Netherlands, Enschede
Audio files: 143
G2 patch files: 318

PostPosted: Mon Jan 02, 2012 1:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

roglok wrote:
Would it work to tap pin 7 of the op-amp in Ray's schematics and simply add this circuit?


It should, yes.

_________________
Jan
Back to top
View user's profile Send private message Visit poster's website
Captain Biscuits



Joined: Jun 11, 2010
Posts: 112
Location: Northampton, UK

PostPosted: Mon Jan 02, 2012 2:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

The schematic for Ray's Noise Cornucopia is probably worth a look. It uses pretty much the same noise source and then uses that noise (the output of pin 7 as you say) to create several different noises. He describes his Low Pass White Noise as "pinkish" so it might depend on just how pink you want your noise to be Smile
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 156
Location: uptown

PostPosted: Mon Jan 02, 2012 3:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks guys!

Quote:
it might depend on just how pink you want your noise to be


Pinkish sounds alright to me Smile Although it requires another IC, I'll probably go for the Noise Cornucopia filter since it throws in some extra high pass noise..
Back to top
View user's profile Send private message
fluxmonkey



Joined: Jun 24, 2005
Posts: 695
Location: cleve

PostPosted: Tue Jan 03, 2012 2:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

noise cornucopia is my fave analog noise source, well worth the build. but if you want simpler, there's an even older MFOS design buried in The Cave:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

i've built it, i like it. home-etchable PCB layout is there, too

_________________
www.fluxmonkey.com
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 156
Location: uptown

PostPosted: Tue Jan 03, 2012 4:33 pm    Post subject: Reply with quote  Mark this post and the followings unread

ah, now i see... the filter network should be in the feedback path of the amp.

anyway, i have already created a stripboard design for the first part of noise cornucopia (white, lp + hp noise), so i'll probably stick with that. the analog noise is planned as an addition to the cgs digital noise generator, which already features random gates, so the only thing a full build of noise cornucopia would add is grainy noise.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: dnny, Uncle Krunkus, v-un-v
Page 1 of 1 [7 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » MusicFromOuterSpace.com designs by Ray Wilson
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
mps board

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use